Cyclical Ketogenic Diets Review

Keto Resource

Many people always desire to lose weight within a short period. Dieting is easy the first few days, but without a plan, one is subjected to peer pressure and can easily fall back on their program. Gaining weight is very easy for most people, but losing it is another task that needs patience as it does not happen overnight. The Keto 28 day challenge works towards helping individuals achieve their dreams by losing weight on shorter duration of time as compared to other diet plans. It focuses on making its users lose weight and become lighter. The reason why most people gain more weight even when they are on a new diet is the lack of a plan. Lacking a diet plan makes one to make bad choices when choosing the type of food to eat and the quantities that they take. It's time to take the 28 day Keto challenge to get back in shape and have that good and light body that you have always desired. The plan also makes an individual sleep better, wake up more rested, improve hair growth, and have more energy as compared to the earlier days without Keto. Continue reading...

Keto Resource Summary

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Polysaccharides are storage and transport forms of carbohydrates produced by photosynthesis

In higher plants, photosynthesis in the leaves provides substrates, such as carbohydrates, for the various heterotrophic plant tissues (e.g., the roots). Substrates delivered from the leaves are oxidized in the root cells by the large number of mitochondria present. The ATP thus generated is required for driving the ion pumps of the roots by which mineral nutrients are taken up from the surrounding soil. Therefore respiratory metabolism of the roots, supported by photosynthesis of the leaves, is essential for plants. The plant dies when the roots are not sufficiently aerated since not enough oxygen is available for their respiration. The various plant parts are supplied with carbohydrates via the sieve tubes (Chapter 13). A major transport form is the disaccharide sucrose, but in some plants also tri- and tetrasaccharides or sugar alcohols. Since the synthesis of carbohydrates by photosynthesis occurs only during the day, these carbohydrates have to be stored in the leaves to ensure...

Storage and reserve carbohydrates

In addition to carbon allocation into structural components some of the photosynthate is also allocated to a pool of mobile non-structural carbon compounds. This pool represents either storage or reserves and is composed of several compound classes (Chapin et al. 1990 Gower et al 1995). In trees within the timberline ecotone of the central European Alps, the two most important mobile carbon compounds are non-structural carbohydrates (starch, low molecular weight sugars) and lipids (acylglycerols) (cf. Hoch and K rner 2003 Hoch et al. 2003). Depending on the source-sink balance (net canopy photosynthesis versus carbon use for maintenance and growth) non-structural carbon compounds may either accumulate or decrease. Potential periods of carbon shortage in trees at the alpine timberline are the period of winter dormancy and the period of bud break and shoot elongation in spring when carbon demand exceeds carbon supply by photosynthesis (see Fig. 6.16). The largest fraction within the...

Carbohydrates In Leaves

Starch and sucrose are the dominating non-structural carbohydrates in tree leaves and generally function as storage and transport metabolites. Other soluble sugars like hexoses (glucose and fructose), members of the raffinose family (raffinose, stachyose), as well as sugar alcohols are synthesised to considerable amounts under certain metabolic situations and are involved in carbon transport, cell elongation and cryoprotection (1-3). As end-products of photosynthesis starch and sucrose can be converted into each other. Pool sizes of both carbohydrates are determined by their relative rates of synthesis and degradation as well as transport activities (import and export). After the initiation of frost adaptation, all levels of soluble sugars (sucrose, glucose, fructose, raffinose and stachyose) decreased, while starch contents increased dramatically during a period of a few weeks reaching up to 13 of the dry matter (8, 15). Inspite of the accumulation of carbohydrates in one-year-old...

Carbohydrates In Roots

The roots of most trees are invaded by mycorrhizal fungi. These interact specifically with the fine root system (less than 1 mm diameter) and, due to their high carbon demand, affect the carbon status of the whole root system. Carbon metabolism of roots of trees has thus to be seen as the consequence of organismic interaction in which bacteria of the rhizosphere are also involved. With regard to mycorrhiza, the most common of these symbiotic associations in trees of temperate forests are ectotrophic. Tropical trees and many terrestrial flowering plants develop vesicular-arbuscular (VA) mycorrhizas. Estimates are that up to 90 of angiosperms establish this kind of symbiosis (91). The development of these symbiotic structures is a complex process which depends on a variety of internal and external factors of which mineral nutrition and the supply of carbohydrates by the host plant are most important (for a recent overview on types of mycorrhiza and function see reference 92). 4.2....

Production of Novel Carbohydrates in Transgenic Plants

In addition to attempts aiming at manipulating the contents and properties of endogenous carbohydrates, there have been several successful approaches for the production of novel carbohydrates in transgenic plants. By expressing enzymes that act on sucrose or sucrose biosynthetic intermediates, novel compounds can theoretically accumulate to high levels. Fructans, or polyfructosylsucroses, are alternative storage carbohydrates that are highly soluble and are stored within the vacuole as opposed to the plastid they are present in approximately 15 of all flowering plants (Hellwege et al., 2000). Fructan synthesis is initiated by sucrose sucrose 1-fructosyltransferase (SST) which catalyses the fructosyltransfer from one sucrose molecule to another, resulting in the trisaccharide 1-kestose. In subsequent steps fructosyltransferase (FFT) catalyses the reversible transfer of fructosyl residues from one fructan to another, producing a mixture of fructans with different chain lengths (Ritsema...

Carbohydrates And Related Compounds

Carbohydrates are the most abundant class of organic compounds found in living organisms. They originate as products of photosynthesis, an endothermic reductive condensation of carbon dioxide requiring light energy and the pigment chlorophyll. Carbohydrates are a major source of metabolic energy, both for plants and for animals that depend on plants for food. Apart from the simple sugars, they provide a means of storing energy (starch) that meets this vital nutritional role and transport of energy (as sucrose). Carbohydrates also serve as a structural material (hemicellulose, cellulose), as a component of the energy transport compound ATP, recognition sites on cell surfaces, one of three essential components of DNA and RNA and plant glycosides. They also play a number of ecological roles, in plant-animal interactions (flower nectar is mainly sugars), in protection from wounds and infections, and in the detoxification of foreign substances. The major simple sugars present in plants are...

The glycolysis pathway plays a central role in the utilization of carbohydrates

The carbohydrates delivered by phloem transport to the sink cells are fuel for the energy metabolism and also a carbon source for the synthesis of the cell matter. The glycolysis pathway, which is present at least in part in almost all living organisms, has a fundamental role in the utilization of carbohydrates. The enzymes of this pathway not only occur in sink tissues but are also present in all plant cells. Each cell has two sets of glycolytic enzymes, one in the cytosol and one in the plastids. Some of the plastidic enzymes participate in the Calvin cycle, as discussed in Chapter 6. In the plastids of some plants, the glycolysis pathway is incomplete because one or two enzymes are lacking. The corresponding glycolytic enzymes in the cytosol and in the plastids are isoenzymes encoded by different genes.

Carbohydrates In Wood

In all living perennial organs of a woody plant carbohydrates serve different purposes such as organic osmolyte, carbon transport, and most importantly, for carbon storage. In angiosperm and gymnosperm trees, bark and living wood parts of the trunk are the dominating storage compartments. These storage tissues are filled during favourable periods and cleared at times of demand such as leaf growth, formation of new roots and twigs, and cambial growth of trunks and roots in early spring and during summer. According to the predominant carbon storage compounds, starch or fat, trees are classified, as starch trees like most ring-porous angiosperms and some conifers like species of Abies and Picea or fat trees like most diffuse-porous angiosperms and species of Pinus (61-62). In the following, storage carbohydrates of trunk tissues, their nature, localization within the organs as well as their synthesis and cleavage will be summarized. The radial and seasonal distribution will be discussed...

Carbohydrates

Carbohydrates are a diverse group of compounds composed of the elements carbon (C), hydrogen (H), and oxygen (O) with the empirical formula CH2O n, where n represents the number of CH2O units in the compound. The ultimate source of all carbohydrates is photosynthesis, in which the energy of sunlight is used to chemically fix atmospheric CO2 into carbohydrate. Carbohydrates constitute as much as 80 percent of the dry weight of a plant. This is largely due to the presence of cell walls made of complex carbohydrates surrounding each plant cell. Sugars, also called saccharides, are carbohydrates. Common sugars occurring in nature have from three (glyceraldehyde) to seven (sedoheptu- Carbohydrates are important in human nutrition, often constituting the major source of calories in the diet. Glucose, fructose, sucrose, and starch are readily digested by humans. Cellulose and the other complex carbohydrates of the plant cell wall are not readily digested, but constitute useful dietary fiber.

Mycorrhiza and growth of the host

Increases of the rate of growth of mycorrhizal plants measured in these ways are usually observable when the potential for active photosynthesis is high (e.g. adequate light) and when there is a deficit or rather no excess of one or more essential nutrient such as phosphate or nitrogen source. Where increases are not observable they are often associated with very ready availability of nutrients or a low light supply. In addition, there are variations in the efficiency of the fungi which can form mycorrhiza, and a strain may be ineffective or inefficient in some environmental conditions. In some cases there may be little effect of mycorrhizal formation, or perhaps an actual decrease in growth rate of the host may be observed. In some cases, where growth experiments have been performed on a range of phosphate concentration in soil, a depression of growth in mycorrhizal plants may occur at a high nutrient level. The causes of this are discussed by Harley and Smith, S. E. (1983) with many...

