The effects of arbuscular mycorrhizal fungus and water stress on some antioxidant enzymes activities and nutrients uptake of two citrus rootstocks

Water stress is the main cause for crop yield reduction in the majority of agricultural regions of the world because it affects almost all plant functions. The effects of Glomus mosseae on growth, nutrients uptake, and antioxidant enzymes of sour orange (Citrus aurantium) and rough lemon) Citrus jambheri) rootstocks were assessed in sterilized soil under greenhouse conditions. A three-factor experiment was set up in a completely randomized design with three replicates of each treatment. Treatments consisted of water stress at four levels (irrigation intervals of 2, 4, 6, and 8 days) and mycorrhizal treatments at two levels (inoculation with G. mosseae and non-mycorrhizal control). Mycorrhizal seedlings of two citrus rootstocks were successfully infected by G. mosseae. As water stress increased, root colonization, shoot dry weight, shoot N, P, Mn, Cu, and Fe uptake of two citrus rootstocks significantly decreased but shoot Zn uptake and the antioxidant enzymes [superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (G-POD) and ascorbate peroxidase (APX)] activities of two citrus rootstocks leaves increased. With inoculation of seedlings by G. mosseae compared with control, shoot dry weight, N and P uptake, and antioxidant enzymes activities increased. It may be concluded that mycorrhizal inoculation notably influenced shoot nutrients uptake and leaves antioxidant enzymes activities in citrus and an increase in these parameters alleviated water stress.