Résumé
Objective:To explore the allelopathic effect of garlic volatiles on Angelica sinensis by studying the allelopathic effect of both living garlicand isolated garlic sprout volatiles on A. sinensis, and provide certain theoretical basis for Angelica garlic interplanting mode to alleviate the stress of continuous cropping A. sinensis. Method:Through the determination and analysis of the growth indexes and leaf protective enzyme system of A. sinensis，the adaptability of A. sinensis to continuous cropping stress and non-continuous cropping stress environment under the influence of the volatiles of living garlic and isolated garlic sprout as well as the mechanism of resistant growth and development were discussed. Result:The overall analysis showed that the growth index and leaf protective enzyme activity of isolated garlic sprout with alleloinductive treatment（DC2）under continuous cropping stress were increased by 17.51% and 48.34% respectively as compared with those under single cropping（CK1）. The growth index and leaf protective enzyme activity of angelica under continuous cropping and intercropping（LC2）were increased by 16.63% and 36.65% as compared with those under monocrop cropping（CK2）. Those indicated that the volatiles of isolated garlic sprout had more significant effect than those of live garlic on alleviating the stress of continuous cropping of A. sinensis. Conclusion:Regardless of the presence of continuous cropping obstacle，appropriate concentrations of living garlic and isolated garlic sprout volatiles had an allelopathic promoting effect on angelica root growth index and leaf protective enzyme activity，and the effect was more obvious in continuous cropping stress conditions，so intercropping garlic has a certain role in alleviating angelica's continuous cropping stress.
Résumé
Objective To study the physiological characteristics of Codonopsis Radix under drought stress; To reveal the physiological mechanism of Codonopsis Radix in response to drought stress. Methods Method of pot experiment was used to set up 4 water treatments: normal water supply, mild stress, moderate stress and severe stress. Through the determination of leaf relative water content, cell membrane permeability, osmotic adjustment contents and protective enzyme activity, the effects of drought stress on physiological characteristics of Codonopsis Radix were studied. Results With the drought stress increased, the chlorophyll a, total chlorophyll content and leaf relative water content of Codonopsis Radix decreased, but chlorophyll b had no obvious change; The conductivity increased first and then decreased; MDA contents increased first and then decreased and then increased; There was no significant change in the rate of superoxide anion production; POD and CAT activity increased; SOD had no significant change; The proline content increased first and then decreased; soluble sugar decreased; soluble protein had no significant change. Conclusion Under the condition of drought stress, by increasing the content of proline to regulate cell osmotic potential, Codonopsis Radixcan increase the antioxidant enzyme activity to reduce membrane lipid peroxidation damage to cells.
Résumé
Objective: To investigate the effect of NaCl stress on growth and physiological-biochemical characteristics of Stellaria dichotoma amdits mechanism. Methods: In this study, one-year-old S. dichotoma was cultivated in pot at four NaCl levels (0.2%, 0.3%, 0.4%, and 0.5%) and the plant growth parameters and physiological-biochemical characteristics were determined. Results: NaCl stress had no significant effect on S. dichotoma growth at 0.3% NaCl. However, NaCl stress significantly inhibited the growth of S. dichotoma at 0.4% NaCl or above, and this inhibition was greater at higher concentration. The activities of SOD, POD, and CAT increased first and then decreased as NaCl concentration increased; The content of MDA and proline significantly increased as NaCl concentration increased, while membrane permeability and soluble protein content significantly decreased as NaCl concentration increased. Conclusion: S. dichotoma has osmotic stress resistance ability and reactive oxygen scavenging capacity at light NaCl stress, which causes S. dichotoma growth no inhibited at a certain extent NaCl stress.