关键词: 镉离子, 镉离子, 水丝蚓, 半致死浓度(LC₅₀), 超氧化物歧化酶(SOD), 过氧化氢酶(POD)

Abstract: This study aims to explore the salt and alkali resistance of different red-spotted stonecrops’seed and seedling, and provide theoretical basis for the application of landscape vegetation in saline area. Nine different concentrations of salt water and the distilled water (control) were set up to process the seeds of Sedum aizoon and Sedum spectabile Boreau, various seed germination parameters and seedling growth were observed. The results showed that seed germination parameters, root number and root length of seedling significantly declined with the increase of salt water solution concentration for both the two red-spotted stonecrops. At the same time, germination rate and uniformity significantly reduced. However, in low concentration salt stress (0.2%-0.4%), part of the germination parameters, seedling root number and root length were higher than those of the control, showing a certain catalytic role. The seeds of Sedum aizoon almost lost germination ability when salt water concentration was higher than 1.4%, while the germination rate was 20% when the concentration was 1.8% for Sedum spectabile Boreau. Through regression analysis, the salt tolerance threshold and limit value of Sedum aizoon seed were 0.92% and 1.76% respectively, 1.47% and 1.97% for Sedum spectabile Boreau. Both Sedum aizoon and Sedum spectabile Boreau seeds had strong ability to resist salt stress, by contrast, Sedum spectabile Boreau seed has much stronger resistance ability to salt stress.