Response To Seed Germination On Main Ecology Factors Of Four Species Of Salsola L. In Xinjiang

Seed germination and seedling growth are important development stages in the life cycle of plant. Adaptation to salinity in these stages may determine temporal and spatial distribution of halophytes on saline habitats. Due to heavy salinity stress in soil surface, seed germination plays an important role in adapting to salt environment. Salsola L., included in Chenopodiaceae, is distributed on salt desert and saltpan. Therefore, they not only can tolerate drought and leanness but also have terrible strong tolerance ability to saline habitats, and are one of the most important vegetation types.The paper integrated the effect of temperature, water and salt stress on the seed germination of four halophytes: Salsola nitraria, Salsola subcrassa, Salsola affilis and Salsola brachiataby simulation experiments in growth chamber. The results were as following:The optimal constant temperatures for S.nitraria, S.subcrassa, S.affilis and S.brachiata were 25℃, 20℃, 15℃and 20℃. It indicated that S.nitraria can germinate at higher temperature, but S.subcrassa, S.affilis and S.brachiata got higher germination percentage at lower temperature.A trend can be observed in four species of Salsola L. in saline and PEG solutions: the germination percentage and germination rate of both species decreased with decreasing water potential in all types of solutions. The lowest water potential of germination of respectively approached-7.2 MPa,-5.14 MPa,-7.2 MPa and -6.15 MPa on NaCl stress, and salsola subcrassa represented terrible strong tolerance to salinity; The lowest water potential of germination of four species of Salsola L were not exceed–2.26 MPa on PEG solutions and salsola nitraria represented terrible strong tolerance to water stress. NaCl and iso-osmotic PEG had inhibitory effect on the germination of all the seeds, and the inhibitory effects of PEG were greater than those of iso-osmotic NaCl. It displayed that the osmotic stress is the main factor that affects germination of halophyte. Compared to PEG stress, NaCl can accelerate seed germination. It suggested ion effect represented positive effect.Four species of Salsola L. can recovery germination fast when salinity stress was alleviated. And disclosed that hypersaline conditions can induce dormancy of these species. In the same water potential, the recovery percent in NaCl solutions were greater than that in PEG solutions. The percent germination, however, was not exceeding 20% in the PEG solution. It exposed the effect of osmotic stress on germination of the four species were greater than that of ion stress.The paper studied the characteristics of seed germination four species of Salsola L. It was significant in recovering vegetation and improving ecological environment.