Response Of Pyrus Betulaefolia Bunge Under Alkali Stress

Supported by national public welfare industry special funds "research on integration technology of severe saline-alkali soil vegetation restoration in the north of Shanxi province". The Pyrus betulaefolia Bunge is the object of this experiment conducted in a method of randomized groups in Taier nursery. The adaptive mechanism and influence of Pyrus betulaefolia Bunge under seven kinds of alkali stress was discussed from several aspects as growth status, the alkali harmsymptoms, activity of antioxidant enzymes (POD,SOD,CAT) and the levels of each elements in the cytosol of plant cells (Fe,Mg,Cu,Zn) in order to provide the basis for planting Pyrus betulaefolia Bunge on saline-alkali soil, mostly alkali soil, Several following aspects of this experiment were studied in this dissertation.I. The alkali harm symptoms of Pyrus betulaefolia Bunge showed that alkali pollution index increased with the increasing alkali concentration and the longstanding alkali stress.II. The plant height relative growth of Pyrus betulaefolia Bunge showed that the growth status of Pyrus betulaefolia Bunge was affected by alkali stress directly. The plant height relative growth of Pyrus betulaefolia Bunge was increased by the low concentration alkali stress, but reduced by the high concentration alkali stress increasingly.III. The activity of antioxidant enzymes (POD, SOD, CAT) of Pyrus betulaefolia Bunge showed that SOD, POD and CAT bioactive content in the cells of the seeding increased in varying degrees in order to protect the leaf membrane system from alkali stress. Comparing the content of superoxide dismutase(SOD), peroxidase(POD), catalase(CAT) in the cells of Pyrus betulaefolia Bunge, a inequality, SOD>CAT>POD, could be obtained. Particularly, the content of superoxide dismutase(SOD) order showed:root>stem>leaf; the content of peroxidase(POD) order showed:stem>leaf>root; the content of catalase(CAT) order showed:leaf>stem> root.IV. The pH value of soil would increase observably and the electrical conductivity would be reduced slightly with the concentration of alkali stress increasing. The pH values and the electrical conductivity values were different under variying concentration of alkali stress. The content of elements in the soil was affected by the alkali stress to varying degrees. The cintent of elements order showed:Mg>Fe>Zn>Cu.Ⅴ. The content order of elements(Cu, Mg, Zn, Fe) in the cells of Pyrus betulaefolia Bunge under varying concentration of alkali stress showed:Mg>Fe>Cu>Zn. To be more specific, the content of Fe order in the root, stem and leaf of Pyrus betulaefolia Bunge showed:root>leaf>stem; the content of Cu order showed:stem>root>leaf; the content of Mg order showed:leaf>stem>root; the content of Zn order showed:stem>leaf>root.