Seasonal Patterns Of Carbohydrate Production

Before considering the partitioning of carbohydrates, seasonal production of carbohydrates must be understood. Temperate tree fruit are perennial plants with permanent structures that provide physical frameworks of canopies and root systems that do not need to be reproduced each season, as in annuals. Additionally, these structures contain reserves of carbohydrates and mineral nutrients that can immediately be used for early growth. Temperate tree fruit can develop full canopies and intercept sunlight to produce carbohydrates very early in the season compared to annual crops because they have thousands of preformed buds. Indeed, orchards may almost reach full light interception at the time many annual crops are planted. This leads to a rapid increase in total carbohydrate production early in the season. Photosynthesis produces carbohydrates for growth and energy. The energy needed to drive growth and maintenance of a tree is generated by using carbohydrates. The percentage of fixed...

The mechanisms regulating NO3 uptake

Experimentally, NO3- uptake can be increased in parallel with the growth rate by increasing light intensity (e.g. Gastal and Saugier 1989). The diurnal regulation of NO3- uptake (higher rate during the light period, lower rate during the dark period) has been considered as a specific example of its regulation by light (Delhon et al. 1995). The stimulation of NO3- uptake by light is attributed to photosynthesis, since it could be prevented by decreasing the atmospheric CO2 concentration (Delhon et al. 1996). Moreover, the addition of carbohydrates to the nutrient solution is known to increase NO3- uptake (Hanisch Ten Cate and Breteler 1981). Blocking phloem translocation in soybean plants by means of stem girdling led to a decline in the rate of NO3- uptake, which is partially restored by adding glucose to the nutrient solution (Delhon et al. 1996). No consensus exists that an energetic shortage might occur in roots, even at night, and an increased energisation of the plasma membrane...

Environmental Factors Affecting Partitioning Light Availability

With fruiting trees, the effects can be complex. If fruit set has already occurred, low light reduces fruit growth and especially vegetative growth, as the fruit compete strongly for carbohydrates. If, however, low light occurs early in the season before fruit are set, growing shoots tend to be stronger competitors and fruit set may be reduced, even leading to complete defruiting. Then, partitioning develops as just described for nonfruiting trees.

Malespecific Health Considerations

No single nutrient is more important than zinc for maintaining a man's overall reproductive and sexual functioning. In fact, the prostate is the richest reservoir of zinc within the body. Zinc helps to ensure overall virility, including erectile function and sperm quality.6,7 Diet also can play a critical role in prostate health. Eating a diet high in protein can inhibit the enzyme, 5-alpha reductase. This enzyme converts testosterone into the more potent hormone dihy-drotestosterone (DHT), which when levels are elevated, causes the increased growth of the prostate, leading to pelvic congestion and an obstructed flow of urine. In contrast, a diet that is high in carbohydrates can actually contribute to a buildup of DHT. Recommendations for maintaining a healthy prostate call for a dietary balance of protein, 44 complex carbohydrates, 35 and mostly unsaturated fats, 21 .8

Carnivorous PlantsAn Introduction

Green plants can derive a large part of their chemical requirements for sustaining growth and reproduction from some very basic but essential elements. These include energy from sunlight, oxygen and carbon dioxide from the air, and water and certain minerals from the earth or water in which the plants grow. Through photosynthesis, in which green chlorophyl plays so large a part by transforming sunlight into chemical energy, carbohydrates are built up from water and carbon dioxide. These various carbohydrates themselves are used as energy sources and building blocks for synthesizing myriad other chemical materials needed by the plant products such as amino acids and proteins, vitamins and hormones, and even small quantities of fats.

Concepts And Definitions

Ideally, photoautotrophic micropropagation should be segregated from sugar-free micropropagation. However, in this chapter, while we will define photoautotrophy as the plant nutritional type where only endogenous carbohydrate is used as the energy source, for all practical purposes photoautotrophic micropropagation refers to micropropagation with no sugar added to the medium. Sugars and other carbohydrates may be significant components of agar and other gelling agents, but perhaps it is reasonable not to consider it as an exogenous carbohydrate source in the practical definition of photoautotrophic micropropagation.

Life histories reproductive strategies and allocation

It has been suggested that, to some extent, plants can escape the seed size--number trade-off by modifying the chemical composition of their seeds (Lokesha et al., 1992). There is some evidence that light wind-dispersed seeds are better dispersed than heavier seeds of similar morphology (e.g. Meyer & Carlson, 2001), although this may not apply to all dispersal modes (Hughes et al., 1994a). Since fats yield about twice the energy of carbohydrates per unit mass, a plant could make seeds half as heavy by replacing stored carbohydrate with fats. In fact, the majority of plant species mostly store fats in their seeds, although there are costs lipid synthesis is more energetically demanding than either protein or carbohydrate production. If lighter seeds are dispersed more effectively by wind, then we might expect fat storage to be more prevalent in

Mitochondria are the power station of the cell

In the process of biological oxidation, substrates such as carbohydrates are oxidized to form water and CO2. Biological oxidation can be seen as a reversal of the photosynthesis process. It evolved only after oxygen accumulated in the atmosphere during photosynthesis. Both biological oxidation and photosynthesis serve the purpose of generating energy in the form of ATP. Biological oxidation involves a transport of electrons through a mitochondrial electron transport chain, which is in part similar to the pho-tosynthetic electron transport discussed in Chapter 3. The present chapter will show that the machinery of mitochondrial electron transport is also assembled of three modules. The second complex has the same basic structure as the cytochrome- complex of the chloroplasts. As in photosynthesis, the mitochondrial oxidative electron transport and ATP synthesis are coupled to each other via a proton gradient. The synthesis of ATP proceeds by an F-ATP synthase, which was described in...

Overview of Aleurone Ontogeny

The final stage in the life of an aleurone cell occurs after seed imbibition when the embryo sends a GA signal that induces the germination function of the aleurone. Hydrolase genes such as a-amylase are induced and their products secreted into the starchy endosperm for the remobilization of stored carbohydrates and amino acids to supply the growing seedling. This is a terminal process in that the aleurone cells expend all their resources and undergo non-apoptotic programmed cell death (Bethke et al. 1999 chapter by Nguyen et al., in this volume).

Conclusions And Future Lines Of Research

Iron deficiency in trees develops progressively over the years unless some kind of Fe fertilization is used. This deficiency is assumed to deplete progressively the pools of Fe, carbohydrates and other nutrients in the tree. There are no studies, however, on the effects of the chlorosis evolution over

Nitrogen Use Efficiency Nue Interactions between photosynthesis and nitrogen

Since the eighties of the last century it is well known that growth conditions leading to higher levels of endogenous NH4+and or relatively low levels of carbohydrates result in relatively high levels of GDH. At that time the regulation of nitrate reductase appeared to be fairly straight forward, but regulation of NH4+ assimilation appeared to be complex (Oaks 1986). That photosynthesis supplies

Heterogeneity of Light Use Across the Leaf Lamina

In full grown leaves, Fv Fm was higher in intercostal tissue than in vein tissue. This indicates that in early phases of post-emergent leaf development, an increased amount of photosynthates might be required for energy-consuming growth processes within the leaf vein tissue, while differentiation of the pho-tosynthetic machinery can proceed more slowly in intercostal tissue. There, carbohydrates can be supplied in sufficient amount via phloem import.

Variation of Diel Leaf Growth Cycles

For extreme situations it has been shown that alterations of the diel variation of carbohydrate metabolism can induce changes of the diel leaf growth pattern. In leaves of Populus deltoides that were exposed to a three-times elevated CO2-content, a strong, transient decay of growth rate was observed during the afternoon, which temporally coincided with a transient decrease of glucose content (Walter et al. 2005). An amplification of nocturnal growth activity was found in leaves of transgenic potato plants that showed an increased starch content at the end of the day (Kehr et al. 1998), indicating that the pool of transitory starch is of utmost relevance for nocturnal growth activity. A clear indication how carbohydrate metabolism affects diel leaf growth cycles was recently observed in Arabidopsis thaliana Starch-free-mutant plants (stfl, Kofler et al. 2000) that do not possess a relevant pool of transitory starch showed much lower growth rates than wild-type plants at night, but were...

Formation of Humic Substances and Organomineral Complexes

Humic substances are formed through biotic and abiotic processes (Stevenson, 1994 Huang, 2004). A variety of biomolecules, such as carbohydrates, phenolic compounds, and amino acids, can participate as raw materials. Soil mineral surface chemistry plays a vital role in the catalysis of abiotic formation of humic substances. The Maillard reaction (Maillard, 1913) is perceived to be a major pathway in humification because of significant similarities between humic substances and melanoidins formed through this pathway involving sugar-amino acid condensations (Ikan et al., 1996). The presence of characteristic products of the Maillard reaction (alkyl pyrazines) was detected in archaeological plant remains up to 1500 years in age (Evershed et al., 1997). The great appeal of the Maillard reaction in humification processes lies in the two types of precursors, sugars and amino acids, which are among the most abundant constituents of

Small Scale Variation of Leaf Growth

Carbohydrate production of the growing leaf itself might affect the homogeneity of growth distribution within the lamina (Walter et al. 2005) When comparing leaves of Populus deltoides that were exposed to the sun with leaves that were completely shaded, but growing on sunlit trees, it was observed that relative growth rate distribution across the lamina was more patchy and temporal fluctuation of average relative leaf growth rate was much stronger in leaves that grew in the shade. At night, leaves of both populations showed comparable temporal fluctuations of relative growth rate. This leads to the speculation that in shaded leaves the fluctuating but strong import of carbohydrates from source leaves led to spatial and temporal heterogeneities of growth that were dampened in the case of sunlit growing leaves by the stabilizing effect of carbohydrates produced on-site .

