Suvh Proteins

In 2002, two independent mutant screens revealed roles for SUVH4 KRYP-TONITE in H3K9 methylation and gene silencing in Arabidopsis (Jackson et al., 2002 Malagnac et al., 2002). In these screens, suvh4 mutations were identified by their effects on the expression of the SUPERMAN locus, thereby affecting the number of floral organs (Jackson et al., 2002), or by the derepression of silenced PHOSPHOANTHRINILATE ISOMERASE (PAI) genes (Bender, 2004b Luff et al., 1999 Malagnac et al., 2002)....

Considerations About The Optimum Water Supply

In <a title="Growing Tomatoes in Soilless Culture" class="intexttaglink" data-tid="10517" href="/soilless-culture.html">soilless culture, an accurate and dynamic control of the water supply is needed to meet plant water requirements due to the low water holding capacity of the system (De Boodt and Verdonck, 1972). Optimum water supply should fulfil plant demand and also prevent salt accumulation in the substrate area surrounding the root. However, under conditions of high transpiration (e.g. at midday in summertime), supply of water may be often insufficient leading to temporal water stress in the plant. In...

References

Abad, P., Favery, B., Rosso, M.-N., Castagnone-Sereno, P., 2003. Root-knot nematode parasitism and host response molecular basis of a sophisticated interaction. Mol. Plant Pathol. 4, 217-224. Abad, P., Gouzy, J., Aury, J.M., Castagnone-Sereno, P., Danchin, E.G., Deleury, E., et al., 2008. Genome sequence of the metazoan plant-parasitic nematode meloidogyne incognita. Nat. Biotechnol. 26, 909-915. Alkharouf, N.W., Klink, V.P., Chouikha, I.B., Beard, H.S., MacDonald, M.H., Meyer, S., et al.,...

Adaptation To Plant Parasitism

(A) Root-knot nematode life cycle (B) Cyst nematode life cycle Fig. 2. Life cycles of (A) root-knot nematodes and (B) cyst nematodes (adapted from Williamson and Gleason, 2003). Fig. 3. Nematode adaptation to plant parasitism. (A) Schematical representation of the anterior region of a J2 sedentary endoparasitic nematode (from Vanholme et al., 2004). (B) Esterase activity from Meloidogyne incognita amphids. (C) Feeding tube induced by the PPN Rotylenchulus reniformis in a cotton root cell (from...

Measurement Of Plant Nutrient Uptake

Plant nutrient uptake can be determined by measuring nutrient depletion in the root environment and by quantifying nutrient content in plant tissues. 1. Measurement of nutrient depletion in the root environment This method is based on determining the difference in the amount of a certain ion in the root environment throughout a given period of time. This difference is associated with plant nutrient uptake, which can be calculated as (V1-C1)-(V2-C2) (Cabrera et al., 1995). In this equation, V1...

Considerations About The Optimum Oxygen Concentration In The Nutrient Solution

Oxygen is essential for the functioning of roots, hence, its deficiency is an important concern. Problems with oxygen supply may periodically appear in soil conditions after rains. Also, in soilless systems, water and nutrients are supplied continuously and these wet conditions limit diffusion of oxygen to the root system (Veen, 1988). Oxygen deficiency stress in plants is distinguished by three physiologically different states transient hypoxia (insufficient supply of oxygen), possible anoxia...

The Involvement Of Plant Hormones In The Transduction Of The Stress Signal

Plants produce increased amounts of hormones such as ABA and ethylene during biotic and abiotic environmental stress. In addition, salicylic acid (SA) and JA may be involved in some parts of stress response (Parida and Das, 2005 Xiong et al., 2002b). The interaction of theses hormones can be important for the plant stress tolerance A distinct supply of ethylene enhances ABA effects in seeds (Gazzarrini and McCourt, 2001) but counteracts ABA effects in vegetative tissues under drought stress...

Antioxidative Responses

Ionic and or osmotic stresses imposed by high salinity on plants may create secondary stresses such as the accumulation of toxic or unwanted compounds, disturbance in cellular metabolism and nutritional disorders. In fact, environmental conditions (salinity, drought, heat cold, light and other hostile conditions) may trigger in plants an oxidative stress, generating the formation of ROS (Jaleel et al., 2009). During salinity-induced oxidative stress, availability of atmospheric CO2 is reduced...

Diagnosis Of Plant Stress Caused By Water Supply

If water supply is higher than that required by plant, salt may lixiviate from the root environment possibly leading to nutrient deficiencies. In contrast, if water supply is lower than plant demand, plant water status may decrease. When water deficit is very limiting, plants wilt and visual symptoms are clear. However, water supply can be at suboptimum levels while showing no visual symptoms. In that case, several techniques based on the effects of water deficit on plant functions can help...

