Plant responses to drought and rewatering

Abstract

Plants would be more vulnerable to water stress and thereafter rewatering or a cycled water environmental change, which occur more frequently under climatic change conditions in terms of the prediction scenarios. Effects of water stress on plants alone have been well-documented in many reports. However, the combined responses to drought and rewatering and its mechanism are relatively scant. As we known, plant growth, photosynthesis and stomatal aperture may be limited under water deficit, which would be regulated by physical and chemical signals. Under severe drought, while peroxidation may be provoked, the relevant antioxidant metabolism would be involved to annihilate the damage of reactive oxygen species. As rewatering, the recoveries of plant growth and photosynthesis would appear immediately through growing new plant parts, re-opening the stomata, and decreasing peroxidation; the recovery extents (reversely: pre-drought limitation) due to rewatering strongly depend on pre-drought intensity, duration and species. Understanding how plants response to episodic drought and watering pulse and the underlying mechanism is remarkably helpful to implement vegetation management practices in climatic changing.

Figure 1

Simplified representation of some response routes in plants subjected to drought and subsequent rewatering. Note: From bottom, stomatal conductance and net photosynthetic rate are reduced as plants were subjected to different extent drought stresses in which involve some signals such as ABA; photosynthetic apparatus may be damaged under severe/extreme drought, e.g., leading to declines in PSII photochemical efficiency and enhancing peroxidation. Plant growth rate would decrease gradually with water deficit. Following rewatering, the gas changes and plant growth may be recovered, to which the extent depends obviously on intensities of drought stress.