Effects of Salicylic Acid Foliar Spray on Lead Stress Mitigation in Brassica juncea L.

Background. Heavy metal (HM) contamination has emerged as a pressing global concern, posing severe risks to all forms of life, including plants, animals, microorganisms, and aquatic ecosystems. The primary sources of HM pollution are various anthropogenic activities, such as industrial emissions, improper waste disposal, deforestation, urbanization, and overpopulation, as well as natural phenomena including volcanic eruptions. Lead (Pb) is a highly toxic HM, adversely affecting plant growth, development, and productivity. Method. This study evaluates the effect of salicylic acid (SA) foliar spray on Brassica juncea L. under lead stress (10 ppm and 30 ppm concentrations). Results. Lead stress significantly reduced root length (by 53-59%), chlorophyll content (chlorophyll a by 65-78%, chlorophyll b by 57-76%), and protein content (by 54-65%). However, salicylic acid application improved all parameters, including 24-30% increase in chlorophyll and 40% increase in protein content. Conclusion. The findings highlight salicylic acid’s protective role in enhancing plant resilience and its potential as a practical approach to manage HM stress in contaminated soils.