Nutritional Strategies for Prevention

The fiber from wheat bran, for example, is deserving of special attention, as it may be able to decrease the risk of colon cancer via various mechanisms. One of the principal ways in which a high cereal fiber diet may be beneficial is by decreasing the amounts of secondary bile acids that are irritating to the colonic mucosa. In fact, at least one of these secondary bile acids, deoxycholic acid, increases the proliferation of colonic epithelial cells.12 Research has shown that these bile acids, including deoxycholic acid, were significantly reduced when subjects consumed 10 g per day of wheat bran, but not oat bran, as an addition to their typical Western diet.13 Also, intake of dietary carbohydrates, particularly from degradation-resistant starches and dietary fiber, are fermented in the colon and form short chain fatty acids (SCFA), primarily acetate, propionate, and butyrate. These SCFAs have been shown to decrease proliferation and migration in experimentally induced cancer cell...

Mode of action studies

Be predicted for herbicides because of the wide variety of organic phases within a plant, such as hydrocarbon waxes, triglycerides, proteins, lignins or even carbohydrates. However, Briggs and colleagues (Bromilow et al., 1986I have found that the partition coefficient can give a good prediction of systemicity. For acids and bases the dissociation constant of the chemical and the natural pH of the various plant compartments will also determine the proportion of ionised and non-ionised forms present. Ionisation decreases log Kow and so can have a dramatic effect on the movement of a compound in a plant. Most phloem-mobile, systemic compounds are therefore weak acids with log Kow in the range of -1 to 3, but the immobile soil-applied herbicide diflufenican has a log Kow value of 4.9 (Table 2.9).

Specialized Staining Techniques

The PAS reaction is useful for looking at cell walls, especially in meris-tematic tissues (Baum and Rost 1996). Total carbohydrates of insoluble polysaccharides (e.g., starch and cellulose) stain magenta to purplish red. Aldehyde-fixed tissue reacts with SchifPs bases to yield a false positive background, but this is not a problem in most situations. If problems are experienced, the reaction can be blocked (see Ruzin 1999).

13CNMR studies of carbon metabolism

Carbon-14 has been used to enable measurements of flux through metabolic pathways for decades. Significant information is provided by purification and chemical degradation of metabolic intermediates and measurement of the specific activity of each carbon of a metabolite. Due to a practical limit on the number of measurements that can be made, the metabolic analysis provided by most 14C investigations is limited. NMR offers several advantages for metabolic studies, including identification and quantitation of multiple metabolites (e.g. amino acids, carbohydrates, organic acids, etc.) from a single spectrum (Fig. 4). Carbon-13 has a natural abundance of only 1.1 therefore most 13C-NMR studies require the preparation to be enriched with 13C, or are restriced to investigations of highly concentrated metabolites such as fatty acids, glycogen and storage carbohydrates (Fig. 4). For many experiments this is an advantage, as specifically labelled compounds can be added to cell preparations...

General Anatomical Characteristics Of In Vitro Plants

Most of the researches pointed out that under these conditions the anatomical features of the plants are at least to some extend different (abnormal) than the normal in vivo plants, they have a significantly higher content of carbohydrates, mostly in the leaves (Kozai and Zobayed, 2001). Thus the leaves have a poorly developed internal structure and become physiologically abnormal and simply act as a storage organ. It has also been concluded that the poor ventilation or restricted air exchange in the conventional culture vessel can lead to the development of abnormal anatomical features which could prevent or reduce the plant's ability to acclimatize ex vitro (Zobayed et al., 2001a).

Carbohydrate biosynthesis

Mannitol is the main soluble carbon storage compound in several fungi, including those that are ectomycorrhizal (Martin et al., 1987), and it has been suggested that it plays an important role in the carbon transfer between the mycorrhizal symbionts. However, its metabolism is poorly known. A problem that is suitable for NMR analysis is the determination of its pathways of synthesis and degradation. When C. geophilum, Sphaerosporella brunnea and Piloderma croceum were fed with l-13C glucose, this polyol contained the highest proportion of carbon from assimilated glucose (Martin et al., 1985a, 1988) (Fig. 5), indicating that it is an important component of carbohydrate conversion and biosynthesis. More than 70 of the 13C label accumulated in mannitol. Mannitol has been proposed to be metabolized in a cyclic pathway in certain Fungi Imperfecti (Hult and Gatenbeck, 1978) and in ectomycorrhizal fungi (Ramstedt et al., 1987). The enzymes mannitol 1-P dehydrogenase (NADH-dependent),...

The Microtubule Associated Cellulose Synthase Compartment

The plasma membrane is the interface between the cytosol symplast and cell wall apoplast. The proteins on the PM are among the regulators of the components that enter and exit the cell. The cell wall is comprised of carbohydrates (e.g., cellulose, hemicelluloses, pectins), polyphenols (e.g., ligins), minerals (e.g., boron, silica), and sometimes waxes (e.g., suberin, cutin) that are secreted into the extracellular space. Once in the apoplast, these cell wall components often undergo modification due to developmental programs (e.g., cell enlargement, cell loosening in maternal tissues for pollen tube extension) or in response to biotic or abiotic stressors. These changes can be achieved by secretion of cell wall remodeling proteins, which may function enzymatically (cellulases, pectinase) or nonenzymatically (expansions) (reviewed in Lebeda et al. 2001 Sampedro and Cosgrove 2005).

Carbon nutrition of mycorrhizal fungi A External organic carbon sources

The very limited in vitro growth of hyphae from germinated spores of arbuscular mycorrhizal fungi may be somewhat stimulated by addition of nutrients to the medium. Although some early work indicated that sugars are inhibitory or non-stimulatory (see Hepper, 1987), it now appears that sucrose and glucose can be stimulatory at low concentrations (Siqueira et al., 1982 Carr et al., 1985 Siqueira and Hubbell, 1985). The optimum levels for stimulation of around 2 gkg ' fresh wt are similar to the concentrations of ethanol-soluble carbohydrates recorded in mycorrhizal leek roots (Amijee et al., 1990).

Low Nutritive Quality Of Douglasfir Foliage

Budworm (Clancy, 1991a, 1992a, 1992b, 2001 Clancy & King, 1993 Clancy et al., 1993). This is somewhat surprising given the tremendous variation in foliar concentrations of primary metabolites (i.e., nitrogen, carbohydrates, and minerals) in trees that is associated with the age of the tree and the leaves or needles, the genotype of the tree, and the environment the tree is growing in (Clancy et al., 1995). Nitrogen (N), or protein, is considered to be the most important nutrient for insect growth and survival (Mattson, 1980 Mattson & Scriber, 1987). However, the importance of N as a key nutrient is probably not strictly cause and effect, but is related to the strong link between N and many other important nutritional factors in plants (Clancy et al., 1995). The western spruce budworm's response to increased N in artificial diets was neither positively linear nor convex, and it was dependent on levels of minerals in the diets (Clancy, 1992a). Host plant N appears to determine the...

Seed Filling Phase III

Seeds cannot grow without a supply of assimilate so the photosynthetic productivity of the plant community during phase III is important. The total seed growth rate (g per m2 day-1) is directly affected by the assimilate supply (Table 6.2) (Egli, 1999) through effects on seed number and individual seed growth rate (Egli and Bruening, 2001). There are two sources of assimilate current photosynthesis and remobilization of stored carbohydrates. The potential contribution from stored carbohydrates (starch) is apparently relatively small in soybean (

Engineering Soluble Sugars

For several crop species, soluble sugar content is much more important than that of starch. This is either because soluble sugars such as sucrose are major reserve carbohydrates (e.g. in sugar cane and sugar beet), or, as in fruit-bearing species, because sugar is an important component of taste. An increase in sugar content in strawberry has been achieved through fruit-specific antisense repression of AGPase. Transgenic strawberry fruits showed a decrease in starch content of approximately 50 and an increase in total soluble solids of up to 37 (Park et al., 2006). In general, relatively little is known at the biochemical or genetic level about the factors that control the rate of sucrose storage in sugar beet taproots or sugar cane nodes. This reflects the intractability of both crops using genetics and the difficulties in assessing storage metabolism at the biochemical level. Factors controlling sucrose accumulation in storage tissues are photoassimilate partitioning on the whole...

Proteomics Of Model Legume Medicago Truncatula

Analyzed soy proteins from seeds used in most clinical studies of hypercholesterolemia. Multiple samples used in Europe and the United States were analyzed by 2-DGE and MS 41 . The authors reported on the difference in soy proteins used in different clinical studies and discussed the implications of these results on the outcome of clinical studies. In another study, 422 proteins were identified in developing soybean seeds by 2-DGE and MS 42 . This research addressed the use of near-infrared reflectance spectroscopy in combination with chemical analysis for predicting protein and carbohydrate composition. Also, they reported a negative correlation between the seed storage protein G1 glycinin precursor and carbohydrates such as nonstarch polysac-charides and raffinose. As the first of its kind, recent research has applied comparative proteomics to analyze storage proteins in wild and cultivated soybean seeds 43 . The authors reported a higher degree of electrophoretic heterogeneity in...

