不同杨树无性系光合作用与其抗旱能力的初步研究

不同杨树无性系光合作用与其抗旱能力的初步研究刘建伟，刘雅荣，王世绩（中国林业科学研究院林业研究所北京１０００９１）关键词杨树无性系，光合作用，水势补偿点，水分胁迫，抗旱在水分逆境的研究中，净光合速率的降低已成为显著的特征，针叶、阔叶树的种间变化曾有许...

RELATIONS BETWEEN THE NET PHOTOSYNTHESIS AND THEIR DROUGHT TOLERANCE IN SIX POPLAR CLONES

In order to test the drought tolerant ability,the six poplar clones were treated with PEG(mW 6000)solution at three osmotic potential levels(-0.4 MPa, -1.0MPa,-1.6MPa),and their net photosyathesis rates(Pn)were siudied in growth culture chamber. The results show that under -1.6MPa stress Popelys simonii,P.poplaris 36 and 44 kept more photosynthesis product accumulation until the second day, however,that of P.nigra,P.euramericane 25/86 and 28/86 decreased to consumption level since the first day.And also there was the same trend in Pn decline under -1.0 MPa stress.According to this significant difference in Pn of different clones under medium and severe water stress,the concept of water potential conpensation point of net photosynthesis rate(Pn=0)is determined as a indicator evaluating drought tolerance.Thus, the six poplar clones can be divided into two types:The former group in which the water potnetial compensation point appears later,has a higherability to drought tolerance,and the latter group has a lower drought tolerance since the Water potential compensation point appears earlier.This will be significantly important for early identificantion and selection of genetic variation in drought tolerance for poplar clones.