Comparative Study of the Priming Effect of Abscisic Acid on Tolerance to Saline and Alkaline Stresses in Rice Seedlings

Abstract

The plant hormone abscisic acid (ABA) regulates the plant response to environmental stress; therefore, ABA priming is an effective strategy for enhancing stress tolerance in rice. In this study, we investigated the priming effects of 1 and 5 µM ABA on the biochemical and physiological traits associated with seedling growth performance in two rice cultivars exposed to saline (100 mM NaCl) and alkaline (15 mM Na2CO3) stress via root drenching. ABA pretreatment effectively reduced damage in rice seedlings by mitigating the increases in Na+/K+ ratio, membrane injury, contents of Na+, malondialdehyde, hydrogen peroxide, and superoxide anion radical, and prevented reductions in K+ and total chlorophyll contents, and ROS-related enzyme activities in both cultivars under saline and alkaline stresses. Rice seedlings with ABA pretreatment under alkaline stress had a stronger ability to maintain ion homeostasis, eliminate ROS, and induce changes in endogenous ABA levels via the upregulation of OsHKT1;5, OsSOS1, OsNHX5, OsPOX1, OsCATA, OsNCED3, OsSalT, and OsWsi18 and downregulation of OsRbohA than under saline stress. The saline–alkaline (SA)-sensitive cultivar demonstrated greater sensitivity to the priming effect of ABA than that of the SA-tolerant cultivar under both stress conditions. These findings have implications for rice adaptation to SA soils.

Iris typhifolia Responses to Saline–Alkali Stress: Germination, Antioxidant Activity, Hormones, and Photosynthetic Performance

“…The MDA concentration can reflect the level of membrane lipid peroxidation and can thus indicate the degree of membrane damage under stress conditions [51]. It is usually enhanced with stress treatments [52,53]. In this study, the MDA concentration of I. typhifolia seeds exhibited a slight increase at T50, reaching its peak at T200.…”

“…In response to saline-alkali conditions, plants typically close their stomata, a process that reduces water loss and serves as a survival strategy [66]. A previous study illustrated that gs is the most crucial photosynthesis parameter under abiotic stress [53]. In this study, the gs values of I. typhifolia all declined under artificial saline-alkali stress (T50-200 for over 7 d).…”

Overexpression of Abscisic Acid Biosynthesis Gene OsNCED3 Enhances Survival Rate and Tolerance to Alkaline Stress in Rice Seedlings

“…Previous research has revealed that ABA serves as a key factor in improving the tolerance of rice seedlings to saline–alkaline stress, showing broad application prospects in agricultural practices and production [ 39 , 40 ]. However, issues such as high cost and photodecomposition limit the application.…”