Changes in Organic and Inorganic Osmolytes of Maize (Zea mays L.) by Sulfur Application Under Salt Stress Conditions

Abstract

Mineral nutrients have favourable potential in alleviation of salinity problem in plants. Sulfur has specific functions in regulating plant growth, metabolism, enzymatic reactions and osmolyte homeostasis in plants. Hence, an experiment was carried out to explore the role of sulfur in ameliorating salt toxicity in maize by changes in organic and inorganic osmolyte contents. A range of sulfur levels (40, 80 mM) were used to induce salinity tolerance in maize. Various treatments of salinity (25, 75 mM) were applied by using sodium chloride. Results revealed that glycine betaine, proline, total soluble sugars, total soluble proteins and total free amino acids contents were increased by applying salinity while the application of sulfur lowered the proline and increased other studied organic osmolyte contents in all studied maize organs (leaf, shoot, root). The maximum improvement in organic osmolyte contents were found at 40 mM sulfur, however, at 80 mM sulfur proline contents were reduced. Applied salinity increased leaf tissue concentration of Na+ and decreased that of K+, Ca2+, NO3-, PO43-, SO42- leading to a severely declined in K+/Na and Ca2+/Na+ ratio. However, application of sulfur reduced the Na+ contents and improved K+, Ca2+, NO3-, PO43-, SO42-, K+/Na+ and Ca2+/Na+ ratio in the salinity grown plants. Moreover, 40 mM level of sulfur was greatly effective in osmolyte homeostasis at all levels of salinity. This indicated that use of sulfur (40 mM) ameliorated the effect of salinity by changing organic and inorganic osmolyte contents in maize plants.

Salicylic acid ameliorates salinity tolerance in maize by regulation of phytohormones and osmolytes

“…The obtained results demonstrated that pre-soaking treatment of SA induced more accumulation in the proline levels in maize leaves. This finding was in agreement with other studies (Ahmad et al 2018, Sharma et al 2019. The enhancement in proline metabolism is correlated with the stress tolerance mechanism in plants under salinity (Ahmadi et al 2018).…”

“…The current investigation showed that salinity stress enhanced the TSS content in maize plants. This result has been reported in many investigations with maize plants (Riffat andAhmad 2018, El-Katony et al 2019). During the conditions of high drought or salinity, various sugar contents usually elevate even if there is a decrease in the assimilation of CO 2 (Sharma et al 2019).…”

“…In this regard, Sharma et al (2019) reported that the sig- Various abiotic stresses enhance the soluble protein accumulation in plants that may supply nitrogen storage for utilisation and support in osmotic adjustment (Ahmed et al 2019). The soluble proteins help in raising the level of nitrogen that enhances growth and development in plants under stress conditions (Riffat and Ahmad 2018). The current study showed an increase in TSP content with increasing NaCl level.…”

“…The obtained result indicated that salt stress-induced a noticeable enhancement in the proline level in maize plants. The elevation of proline observed in salt-treated plants indicates an adaptive strategy for the regulation of the transcript levels of salinity, stress proteins, subcellular structure stability, osmotic adjustment, and cellular adaptation to salinity stress, which are investigated by various studies (Riffat andAhmed 2018, Cai and. These results indicated that the improvement in proline content might be from the metabolic responses involved in the translocation pathway, which help in recognition of the different abiotic stresses to induce the physiological responses (Elhakem 2019, Sohag et al 2020).…”

“…Maize (Zea mays L.) is one of the essential cereal crops. Moreover, it is a fundamentally valuable global food crop (Riffat and Ahmad 2018). The plant is considered as a moderately salt-sensitive C4 species, with broad genotypic variability that permits its cultivation in an extensive range of soils, as well as below variable conditions of climate (El-Katony et al 2019).…”