Effect of sodium hydrosulfide on physicochemical characteristics and melatonin mediated stress mitigation in bitter gourd (Momordica charantia L.) grown under lead stress

Lead (Pb) is a toxic heavy metal that contaminates soil and water resources after its discharge from different industries. This research study was held to check the consequence of Pb stress and NaHS growth regulator on physicochemical features of Mamodica charantia. A pot experiment was conducted to determine the effect of NaHS (1 Mm and 1.5 Mm) for the screening of M. charantia exposed to severe Pb (500 ppm,1000 ppm and 2000 ppm) stress. Our results depicted that maximum growth of plants was recorded at 1.5 mM concentration, while inhibition was observed in the plants of M. charantia at highest concentration of lead chloride (2000 ppm). Significant positive change in agronomical structures of bitter melon like leaf, root, shoot, branches, root length and shoot length recorded at high concentration of NaHS growth regulator (1.5 mM). In case of lead stress study, plants show reduction in growth and development due to production of ROS species. ROS species reduced the concentration of divalent cations such Zn2+, Mn2+, Mg2+, Ca2+, and Fe2+ by restricting the flow of water. Leaves of M. charantia had lessen carotenoid and chlorophylls and enhanced activity of chlorophyllase in leaves. Bio-logical content of antioxidants (CAT and POD), Protein and Proline were found maximum in NaHS treated plants while minimum in stressed plants. Nutrient content of root and shoot (K, Na and Ca) and morphological char-acteristics also behaved differently on different concentration of NaHS and Pb stress. Here, we concluded that the application of NaHS under the exposure to Pb stress significantly improved physiological and biochemical structures of M. charantia.