| As a perennial herb, Trichosanthes kirilowii Maxim have high economic values. Therefore, this article mainly study the effects of exogenous salicylic acid (SA) on Trichosanthes kirilowii Maxim under low temperature stress, then to filter out the Trichosanthes kirilowii Maxim cold resistance genotype in Sanmenxia and cold sensitive genotype in Anqing as the experimental materials, and research the affection of Exogenous SA that have different concentrations on physiological growth of Trichosanthes kirilowii Maxim, antioxidant enzyme activity, isozyme, AsA-GSH circulatory system, polyamine metabolism and so on in low temperature.1. Study the effects of exogenous SA on the membrane lipid peroxidation degree and antioxidant enzyme. The results show that, under the low temperature stress, T0group, their relative water content of leaves are decreased, while cell membrane permeability, proline, soluble protein content and protective enzymes increased. By using0.25-0.5mmol/L SA, the relative water content are reduced, the membrane permeability also decreased under the chilling injury. Under low temperature stress, the enzyme activity of SOD, POD, PPO, EST and CYT are increased, this shows that low temperature stress has a certain effect on the physiological action of Trichosanthes kirilowii Maxim, generate more active oxygen radicals, start its self-protecting mechanism, enhance the activity of protective enzyme in protective enzyme system and reduce the damage of cell membrane. However, spaying SA treatment group, the activity of various enzymes appeared different changes. This is probably demonstrated that SA induces plants to produce a series of physiological response reactions and reduce the damage effects in low temperature.2. Study the effect of exogenous SA on antioxidase of Trichosanth.es kirilowii Maxim. Results show that different SA treatments have obvious influences on five isozymes, but the reactions of these five isozymes are different. In general, the suitable concentration (0.25-0.5mmol/L) of SA treatment enhance the SOD, POD, PPO activity of Trichosanthes kirilowii Maxim in Sanmenxia while reduce the SOD, POD, PPO activity in Anqing. It also enhances CYT activity in Sanmenxia and EST activity in Anqing, While decrease EST activity of Sanmenxia varieties and CYT activity of Anqing varieties.3. Study the effect of exogenous SA on polyamine metabolism of Trichosanthes kirilowii Maxim. The result shows that under low temperature stress, Spm and Put content was increased first and then decreased, while Spd content was decreased first and then increased in Sanmenxia. The overall trend of Anqing in the polyamine content was similar with Sanmenxia. The suitable concentration of SA can obviously increase the content of Spm and Spd, thereby increasing the low temperature stress tolerance of Trichosanthes kirilowii Maxim. During the stress period, the activities of ADC were increased, while ODC activity decreased on the whole stress period in Sanmenxia, in contrast with the change trend of ADC activity. The trend of Anqing ADC activity in contrast with Sanmenxia, and the variation trend of ODC activity is similar to Sanmenxia. PAO activity was first increased and then decreased on the whole stress period, The changes of DAO activity and PAO activity in the similar. Through analysis of gray correlation, spraying SAhas a significant effect on Put content.4. Study the effect of exogenous SA on growth characteristics, antioxidant content and antioxidant enzyme activity of Trichosanthes kirilowii Maxim. The result showed that:The Trichosanthes kirilowii Maxim seedlings under low temperature stress, treatment group, chilling injury index, MDA content, H2O2content and APX activity increased significantly; DHA, GSH and GSSG content and the GR, MDHAR, DHAR activity rose at first and then increased again after a brief decline tendency; AsA content, AsA/DHA and GSH/GSSG ratio changed in the opposite trend in stress five days, indicating the differences of the two T. kirilowii cultivars in cold tolerance. Spraying suitable concentration of SA can reduces chilling injury index of plant, the MDA content, H2O2content of the cells and can maintain higher relative coordination and balance APX, GR, MDHAR and DHAR activity. Obtained by the analysis of membership function, SA can alleviate the effect of Trichosanthes kirilowii’s low temperature stress, but cannot eliminate the inhibitory effect of low temperature stress on the growth of Trichosanthes kirilowii Maxim, while high concentration of SA may even produces a new stress affection of Trichosanthes kirilowii Maxim.5. Prediction of Trichosanthes kirilowii Maxim in Chinese suitable area by using MaxEnt software. The results showed that Trichosanthes in our country have a wide adaptable range, high suitable area mainly distributed in Shanghai, Hebei, Shandong, Jiangsu, Henan, Anhui, Zhejiang, Fujian and other provinces... |
PDF Full Text Request