AN ANALYSIS OF SHOOT MULTIPLICATION AND REJUVENATION OF CHINESE-FIR IN VITRO

Segments of stem cutting from 1-5-and 10-year-old Chinese fir (Cunninghamia lanceolata) were cultured in vitro on GN (NH4+:NO3-=1:2.86) medium containing BAP (0.75mg/l) and IBA (0.25mg/l).After four successive subculture lasted for one year,the results show that there is a great difference in yields of shoots and nursery stocks due to different ages of maternal plants of the explants.For example,an explant which was one year old obtained 170.3-445.7 shoots on average,including 78-194.9 efficient shoots.Among these shoots there were 11.1-25.1 shoots of 1 degree (advanced,able to be on subculture);36.1-87.9 shoots of 2 degree (moderate,able to be rooted) and 29.5-78.6 shoots of 3 degree (to be needed to subculture).And it is estimated that the yield of nursery stocks can reach 34.7 on average.With the increase of ages of maternal plants of the explants,the above data decreased.However,the yield of shoots per explant,5-and 10-year-old,was 4.1-234,3 because of an effect of rejuvenation in vitro as well as a great difference in shoot multiplication.Thus,there is a possibility in selecting rejuvenated cultures.Besides,this paper put forward a preliminary analysis on the effect of production of shoot multiplication.