Study On The Enhancement Of Cold Resistance In Cucumber Seedlings By Exogenous GB

In this paper, we had researched the effect of GB on the cold resistance of cucumber seedlings and its mechanism. Furthermore, the changes of GB content in seedlings during the cold treatment were measured by HPLC.Exogenous GB could obviously improve cold resistance of seedlings. It is shown that when seedlings was treated by different concentration of GB through the root-absorbing, the survival rate, chlorophyll content and photosynthetic rate of seedlings were obviously higher than those of control, GB concentration of 5.0mmol/L was the best for promoting cold-resistance of the seedlings. Moreover, when the seedlings were treated by spraying leaves with GB, the cold-resistance of seedlings was also increased, in which, GB 25.0mmol/L was the best concentration, but at high concentration of GB ,50.0mmol/L would be toxic to seedlings.Cucumber seedlings were unable to synthesize detectable amount of GB under cold stress(6眑癈) or room temperature (20~26癈), and they could easily absorb exogenous GB. The amount of GB absorbed by the seedlings increased with concentration of GB concentrations in the range of 0~25.0mmol/L.Under cold stress, exogenous GB could reduce slowly the content of chlorophyll and increase of relative permeability of membrane, reduce the accumulation of MDA and proline, inhibit the reduction of SOD and CAT activities and increase the POD activityThe results above showed that exogenous GB may prevent lipid peroxidation of cell membrane, protect the integrity and stability of themembrane and enhance the cold resistance of cucumber seedling.