Abstract
Drought and waterlogging seriously affect the growth of plants and are considered severe constraints on agricultural and forestry productivity; their frequency and degree have increased over time due to global climate change. The morphology, photosynthetic activity, antioxidant enzyme system and hormone levels of plants could change in response to water stress. The mechanisms of these changes are introduced in this review, along with research on key transcription factors and genes. Both drought and waterlogging stress similarly impact leaf morphology (such as wilting and crimping) and inhibit photosynthesis. The former affects the absorption and transportation mechanisms of plants, and the lack of water and nutrients inhibits the formation of chlorophyll, which leads to reduced photosynthetic capacity. Constitutive overexpression of 9-cis-epoxydioxygenase (NCED) and acetaldehyde dehydrogenase (ALDH), key enzymes in abscisic acid (ABA) biosynthesis, increases drought resistance. The latter forces leaf stomata to close in response to chemical signals, which are produced by the roots and transferred aboveground, affecting the absorption capacity of CO2, and reducing photosynthetic substrates. The root system produces adventitious roots and forms aerenchymal to adapt the stresses. Ethylene (ETH) is the main response hormone of plants to waterlogging stress, and is a member of the ERFVII subfamily, which includes response factors involved in hypoxia-induced gene expression, and responds to energy expenditure through anaerobic respiration. There are two potential adaptation mechanisms of plants (“static” or “escape”) through ETH-mediated gibberellin (GA) dynamic equilibrium to waterlogging stress in the present studies. Plant signal transduction pathways, after receiving stress stimulus signals as well as the regulatory mechanism of the subsequent synthesis of pyruvate decarboxylase (PDC) and alcohol dehydrogenase (ADH) enzymes to produce ethanol under a hypoxic environment caused by waterlogging, should be considered. This review provides a theoretical basis for plants to improve water stress tolerance and water-resistant breeding.
Highlights
Drought and waterlogging stress have seriously affected the growth of plants due to extreme climate change; these stresses are an important limiting factor for global agricultural and forestry productivity [1]
The response and adaptation mechanisms of plants have been the focus of Forests 2022, 13, 324 physiological and ecological research related to water stress
Ci increases or decreases with the deepening of stress, while the stomatal limit (Ls ) first increases and decreases. These results indicate that the decrease in photosynthetic rate (Pn) under drought stress is mainly caused by nonstomatal factors [74,75]
Summary
Drought and waterlogging stress have seriously affected the growth of plants due to extreme climate change; these stresses are an important limiting factor for global agricultural and forestry productivity [1]. A large number of stress response genes are activated through complex signal signal transduction networks and synthesize many functional proteins to improve the transduction networks and synthesize many functional proteins to improve the ability of ability of plants to resist water stress [8,9]. Based on the research results, this review discusses and compares the changes to to plant plant morphology, morphology, structure, structure, physiology physiology and and molecular molecular mechanisms mechanisms under under changes drought and waterlogging stress. These are important factors to understand plant reguladrought and waterlogging stress.
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