Does Photoinhibition Limit the Carbon Available to the Plant

Continues to siphon off absorbed energy upon a return to non-excessive light conditions (e.g. Ball et al., 1991 Long et al., 1994 Melis, 1999 Werner et al., 2001 Zhu et al., 2004). This view has persisted for many years due primarily to the perspective that damage to D1 is suffered during photoinhibition (see Adir et al., 2003 for an historical review Hader, Huner et al., Nishiyama et al., Yokthongwattana and Melis, this volume) and that this lesion of the photosynthetic apparatus, or impairment of photosynthesis, must limit the supply of carbohydrates to the rest of the plant. Thus, there is considerable support for the view that photoinhibition is something that should be protected against (e.g. Endo and Asada, this volume), when in reality photoinhibition may be a means by which plants sustain photoprotection.

CO2 fixed during the night is stored as malic acid

Nocturnal fixation of CO2 is catalyzed by phosphoenolpyruvate carboxylase, in the same way as in the metabolism of C4 plants and guard cells (Fig. 8.4). In many CAM plants the phosphoenolpyruvate required is generated from the degradation of starch, but in other plants soluble carbohydrates, such as sucrose (section 9.2) and fructanes (section 9.5), may also serve as carbon stores. Figure 8.17 shows a scheme of the CAM metabolism using starch as a carbon reservoir. The starch located in the chloroplasts is degraded to triose phosphate (section 9.1), which is then exported via the triose

Recognition Centers on Membrane Differences

Other researchers hypothesized that the induction of lamellocyte proliferation during sterile wounding may arise following recognition of damage to cell membranes at the wound site (Markus et al. 2005). Recent research in self-recognition has focused on the shielding of self membranes from encapsulation by membrane-bound carbohydrates and sialic acid. In other insects, host cells are more likely to be encapsulated when they lose these groups (Lackie 1980 Karacali et al. 2000). Binding requires recognition, making it more difficult to differentiate between mechanisms for each. General studies of encapsulation of beads with different attached functional groups have been performed in the moth Pseudoplusia inclu-dens, and have identified chemical properties and functional groups that make foreign matter more readily encapsulated. Specifically, foreign matter is readily encapsulated when it is cationic, or linked to sulfonic groups or some amino groups. Matter with attached carbohydrate...

Tree Growth and Symbiotic Associations

A. mangium can grow well on infertile soils, including those under grasslands, in part because of its association with symbiotic soil organisms, including mycorrhiza and Rhizobium (dela Cruz and Garcia 1991) (Plate 6.1). The tree roots provide these organisms with excess carbohydrates and

Deposition Of Protein

The developing endosperm is supplied with both carbohydrates and nitrogen by the maternal tissues. The nitrogen supplied by the maternal tissue is mobilized not only from nutrients taken up from the soil, but also from proteins that are hydrolyzed in senescing leaves and in the degrading parts of the ovule (95). Changes in the proteinase complement during leaf senescence may be related to the regulation of nitrogen mobilization in barley (96) cysteine proteinases have been shown to be involved in leaf senescence in both monocotyledonous and dicotyledonous plants (97, 98). Two proteinases, nucellin (99) and nucellain (100), have been identified to be also present during autolysis of the nucellus in barley. Nucellin is an aspartic proteinase, whereas nucellain, localized in the cell wall, shows homology to an vacuolar-processing enzyme of castor bean (Ricinus communis). The exact hydrolytic roles of these proteases, in leaves or nucella, have however not yet been determined. Therefore...

Starch and sucrose are the main products of CO2 assimilation in many plants

In most crop plants (e.g., cereals, potato, sugar beet, and rapeseed), carbohydrates are stored in the leaves as starch and exported as sucrose to other parts of the plants such as the roots or growing seeds. CO2 assimilation in the chloroplasts yields triose phosphate, which is transported by the triose phosphate-phosphate translocator (section 1.9) in counter-exchange for phosphate into the cytosol, where it is converted to sucrose, accompanied by the release of inorganic phosphate (Fig. 9.1). It is essential that this phosphate is returned, since phosphate deficiency in the chloroplasts would cause photosynthesis to die down. Part of the triose phosphate generated by photosynthesis is converted in the chloroplasts to starch, serving primarily as a reserve for the following night period.

Sourcesink Relationships

There is strong competition between the different parts of the vine, and the bunches are weak sinks until ripening commences (Hale and Weaver 1962). Post-veraison, carbohydrates are imported into the berry at a higher rate and clusters become very competitive sinks. However, shoot growth during ripening may slow sugar accumulation in the berry. At any stage, berry growth and development are affected by modification of the carbohydrate supply to the berry. These modifications are brought about by adjusting the number of bunches in relation to the leaf area in order to achieve the required grape maturation. With regard to leaf removal, a large decrease in leaf area just after fruit set can induce a reduction in berry growth. In this situation, Kaps and Cahoon (1992) showed that berry weight at maturity is related to the ratio leaf area fruit weight. Noteworthy in our dataset for fresh weight and berry water content (Fig. 2a,c), val

Plant Mechanisms to Cope with Cadmium

At root level, plants have developed extracellular strategies to avoid Cd toxicity and especially interesting is the relationship with mycorrhizal fungus (Jentschke et al. 1999 Courbot et al. 2004 Janouskova et al. 2006) or with some bacterial strains from the rhizosphere which can reduce Cd concentration in the shoot of the hyperaccumulators A. halleri, and which highlights the importance of plant-microbe interactions in Cd toxicity (Farinati et al. 2011). Additionally, the evaluation of interactions between heavy metal contamination and beneficial rhizosphere microbes adapted to the contaminated soils and their effects on plant development has shown that the microbes are not only able to grow but also to improve plant development under polluted conditions (Azcon et al. 2010). Interestingly, it seems that toxicity of heavy metal to microorganisms is due, in part, to oxidative stress, and it has been hypothesised that the metal resistance of microorganisms and their beneficial effect...

Berry Growth And Development

Water availability to the plant is an important factor in organ enlargement, but it also interacts closely with photosynthesis and berry carbohydrates supply (Ollat et al. 2002). Berry size is affected by water deficit from anthesis to maturity however, final berry size is more influenced by water deficits between flowering and veraison (Becker and Zimmermann 1984, Poni et al. 1994, Ojeda et al. 2001). Ojeda et al. (2001) observed that water limitation during the first growth phase of the berry (before veraison) does not affect cell division but decreases cell volume. The results show that vine water status is a more important factor than leaf area with regards to determining final berry size (Fig. 2).

Propagation of systemic RNA silencing 3341 Longdistance movement of RNA silencing

Long-distance transport occurs in the phloem. Long-distance movement of molecules in plants can occur through the xylem and the phloem conduits, both of which are restored upon graft junctions. However, only the phloem distributes the photoassimilates throughout the plant, following a specific pattern whereby mature, photosynthetically autonomous organs export - but do not import - carbohydrates. These tissues are said to be 'source' of phloem. Conversely, import of carbohydrates occurs in the new growth (meristems, primordia, young leaves), which has not yet reached photosynthetic autonomy and is therefore a 'sink' of phloem. The intermediate situation is the sink-to-source transition, which typically occurs in leaves in a basipetal direction down the leaf axis towards the petiole.

Nitrate assimilation also takes place in the roots

As mentioned, nitrate assimilation occurs in part, and in some species even mainly, in the roots. NH4+ taken up from the soil is normally fixed in the roots. The reduction of nitrate and nitrite as well as the fixation of NH4+ proceeds in the root cells analogously to that of the mesophyll cells. However, in the root cells the necessary reducing equivalents are supplied exclusively by oxidation of carbohydrates. In roots the reduction of nitrite and the subsequent fixation of NH4+ (Fig. 10.8) occur in the leucoplasts, a differentiated form of plastids (section 1.3).

Necessity Of Photoautotrophic Micropropagation In Woody Transplant Production

Photoautotrophic micropropagation requires the growth of chlorophyllous explants on a sugar-free medium under pathogen-free and favorable in vitro environmental conditions, which enable plants in vitro to photosynthesize and produce their own carbohydrates for growth. A photoautotrophic micropropagation system with the improvement of in vitro aerial and root zone environments has significantly enhanced the growth of plants in vitro, increased the multiplication rate and thus, shortened the multiplication period of plants in vitro (Kozai et al., 1988).

Uptake and loss of carbon dioxide

Photosynthesis is the process by which plants absorb light energy and convert atmospheric CO2 to carbohydrates that are available for further biochemical processes. In parallel, during daylight hours leaves also release CO2 - through mitochondrial respiration as well as photorespiration, the latter linked to the oxygenase activity of the enzyme ribulose-bisphosphate carboxylase-oxygease (Rubisco) - so that there is a net CO2 uptake, termed as apparent net photosynthesis. Net photosynthesis is regulated simultaneously by many factors.

The end product of nitrate assimilation is a whole spectrum of amino acids

As described in Chapter 13, the carbohydrates formed as the product of CO2 assimilation are transported from the leaves via the sieve tubes to various parts of the plants. The transport forms of the carbohydrates are sucrose, sugar alcohols (e.g., sorbitol), or raffinoses, depending on the species. There are no such special transport forms for the products of nitrate assimilation. All amino acids present in the mesophyll cells are exported via the sieve tubes. Therefore the sum of amino acids can be regarded as the final product of nitrate assimilation. Synthesis of these amino acids takes place mainly in the chloroplasts. The pattern of the amino acids synthesized varies largely, depending on the species and the metabolic conditions. In most cases glutamate and glutamine represent the major portion of the synthesized amino acids. Glutamate is exported from the chloroplasts in exchange for malate and glutamine in exchange with glutamate (Fig. 10.6). Also, serine and glycine, which are...

