The Responds Of Three Halophytic Species Seed Germination To Main Ecological Factors In Xinjiang

In this paper, seed germination ecology of three halophytes Salicornia europaea, Atriplex tatarica and Chenopodium iljinii was studied by using the seeds of the three species collected from saline desert in North Xinjiang, including the effects of temperature stress, salt stress and water stress on seed germination and germination recovery after seeds were transferred to distilled water.The seeds of all the three species could germinate under the temperature of 5-35℃. The results indicated that the optimal temperatures for seed germination of Salicornia europaea, Atriplex tatarica and Chenopodium iljinii are 30℃,25℃and 25℃respectively. Both lower temperature and higher temperature repress the germination of the three species. The responses of the seeds to NaCl concentration among the three species were very similar. Lower concentrations of NaCl less inhibit seed germination and when the salinity above a certain concentration, seed germination decreased with the increase of salinity. In the end, germination was completely inhibited. However, the salinities of inhibit germination were different among the three species. The seed of Salicornia europaea has the highest adaptability to salty environment, even a few seeds germinated under the 1.0 mol/L NaCl. The seed of Chenopodium iljinii was stimulated by NaCl in 0.1 mol/L, under such salt concentration the germination rate was 85%, higher than distilled water control. The inhibiting effect of water stress by soaking the seeds in PEG-6000 solution increased with osmotic potential, whereas the germination was lower than in NaCl solution at the same osmotic potential. After the stresses were relieved by transferring the seeds of the three species to distilled water, the seeds still germinated greatly. All the three species seeds have higher germination recovery percentage, which increases with concentration and osmotic potential of NaCl and PEG solutions. Atriplex tatarica was the most tolerant to drought, then followed Salicornia europaea and Chenopodium iljinii.The results showed that the seeds of the species are with well adapted mechanism to the saline environment and as well the seed germinations are tolerant to certain drought stress, however, the salt and drought stresses repress the seed germination in general. The depressed seeds by the adverse conditions would recover to germination once the stresses relieved during the proper season and suitable environment. The three species were very salt tolerant. The ability of seeds when the salt stress was decreased is one of the special adaptive strategies for them to inhabit the salt desert environment. This adaptive strategy help the populations of three species successfully survive and reproduce in the salt desert of Xinjiang.