摘要:
设定对照(CK,即常规生长)、轻度干旱(T1)、湿土壤(T2)和水淹(T3)4个处理组,研究枫杨(Pterocaryastenoptera C.DC.)幼苗在不同土壤水分条件下的光合生理反应.研完显示不同土壤水分对枫杨幼苗叶片净光合速率、气孔导度、水分利用效率和光合色素含量等参数有不同影响.胁迫初期(25 d),植株的各项生理指标变化较小,T3净光舍速率Pn比对照下降了25.4，.50天后,Pn下降比例大小为T1(60.3，)>T3(47.8，)>T2(28.1，),随后趋于稳定;蒸腾速率Tr和气孔导度Gs的变化趋势基本一致,T2和T3与对照无显著差异,T1则显著低于对照;T1有较高的水分利用效率(WUE),以对抗干旱缺水的逆境.T3光合色素含量持续处于最低状态,T1则与对照总体没有显著差异.各组叶绿素与类胡萝卜素含量之比界于4.475～6.920之间波动.而叶绿素a与叶绿素b的含量之比界于2.518～3.216之间波动.本实验证实枫杨幼苗兼具一定的耐水淹和耐旱的能力,也表明枫杨树种可用于三峡库区消落带的植被恢复构建.
Abstract:
In an experiment reported in this paper, Pterocarya stenoptera C.DC.seedlings were subjected to 4 water condition treatments, i.e.control (CK, normal water condition), T1 (light drought stress), T2 (wet soil) and T3 (soil submersion), and their photosynthetic responses were investigated.The results showed that different soil water conditions influenced, to different extents, the net photosynthetic rate (Pn), stomatal conductance (Gs), water use efficiency (WUE) and photosynthetic pigment content of the P.stenoptera seedlings.In the early period of stress (25d) of T3, these indices changed little and only Pn decreased by 25.4% compared with the control.Pn decreased by 60.3%, 47.8% and 28.1% in T1, T3 and T2, respectively, after 50 days and appeared relatively stable thereafter.Tr and Gs showed a similar change trend in various treatments.T2 and T3 had no significant difference from the control in the two in-dices, while T1 was significantly lower than it.T1 kept high water use efficiency against the drought stress.T3 had the lowest content of photosynthetic pigment, while T1 did not differ from CK in the con-tent of chlorophylls and carotenoids as a whole.The ratio of chlorophylls to carotenoids ranged from 4.475 to 6.920 and the ratio of chlorophylls a to b varied from 2.518 to 3.216 in these treatments.The above re-sults proved that P.stenoptera, seedlings are fairly tolerant to both waterlogging and drought stress and that P.stenoptera, can be a candidate species in the construction of the protection vegetation system of the Three Gorges Reservoir Region.
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