Immobilization and Movement of Nutrients by Fungi

During the course of decomposition, mineral nutrients are sequestered by decomposer soil organisms by being incorporated into the organism's biomass. The residence time of these elements is usually equivalent to the turnover time (lifespan) of that organism. During this period, the element is not in a soluble form in the soil solution, but is immobilized in microbial tissue. The amount of accumulation within the fungal component varies among ecosystems, depending on the chemical composition of the plant parts available for decomposition and the main fungal groups involved in the process. Shorter-lived, ephemeral molds, utilizing simple carbohydrates, thus have lower investment in biomass than longer-lived basidiomycetes growing on woody resource the potential accumulation in basidiomycetes is therefore greater. Unlike bacteria, fungi are larger organisms and their rate of turnover is lower, particularly in the long-lived Basidiomycotina. A discussion of the role of basidiomycetes in...

The Plasma Membrane and the Cell Wall

Abstract Plant cell walls are among the features that distinguish plants from animals. The cell wall contributes to internal cellular turgor pressure while offering protection to the cell from external threats. The cell wall is also flexible, and its content and structures are modulated according to growth and tropisms. A typical plant cell wall is primarily composed of carbohydrates synthesized either at the plasma membrane (PM) or in the trans-Golgi network cellulose and callose are produced at the PM, whereas the matrix polysaccharides, i.e., pectins and hemi-celluloses, are synthesized in the Golgi apparatus and are subsequently transported across the PM via exocytosis. The wall also contains enzymes and structural glycoproteins. The cell wall is formed by independent and coordinated mechanisms based on physical properties and self-assembly, as well as the action of cell wall-modifying enzymes. Thus, the plant cell wall physiology is dynamic and includes coordinated sugar...

Integration Of Processes In The Whole Plant Bottomup

Similar models, but of slightly greater complexity, are also able to explain observations of preferential root growth into nutrient-rich soil patches. Van Oijen et al. (1986) implemented the following mechanism in their model The root system was divided into two parts, one in N-rich medium, and the other in N-poor medium. Growth rate of each root part, and of the shoot, depended on the concentrations of N and C substrate in that plant part, and transport between root parts was only possible via the shoot. N uptake of the root in poor medium was obviously hampered, so growth of this root depended fully on organic N received from the shoot in the phloem. This allowed some growth, but at low rate, leading to accumulation of unused carbohydrates and subsequent inhibition of the Munch-type phloem inflow. High rates of phloem import, and growth, were maintained in the root part growing in rich medium. This model was able to account with great accuracy for observations on maize roots in...

Chun Hu David D Kitts and Jerzy Zawistowski

Living organisms are exposed to 20.93 oxygen in air, which contributes to a dependency on biological oxidation reactions as a source of energy required for natural growth and metabolism. Under normal conditions, 2 of the oxygen consumed by mitochondria is incompletely reduced, thus resulting in the production of oxygen radicals (Boveris and Chance, 1973). If mitochondria electron transport is compromised, the percentage of oxygen incompletely reduced will increase. There is a potential, therefore, for a relatively small percentage of oxygen derived from systemic respiration to be transformed to bioactive agents, which in turn can ultimately lead to peroxidation reactions of cellular constituents that are composed of nucleic acids, lipids, proteins, and carbohydrates. In addition to endogenously derived reactive oxygen species (ROS), living organisms can also be exposed to ROS derived from exogenous sources such as environmental exposure to ultraviolet light, smoking, and pollution....

Obligate Hemiparasite to Holoparasite Loss ofAutotrophic Functions

The increasing use of and dependence on host carbohydrates allows a relaxation in parasite photosynthesis. This is accompanied in many cases by rearrangements and deletions to the parasite chloroplast genome (Morden et al. 1991 Bommer et al. 1993 Delavault et al. 1996). Of course, once the chloroplast genome has undergone extensive deletions, the parasite is fixed as a heterotrophic holoparasite.

Additional structural and compositional analyses of cell wall fractions

Chromatography (HPAEC 0bro et al. 2004) or by GC-MS analysis after monosaccharide derivatization to their corresponding alditol acetates or trimethylsilane derivatives (Albersheim et al. 1967 York et al. 1985). Additional information about the polysaccharide can be obtained by determination of the glycosidic linkage of the sugars present in the wall sample (Ciucanu & Luca 1990) . Non-carbohydrate substituents such as acetyl or methyl esters can also be determined (see Klavons & Bennet 1986 Voragen et al. 1986). However, determination of the sequence and arrangement of the sugar moieties usually involves detailed characterization of smaller oligo-saccharide fragments.

Starch is deposited in plastids

In storage tissues, the delivered carbohydrates are mostly converted to starch and stored as such. In apoplastic phloem unloading, this may proceed by two alternative pathways. In the pathway colored red in Figure 13.5, the sucrose is taken up from the apoplast into the storage cells and converted there via sucrose synthase and UDP-glucose-pyrophosphory-lase to fructose and glucose 1-phosphate. In this reaction, pyrophosphate is consumed and UTP is generated. Phosphoglucomutase converts glucose 1-phosphate to glucose 6-phosphate. Alternatively, the enzyme invertase first hydrolyzes sucrose in the apoplast to glucose and fructose, and these two hexoses are then transported into the cell. This pathway is colored black in Figure 13.5. A fructokinase and a hexokinase (the latter phosphorylating mannose as well as glucose) catalyze the formation of the corresponding hexose phosphates. Glucose 6-phosphate is transported via the glucose 6-phosphate-phosphate translocator (see section 8.2) in...

Stem Reserves In Grain Filling

Estimates presented by Schnyder (1) in his review and is still the method most often exploited since 1993 (10-26). Although it may be logical to suggest that losses in stem reserves during peak periods of grain weight gain are related it must be remembered that there is not a cause and effect relationship between the two. Simultaneous decreases of fructan with an increase in fructan hydrolytic activity represents a closer association (10, 11). By labeling the carbon used for CO2 fixation it is possible to show carbon transfer from the stem to the grain (26, 27), but determining amounts of carbon moved is more difficult because of the time lapse between labeling and repartitioning. Respiration of radiolabeled carbohydrates and subsequent refixation could provide error in calculations of repartitioning. The research reported since the 1993 review have used mass balance and labeling of reserves as methods of choice, although both are somewhat imprecise.

Molecular Physiological Aspects of the AM Symbiosis Post Penetration

Abstract The establishment of an arbuscular mycorrhizal symbiosis is characterised by several stages until the fungus has penetrated the root epidermis. The present chapter deals with the subsequent phase where the fungus colonises the root cortex and, when the different functions of the symbiosis are realised. After summarising the morphological and cytological characteristics of this symbiotic phase, different strategies will be described which have been followed to understand the molecular-physiological basis of the symbiosis. Non-targeted approaches resulted in new hypotheses concerning mycorrhizal functioning based on the identification of differentially expressed transcripts or proteins. Some of these hypotheses were further proofed by various biological techniques as localisation of the gene products or down-regulation of the genes in transgenic plants. In contrast targeted approaches were directed to particular plant and fungal functions. Among those functions, the present...

Nuclear Magnetic Resonance in Stilbene and Wine Research

Recently, a NMR-based metabolomic studies related to stress responses in grapevines affected by the esca wood disease (a fungal community infection that leads to grapevine apoplexy) was published. In this work the metabolic changes in control versus diseased leaves were fingerprinted using 1D and 2D NMR. Principal component analysis (PCA) of the NMR spectra showed a clear separation between the groups, indicating a difference in compound production due to the esca disease. The study revealed a significant increase in phenolic compounds accompanied by a decrease in carbohydrates, suggesting that carbon and energy were rerouted from primary to secondary metabolism in the diseased leaves 125 .

Nitrate transporters and white photosynthetic active light

Photosynthesis and carbon metabolism were recognised as important for nitrogen assimilation already in the early days of research on nitrogen assimilation back in the 50's using unicellular algae as the experimental system as reviewed by Huppe and Turpin (1994). An early observation was that nitrogen-sufficient algae required light to assimilate nitrogen, but nitrogen-limited cells rapidly assimilated nitrogen in the dark. Intracellular carbohydrate stores decreased during dark assimilation and assimilation ceased when these stores were depleted (Huppe and Turpin 1994). From experiments on photosynthesis and uptake of 15NO3- in maize seedlings, Pace et al. (1990) concluded that NO3- uptake and reduction were regulated by the supply of energy and carbon skeletons required to support these processes. Also in ryegrass NO3- uptake was closely related to photosynthesis with a time lag of about 5 h between photosynthesis and uptake (Scaife 1989). Furthermore diurnal regulation of nitrate...

