Role of foliar application of sulfur-containing compounds on maize (Zea mays L. var. Malka and hybrid DTC) under salt stress

Abstract

Soil salinity is one of the major abiotic stresses that drastically reduce crop yield worldwide. The problem of soil salinity is further aggravated when soil is depleted of essential major nutrients such as sulfur. Exogenous application of sulfur can ameliorate negative effects of salt stress on plants. Keeping this in view, a pot experiment was conducted to assess the effect of different sulfur-containing (SC) compounds on maize (Zea mays L. var. Malka and hybrid DTC) under salt stress. Two-week-old maize plants were subjected to two levels of salt (i.e., 0 and 90 mM NaCl) stress. After 2 weeks of salt stress application, plants were foliarly sprayed with different levels of SC compounds, i.e., control (non-spray), FeSO4 (10 mM), LiSO4 (10 mM), cysteine (20 mM) and mixture (in 1:1:2 ratio). Foliar application of SC compounds was performed twice (30 ml per pot each time) at 1-week-interval after salt stress application. Data of 7-week-old maize plants were collected for the determination of various growth and physicochemical parameters. Salt stress significantly decreased the growth of both maize genotypes. However, foliar application of different SC compounds significantly increased root and shoot biomass, length of root and shoot, relative water content (RWC% sprayed with mixture), total soluble proteins, total soluble sugars, ascorbic acid contents and total phenolics, while it (cysteine) decreased RWC (%) (in var. Malka), free proline, glycinebetaine (GB) and flavonoid contents. A differential response among the used SC compounds was observed in increasing the growth parameters of both maize genotypes. Overall, FeSO4 (10 mM), LiSO4 (10 mM) and mixture (in 1:1:2 ratio) were better than cysteine (20 mM) alone.