Mechanistic Insights into Potassium-Conferred Drought Stress Tolerance in Cultivated and Tibetan Wild Barley: Differential Osmoregulation, Nutrient Retention, Secondary Metabolism and Antioxidative Defense Capacity

Abstract

Keeping the significance of potassium (K) nutrition in focus, this study explores the genotypic responses of two wild Tibetan barley genotypes (drought tolerant XZ5 and drought sensitive XZ54) and one drought tolerant barley cv. Tadmor, under the exposure of polyethylene glycol-induced drought stress. The results revealed that drought and K deprivation attenuated overall plant growth in all the tested genotypes; however, XZ5 was least affected due to its ability to retain K in its tissues which could be attributed to the smallest reductions of photosynthetic parameters, relative chlorophyll contents and the lowest Na+/K+ ratios in all treatments. Our results also indicate that higher H+/K+-ATPase activity (enhancement of 1.6 and 1.3-fold for shoot; 1.4 and 2.5-fold for root), higher shoot K+ (2 and 2.3-fold) and Ca2+ content (1.5 and 1.7-fold), better maintenance of turgor pressure by osmolyte accumulation and enhanced antioxidative performance to scavenge ROS, ultimately suppress lipid peroxidation (in shoots: 4% and 35%; in roots 4% and 20% less) and bestow higher tolerance to XZ5 against drought stress in comparison with Tadmor and XZ54, respectively. Conclusively, this study adds further evidence to support the concept that Tibetan wild barley genotypes that utilize K efficiently could serve as a valuable genetic resource for the provision of genes for improved K metabolism in addition to those for combating drought stress, thereby enabling the development of elite barley lines better tolerant of abiotic stresses.

How Does Stomatal Density and Residual Transpiration Contribute to Osmotic Stress Tolerance?

“…Wild barley ( Hordeum spontaneum ) is an ancestor of cultivated barley, which has evolved efficient mechanisms to survive in severe environmental conditions [ 111 , 112 ] and has a wide range of adaptability to drought, salinity, and extreme temperatures and stress conditions [ 113 , 114 ]. Wild wheat and barley genotypes generally have a better survival capacity when exposed to extreme saline and drought conditions when compared to cultivated wheat and barley.…”

Discovering the Potential Impact of Selenium to Alleviate Drought Stress in Barley (Hordeum Vulgare L.) via Physiological Interferences

“…The treatment with Se helped improve biomass in cereal seedlings in contrast to the untreated drought treatment (Cipriano et al, 2022). Additionally, Se treatment helped rescue of biochemical enzymes activity and increased the chlorophyll content (Zeeshan et al, 2021). Barley, a multipurpose crop used for human nourishment and animal fodder, has been domesticated since the early days and continues to play a critical role in modern farming, advancing research in genetics, physiology, pathology, biochemistry, and biotechnology (Harwood et al, 2019).…”

Endophyte Inoculation and Elevated Potassium Supply on Productivity, Growth and Physiological Parameters of Spring Barley (Hordeum vulgare L.) Genotypes over Contrasting Seasons

“…Appropriate timing of application is essential to ensure that plants have sufficient nutrients for growth and to maintain osmotic potential in their tissues [ 28 ]. This is crucial for proper water management through stomatal regulation [ 29 , 30 ]. Potassium is a basic element in helping plants overcome the effects of drought.…”

“…This study hypothesizes that potassium supplementation and S. indica inoculation significantly enhances the drought resilience and productivity of spring barley genotypes adapted to local conditions, as well as those originating from arid regions. While previous studies have explored the individual effects of potassium and endophytes on plant stress responses [ 14 , 15 , 21 , 22 , 28 , 29 , 30 , 31 ], their combined impact on various spring barley genotypes, particularly under field conditions, remains insufficiently understood. By investigating genotype-specific traits associated with drought resilience and evaluating the effects of these interventions on productivity and growth parameters, the study aims to offer insights into strategies for stabilizing crop production under non-standard climatic conditions.…”