Exogenous melatonin confers drought stress by promoting plant growth, photosynthetic efficiency and antioxidant defense system of pea (Pisum sativum L.)

•Melatonin supplementation improved the water-holding capacity of pea plants.•Melatonin scavenges harmful ROS and helps maintain the cellular redox balance.•Melatonin enhanced the photosynthetic enzymes activity.•Melatonin application promoted plant growth and enhance yield in pea plants.