Modeling of Reproductive Output

We assume a plant that consists of two parts a vegetative body and the reproductive structure (Fig. 6.1). Only the vegetative body produces carbohydrates, Figure 6.1 Model of growth and reproduction. The plant consists of a vegetative body (x) and a reproductive part (y). The vegetative body produces carbohydrates at a rate of p and allocated part (u) of carbohydrates to the reproductive part. which is subsequently allocated for growth of both parts. Growth of the reproductive structure is supported by translocation of carbohydrates from the vegetative part. Let x and y be dry mass in the vegetative body and in the reproductive part, respectively. The growth of the plant is described by the following equations

The Ground Tissue System

Typically the cortex of roots, the pith of stems, the mesophyll of leaves, and the edible parts of fruits are composed entirely of parenchyma tissue. Although parenchyma cells making up this tissue vary in size, shape, wall structure, and function, generally they are living at maturity, are polyhedral in shape, have thin cell walls, and perform many of the basic physiological functions of the plant. Parenchyma tissue in the cortex and pith regions of roots and stems are often specialized for storage of carbohydrates, proteins, fats, and oils. Water is stored in the mesophyll of succulent plants. Cells in the mesophyll of leaves contain chloroplasts and are specialized for photosynthesis. There are two types of leaf mesophyll palisade mesophyll is composed of columnar-shaped cells near the upper surface of the leaf, and branched spongy mesophyll is next to the lower surface.

The de novo synthesis of fatty acids takes place in the plastids

The carbon fixed by CO2 assimilation in the chloroplasts is the precursor not only for the synthesis of carbohydrates and amino acids, but also for the synthesis of fatty acids and various secondary metabolites discussed in Chapters 16 to 18. Whereas the production of carbohydrates and amino acids by the mesophyll cells is primarily destined for export to other parts of the plants, the synthesis of fatty acids occurs only for the cell's own requirements, except in seeds and fruits. Plants are not capable of longdistance fatty acid transport. Since fatty acids are present as constituents of membrane lipids in every cell, each cell must contain the enzymes for the synthesis of membrane lipids and thus also for the synthesis of fatty acids.

Conclusion And Future Strategies

In 1999 the temperature in the field during collection of the samples was in excess of 32 C so that grains filled rapidly and photosynthesis was adversely affected. Dependence on stored carbohydrates was great and this demonstrates the ability of wheat stored carbohydrates to supplement current photoassimilates so that gradients in the kernel do not fluctuate greatly. Stem storage then has two important functions, first as a supplement to source supply and second as a modulator of the signal molecules sucrose and glucose. Remobilization of stored stem reserves, as a source for carbon, could be beneficiad for greater productivity (25) but this would clearly reduce the flexibility of wheat and barley to respond to reductions in source supply during graiin fill. Progress in assessing the contributions of fructan to grain yield remains elusive, however Gebbing et al. (28) could use data collected using the stable isotope 13C to assess remobilization of stem...

Carbon Distribution and Transfer to the Fungus

If more CO2 is assimilated as it has been pointed out, the Calvin cycle should be more active and photochemical reactions result in higher levels of energy and reduction equivalents. This should increase the amounts of leaf carbohydrates, suggested the mycorrhization-induced expression of a gene encoding a hexose transporter (Garcia-Rodriguez et al. 2005). The exact role of the transporter is not clear, because it is not known where it is localised and from which to which compartment it transports the hexoses. Reports on enzyme activities in leaves of mycorrhizal plants are rare. In only one paper, sucrose phosphate synthase was analysed, but the activity was not significantly affected (Black et al. 2000). Up regulation of invertase activity in leaf apoplasts, however, had a strong negative effect on mycorrhization indirectly indicating the important role of sucrose production (Schaarschmidt et al. 2007a). Up-loading of the phloem by sucrose is mediated by sucrose transporters (K hn...

Diagnosing response thresholds

The approach to the quantification emanates from the structural dynamic models of ecosystems (e.g. J0rgensen, 1992) and Nielsen's (1992) clever thermodynamic working of the energy exchanges of ecosystems. This recognises that useful, shortwave energy comes from the sun and some of this is intercepted by photoautotrophs to generate and transfer the reductive power to synthesised carbohydrates and proteins (see Box 8.1). The incipient ecosystem does not acquire energy so much as it intervenes in the abiotic dissipation of radiant solar energy. Like a water-wheel in a stream, the biotic component diverts part of the general (entropic) flux into useful work. The capacity to build and organise ecosystems comes via the energy that is harvested in primary production. So long as the biotic energy harvesting rate exceeds its biotic dissipation (in respiration, maintenance and transfer), there is a net assembly of biomass. In other words, while the balance of its exchanges is positive, the...

Reactions with toxic intermediates take place in peroxisomes

When carbohydrates are synthesized from the degradation products of membrane lipids in the senescent leaves and are transferred to the stem via the phloem (section 19.7). During senescence, one can indeed observe a differentiation of leaf peroxisomes into glyoxysomes (alternatively termed gerontosomes). The hydrophobic amino acids leucine and valine are also degraded in peroxisomes.

How Pathogens Cause Disease

Pathogens impede normal growth of plants in many ways. They attack and kill seeds and seedlings (damping off diseases). They invade and kill roots, preventing absorption of water and mineral nutrients (root rots). They invade and plug xylem tissue, preventing movement of water and minerals to leaves and growing points (vascular wilts). They kill leaves, preventing photosynthesis and production of carbohydrates (leaf spots and blights, downy mildews, powdery mildews, and rusts). The phloem tissue may be invaded and killed, preventing translocation of the carbohydrate produced in photosynthesis to other parts of the plant (phloem necrosis). After the crop has been produced, pathogens may rot fruits and vegetables in transit or storage or in the marketplace (fruit and vegetable rots). A few pathogens cause disease by inducing abnormal growth, thus stunting normal growth (galls).

Secondary metabolites fulfill specific ecological functions in plants

In addition to primary metabolites such as carbohydrates, amino acids, fatty acids, cytochromes, chlorophylls, and metabolic intermediates of the anabolic and catabolic pathways, which occur in all plants and where they all have the same metabolic functions, plants also produce a large variety of compounds, with no apparent function in the primary metabolism, and therefore are called secondary metabolites. Certain secondary metabolites are restricted to a few plant species where they fulfill specific ecological functions, such as attracting insects to transfer pollen, or animals for consuming fruits to distribute seeds, or as natural pesticides that act as defense compounds to combat herbivores and pathogens.

Anoxia and Seagrass Dieoff

Insufficient oxygen supply to meristems and roots of seagrasses may have severe implications for seagrass growth and survival. Tissue anoxia impairs growth of roots, nutrient uptake and translocation of nutrients and carbohydrates (Smith et al., 1988 Zimmerman and Alberte, 1996), and the disappearance of the oxic microshield around roots and rhizomes normally provided by the radial oxygen loss allows the invasion of reduced phytotoxins from the sediment to the plant tissues. Periodical invasion of sulfide from the sediment into roots of wetland plants has been indicated by the composition of sulfur isotopes in the roots (Carlson and Forrest, 1982 see also Koch et al., Chapter 8), and invasion of gaseous sulfide into seagrass lacunae has been measured using microelectrodes both under laboratory and field conditions for Zostera marina and Thalassia testudinum (Pedersen et al., 2004 Borum et al., 2005). It is not known whether the events of sudden seagrass die-off, which have been...

RhamnogalacturonanII fragments

(O'Neill et al. 2004 Scheller et al. 2007). The latter are derived from 12 different kinds of sugars, including some rare carbohydrates such as aceric acid (Ace) and 3-deoxy-D-lyxo-2-heptulosaric acid (Dha). The structures of RG-II side chains are well established and to date synthetic efforts have focused on fragments of these side chains, in particular chains A and B.

Selective Oxidation of the Primary Hydroxyl Group

Platinum (catalyst) and molecular oxygen (oxidant) have been used to selectively oxidize carbohydrates (Abbadi and van Bekkum, 1996 Gallezot and Besson, 1995) such as sucrose (Fritsche-Lang et al., 1985 Kunz and Recker, 1995). Inulin is readily oxidized using O2 and platinum in the presence of sodium hydroxide (Verraest et al., 1998). Oxidation occurs selectively at the C-6 position with a relatively high yield (79 ). Sucrose is also selectively oxidized at the C-6 and C-6' positions under similar conditions (Edye et al., 1991, 1994). The molecular weight of the inulin influences the reaction rate and degree of oxidation. Nystose (GF3) had a degree of oxidation of 40 . As the chain length increases, the degree of oxidation declines. Inulin with an average degree of polymerization of 10 had a degree of oxidation of 28 , while at an average degree of polymerization of 30, it decreased to only 20 . In addition, the amount of by-products increases with increasing chain length and degree...

Postharvest Fruit Physiology

Postharvest fruit physiology describes the interaction of the physiological and biochemical events associated with ripening and senescence. Fruit continue to function metabolically after harvest, but in the absence of carbohydrates, nutrients, and water supplied by the tree. In some cases, the fruit are eaten immediately. However, handling, storage, and transport technologies are usually used to maintain the rate of fruit ripening and therefore quality. The postharvest period hence involves the appropriate management of stress to minimize metabolic rates and or enhancement of injurious metabolic processes.

Biology and Habits

The digestive juice of X. globosa does not contain cellulase and consequently it does not digest cellulose. There are no mycetocytes in any parts of the body. The principal food supply is from other carbohydrates and soluble sugars in the sapwood. The heartwood of Albiziti lebbek contains only small traces of starch and sugar this explains why the larval tunnels do not penetrate the heartwood of that species.

