Effects of Copper Heavy Metal and Interaction With Nitric Oxide on Growth Parameters, Photosynthetic Pigment, Soluble Carbohydrate Content and Antioxidant Enzymes in Portulaca oleracea L.

Abstract Copper is one of the heavy metal in plant that causes toxicity at high concentration via producing reactive oxygen species. Nitric oxide can protect cells from oxidative stress produce by reactive oxygen species. Effect of different concentrations of copper (1000, 1500 and 2000 μM) and interaction with nitric oxide (100 and 150 μM) were studied on growth parameters (shoot and root length) and some physiological factors (chlorophyll a, chlorophyll b, soluble carbohydrate), antioxidant enzymes (catalase, peroxidase and ascorbate peroxidase) in Portulaca oleracea L. For this purpose, an experiment was done in complete block random design with three replications under pot condition. Our result showed that nitric oxide treatment increased shoot and root length, shoot and root fresh weight as well as chlorophyll a and b content under copper stress. Therefore, in stressed plants treated with nitric oxide growth parameter improved and damage to pigments decreased. Copper stress did not affect soluble carbohydrate and increased antioxidant enzyme activity but nitric oxide increased soluble carbohydrate content and decreased antioxidant enzyme activity with exception of catalase and peroxidase. Pre-treatment with nitric oxide had protective role under copper treatment stress with interaction with ROS and photosynthetic pigments.