Improvement of physio-biochemical attributes and mitigation of salinity stress by combined application of melatonin and silicon nanoparticles in Brassica oleracea var. botrytis

Abstract

Salinity is a significant abiotic stress in arid and semiarid areas, threatening global food security. This research explored the potential of silicon nanoparticles (Si-NPs) and Melatonin (MT) to alleviate salinity stress in Brassica oleracea var. botrytis. The study used varying Si-NPs concentrations viz. NP0 (distilled water), NP1 (50 mg/L), NP2 (100 mg/L), and NP3 (200 mg/L) and Melatonin following a completely randomized design (CRD). Salinity hindered the growth and phytochemical attributes of B. oleracea seedlings. However, applying Si-NPs and MT mitigated this stress. Maximum fresh root weight of seedlings was observed when seeds were primed with 80 mg/L Si-NPs under 200 mM salt concentration, and the highest root length was noted with 60 mg/L and 80 mg/L Si-NPs. Seeds primed with 40 and 80 mg/L Si-NPs displayed the highest leaf count in seedlings under 50- and 100-mM salt concentrations, respectively. At 200 mM salt concentration, 40 mg/L and 60 mg/L Si-NPs priming notably enhanced total chlorophyll contents. Relative chlorophyll contents significantly increased with Si-NPs priming of 40 mg/L, 60 mg/L, and 80 mg/L under varying salt solutions along with melatonin. Exposure to 200 mM Si-NPs led to enhanced superoxide dismutase production in plants compared to control. Si-NPs and MT supplementation notably elevated osmolyte levels in salt-stressed B. oleracea seedlings compared to other treatments. Hence, treatment of Si-NPs and MT might be effective against abiotic stress in B. oleracea. This study offers valuable insights for cultivating economically important crops in high salt-stressed agricultural lands.