Relationship between Endogenous ZT,ABA and Age of Chinese Fir as well as It’s Rejevenation by Tissue Culture

The change on contents of ZT, ABA and tannin in shoot of material trees and their cultures in Chinese Fir (Cunninghamia lanceolate) were analyzed. Results show: the contents of ABA and tanin were both positively correlated to tree age at all seasons. Yearly fluctuation of ABA content showed almost identical in shoots from 2,10 and over 20-year-old material trees, which was the highest in peak periods of shoot growing and the lowest in midsummer. According to ABA level, The peak period in spring was the best time for collecting materials for culture in vitro. ZT content had a marked rise while ABA level dropped dramatically in explants both from 2-and-lo-year-old material trees after 3-month original culture. Such changes were more striking in explant from 2-year-old material. After four successive subculture lasted for one year, the ZT content declined, but their difference was reduced between cultures from trees at different ages. At the same time ABA content increased again. The changes of their contents affected the capacity of shoot multiplication during culture in vitro.