Effect of sodium nitroprusside (SNP) and salicylic acid on growth characteristics and stress resistance indices of the purslane (Portulaca oleracea L.) under salinity stress conditions

Salinity, as one of the most critical environmental stresses, adversely affects the growth and productivity of agricultural crops. This study aimed to investigate the impact of salicylic acid (SA) and sodium nitroprusside (SNP) applications on growth traits and mineral nutrient uptake in purslane (Portulaca oleracea L.) under salt stress. The research was conducted as a factorial experiment in a completely randomized design with three replications. Experimental treatments included three salinity levels (۰, ۲.۵, and ۵ dS/m induced by NaCl) and five foliar application treatments (control, ۰.۵ and ۱ mM SA, ۵۰ and ۱۰۰ mM SNP). The results indicated that severe salinity stress (۵ dS/m) significantly reduced plant height (۳۵%), shoot dry weight (۳۲%), root dry weight (۲۰%), flower number, and leaf nitrogen content (۳۲%). However, the application of SA and SNP partially mitigated the adverse effects of salinity. Specifically, ۱ mM SA exhibited the most pronounced improvement in growth parameters, mineral uptake, and photosynthetic content. The highest sodium (Na⁺) leaf-to-root ratio was observed under moderate salinity (۲.۵ dS/m) without foliar treatment. Under severe stress (۵ dS/m), the ۵۰ mM SNP treatment resulted in the highest chlorophyll a to b ratio (۲.۶۹). Additionally, the highest accumulation of Na⁺ and chloride (Cl⁻) in leaves and roots was recorded at ۵ dS/m salinity, while ۱ mM SA at the same salinity level showed the highest Cl⁻ leaf-to-root ratio. In conclusion, purslane demonstrated relative tolerance to salinity up to ۲.۵ dS/m, and Salicylic acid (۱ mM) is recommended to alleviate stress effects at higher NaCl concentrations.

کلیدواژه ها:

Environmental stress ، Foliar application ، Ion toxicity ، Portulaca oleracea (purslane) ، Sodium-to-potassium ratio (Na⁺/K⁺) ، تنش محیطی ، خرفه ، سمیت عناصر ، محلول پاشی ، نسبت سدیم به پتاسیم