Adaptive Strategies Of The Three Halophytic Species In Xinjiang In Their Seed Germination And Early Seedling Growth Stage

The small leafy succulent shrubs Halocnemum strobilaceum, Kalidium capsicum and Kalidium foliatum occur in saline deserts in northwest China and they are dominant species in this area. Using seeds collected in Xinjiang, we studied the seed germination ecology of the three species. The research aspects include: (1) Effects of temperature, light on seed germination. (2) Effect of NaCl concentration on seed germination and germination recovery after seeds were transferred to distilled water, on radicle elongation and elolngation recovery after seedlings were transferred to distilled water. (3) Effect of cold stratification on dormancy-breaking of the three species and the on their tolerance to salt.The freshly matured seeds of H. strobilaceum, K. capsicum and K. foliatum have non-deep physiological dormancy. They needed 4, 4 and 6 weeks of cold stratification to break the dormancy, respectively. After the dormancy had been broken, the optimal condition for seed germination of H. strobilaceum was at 25-30°C in light, for germination of K. capsicum seeds was at 15-30°C in light or in darkness and for seed germination of K. foliatum was at 25°C in darkness.The responses of the seeds of the three species to NaCl concentration were very similar. Low concentrations of NaCl did not inhibit seed germination and when the salinity was above a certain concentration, seed germination decreased with the increase of salinity. In the end, germination was completely inhibited. However, the NaCl concentrations which start to inhibit seed germination and the salinities to completely inhibit germination were different for the three species. The NaCl concentrations which start to inhibit seed germination for H. strobilaceum, K. capsicum and K. foliatum were 0.4, 0.2 and 0.2 M NaCl, respectively. The salinities...