Seed Dispersion and Seed Bank Characteristics of Terminalia franchetii in Dry-hot Valley of Jinsha River

Abstract:

The seed dispersal pattern, spatial distribution characteristics and seed bank dynamics of Terminalia franchetii in Dry-hot Valley of Jinsha River were investigate by random sampling and follow-up survey. The seed dispersal pattern had obvious direction influenced by strong wind, and the dispersal distance was more than 1.6 times of tree height. There was significant difference in soil seed bank among the different community types, but the change trends were consistent during different time. The soil seed bank was relatively small in rainy season (June, August, and October), and it was gradually increased from December to April of next year. The canopy seed bank started to shed in October, and reached to peak in March of next year (more than 15% of seeds shedding), and then the seed shedding rate became slow again, and seed shedding rate was the lowest in June and July of next year. However, there were nearly 15% of seeds existed in the canopy until October of next year. In summary, the lack of seed sources should not be the reason of T. franchetii seedling regeneration failure, and it might be associated with other factors which influence the community natural regeneration, such as the quality of seeds and community environment. Simultaneously, T. franchetii soil seed bank was closely related to the shedding process of canopy seed bank. Canopy seeds shedding might be closely related to the climatic factors, and might be a positive correlation with wind power, and be a negative correlation with rainfall and relative humidity. This might be an adaptive characteristic to Dry-hot valley environment in a long time.

Key words:Jinsha River;Dry-hot valley;Terminalia franchetii;Seed bank;Climate