Assessment enhancing drought tolerance in henna (Lawsonia inermis L.) ecotypes through sodium nitroprusside foliar application

Drought is a major abiotic stress affecting plant growth and productivity worldwide. Henna (Lawsonia inermis L.) is an economically important plant species that is widely cultivated due to its natural dye properties and medicinal uses, and it is highly susceptible to drought stress, which limits its growth and development. This study was conducted with the aim of investigating the effect of foliar spraying of sodium nitroprusside (SNP) on the yield of henna ecotypes (Lawsonia inermis L.) under drought stress conditions in Shahdad-Iran. The experiment was conducted in the form of a split factorial design based on randomized complete block design (RCBD) in three replications. Three ecotypes of henna (Rudbar-e-Jonub, Shahdad, and Bam) were used as plant material. The findings showed that with the onset of drought, photosynthetic pigments, growth indices, net photosynthesis, and yield of dry matter of henna plant leaves decrease. However, when SNP spray treatment was applied, it significantly improved things like leaf area index, crop growth rate, net photosynthesis and leaf dry matter yield, especially when drought levels were at 25 and 50%. The natural water content of Shahdad genotype in henna plants showed the highest percentage increase in these measurements compared with other henna plant species. It can be concluded that SNP spray can increase the yield of henna plant under drought stress conditions.