The Effects of Temperature, Light and Moisture on the Seed Germination of Siphonostegia chinensis Benth

To explore the optimum temperature, light intensityand water conditions for seed germination of Siphonostegia chinensis Benth.,seed germination experiment were carried out under different temperatures（5/15, 10/20, 15/25, 20/30℃）, different light intensity（14h light/10h darkness, complete darkness）and different concentrations（0％, 5％, 10％, 15％, 20％）of PEG-6000 solution. In terms of concentration, 5% PEG was regarded as the low level, 10% and 15% as the medium level, and 20% as the high level. The results showed that (1) Germination rate, germination potential, and germination index were increased with the rise of temperature. In addition, seed germination was significantly higher under the dark conditions than that with the 14h light/10h darkness. (2) No seed germination occurred when the temperature was below 10/20 ºC at 14h light/10h darkness. (3) Under 14h light/10h darkness, the germination rate, germination potential and germination index first increased and then decreased with the increase of PEG concentration. The low concentration was more beneficial to the seed germination. (4) Under the condition of complete darkness, the germination rate, germination potential and germination index decline with fluctuation with the increase of PEG concentration. Seed germination of Siphonostegia chinensis Benth. was inhibited in high concentration of PEG.