Introduction
Biosphere’s continued exposure to abiotic stresses, for example, drought, salinity, extreme
temperatures, chemical toxicity, oxidative stress, etc., cause imbalances in the natural status
of the environment. Each year, stresses on arable plants in different parts of the world
disrupt agriculture and food supply with the final consequence - famine. Factors controlling
stress conditions alter the normal equilibrium, and lead to a series of morphological,
physiological, biochemical and molecular changes in plants, which adversely affect their
growth and productivity. The average yields from the major crop plants may reduce by
more than 50% owing to stresses. However, plants also have developed innate adaptations
to stress conditions with an array of biochemical and physiological interventions that
involves the function of many stress-associated genes. In this chapter, we aim at the stresses
related to water and the expression 'drought' which is derived from the agricultural context,
is used as equal to water stress throughout the article.
Water, comprising 80-90% of the biomass of non-woody plants, is the central molecule in
all physiological processes of plants by being the major medium for transporting
metabolites and nutrients. Drought is a situation that lowers plant water potential and
turgor to the extent that plants face difficulties in executing normal physiological
functions. However, a few groups of animals and a wide variety of plants are known for
their tolerance to desiccation during the adult stages of their life cycle. Though our
knowledge on plant’s drought tolerance is ancient, the modern scientific study of drought
tolerance started in 1702 with Anthony von Leeuwenhoek’s discovery of the survival of
rotifers without water for months.
IntroductionBiosphere’s continued exposure to abiotic stresses, for example, drought, salinity, extremetemperatures, chemical toxicity, oxidative stress, etc., cause imbalances in the natural statusof the environment. Each year, stresses on arable plants in different parts of the worlddisrupt agriculture and food supply with the final consequence - famine. Factors controllingstress conditions alter the normal equilibrium, and lead to a series of morphological,physiological, biochemical and molecular changes in plants, which adversely affect theirgrowth and productivity. The average yields from the major crop plants may reduce bymore than 50% owing to stresses. However, plants also have developed innate adaptationsto stress conditions with an array of biochemical and physiological interventions thatinvolves the function of many stress-associated genes. In this chapter, we aim at the stressesrelated to water and the expression 'drought' which is derived from the agricultural context,is used as equal to water stress throughout the article.Water, comprising 80-90% of the biomass of non-woody plants, is the central molecule inall physiological processes of plants by being the major medium for transportingmetabolites and nutrients. Drought is a situation that lowers plant water potential andturgor to the extent that plants face difficulties in executing normal physiologicalfunctions. However, a few groups of animals and a wide variety of plants are known fortheir tolerance to desiccation during the adult stages of their life cycle. Though ourknowledge on plant’s drought tolerance is ancient, the modern scientific study of droughttolerance started in 1702 with Anthony von Leeuwenhoek’s discovery of the survival ofrotifers without water for months.
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