Studies On The Drought Resistance And Saline-alkali Tolerant And Methods To Break Seed Dormancy Of Sophora Viciifolia

Based on investigation of vegetation in the Water Source Area of Danjiangkou Reservoir, several water and soil conservation plants, with high tolerance of drought, leanness and salinity, were selected preliminarily. Sophora viciifolia, a legume shrub, distributed widely in this area and were chosed to study in the purpose of promoting the vegetation rehabilitation of the Water Source Area. In this research, the hard characteristics, the resistance ability to drought-and-salinity of Sophora viciifolia seeds were studied, and also the effect of different pre-treatments on the seeds. The main results were as follow:A preliminary selection indicated that 69 plants from the flora have the ability to resist arid soil and can be used to water and soil conservation. Further correlation analysis of 19 populations and their environments in Xiaoqinghe valley by the method of DCCA, 20 species with strong tolerant of saline and alkaline were selected out, including Sophora davidii, Ziziphus jujuba var. spinosa, Vitex negundo. van cannabifolia, Coriaria nepalensis, Platycladus orientalis, Cudrania tricuspidata, Rosa cymosa, Lespedeza chinensis, Eulaliopsis binata and Carex sendaica.The hard seed coat was the constraint for imbibition and germination, and the rate of hard seed could reached to a level of 86.5%. Immersion in concentrated sulphuric acid for 30 minutes and abrasion between two sheets of sandpapers could break the physical dormancy of Sophora viciifolia seeds greatly. A higher vigor was observed in hard seeds than non-hard seeds.Sophora viciifolia seeds have strong tolerance of drought. The promotion of lower drought on seed germination and root growth of seedlings were observed in our experiments. Seeds treated with 150—200g/L concentration of PEG obtained the highest germination rate, the corrected germination index and the average root length, and 300g/L concentration made the lowest ones.Sophora viciifolia seeds had strong tolerance to salinity. The seed germination and seedlings growth did not be affected nearly when the 150mmol/L concentration of NaCl was used, and be inhibited greatly when 300mmol/L concentration used but with more than 30% seed germination rate. The root of seedlings was more sensitive to salinity than shoot.Sophora viciifolia seeds had strong tolerance to alkalinity. The seed germination and seedlings growth did not be affected nearly when the 20mmol/L concentration of Na₂CO₃ was used, and be hurted greatly when more than 30 mmol/L concentration used especially to roots which were fat, short and swollen. The root of seedlings was more sensitive to alkalinity than shoot, and 30 mmol/L was the critical value.