Saline Agriculture

The rapidly increasing human population in the arid and semi-arid regions of the world has tremendously increased the pressure on the availability of good quality water and land resources for human usage, industry and agriculture. In addition, improper and poor quality irrigation practices have increased the level of under-ground water and large areas have become water logged which eventually results into higher salinities of the soil (Yensen 2006). Salinity affects the growth of the plant to a...

Introduction

Extrinsic Stress Tolerance In the field of plant physiology, environmental stress (or strain) refers to a state or event causing a deviation in plant growth relative to its optimal development (Larcher 1987, 2003). As shown in other chapters of this volume, potential environmental stress factors are many (e.g., radiation, temperature, water, nutrient availability) and often grouped according to their abiotic or biotic origins (Fig. 11.1) . From this definition, such stressors...

Strategies for Minimizing N Pollution in Agriculture

Various strategies were adopted to minimize the N loss from the agricultural fields. Split application of N, use of slow-release fertilizers, nitrification inhibitors (NIs), and the use of organic manures are some agronomic techniques used. Bulk of the fertilizer nitrogen in India is broadcast on surface and both surface runoff (on sloppy lands) and ammonia volatilization lead to N losses. This can be easily overcome by deep placement of N a few centimeters below soil surface. For example,...

Effect of Other Nutrients

The increasing world population makes high yield crop production a necessity in agriculture. The use of fertilizers has raised crop yield considerably (Stewart et al. 2005). The expansion of agriculture has lead to an important increase in global K+ consumption 4.4 per year between 1999 and 2005 and K+ fertilization to maintain crop production is a regular cultural practice. Global K+ consumption reached 33.9 Mt K2O in 2008. In some cases, over-fertilization occurs, which implies a financial...

Enhanced UVB Radiation

Different to polar studies, earlier researches on nonpolar terrestrial plants were mainly focused on the effects of artificially increased UV-B radiation on crop species rather than ecosystems (Flint et al. 2003). Although, such researches were important to understand the physiological responses and identify possible targets for the UV-B radiation, extensive recent studies have shown that effects of the artificially manipulated UV-B have been often overestimated (Rozema 2000). Moreover, the...

And Characterization

With the initiation of miRNA research, a lot of work has been carried out since then. Fifteen classes of miRNAs have been identified and well characterized from the model plant Arabidopsis (Bartel and Bartel 2003). Twenty miRNA families have been computationally predicted in case of Oryza, out of which 14 miRNAs have been experimentally isolated and characterized (Sunkar et al. 2005). Similarly, eight novel miRNAs have been isolated and characterized from Medicago (Szittya et al. 2008) . miRNAs...

Nitrogen Removal by Crops

From the human nutrition point of view, rice and wheat are the most important cereals and their production in north-west India in rice-wheat cropping system, which covers about 10 million hectares, is the backbone of the India's food security (Prasad 2005) . Rice-wheat cropping system produces 5-14 ton ha year grain and this depends heavily on nitrogen fertilization which ranges from 100 to 150 kg N ha crop or even more, especially in rice. From the animal nutrition point of view, maize,...

Physiological and Molecular Aspects for Improving NUE

NUE at the plant level is its ability to utilize the available nitrogen (N) resources to optimize its productivity. In terms of agriculture, it is the optimal utilization of nitrogenous manures or fertilizers for plant growth, yield, and protein content, as atmospheric nitrogen gas is not utilized by higher plants, except symbiotic legumes. The inherent efficiency of the plant to utilize available N for higher productivity needs to be tackled biologically (Abrol et al. 1999 Abdin et al. 2005) ....

Conclusion and Future Perspectives

Present review provides an overview of plant nutriomics, which is still at a conceptual stage. Although considerable efforts are in progress with the aim at enhancing plant nutrient efficiency through molecular and genetic approaches. We have focused here largely on nitrogen with which we have been working on along molecular biology lines. Crop response to N and NUE is very low in developing countries including India. Use of NIs and slow-release nitrogen fertilizers and efficient crop and...

Wetland Restoration and Revegetation

Mangrove forests are ecologically important coastal ecosystem currently covering 146,530 km of the tropical shorelines of the world (FAO 2003). There has been a steady decline from 198,000 km of mangroves in 1980 and 157,630 km in 1990 (FAO 2003) which represents about 2 and 1 losses per year between 1980-1990 and 1990-2000, respectively (Lewis 2005). Mangroves have provided ecological benefits in terms of shorelines stabilization, reduction in wave and wind energy against shorelines thus...

