Special issue in honour of Prof. Reto J. Strasser - Photosynthetic activity as assessed via chlorophyll a fluorescence suggests a role of potassium channels in root to shoot signaling

Abstract

Potassium is indispensable for plant growth. Recently, a role of K + channels has emerged in sensing and transducing stress and nutrient status. Tetraethylammonium (TEA +) is a specific blocker of K + transport and affects K + channel gene expression. Two barley varieties with contrasting salinity tolerance, and a chlorophyll bless mutant, were grown either in the presence of TEA + alone or combined with NaCl, at two different concentrations of external K + and Ca 2+ , and were analyzed nine days after germination. Chlorophyll a transients monitored via JIP-tests were used to evaluate the state of the photosynthetic machinery. In contrast to reported responses to K + deficiency, TEA + inhibited shoot growth while inducing root growth and increasing photosynthetic performance. Both TEA + and NaCl induced the appearance of negative K-bands in OJIP kinetics and an increase in PIABS, indicating a stimulation of photosynthesis by increased sink strength in the context of root to shoot signaling.

Potassium stimulates fruit sugar accumulation by increasing carbon flow in Citrus

“…Potassium (K), as one of the macronutrients of plants, is essential for the growth and development of plants (Voitsekhovskaja et al, 2020). K is usually present in plants as K + involved in numerous physiological processes, including regulation of photosynthesis, improvement of photoassimilate transport, increment of source carbohydrate synthesis, maintenance of cytoplasmic pH homeostasis (Reddy and Zhao, 2005; Oosterhuis et al, 2013; Wu et al, 2021).…”