【摘要】 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...更多还原

【Abstract】 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.更多还原