Conclusion and Future Perspective

The enhanced UV-B radiation produced important physiological and morphological effects on the terrestrial plants, but most of these studies were carried out in greenhouses and growth chambers. Then the extrapolation and quantification of the observed indoor effects to field experiments is very complex, because they can reflect exacerbated responses of the plants and confuse the interpretation of physiological and morphogenic responses, as well as the molecular analysis at both individual...

Root and Excess Water

Excess water in soil determines the full filling of the pore space restricting the diffusion of oxygen by 104-fold than in air (Drew and Armstrong 2002) and causing a stress, named waterlogging, with dramatic impact on plant growth and productivity. Climate change provisions provide that, as a consequence of anomalous weather patterns, waterlogging could be a more exceeding problem for many plant communities. Under oxygen absence (anoxic soil) or under severe hypoxic conditions, the cytochrome...

Sources of ROS in Plants Exposed to Cadmium

The reactive oxygen species are mainly singlet oxygen ('O2), superoxide radical (O2-), hydroxyl radical ( OH) and hydrogen peroxide (H2O2) which are by-products of normal aerobic metabolism such as respiration and photosynthesis. Their steady-state levels are determined by the interplay of different ROS-producing and ROS-scavenging mechanisms. This balance is maintained by enzymes such as superoxide dis-mutase (SOD), which remove O2- radicals, and catalase (CAT), peroxidase (POX), and...

In Agriculture An Environment Perspective

Khalid Rehman Hakeem, Ruby Chandna, Altaf Ahmad,and Muhammad Iqbal Increased use of nitrogenous (N) fertilizer has significantly altered the global N-cycle and produced nitrogenous gases of environmental consequence. While nitrous oxide (N2O) emissions contribute to global greenhouse gas accumulation and the stratospheric ozone depletion, degradation of groundwater quality by N use in agriculture is fundamentally a nitrate leaching problem. Despite these evident negative environmental impacts,...

Proteomics Approach to NUE

The ability of crop plants to cope up with the variety of environmental stresses depends upon a number of changes in their proteins, which may be up- and downregulated as a result of altered gene expression. Under a stressful condition, the modifications in the expression levels of these proteins could provide us valuable information about the nature of stress factor as well as the physiological and molecular state of a biological system. Hence, provides us some clues to understand the nature...

Plant Responses to Cadmium

Information on molecular mechanisms and signaling events underlying plant transcriptional responses to Cd is rather limited as compared to research in the field of cadmium toxicity. The mechanism by which Cd modulates the levels of expression of most genes is not clearly understood, while our knowledge of global changes in the expression of Cd-responsive genes is also limited. A number of studies have been carried out involving both small-scale experiments and whole-genome approaches. Their...

References

Abiko M, Akibayashi K, Sakata T, Kimura M, Kihara M, Itoh K, Asamizu E, Sato S, Takahashi H, Higashitani A (2005) High-temperature induction of male sterility during barley (Hordeum vulgare L.) anther development is mediated by transcriptional inhibition. Sex Plant Reprod 18 91-100 Acevedo E, Nachit M, Ferrar GO (1991) Effects of heat stress on wheat and possible selection tools for use in breeding for tolerant. In Saunders DA (ed) Wheat for the nontraditional warmer areas areas. CIMMYT,...

UVB Radiation and Signaling Pathways

The UV-B radiation triggers diverse responses involving a differential regulation of the genes and participate in several protective pathways including the DNA repair, detoxification of ROS, and production of secondary metabolites as well as in photomorphogenic events (Agrawal et al. 2009) . The UV-B responses can be elicited with either high fluence (HF-UV-B, over 15 kJ m-2), intermediate fluence (IF-UV-B, 5-7 kJ m-2), low fluence (LF-UV-B, 1-3 kJ m-2), or very low fluence (VLF-UV-B, less than...

Morphogenic Responses

Studies carried out in greenhouses or in growth chambers using ultraviolet lamps and filters to simulate different solar UV-B enhancements have been conducted on a variety of terrestrial plants, including economically important crops (Santos et al. 2004) and wild plant species (Zu et al. 2010). Overall these studies showed that the UV-B enhancement besides physiological effects induces a range of morphological changes including (a) increase decrease of the leaf area and leaf thickness (Gonz lez...

