Exogenous hydrogen sulfide alleviates salt stress in wheat seedlings by decreasing Na + content

Hydrogen sulfide (H 2 S) is an important gaseous molecule in a number of plant developmental processes and stress responses. Triticum aestivum L. (LM 15) is a salt-sensitive wheat cultivar that was used here to examine the effect of exogenous H 2 S on seedling growth, Na + and K + concentration, and Na + transportation under NaCl stress. The results showed that pretreatment with 0.05 mM sodium hydrosulfide (NaHS), a H 2 S donor, for 12 h significantly alleviated the growth inhibition of wheat seedlings under 100 mM NaCl. In addition, pretreatment with NaHS decreased the Na + concentration, Na + /K + ratio, the selective absorption capacity for K + over Na + and Na + efflux ratio, and increased the selective transport capacity for K + over Na + under salt stress. Additional experiments with CaCl 2 (an inhibitor of nonselective cation channels—NSCCs), TEA + (an inhibitor of low affinity K + transporter) or amiloride (an inhibitor of salt overly sensitive 1—SOS1) showed that NSCCs and SOS1 were the major pathways by which H 2 S reduced Na + concentration in wheat seedlings. These results showed that exogenous H 2 S alleviated growth inhibition by maintaining a lower Na + concentration in wheat seedlings under NaCl stress via the regulation of NSCCs and SOS1 pathways.