Abstract
Drought stress is a major global issue limiting agricultural productivity. Plants respond to drought stress through a series of physiological, cellular, and molecular changes for survival. The regulation of water transport and photosynthesis play crucial roles in improving plants’ drought tolerance. Nitrogen (N, ammonium and nitrate) is an essential macronutrient for plants, and it can affect many aspects of plant growth and metabolic pathways, including water relations and photosynthesis. This review focuses on how drought stress affects water transport and photosynthesis, including the regulation of hydraulic conductance, aquaporin expression, and photosynthesis. It also discusses the cross talk between N, water transport, and drought stress in higher plants.
Highlights
Crop production is facing threats from both biotic and abiotic stresses
Our results demonstrated that ammonium nutrition enhanced drought tolerance in rice seedlings when compared with nitrate nutrition (Guo et al, 2007a; Li et al, 2009a), which is associated with the regulation of aquaporin expression
After 24 h of water stress treatment with polyethylene glycol (PEG) 6000, the expression and activity of aquaporins were enhanced in plants supplied with ammonium when compared with normal water treatment, whereas no increase was observed in plants supplied with nitrate (Ding et al, 2015, 2016b)
Summary
Drought stress is considered to be one of the most devastating abiotic stresses, and it decreases crop yield, in arid and semiarid areas (Chaves et al, 2003; Parry et al, 2007; Lambers et al, 2008). The decrease in yield varies from 13 to 94% in the investigated crops that were under drought stress (Farooq et al, 2009). Drought stress induces an array of physiological and biochemical adaptations of metabolism for survival by increasing the drought resistance through three strategies, namely, “drought escape,” “drought avoidance,” and “drought tolerance” (Morgan, 1984; Xu et al, 2010; Vilagrosa et al, 2012). Strategies of drought escape include reducing life span and inducing vegetative dormancy to escape severe drought stress (Geber and Dawson, 1990; Vilagrosa et al, 2012). Strategies of drought tolerance mainly include improving osmotic adjustment ability, increasing cell wall elasticity to maintain tissue turgidity, increasing antioxidant metabolism, increasing compatible solutes, and enhancing the resistance to xylem cavitation (Morgan, 1984)
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