Phytohormone-Mediated Stomatal Response, Escape and Quiescence Strategies in Plants under Flooding Stress

Abstract

Generally, flooding causes waterlogging or submergence stress which is considered as one of the most important abiotic factors that severely hinders plant growth and development. Plants might not complete their life cycle even in short duration of flooding. As biologically intelligent organisms, plants always try to resist or survive under such adverse circumstances by adapting a wide array of mechanisms including hormonal homeostasis. Under this mechanism, plants try to adapt through diverse morphological, physiological and molecular changes, including the closing of stomata, elongating of petioles, hollow stems or internodes, or maintaining minimum physiological activity to store energy to combat post-flooding stress and to continue normal growth and development. Mainly, ethylene, gibberellins (GA) and abscisic acid (ABA) are directly and/or indirectly involved in hormonal homeostasis mechanisms. Responses of specific genes or transcription factors or reactive oxygen species (ROS) maintain the equilibrium between stomatal opening and closing, which is one of the fastest responses in plants when encountering flooding stress conditions. In this review paper, the sequential steps of some of the hormone-dependent survival mechanisms of plants under flooding stress conditions have been critically discussed.

Differential Response of Sugar Beet to Long-Term Mild to Severe Salinity in a Soil–Pot Culture

“…Reports show that high salt stress accumulates ABA (abscisic acid) in various plants [97], such as Arabidopsis [98] and maize [99]. Thus we speculate, sugar beet plants may accumulate ABA which induces stomatal closure and leads to lower Gs and E under osmotic stress conditions [100,101]. Lower transpiration rate leads to a compromised value of WUE [102].…”

Waterlogging Causes Early Modification in the Physiological Performance, Carotenoids, Chlorophylls, Proline, and Soluble Sugars of Cucumber Plants

“…Since g s is responsive to almost all external and internal factors related to stress factors, it represents a highly integrative basis for the overall effect of waterlogging on photosynthetic parameters [9,22]. Previous research on g s reactions could be due to hypoxia stress-induced responses related to ethylene production which possibly caused stomatal closure [23,24,25]. The WUE, estimated by calculating A /g s , showed a decreasing quadratic trend in both waterlogged and non-waterlogged treated plants as g s increased and peaked roughly around the g s value of 0.37 mol·m −2 ·s −1 .…”

Molecular Mechanisms of the 1-Aminocyclopropane-1-Carboxylic Acid (ACC) Deaminase Producing Trichoderma asperellum MAP1 in Enhancing Wheat Tolerance to Waterlogging Stress

“…To our knowledge, there is no previous study on ACC deaminase-producing fungal endophytes for growth promotion and WS alleviation through bio-reduction of ET in wheat. WS can influence the molecular and biochemical prospects of plant growth and lead to morphological and physiological irregularities in plants ( Rauf et al, 2013b ; Bashar et al, 2019 ). It is reported that various endophytic fungi can act as external factories of phytohormones, enzymes, and secondary metabolites and therefore have an impact on growth attributes of respective mutant such as GA-deficient rice mutant ( Waito-C rice ) ( Sturz et al, 2000 ; Guo et al, 2015 ).…”