摘要:植物对光能的高效吸收、传递和转换机理是光合作用的核心。为了厘清西鄂尔多斯地区4种荒漠植物光合生理生态适应性和生境适宜性，运用LI-6800光合作用测定系统对四合木（Tetraena mongolica）、霸王（Sarcozygium xanthoxylon）、沙冬青（Ammopiptanthus mongolicus） 和白刺（Nitraria tangutorum）进行光合作用日变化进行了测定。研究结果表明：（1） 4种荒漠植物的光合作用日变化的净光合速率（Pn）、蒸腾速率（Tr）、气孔导度（Gs）和胞间CO₂浓度 （Ci） 均表现出明显的分异；（2） 净光合速率均呈"双峰"曲线的变化趋势，4种荒漠植物的净光合速率（Pn）依次排序为四合木（4.37μmol m^-2 s^-1） > 霸王 （3.58 μmol m^-2 s^-1） > 沙冬青 （2.63 μmol m^-2 s^-1） > 和白刺（2.26μmol m^-2 s^-1）。说明四合木和近缘种霸王比其他二种荒漠植物具有较强的光合生理生态适应性与生境适宜性；（3） 从影响光合作用的有关生理生态因子来看，净光合速率与气孔导度与蒸腾速率、水分利用效率呈现明显的正相关性，与微气象因子大气相对湿度（RH）的相关性不明显；（4） 水分因子是限制4种荒漠植物生长的重要因素之一。该研究以期为我国西北荒漠区珍稀濒危植物的保护提供案例借鉴与理论依据。



Abstract:The efficient mechanism of plant absorption, transmission and conversion of light energy are the core of photosynthesis. To clarify the photosynthetic adaptability and habitat suitability of four desert plants in Western Ordos, the LI-6800 photosynthesis system was used to measure diurnal variations in photosynthesis in four desert plants, namely, Tetraena mongolica Maxim, Zygophyllum xanthoxylum, Nitraria tangutorum, and Ammopiptanthus mongolicus in Western Ordos. The results showed that: (1) Significant differences existed in the net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs), and intercellular CO₂ concentration among the four desert plants. (2) Pn of the four plants showed a "bimodal" curve. The order of Pn among the four plants was as follows: T. mongolica (4.37 μmol m^-2 s^-1) > Z. xanthoxylum (3.58 μmol m^-2 s^-1) > A. mongolicus (2.63 μmol m^-2 s^-1) > N. tangutorum (2.26 μmol m^-2 s^-1); this indicated that T. mongolica and its relatives have stronger photosynthetic physiological adaptability than the other plants. (3) According to the physiological and ecological factors that affect photosynthesis, Pn has an obvious positive correlation with Gs, Tr, and water use efficiency, but not with relative humidity. (4) The moisture is an important limiting factor for the growth of the four desert plants. The aimed to provide a basis for the protection of desert plants in northwestern China.





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