PLANT DROUGHT TOLERANCE: SOME GENETICS AND AGRONOMICS RELEVANT ASPECTS FOR BREEDING IN FORAGE SPECIES

Abstract

The agronomic effects of drought on forage species and grassland are related with productivity and pasture persistence. The water shortage produce a growth reduction caused by decreased turgor at cellular level, changes in membrane fluidity and composition, decrease of photosynthetic electron transport, changes in solute concentration and metabolism in general. Plants have developed several mechanisms for tolerate drought stress in additive action and synergy. They are the origin for morphological adaptations, which will give place to a stable acclimation for drought tolerance. In grasses, water stress produce decrease in leaf growth and the number of tillers, in white clover result in a severe reduction in stolon elongation. The roots architecture, mass and depth, for specie, in particular, can be determinant in its response to water stress. Reduction of soil water availability in pastures also produces changes in fertilizer use efficiency, nutritive value, incidence of pests and diseases, and grazing animals performance. Morphological modifications reduce water loss which are associated to changes in leaf anatomy as presence of trichomes, decrease of leaf area or loss of any leaves, change in position respect to radiation, increase of cuticle thickness and decrease of stomatal density. Leaves can modify cuticle thickness or compositions thanks to a phenotypic plasticity given for regulation of cutin pathway biosynthesis and transport of lipidic component to a leaf surface. The agronomic effects of drought on forage species and grassland are related with productivity and pasture persistence. The water shortage produce a growth reduction caused by decreased turgor at cellular level, changes in membrane fluidity and composition, decrease of photosynthetic electron transport, changes in solute concentration and metabolism in general. Plants have developed several mechanisms for tolerate drought stress in additive action and synergy. They are the origin for morphological adaptations, which will give place to a stable acclimation for drought tolerance. In grasses, water stress produce decrease in leaf growth and the number of tillers, in white clover result in a severe reduction in stolon elongation. The roots architecture, mass and depth, for specie, in particular, can be determinant in its response to water stress. Reduction of soil water availability in pastures also produces changes in fertilizer use efficiency, nutritive value, incidence of pests and diseases, and grazing animals performance. Morphological modifications reduce water loss which are associated to changes in leaf anatomy as presence of trichomes, decrease of leaf area or loss of any leaves, change in position respect to radiation, increase of cuticle thickness and decrease of stomatal density. Leaves can modify cuticle thickness or compositions thanks to a phenotypic plasticity given for regulation of cutin pathway biosynthesis and transport of lipidic component to a leaf surface. The agronomic effects of drought on forage species and grassland are related with productivity and pasture persistence. The water shortage produce a growth reduction caused by decreased turgor at cellular level, changes in membrane fluidity and composition, decrease of photosynthetic electron transport, changes in solute concentration and metabolism in general. Plants have developed several mechanisms for tolerate drought stress in additive action and synergy. They are the origin for morphological adaptations, which will give place to a stable acclimation for drought tolerance. In grasses, water stress produce decrease in leaf growth and the number of tillers, in white clover result in a severe reduction in stolon elongation. The roots architecture, mass and depth, for specie, in particular, can be determinant in its response to water stress. Reduction of soil water availability in pastures also produces changes in fertilizer use efficiency, nutritive value, incidence of pests and diseases, and grazing animals performance. Morphological modifications reduce water loss which are associated to changes in leaf anatomy as presence of trichomes, decrease of leaf area or loss of any leaves, change in position respect to radiation, increase of cuticle thickness and decrease of stomatal density. Leaves can modify cuticle thickness or compositions thanks to a phenotypic plasticity given for regulation of cutin pathway biosynthesis and transport of lipidic component to a leaf surface. The agronomic effects of drought on forage species and grassland are related with productivity and pasture persistence. The water shortage produce a growth reduction caused by decreased turgor at cellular level, changes in membrane fluidity and composition, decrease of photosynthetic electron transport, changes in solute concentration and metabolism in general. Plants have developed several mechanisms for tolerate drought stress in additive action and synergy. They are the origin for morphological adaptations, which will give place to a stable acclimation for drought tolerance. In grasses, water stress produce decrease in leaf growth and the number of tillers, in white clover result in a severe reduction in stolon elongation. The roots architecture, mass and depth, for specie, in particular, can be determinant in its response to water stress. Reduction of soil water availability in pastures also produces changes in fertilizer use efficiency, nutritive value, incidence of pests and diseases, and grazing animals performance. Morphological modifications reduce water loss which are associated to changes in leaf anatomy as presence of trichomes, decrease of leaf area or loss of any leaves, change in position respect to radiation, increase of cuticle thickness and decrease of stomatal density. Leaves can modify cuticle thickness or compositions thanks to a phenotypic plasticity given for regulation of cutin pathway biosynthesis and transport of lipidic component to a leaf surface.