Drought Stress: Responses and Mechanism in Plants

Abstract

The function of water for plants is crucial, including playing the roles in metabolic reactions. The aims of this article are to give information on the effects of drought stress on plant morphology, physiology, and biochemistry, as well as mitigation methods in drought stress management for plant production. Plants manage drought stress using a mechanism, namely drought escape, drought avoidance and drought tolerance. Drought escape is the ability of plants to accelerate flowering or life cycle, drought avoidance is the ability of plants to reduce water loss and increase water absorption through morphological changes in the root system, drought tolerance is the plant adaptation to drought by changes in plant physiological and biochemical processes. Physiological changes that occur include closing the stomata and decreased photosynthesis. The biochemical responses include the synthesis of solute compounds as a form of osmotic adjustment in the cell called osmotic adjustment to reduce water loss from the cell. The biochemical indicators are the increased concentrations of abscisic acid (ABA), proline, and sugar (trehalose). ABA acts as a signal to stimulate stomatal closure to reduce the transpiration rate. Proline is an indicator of plants adapting to drought stress, playing a role in the osmotic adjustment of cells to retain in the cell. Trehalose is a compatible sugar acting as an osmoprotectant, it can maintain the integrity of cell membranes (water replacement) and form hydrogen bonds (water entrapment). Plants under drought stress conditions can adapt by making morphological, physiological, and biochemical responses by osmotic adjustment. These conditions need to be managed so that appropriate strategies and technologies are needed as mitigation measures.

Effect of Water Stress and Selenium Spraying on Vegetative and Yield Indicators of Garlic Allium sativum L.

“…Drought stress boosts the reduction in the net rate of photosynthesis and changes the metabolic carbon distribution, which ultimately leads to waste, energy dispersion, and a decline in yield [25]. The lack of water adversely affects cell division and differentiation and reduces the stabilization of CO 2 ; thus, the photosynthesis process would be reduced, and the accumulation of ROS may increase, all of which may result in a lack of plant production [26]. The results of Table (3) also showed significant superiority in the weight of bulb, number of cloves per bulb, and garlic bulb yield when plants were sprayed with a concentration of Se (20 mg.L -1 ) achieving the highest mean for (80.95 g.plant -1 ), (37.10 cloves.bulb -1 ), and ( 21.76 t.ha -1 ), respectively.…”

Growth Performance and Osmolyte Regulation of Drought-Stressed Walnut Plants Are Improved by Mycorrhiza

“…Osmolytes in osmoregulation create a more water-absorbent environment in plant cells, allowing them to withstand drought [39]. Moreover, small molecules of osmolytes including soluble carbohydrates, proteins, free amino acids, betaine, and proline have a neutral charge and are required for protective membranes and the denaturation of proteins as well as for osmotic potential and cell expansion under stress [39,40]. In the present study, glucose, fructose, betaine, and proline levels in leaves were increased under drought treatment, indicating that both inoculated and uninoculated walnuts actively accumulate osmolytes to resist drought.…”

Water for agriculture: more crop per drop

“…Here, we do not attempt to provide a full review on drought stress, because recent reviews are available (Dietz et al 2021;Pamungkas & Farid 2022). Rather, we will summarize options to improve the efficiency of water use for agricultural crop production, with or without irrigation.…”