摘要
对分布于荒漠绿洲过渡带的柽柳(Tamarix ramosissima)和泡泡刺(Nitraria sphaerocarpa)光合和水分代谢特性进行了比较研究。结果表明,柽柳和泡泡刺:①净光合速率与环境因子响应具"光合下调"现象,其曲线符合Gaussmodel。②净光合速率最大值分别为20.2μmol CO2.m-2.s-1和23.8μmol CO2.m-2.s-1;光补偿点和饱和点为244.62μmol.m-2.s-1和1 180.31μmol.m-2.s-1,73.67μmol.m-2.s-1和1 467.85μmol.m-2.s-1。③净光合速率近似双峰型抛物线;光能利用效率单峰曲线;柽柳蒸腾速率和水分利用效率为单峰旗形,泡泡刺波浪型。④泡泡刺利用较高的净光合速率、蒸腾、水分利用效率,柽柳通过高光能利用效率来适应荒漠生态环境。因此,光抑制所导致的"光合下调"现象是柽柳和泡泡刺对水分胁迫所产生的保护性机制,反映了荒漠植物在与环境协同进化过程中的生态适应性;较低的水分利用效率是荒漠植物对其环境响应的普遍适应机理。
The photosynthesis and water metabolism of Tamarix ramosissima were studied in comparison with Nitraria sphaerocarpa at desert-oasis ecotone. Results are as follows： ①Responding to the environments, the net photosynthetic rate （Pn） exhibited so-called ＂photosynthetic descent＂ phenomenon and its curve was accorded with Gauss model. ②The respective maximum values of the net photosynthetic rate were 20.2 and 23.8 μmol CO2·m^-2·s^-1. The light compensation and saturation points of Pn were 244.62 and 1 180.31, 73.67 and 1 467.85 μmol·m^-2·s^-1 , and the CO2 compensation and saturation points were 27.3 and 670. 34, 65.89 and 643.5μmol CO2·m^-2·s^-1, respectively. Moreover, the optimum temperature were 35.79 and 35.75 ℃, and the optimum humidity were 17.05% and 14.60%, respectively. ③The curves of the net photosynthetic rates were both approximately accorded with double-peak parabola, whereas the light use efficiency （LUE） presented a unimodal curve. The curves of the transpiration rate （E） and water use efficiency（WUE） were unimodal banner shape for Tamarix ramosissima and wave shape for Nitraria sphaerocarpa. ④Employing relatively high Pn, E and WUE for Nitraria sphaerocarpa and high LUE for Tamarix rarnosissima, they adapted themselves to desert ecological environment. Therefore, the ＂photosynthetic descent＂ phenomenon induced by light restraint was exactly the photoprotection mechanism for Tamarix ramosissima and Nitraria sphaerocarpa in the possess of coping with water intimidation, which reflected the ecological adaptability of the desert plants in the course of cooperative evolution with the environment, and the lower WUE was the adaptability mechanism of the desert plants prevalent in response to the environment.
出处
《中国沙漠》
CSCD
北大核心
2009年第1期101-107,共7页
Journal of Desert Research
基金
国家自然科学基金项目(30771767)
中国科学院西部行动计划(二期
KZCX2-XB2-04-01)资助
关键词
荒漠绿洲过渡带
荒漠植物
光合作用
水分代谢
生态适应性
desert-oasis ecotone
desert plant
photosynthesis
water metabolism
ecological adaptability
