| Effects of extraneous spermidine on antioxidant enzyme activities and other physiological characteristics of pumpkin seedlings under osmotic stress |
|
View Fulltext View/Add Comment Download reader |
| |
| DOI：10.7606/j.issn.1000-7601.2017.04.39 |
| Key Words: pumpkin seedling spermidine osmotic stress osmoregulation substance antioxidant enzyme |
|
| Hits: 1602 |
| Download times: 1142 |
| Abstract: |
| To explore the physiological responses of different concentrations of exogenous (Spd) on pumpkin seedlings under osmotic stress, the effects of extraneous spermidine with different concentrations on pumpkin seedlings growth, reactive oxygen metabolism, antioxidant enzyme activity and the content of non-enzymatic antioxidant and osmotic regulation substances were studied through sand culture method with pumpkin variety-Yinhui No.2 as research material and the water stress simulated by PEG. The results showed that exogenous Spd with concentration of 0.9、1.2 mmol·L-1 respectively increased the biomass of pumpkin seedlings by 43.40% and 36.69%. The accumulation rate of root O·2 and the accumulation of MDA decreased by 56.33% and 43.50%. application of exogenous Spd with concentrations of 0.6、0.9 mmol·L-1 induced to enhance the antioxidant enzyme activity in roots and leaves in varying degrees; especially when treated by 0.9 mmol·L-1 Spd, SOD and APX activity of roots and leaves were 2 times, 1.83 times and 5.47 times, 2.40 times those under osmotic stress; CAT and POD activity were respectively enhanced by 410.89% 300.50% and 331.18%, 276.25%. The Pro and soluble sugar in leaves were increased by 1.76 times and 1.71 times, and the accumulation of soluble protein reached 1.49 times those under osmotic stress, preserving higher osmotic buffering and regulating capacity. The contents of ASA and GSH in roots increased by 2.88 times and 2.41 times. Therefore, under osmotic stress, extraneous 0.9 mmol·L-1 Spd inhibited generation of ROS and alleviated the oxidative damage. Antioxidant activity response and ASA-GSH circulation protected the biological stability of membrane system. Content changes of regulating substance penetration maintained the osmotic balance of cells and the environment while increased the photosynthetic carbon assimilation and accumulation of protein, indicating that extraneous 0.9 mmol·L-1 Spd maintained the normal carbon and nitrogen metabolism of pumpkin seedlings under osmotic stress and alleviated the oxidative damage of pumpkin seedlings. |
|
|
|