高温和干旱对银杏光合作用、叶片中黄酮苷和萜类内酯含量的影响

Effects of high temperature and/or drought on growth and secondary metabolites in Ginkgo biloba leaves

为了探讨高温和干旱的相互作用对银杏(Ginkgobiloba)生长及叶内次生代谢物的影响,设干旱、高温(夜间30℃)和干旱+高温3个处理,测定了2年生银杏幼苗的生长指标、光合特性、叶片水势、气孔导度以及叶内黄酮苷和萜类内酯的含量。与对照(未经干旱或高温处理)相比,高温引起银杏叶片最大净光合速率降低,气孔导度和光补偿点增加;干旱处理后,银杏最大净光合速率、气孔导度和叶片水势均降低,但光补偿点以及叶片黄酮苷和萜类内酯含量增加,表观量子产量变化不明显。高温和干旱共同作用下,银杏光补偿点和呼吸速率增高,光饱和点显著降低,根冠干重比无统计学上显著变化,但总干重降低。上述结果说明干旱和高温降低了银杏对光的适应范围,银杏光能利用效率变低,气孔导度下降,最大净光合速率降低,呼吸作用增强,抑制了生长;干旱引起黄酮苷和萜类内酯含量增加的幅度大于高温。

Growth,leaf water potential,stomatal conductance,leaf photosynthesis(photosynthetic light response curve),and contents of flavonol glycoside,terpene lactone,starch and soluble sugar were investigated in saplings of two-year-old Ginkgo biloba subjected to drought,high night temperature(30 ℃)and drought*high night temperature,in order to determine effects of drought,high temperature and their interaction on these parameters.The results show that compared to saplings free from drought and high temperature in CK,the saplings under high temperature decreased in maximum net photosynthetic rate,leaf water potential and root/shoot ratio,but increased in stomatal conductance and light compensation point,and changes in light saturation point,flavonol glycoside and terpene lactone were not significant.Saplings subjected to drought got lower in maximum net photosynthetic rate,stomatal conductance and leaf water potential,but higher in light compensation,and remained almost unchanged in root/shoot ratio,apparent quantum yield and light saturation point.Under the interaction of high temperature and drought,the saplings rose in light compensation point and dark respiration rate,but fell markedly in light saturation point,and contents of flavonol glycoside and terpene lactone.Although there was no significant change in root/shoot ratio,the total dry weight per plant decreased.The findings suggest that drought and high temperature not only decreased the adaptability to light,light use efficiency,and stomatal conductance of the saplings,but increased dark respiration rate,thus resulting in inhibited growth.High temperature had greater impact on secondary metabolites than drought.