Potassium silicate improves cellular sodium homeostasis in wheat ( Triticum aestivum L.) cultivars differing in salt resistance

Abstract Salinity causes negative impacts on crops. We investigated the effect of potassium silicate (K 2 SiO 3 ) on the cytosolic uptake of sodium, [Na + ] cyt , in mesophyll protoplasts of wheat cultivars differing in salt sensitivity. Protoplasts were isolated enzymatically from 1‐week‐old wheat seedlings of cvs. S‐24 (salt tolerant) and Vinjett (salt sensitive). Protoplasts were loaded with the acetoxymethyl ester of SBFI, and subjected either to NaCl (0, 50, or 100 mM), followed by silicate (0 or 1 mM), or to silicate followed by NaCl. The sodium‐fluorescence changes were quantified by epi‐fluorescence microscopy. The cytosolic [Na + ] uptake was higher in cv. Vinjett (salt‐sensitive), than in cv. S24 (salt‐resistant), which remained low even at high NaCl level. When silicate was added to protoplasts before NaCl, a significant reduction in [Na + ] cyt was observed for both cultivars compared with no silicate, but silicate addition after NaCl was less effective. Silicate treatment during the cultivation also reduced [Na + ] cyt uptake. Pharmacological results indicate that Na + uptake in cv. Vinjett is mediated by both non‐selective, NSCCs, and K‐selective channels, but in cv. S‐24 mainly by NSCCs. Silicate might inhibit Na + influx by these channels. Our novel findings reveal that silicate reduces the cytosolic Na + uptake in wheat mesophyll cells and that the silicate impact depends on the cultivars' exploited Na + uptake proteins. Further investigation is needed to clarify the role of silicate on different Na + uptake channels.