Abstract
Longchun 30, a new wheat variety, was used to investigate seedling growth, element absorption and antioxidant response under 150 mM NaCl and tea polyphenols (TP) (25 and 100 mg L− 1) treatments alone or in combination, thus revealing TP-alleviating mechanism on the salt damage to plants. 150 mM NaCl stress alone inhibited the seedling growth, increased sodium content and reactive oxygen species (ROS) accumulation, but reduced potassium (K) and calcium (Ca) levels at different culture times, thus resulting in the oxidative damage to the leaves. Even though TP treatment alone led to the significant increase of ROS generation, TP-treated leaves exhibited the reduction of relative electrical conductivity and no change of malondialdehyde content. Moreover, high TP concentration alone stimulated the seedling growth. In addition, the activities and gene expression of superoxide dismutase, catalase and peroxidase (POD) as well as diamine oxidase and polyamine oxidase were changed to different degrees due to NaCl or TP treatment alone. Further study showed that the presence of TP promoted the seedling growth, increased K+ and Ca2+ contents, and led to the reduction of ROS accumulation. Taken together, salinity-inhibitory effect on the growth of wheat seedlings might be associated with salt-induced imbalance of element content and the increase of oxidative damage resulting from ROS accumulation, while the application of TP effectively alleviated salinity-inhibitory effect on the seedling growth and improved the tolerance of wheat seedlings to salt environment, which might be associated with the increases of K+ and Ca2+ contents as well as the reduction of oxidative damage in the leaves of wheat seedlings under NaCl and TP treatment in combination.
Effects of Tea Polyphenols on the Activities of Antioxidant Enzymes and the Expression of Related Gene in the Leaves of Wheat Seedlings Under Salt Stress