The Parasitic Life Cycle

Cyst nematodes and RKNs are thought to have evolved the sedentary lifestyle independently (Baldwin et al., 2004 Holterman et al, 2009). However, they have many features in common, including a simple life cycle generally taking 3-6 weeks, depending on the species and environmental conditions (Fig. 1). Both have four juvenile stages in addition to egg-laying adult female these stages are separated by moults, during which the cuticle is replaced. These PPNs spend most of their active lives within...

Molecular Regulation Of Ion Homeostasis And Involvement Of Intermediary Signalling Components

Plants, whether glycophytes and halophytes, cannot tolerate high concentrations of Na+ or Cl_ in the cytoplasm because enzymes (proteins) can be easily precipitated by these ions. Therefore under saline conditions, they either store the excessive salts into the vacuole of metabolic active tissues such as the mesophyll or compartmentalize the ions in not photosynthetic active tissues, or even in adult tissues to facilitate the metabolic functions (Iyengar and Reddy, 1996 Parida and Das, 2005...

Factors That Regulate Nutrient Uptake By The Plant

There are two theories that explain how plants absorb nutrients. 1. First theory nutrient supply as the only factor driving nutrient uptake This theory assumes that the only factor driving nutrient uptake is nutrient supply. This has been supported by Bugbee (2003), who recommended that adding nutrients to the solution depended on what one wanted the plant to absorb. This theory is based on the proved fact that nutrients transporters are induced by the concentration of their own substrate...

Electrical Conductivity And pH In The Nutrient Solution

CONSIDERATIONS ABOUT THE OPTIMUM ELECTRICAL CONDUCTIVITY AND pH IN THE NUTRIENT SOLUTION EC is an index of salt concentration that informs about the total amount of salts in a solution. Hence, EC of the nutrient solution is a good indicator of the amount of fertilizer available to the plants in the root zone (Nemali and Van Iersel, 2004). When plants absorb nutrients and water from the solution, the total salt concentration, that is the EC of the solution changes, and measurements of EC...

Genes And Metabolism

Research on coffee plants has mostly focused on agronomical improvement of the plant. Breeders are especially interested in selecting C. arabica plants with better disease resistance or C. canephora green beans that provide a high-quality coffee beverage. Breeding for complex metabolic compounds is, for the moment, less of a priority. Coffee aroma formation is a very complex process, involving Maillard and Strecker's reactions (Maillard, 1913) as well as thermal degradation during roasting (De...

Temperature

If the root temperature, significantly affected by the management of nutrient solution temperature, strays from the optimum range, several metabolic processes may be affected. This depends on the actual temperature, the duration of the stress, the physiological stage of the crop, the species and even cultivar (Kafkafi, 2008 Rachmilevitch et al., 2006a Sanders and Markhart, 2000). In spite of the importance of root temperature to whole-plant responses, relatively little is known in comparison to...

Inheritance Of Nematode Resistance

Genetic analysis of the inheritance of resistance to nematodes has been investigated widely for cyst nematode and RKN e.g., Cook and Evans, 1987 Roberts, 1992 Williamson and Kumar, 2006 . Genetic loci contributing to resistance have been characterized, and some of the major genes for nematode resistance have been cloned see below . Often resistance was initially identified in wild relatives of cultivated crops, then introgressed using various breeding procedures. In many cases while the...

Molecular Components Regulating Sas Responses

In dark-grown seedlings, phyA and phyB are cytosolic, inactive proteins in the PrA and PrB forms that migrate to the nucleus upon light activation when they convert to PfrA and PfrB, respectively Quail, 2002 . Both Pfr formation and nuclear translocation are necessary for phyB signalling activity Huq et al., 2003 . In the nucleus PHYTOCHROME INTERACTING FACTOR 3 PIF3 , a basic-helix-loop-helix bHLH protein, binds preferentially to the Pfr forms of phyA and phyB Ni et al., 1998 . PIF3...

Bertrand Mattha Us

Contents of Volume 46 INCORPORATING ADVANCES IN PLANT PATHOLOGY Nitric Oxide and Plant Growth Promoting Rhizobacteria Common Features Influencing Root Growth and Development CELESTE MOLINA-FAVERO, CECILIA MONICA CREUS, MAR A LUCIANA LANTERI, NATALIA CORREA-ARAGUNDE, MARM CRISTINA LOMBARDO, CARLOS ALBERTO BARASSI AND LORENZO LAMATTINA How the Environment Regulates Root Architecture in Dicots MARIANA JOVANOVIC, VALERIE LEFEBVRE, PHILIPPE LAPORTE, SILVINA GONZALEZ-RIZZO, CHRISTINE...