The effect of melatonin on yield, growth traits and some physiological parameters of hot pepper under drought stress conditions

Melatonin has different and important roles in many aspects of plant growth and development. Recently, it has been found that melatonin has antioxidant properties and plays a vital role in the processes of germination, maturation, aging, cell protection, and resistance to biotic and abiotic stresses. In this study, the effect of different concentrations of melatonin (۰, ۵۰, ۱۰۰, and ۲۰۰ μM) on yield, growth traits and some biochemical characteristics of hot pepper (Capsicum annuum) under different levels of deficit irrigation (irrigation after ۴۰, ۸۰ and ۱۲۰ mm of evaporation from a class A pan) was investigated. The split plot experiment was carried out in the form of a randomized complete block design with three replications. The results showed that the reduction of irrigation decreased the growth and yield of the plant and increased the content of proline and malondialdehyde. Application of melatonin at all irrigation levels improved the growth and performance of pepper in field conditions. Also, melatonin foliar application decreased the content of proline and malondialdehyde and increased chlorophyll and carotenoid compared to the control. The concentration of ۲۰۰ μM melatonin had a better effect on the growth and yield of pepper than other concentrations. Also, the effectiveness of the melatonin hormone was observed more at the irrigation level of ۱۲۰ mm of evaporation. In general, the results of this research showed that the use of melatonin (especially in concentrations of ۱۰۰ and ۲۰۰ μM) reduced the effects of drought stress in pepper plants by increasing the content of chlorophyll and reducing the accumulation of malondialdehyde and proline.

Keywords:

Antioxidant , Chlorophyll , Drought stress , Evaporation pan , آنتی اکسیدان , تشتک تبخیر , تنش خشکی , کلروفیل