From the Light Reactions to the Calvin Benson Cycle

The job of the photosynthetic light reactions is to provide energy in the form NADPH and ATP for the Calvin-Benson cycle. Although all plants depend on the Calvin-Benson cycle to make carbohydrates, the way they get the carbon dioxide to the cycle varies. The most efficient plants (soybean, for example) require two molecules of NADPH and three molecules of ATP for each molecule of CO2 that is taken up, while some other types of plants (corn, for example) must use more energy to fix a single CO2 molecule. During brief periods photosynthesis in plants can store nearly 30 percent of the light energy they absorb as chemical energy. However, under normal, day-to-day growing conditions the actual performance of the plant is less than one-tenth of the maximum efficiency. The factors that conspire to lower photosynthesis include limitations imposed by molecular reactions and environmental conditions that limit plant performance such as low soil moisture or high temperature. Our increasing...

Naturopathic Approach To Treating Pain

Most importantly, from the perspective of removing the cause, physicians perhaps do their greatest service by altering the course of a person's health away from a protracted period of pain and concomitant disability. The first intervention involves setting a course for healing the tissues that are the source of the pain. Removing dietary perils that prevent the body from being in its optimum state of health includes limiting refined carbohydrates and optimizing protein, micronutrient, and fatty-acid intakes. Excess carbohydrate intake exerts a negative effect on insulin metabolism, provoking weight gain and the inflammatory cascade. Insufficient protein intake, at levels less than 30 of the recommended daily allowance (0.8 g of protein per kg of body weight per day), may limit repair and regeneration. An excess of foods that contain arachidonic acid, a long-chain omega-6 fatty acid, is a known promoter of inflammation,

Host Pathogen Specificity

As described in the previous sections, biotrophic and hemibiotrophic fungi and oomycetes are able to grow within living host cells and tissues. In order to maintain this intimate association, the pathogen alters and manipulates the host metabolism extensively. Among the changes that have been documented in host plants during infection are movement of the host nucleus and endomembrane system to surround the extrahaustorial membrane a redistribution of carbohydrates into infected leaves and an increase in chlorophyll and photosynthetic activity, leading to the green island effect (Scholes and Farrar 1985 Coffey 1972 Leckie et al. 1995 Voegele et al. 2009). These events occur during a compatible interaction but in an incompatible interaction plant cells are able to sense pathogen invasion and react rapidly by mounting a multi-faceted defence response.

Physiology of Young Seedlings

The physiology of epigeously germinating seedlings varies somewhat among species. The epigeous cotyledons of some species store appreciable amounts of carbohydrates. Those of other species, such as pines, accumulate only small amounts, but they become photosynthetically active shortly after they emerge from the ground. Following seed germination, a pine seedling is a system of competing carbohydrate sinks. Seedling development is an integrated continuum, with the site of synthesis of carbohydrates shifting during ontogeny from cotyledons to primary needles to secondary needles. There is a close dependency of growth of one class of foliar appendages on the capacity of the preceding class to synthesize compounds needed for growth. Hence, development of primary needles requires metabolites from cotyledons, and development of secondary needles depends on metabolites from primary needles. The young seedling in the cotyledon stage appears to be operating at threshold levels of growth...

Lifestyle Overlapping

The nematode cuticle consists of several layers of proteins (mainly collagen), lipids and carbohydrates (Bird and Bird 1991). Externally to the cuticle a surface coat (or glycocalix) consisting of glycoproteins can be found (Bird and Bird 1991). The surface coat is probably the part of the nematode surface most relevant to recognition and adhesion of nematophagous fungi, since proteolytic removal of this structure results in reduced adhesion of microorganisms (Bird 1985 Jansson 1993). The eggshell of plant-parasitic nematodes is also a multilayered structure (Wharton 1980 Bird and Bird 1991). The thickest and most important is the chitinous layer which, like the insect cuticle, is also made of chitin and proteins. Regarding nematodes, chitin is, for instance, more abundant in Meloidogyne spp. eggshells, whereas protein is present to a higher degree in Globodera spp. Structurally, Globodera spp. have thicker egg-shells than those of Heterodera spp. (Lopez-Llorca and Robertson 1992).

Translocation and Exudation

(D) Seasonal changes in non-structural carbohydrates (as sucrose-equivalents) in Posidonia oceanica, compared with plant growth rates (Redrawn from Alcoverro et al., 2001). (D) Seasonal changes in non-structural carbohydrates (as sucrose-equivalents) in Posidonia oceanica, compared with plant growth rates (Redrawn from Alcoverro et al., 2001).

Structure and Life Cycle

In both kingdoms, fungi obtain their nutrition by excreting enzymes into the host or any organic material, which is then broken down and absorbed into the hyphal cell to provide the nutrition necessary for growth. Fungi function in the ecosystem as saprophytes, or decomposers. They break down dead organic matter as parasites by attacking living hosts or host cells, and as mycor-rhizae (mycor, meaning fungi, and rhizae, meaning root ) by forming jointly beneficial unions with the roots of higher plants. Fungi and algae combine to form a plant called a lichen. Only fungi and bacteria decompose various kinds of organic matter and change complex organic structures, such as plant cell walls containing lignin or the chitinous exoskeletons of insects, into simple carbohydrates that can then be assimilated by a wide variety of organisms.

Cells Specialized Types

The different types of specialized plant cells are distinguished by cell shape and by properties of the cell wall and protoplast. The plant cell wall is one of the most important distinguishing features of the different kinds of specialized cells. All plant cells have a thin and flexible primary wall, made of the polymer cellulose and other carbohydrates. Other cell types have, in addition to a primary wall, a thick, rigid secondary wall, made of cellulose impregnated with lignin.

Biochemical Aspects of the CAM Pathway

Basically, in CAM plants, CO2 uptake from the environment occurs during the night (phase I, after Osmond 1978) and sometimes during the light period when there is higher air humidity (early morning - phase II, and late afternoon - phase IV). In certain cases, internal CO2 produced by respiration can also be used. In the cytosol, the CO2 is captured in oxaloacetate (OAA) by the enzyme phospho-enolpyruvate carboxylase (PEPC). This enzyme is activated by phosphorylation through a dedicated kinase, which is under circadian control and synthesized de novo each night (Taybi et al. 2000, 2004). OAA is reduced to organic acids, mainly malic acid, which are stored in the large vacuole of the chlorenchyma cells during the night. Therefore, nocturnal acid accumulation is one of the principal diagnostic features of CAM. Subsequent daytime decarboxylation of organic acids releases CO2 in the cytoplasm, which is assimilated into carbohydrates by RUBISCO (C3 cycle - phase III). This increased...

Overall Naturopathic Approach

A more recent study of fasting by patients with RA also has produced some interesting results.39 Specifically, after a week of vegetable-juice fasting, this study found significant decreases in sedimentation rate, CRP, and tender-joint count, as well as experiencing a 37 decrease in the pro-inflammatory cytokine IL-6. In addition, there was a significant increase in DHEA-sulfate levels, which was also seen in patients who were placed on a ketogenic diet.

Adjustment of carbonnitrogen balance in the whole plant Carbonnitrogen in the whole plant throughout life

The CNI of cereal crops varied according to the nitrogen application rate CNI was high at low nitrogen application rates and vice versa, whereas CNI' of legume crops was quite stable regardless of nitrogen application rates (Osaki et al 1992c) (Fig. 3). This difference in the DM,-N, relationship between legumes and cereals cannot be ascribed to the fact that a large amount of energy was lost during nitrogen fixation through respiration in legumes. When the relationship of DM, and N, was examined in isogenic lines of soybean (A62-1. nodulated, and A62-2, nonnodulated), the effect of nodulation for nitrogen fixation on the coefficient CNI' was negligible (Osaki et al 1992c), indicating that the respiratory loss of carbohydrates for nitrogen fixation was not large enough to change the relationship in soybean. Thus, as a result of the variation in CNI and CNI', it is assumed that the variation in the DM, N, ratio is large in cereals and negligible in legumes this was clear from the...

Economic Importance of the Cell Wall

The cell wall is unmatched in the diversity and versatility of its economic uses. Lumber, charcoal, and other wood products are obvious examples. Textiles such as cotton and linen are derived from the walls of unusually long and strong fiber cells. Paper is likewise a product of long fiber cell walls that are extracted, beaten, and dried as a uniform sheet. Cellulose can be dissolved and regenerated as a manmade fiber called rayon or in sheets called cellophane. Chemically modified cellulose is used to make plastics, membranes, coatings, adhesives, and thickeners found in a vast array of products, from photographic film to paint, nail polish to explosives. In agriculture, cell walls are important as animal fodder, whereas in the human diet, cell walls are important as dietary fiber or roughage. Pectin is used as a gelling agent in jellies, yogurt, low-fat margarines, and other foods, while powered cellulose is similarly used as a thickener in foods and as an inert filler in medicinal...

Storing and Handling Fruit

Once fruit are harvested, the main goal is to maintain freshness and quality. Cooling is the primary mechanism used to minimize reduction in quality. A fruit is a living entity and continues to metabolize following harvest. Respiration is a major part of metabolism and is the process of breaking down stored carbohydrates to produce energy. A warm fruit has a higher rate of respiration, which leads to accelerated ripening, depleted energy reserves, and decreased potential storage life. The faster a fruit respires, the quicker it will ripen and eventually deteriorate. For example, lowering the temperature of 'Granny Smith' apples from 20 to 0 C decreases the rate of deterioration by a factor of five. Exposing fruit to direct sunlight can lead to elevated respiration rates and internal fruit temperatures that greatly exceed the surrounding ambient temperature. Removing fruit from direct sunlight is the first step in the cooling process. Placing fruit in the shade or using mechanical...

