Kitoplus® and Melatonin Mitigate Drought Stress Effects and Enhance Stevioside and Rebaudioside-A Production in Stevia

Melatonin and growth stimulants play pivotal roles in the growth process and the production of specific metabolites in medicinal plants. This study aimed to evaluate the effects of melatonin and Kitoplus® on the secondary metabolites of Stevia under drought stress conditions, employing a factorial randomized complete block design experiment with three replications. The treatments included varying concentrations of melatonin (۰, ۷۵, and ۱۵۰ mg L-۱), Kitoplus® (control without Kitoplus®, and ۱%), and drought stress levels (irrigation at two soil moisture levels: full irrigation and ۵۰% of soil field capacity moisture). Melatonin and Kitoplus® were applied via foliar spray four times at ۲۰-day intervals. Following the final application, yield, antioxidant enzyme activities, and secondary metabolite levels were assessed for each sample. Under drought stress, treatments with melatonin and Kitoplus® significantly impacted the studied traits. Results indicated that increasing melatonin concentrations significantly increased fresh and dry weight and total carbohydrates in the treated plants. The highest catalase (CAT) and ascorbate peroxidase (APX) activities were observed in plants treated with melatonin at ۱۵۰ mg L-۱ and Kitoplus® at ۱%. Additionally, the maximum concentrations of Stevioside and Rebaudioside-A were detected in plants subjected to ۵۰% soil field capacity moisture combined with melatonin at ۱۵۰ mg L-۱ and Kitoplus® at ۱%.

کلیدواژه ها:

Kitoplus® ، Rebaudioside-A ، stevioside ، Total carbohydrates