Phytoremediation

Contamination of agricultural soil by heavy metals (such as Cu, Cd, Zn, Mn, Fe, Pb, Hg, As, Cr, Se, Ur, etc.) has become a serious environmental concern due to their potential impact on the ecosystems. Such toxic elements are considered as soil and water pollutants due to their widespread occurrence, and their acute and chronic toxic effect on plants grown in such soils as well as on humans living in their surrounding (Yadav 2010). Plants, as sessile organisms have developed diverse...

DREB1CBF TFs and Cold Stress Response

Cold stress adversely affects all aspects of cellular function. The DREB1 CBF regulon is one of the most important regulatory systems at transcrip-tional level in cold signal transduction in plants. The DREB1 CBF TFs, which specifically bind to the dehydration-responsive cis-element DRE , belong to the AP2_EREBP family that is unique to plants Nakashima et al. 2009 . The DREB1 CBF TFs have been the most extensively studied TFs in the last 20 years aimed at improving plant tolerance to various...

DREB2 and Drought High Salinity Stress Response

Although DREB2A was isolated from the yeast-one-hybrid screening together with DREB1A Liu et al. 1998 , its function has been less reported than that of DREB1A gene. The reason might be that because overexpression of DREB2A led to neither enhanced tolerant phenotype nor alteration in expression of stress-inducible genes. Domain analysis of DREB2A in Arabidopsis protoplasts revealed that DREB2A contains a negative regulatory region and the deletion of this region activated DREB2A protein. The...

Osmotic Adjustment

Osmotic adjustment in response to abiotic stresses is an adaptive mechanism in the halophytes in order to maintain their water balance Flowers and Colmer 2008 . Besides the accumulation of inorganic ions and its sequestration in the vacuole, the osmotic balance between vacuole and cytoplasm is also maintained through the synthesis of organic solutes to retain the stability of the proteins in cells in response to drop in the water potential of the environment Glenn and Brown 1999 . Plant cells...

Signal Transduction Under Cadmium Stress

Cadmium Toxicity Plants

The response to heavy metals depends on a complex signal transduction pathway within the cell which begins with the sensing of heavy metal and converges in transcription regulation of metal-responsive genes Sing et al. 2002 , although much remains to be learned about the molecular components of metal-induced signal transduction. Various transcription factors TFs involved in the regulation of cell response to metal stress have recently been identified Sect. 21.5.2 . The modulation of different...

Role of miRNAs in Abiotic Stress

Abiotic stresses have already been known as the primary plant growth-limiting factors. Abiotic stress is a broad term including various phys-iochemical stresses like salinity, drought, temperature, and oxidative stress Vinocur and Altman 2005 . These stresses have been reported to reduce the average yield of most of the crops by 50 Tuteja and Sopory 2008 . It has been observed that plants possess the ability of monitoring fluctuations occurring around its niche and have the inbuilt capacity to...

Stress Tolerance Variety In Medicinal Plant

Ns nonsignificant, significant at the 0.01, and 0.001 levels of probability, respectively for each Triticum species, different letters in the same column refer to significant differences between genotypes. Source Dias and Lidon 2009 ns nonsignificant, significant at the 0.01, and 0.001 levels of probability, respectively for each Triticum species, different letters in the same column refer to significant differences between genotypes. Source Dias and Lidon 2009 growth and net assimilation rates...

Cadmium Toxicity in Plants

The toxic effects of cadmium on several plant species have been reported by different authors Sanit di Toppi and Gabbrielli 1999 Sandalio et al. 2001 Sch tzend bel et al. 2001 Benavides et al. 2005 , although the mechanisms involved in cadmium toxicity are still not fully understood. Cadmium inhibits seed germination, decreases plant growth, induces premature senescence, and can even trigger cell death in cell suspension cultures Fotjov and Kovarik 2000 McCarthy et al. 2001 Rodr guez-Serrano et...

Enzymatic Antioxidants

SOD is one of the ubiquitous enzymes in aerobic organisms and plays a key role in cellular defense mechanisms against ROS. Within a cell, the SODs constitute the first line of defense against ROS. Its activity modulates the reactive amounts of O2'- and H2O2, the two Haber-Weiss reaction substrates, and decreases the risk of OH radical formation, which is highly reactive and may cause severe damage to membranes, proteins, and DNA reviewed by Ahmad et al. 2010b . SOD was for the first time...