The Characteristics Of Seed Germination And The Effect Of Light On Seedling Growth Of Tetracentron Sinense Oliv

Seed germination and seedling emergence are the most vulnerable and crucial stages in the life history of plant. In order to approach the mechanisms of the barrier on the natural population regeneration of endangered plant Tetracentron sinense Oliv, we studied seed germination and seedlings emergence. Seed germination, germination percentage and germination index of of Tetracentron sinense were determined by the influences of temperature, light, storage condition, and litter layer. The seedlings were cultivated in different light levels (full sunlight, 50%and10% of full sunlight) and their relative growth yield of stem, root and leaf, the leaf differentiation, mortality, chlorophyll fluorescence parameter were investigated and analyzed. The results showed that:1. Tetracentron sinense seed can germinate in a wide range of temperatures (10~30℃). At 30℃, the seed germinated rapidly after incubation for 9d, the high temperature can promote the germination of seed, but as the low light(50Lux), the germination percentage(GP) was low. At 10℃and 5℃, as the temperature was too low, although the light was ample and, the seeds did not germinate. Seeds had a high germination percentage at the end of the germination test at 30℃(D)/20℃(N), 25℃(D)/15℃(N), 20℃(D)/10℃(N), GPs were 87.6%,86.6%,89.3%. The reaction of the seed germination to light is different at different temperatures.2. The seed vigour did not change under the same storage condition(5℃-dry, 5℃-wet, 10℃-dry, 10℃-wet, room) during the three months period, germination percentage was no significant difference among these five storage conditions. After analyzing three conditions of germination percentage, germination index and livability of seedling, we found that 5℃-dry is the most suitable storage condition.3. Litter depth were 0㎝,1㎝ and 2㎝, the seeds could germinate. The 0㎝ depth of litter had the highest germination percentage, that was 61.7%. Under the conditions of 4㎝,6㎝ depth of litter and full litter, there had no seedling appeared. It did not mean seeds could not germinate under the three conditions, but with the increase of litter depth from 2 to 6㎝, longer and longer time was needed to emerge of seedlings. 4. One-month seedlings had the lower mortality and the higher leaf differentiation than another light conditions under 50% of full sunlight. Seedling growth was inhibited under full sunlight and the rate of seedling growth was also low under 10% of full sunlight. Seven-months seedlings gradually died under 10% of full sunlight among two months. The seedling growth had a good condition under 100% and 50% of full sunlight, and five months later the Fv/Fm were determined, their Fv/Fm were among 0.8~0.84, indicating photoinhibition did not happen.We conclude that the litter layer has a significant effect on seed germination, and different seedling growth stages need different light conditions. The one-year seedling has a low rate of growth and is very weak which decrease the population regeneration of Tetracentron sinense.