Abstract:

Carpinus putoensis is an endangered species native to Zhoushan Islands in eastern China. In this study, the biological characteristics, including flowering behavior, pollen viability, stigma receptivity, seed germination and seedling growth, were observed and measured to investigate reasons for the endangerment. The results showed that there were only 6 days overlaps of stigma receptivity with pollen dispersal. Male flowers were quite evenly arranged in different part of crown while female flowers were concentrated in the upper and central crown. Approximately 52.4% of pollens were able to germinate. The pollens survived for only around 6 days in room temperature, however, the pollen viability could last about 10 days after dry storage at 4 ℃. Moreover, there were significant differences in physiological traits of seed between individuals. The seeds of the original mother tree were much better than those of the F₁ generation. The seed could be well stored in mixture with perlite indoor. Additionally, the lateral buds would sprout out and become leading after the apex shoots were damaged. Seedlings grew fast in the period from mid-July to late August. Two-year-old seedlings had heights of 52-76 cm, caliper of 0.69-1.05 cm and the survival rates of 76.8%-100.0%.

Key words: Carpinus putoensis, reproductive mechanism, gene conservation