Effect of seed priming with sodium hydrosulfide (NaHS) on some physiological and anatomical parameters in maize plants under lead stress

Lead as an enormous pollutant in the environment affects the metabolic and physiological activities of living organisms, therefore, has attracted more attention in recent years. In this research, the effect of seed priming with sodium hydrosulfide (hydrogen sulfide donor) on growth parameters, total chlorophyll content, soluble sugars and total protein and anatomical index in maize plant under lead stress was investigated. For this purpose, maize seeds were soaked in sodium hydrosulfide (0.5 mM) for 12 hours. Seedlings were treated with Pb 2.5 mM after planting. The results showed that lead stress reduced growth parameters, total chlorophyll, soluble sugars and total protein contents, and in case of structural studies, increased thickness of root and vascular cylinders and size of root parenchymal and epidermal cells, and decreased the thickness of leaf and middle vein. Seed pretreatment with sodium hydrosulfide resulted in an improvement in growth parameters and increased total chlorophyll, soluble sugars, and total protein contents. Regarding the anatomical parameters, sodium hydrosulfide pretreatment, depending on the parameter type, could compensate anatomical factors that were affected by the Pb stress. According to the results, it seems that Pb stress has harmful effects on maize plant, and hydrogen sulfide as a signaling molecule in different ways could increase plant adaptation to stress conditions.