Supplementation of potassium alleviates water stress‐induced changes in Sorghum bicolor L.

Abstract

This report discusses water stress-induced changes and their amelioration by added potassium in Sorghum bicolor L. Chlorophylls, carotenoids, and the activity of nitrogen metabolizing enzymes viz., nitrate reductase, alanine aminotransferase and aspartate aminotransferase were adversely affected under water stress and restricted irrigation. Osmotic as well as water stress trigger ROS production while potassium ameliorated these changes to some extent and increased the activity of SOD, CAT, APX, and GR and the contents of GSH and AsA. Water stress-induced changes ultimately reflecting on growth and yield parameters like plant height, biomass yield, grain yield, days to flowering, and days to maturity. Added potassium affected these parameters positively, both under normal and stress conditions, indicating the use of potassium as a tool for mitigating the water stress induced deleterious changes in sorghum to some extent by enhancing the nitrogen use efficiency and strengthening the enzymatic and non-enzymatic antioxidant components. The results obtained here exhibited similar trends in seedlings and plants raised in sand cultures and field conditions, making them more meaningful and comprehensible. | INTRODUCTIONInadequate water supply is one of the important factors that limit crop productivity and grain quality. The severity of water stress depends not only on the magnitude and duration of the stress, but also on the developmental stage of the plant at which the stress is imposed.Water stress not only modifies the morphology of a plant but also severely affects its metabolism (Khan et al., 1993;Ober et al., 1991;Saeed et al., 1997). Altered cellular metabolism in response to water stress results in reduced growth and crop yield because of excess production of ROS and damage to cell membranes, proteins, nucleic acids, and other components of the cell (Gill & Tuteja, 2010;Tambussi et al., 2000). Limited water supply affects physiological and biochemical processes in plants such as photosynthesis, enzyme activities, plant water relations, integrity of membranes, all in all resulting in metabolic dysfunctions (Abid et al., 2018;Gill & Tuteja, 2010). Water deficit induces the oxidative stress in plants by the excess production of reactive oxygen species (ROS), which have the potential to cause membrane dysfunction and the leakage of important cellular components like mineral ions, e.g. K + (Blokhina et al., 2003;Kapoor et al., 2020). Potassium (K) nutrition to plants stimulates root growth, which helps with the efficient absorption of soil water (Saxena, 1985). Potassium treatments improved dry matter and total nitrogen content in faba bean plants subjected to restricted water supply during the post flowering period, probably by promoting growth and not by enhancing the nitrogen fixation efficiency (Kurdali et al., 2002). K availability to plants was reported to be related to soil water content, which highly influenced the mass flow and diffusion rates of K in soils (Doussan et al., 2003).

Differential activity of wheat antioxidant defense system and alterations in the accumulation of osmolytes at different developmental stages as influenced by marigold (Tagetes erecta L.) leachates

“…Proteases mitigate this process by degradation of damaged, denatured proteins, remobilizing amino acids and generating molecules involved in signal transduction ( D’Ippólito et al., 2021 ). The upregulation of protease activity in plants facing extreme environments has been reported earlier as well ( Ahanger et al., 2020 ; Tittal et al., 2020 ).…”

The role of WRKY transcription factors in exogenous potassium (K+) response to NaCl stress in Tamarix ramosissima

“…High salt content in soil hinders K + absorption due to competition with Na + , leading to a decrease in the K + /Na + ratio, which results in excessive Na + in plants, inhibiting growth and potentially causing plant death ( Shabala and Cuin, 2008 ; Wang et al, 2019 ). Plant enrichment with K + can enhance their water status, biomass, and salt tolerance ( Tittal et al, 2021 ; Johnson et al, 2022 ). Under salt stress, the Na + content in plants greatly exceeds K + levels ( Chakraborty et al, 2016 ).…”

Chemical activation of Arabidopsis SnRK2.6 by pladienolide B

“…[17][18][19][20] Besides stomatal regulation, potassium has an ameliorative effect in osmotic stress, which is crucial for maintaining water balance. [21][22][23] Manipulating the activity of group III SnRK2s may therefore offer a viable option to regulate ABA signaling pathways and modulate abiotic stress responses in plants. Furthermore, since group III SnRK2s are also involved in various ABA-independent signaling pathways, 24,25 manipulation of group III SnRK2s might also be used for the activation of these other pathways.…”