Transfer and Use by the Fungus

The hexoses taken by the fungus are quickly converted to fungus-specific compounds, therefore maintaining an hexose concentration gradient between plant and fungal tissues, which is thought to maintain the sugar flow toward the fungus (Fajardo-Lopez et al. 2007 Fig. 17.1). Increased carbohydrate export to the root and decreased levels of carbohydrates in ECM plants were observed, while simultaneously the synthesis and contents of fungus-specific compounds such trehalose and manitol, the two main carbohydrates accumulated in fungi, were increased (Hampp et al. 1995 Martin et al. 1998 Fajardo-Lopez et al. 2007 Deveau et al. 2008 Correa et al. 2010). Trehalose biosynthesis was found to occur mainly in hyphae of the plant-fungus interface (Fajardo-Lopez et al. 2007 Deveau et al. 2008 Fig. 17.1).

Appalachian rock pink

Ecology As an important range plant, Timothy grass has been introduced over much of temperate North America, where it has often escaped cultivation and become established in fields, roadsides, and other open habitats. A prolific seed producer, it rapidly colonizes disturbed areas. Once established, Timothy grass stores carbohydrates and other products of photosynthesis in the base of swollen stems and in corms. These nutrient reserves are important to winter survival, to the initiation of early spring growth, and in the production of replacement tillers (shoots) following defoliation by grazers. Grasses, like other wind-pollinated plants, produce enormous amounts of pollen as a mechanism to facilitate successful pollination. A meadow dominated by Timothy grass, for example, can disperse over 1 billion pollen grains in just 2 weeks. Unfortunately, pollen produced by this grass is a common cause of hay fever. No matter how long a naturalized plant such as Timothy grass persists in an...

Dynamics of Carbon and Nitrogen

In the Mediterranean Sea, P. oceanica leaves contain 23-40 of carbon, varying with depth, season and leaf age (Augier and Santimone, 1982 Velimirov, 1987 Duarte, 1990 Alcoverro et al., 1995 Gobert et al., 1995 Mateo et al., Chapter 7). Seasonal and daily variations of soluble carbohydrates, starch, and free amino acids were investigated in detail by Velimirov (1984) Pirc and Wollenweber (1988) Alcoverro et al. (2001b). The carbon fluxes of the beds, resulting essentially from P. oceanica primary production, vary according to

Photoassimilate Influence on Flowering

Flowering may be regulated by C N ratios with high levels being conducive to flowering (Kraus and Kraybill, 1918). Photoassimilates reaching the apical bud from leaves was central to several theories of floral induction (Sachs, 1977 Bernier and Sachs, 1979 Bernier et al., 1981, 1993 Bernier, 1988) including mango (Mallik, 1951 L.B. Singh, 1960 Chacko and Ananthanarayanan, 1982 Rameshwar, 1989) and other species (Allsopp, 1965 Sachs, 1977 Mishra and Dhillon, 1978 Ramina et al., 1979 Bernier et al, 1981 Sachs and Hackett, 1983). The theory of photoassimilate diversion to the apical bud (Sachs et al., 1979) is the basis for the carbohydrate-regulated flowering models (see below). Sugars are utilized during panicle development (Ravishankar and Mohan Rao, 1982). Starch reserves and C N ratios have been correlated with flowering (Mishra and Dhillon, 1978 Suryanarayana, 1978a, b, c Chacko and Ananthanarayanan, 1982 Whiley et al, 1988, 1989, 1991 Robert and Wolsten-holme, 1992 Shivashankara...

Nitrogen fixation and the origins of coupled redox reactions

The paucity of fixed nitrogen almost certainly led to the early emergence of biological nitrogen fixation indeed, dinitrogen reductases are strictly anaerobic enzymes that utilise iron-sulfur cluster motifs as prosthetic groups. Sequence analysis of all extant nitrogenases suggests a single common ancestor. In vivo the enzyme utilises reductant produced via the oxidation of carbohydrates to reduce dinitrogen to ammonium that is, the fixation of nitrogen essentially is a respiratory process that can be summarised by the following balanced reaction

Conspectus of liverwort morphology

Endoplasmic reticulum (Duckett & Ligrone 1995, Suire 2000) or from dictyo-some vesicle fusion (Galatis et al. 1978, Apostolakos & Galatis 1998). The enclosing membrane of the oil body resembles the tonoplast in having an asymmetric, tripartite appearance but differs from it in enzyme composition and transport capabilities (Suire 2000). The oil body interior consists of small osmiophilic droplets suspended in a granular stroma that is rich in proteins and carbohydrates (Pihakaski 1972, Suire 2000). Frequently, in addition to oil bodies, cells contain dispersed lipid droplets (oleosomes) in their cytoplasm. These are droplets of triacylglycerides and neither these, nor the plastoglobules common in plastids, are involved in or part of oil body development (Suire 2000).

Factors that regulate TE cell differentiation

Xylogen is a novel xylogenesis-inducing factor that regulates local promotive effects on TE differentiation in vascular tissues (Motose et al., 2004). Of particular interest, the xylogen protein sequence contains a characteristic motif of the one-cell-wall structural protein, i.e. an arabinogalactan protein (AGP see below). The core structure of Zinnia xylogen is a small 16-kD protein encoded by the ZeXYPl gene. ZeXYP1 proteins consist of four distinct domain sequences a signal pep-tide, the AGP domain, a non-specific lipid transfer protein (nsLTP) domain and a glycosyl phosphatidylinositol (GPI) anchor domain. ZeXYP1 undergoes extensive modification from the binding of sizable carbohydrates to form a 'hard-to-diffuse' local signalling factor. As a result, the molecular weight of mature Zinnia xylo-gen is much larger than that of the core protein itself. Expression of the ZeXYPl mRNA and protein occurs in procambium and immature xylem cells. Immunohis-tochemical analyses of the...

Storage In Source Leaves

As indicated above, sorbitol, together with sucrose and starch is a major end-product of photosynthesis in many species of the Rosaceae family. Significant diurnal variation in sorbitol concentration was observed in apple leaves 89, 90 . In a field experiment, a marked daily fluctuation in sorbitol concentration of leaves was observed from June to October, with more moderate variations in the other carbohydrates, starch, sucrose, glucose and fructose 89 , In the summer, the daytime sorbitol increase tended to approximate the decrease from the previous night. In autumn, the sorbitol increase during the day lagged, resulting in lower diurnal amplitudes. The authors discussed these results as a further evidence that sorbitol is a carbohydrate reserve in apple leaves. In celery, in young, mature and old leaves, mannitol and sucrose were the most abundant carbohydrates 93 . In old and young leaflets and their petioles, there was little diurnal variation in levels of mannitol and sucrose....

Plant Signals Regulating Interactions with Soil Microbes 211 Plant Signals in the Root Nodule Symbiosis

One of the best studied plant-bacterial interactions is that between most members of the legume family with nitrogen-fixing soil bacteria generically called rhizobia (Long 1989 Sprent 2008). Rhizobia are a-proteobacteria that can live feely in the soil as saprophytes, but form a facultative symbiosis with legumes and the nonle-gume genus Parasponia. However, other bacteria can also nodulate legumes, including species of the p-proteobacteria Burkholderia, which were traditionally known as plant pathogens (Moulin et al. 2001). Rhizobia invade the roots of host plants and induce formation of root nodules (RNs), in which they fix atmospheric nitrogen that is transferred to the plant in exchange for carbohydrates. This symbiosis provides the majority of biologically fixed nitrogen and is especially important for low input agricultural systems in Africa and South America (Peoples et al. 2009). Legume-rhizobia symbioses are not the only nitrogen-fixing symbioses, as

Carbohydrate Relations

As emphasized in Chapter 7 of Kozlowski and Pallardy (1997), carbohydrates are the most important constituents of woody plants. They comprise about three-fourths of the dry weight of woody plants and are the primary energy storage compounds and the organic substances from which most other organic compounds are synthesized. The amount of carbohydrates translocated in woody plants exceeds that of all other solutes combined. Carbohydrate transport may occur downward, upward, and laterally. When radioactive sucrose is applied to the cambial region, it moves along the rays to the inner sapwood (Holl, 1975). Sugar uptake from xylem vessels by contact ray cells also occurs and is followed by transport along the rays to the phloem (Van Bel, 1990). Lateral movement of sugar occurs almost entirely through the ray symplast (Sauter and Kloth, 1986). Norway spruce needles transported carbohydrates downward in the shoot axis as well as laterally along the rays (Fig. 3.1). Sugars were transported...

Estimation of Piperine

Iii) Colorimetric methods proposed for estimation of piperine use reagents that react with different parts of the piperine molecule. The earliest method is based on hydrolysing the methylenedioxy group to formaldehyde which is estimated by the distinct colour developed with chromotropic acid. Methylene dioxy groups in the breakdown products of piperine as well as carbohydrates yield formaldehyde under acid conditions to react with chromotropic acid thus giving higher values. The disadvantage with colorimetric methods using nitric acid and sulfuric acid and an aromatic aldehyde are that all compounds with a benzene nucleus can be nitrated and all unsaturated compounds formed by conc. H2SO4 interfere and vitiate the usefulness of the method. Though the colour produced by piperine with phosphoric acid is rather specific for piperine and its isomers several critical experimental variables limit the general use of the procedure for quantitative estimation. According to reports all...

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