Effects of Modifiers on the Growth, Photosynthesis, and Antioxidant Enzymes of Cotton Under Cadmium Toxicity

摘要

The effects of four liquid modifiers (organic-inorganic composite modifier, inorganic polymer compound modifier, polyacrylate compound modifier, and organic polymer compound modifier) on plant growth, cadmium (Cd) content, photosynthetic parameters and antioxidant enzymes were studied in cotton (Xinluzao) under Cd stress (5 mg kg(-1)) in a barrel experiment. The results showed that the Cd treatment of soil increased Cd content in cotton and reduced plant height, net photosynthesis rate (Pn), chlorophyll fluorescence parameters, antioxidant enzyme activity, and biomass. However, the application of liquid modifiers alleviated Cd stress, increased plant biomass, and decreased Cd content in plant organs as well as Cd transport coefficients of the stem and cottonseed. At the same time, there was an increase in gas exchange, photosynthetic pigment content, superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) activity in cotton leaves, whereas malondialdehyde content (MDA) decreased. These results suggest a positive role of liquid modifiers in alleviating Cd stress in cotton, which was due to (1) significant reduction in Cd uptake of roots and Cd-transportation to leaves and (2) improvement in the antioxidant activity, which regulated the oxidants to a level under control, minimizing the oxidative damage in cotton.