Comparative Study On Salt-tolerance At Stage Of Seed Germination And Seedling Of 18 Perennial Grasses

The difference of salt-endurance at stages of seed germination and seedling was studied on 18 grasses through simulating salt stress. The results shown that: (1) Physiological index, such as relative germination percentage, relative germination potential, vigor index, germination index and salt-tolerance index at seed germanous of 18 grass were increased at low degree stress within 0.2-0.4% salt concentration, and were decreased when salt concentration was increasing, while radicle/embryo ratio had opposite changing. It indicated that low salt stress can promote the germination of seed, but high salt stress resulted in decreasing of seed vitality. The descent degrees have relation to different grasses. (2) At stage of seedling, Physiological index, such as the content of free Proline and cell membrane penetration were increased with the increasing salt concentration. Under the low salt concentration (0.3% or 0.6%) the increasing trend is unmarked, with the salt concentration increasing, the increasing trend became marked, which showed that the sensitivity of grasses to low salt stress (below 0.6%) is approach; and relative water content of leaves decrease with the increasing of salt concentration, and the decreasing trend became marked with high salt stress (0.9%), the changing degree have relation to the salt tolerance of grasses. (3) Under salt stress the changing range of different physiologic indexes have relation to different grasses, then the salt-tolerance of different grasses can be evaluated through the changing range of different physiologic indexes was evaluated under salt stress.By means of the physiologic indexes is evaluated synthetically and arranged ordering can obtain of seed germination and seedling respectively, and can obtain salt-tolerance and salt-tolerance ordering of all kinds grasses finally.