孑遗植物四合木(Tetraenamongolica)迁地保护中的光合作用日变化特征与生理生态适应性

摘要

为了进一步廓清迁地保护条件下孑遗植物四合木（Tetraena mongolica）的光合生理生态适应性，在分析了瞬时光合效率的基础上，应用LI-6400光合作用测定系统测定了迁地保护试验区的四合木以及原生境伴生种白刺（Nitraria tangutorum）的光合作用日变化，并测定了其生长量。结果表明：四合木实生苗的生长南北冠幅大小依次为乌海四合木核心区实生苗（26.48 cm×27.26 cm）>鄂尔多斯实生苗（21.27 cm×21.75 cm）>阿拉善实生苗（19.25 cm×18.27 cm）。在原生境地乌海四合木核心区种植的实生苗与阿拉善实生苗之间的生长量存在显著差异（P≤0.01），与鄂尔多斯实生苗之间的生长量存在显著差异（P≤0.05）。迁地保护条件下四合木生实生苗植株叶片光合速率Pn日变化均呈“双峰”曲线。不同试验区四合木光合作用日变化（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。迁地保护四合木条件下原生境地栽培的四合木实生苗的光合速率>鄂尔多斯栽培的四合木实生苗的光合速率>阿拉善栽培的四合木实生苗。鉴此可以作进一步推论，孑遗濒危植物四合木从原生境地西鄂尔多斯核心区（乌海）东移进行迁地保护具有更高的生理生态适应性和生境适宜性。但完成“从种子到种子”进而实现“保存性和代表性”，最终实现四合木迁地保护的“保持性和防止性”，保持其遗传多样性和遗传稳定性，最终成功实现四合木的迁地保护仍有待作进一步探索和深入研究。%In order to further clarify the photosynthesis and physiological adaptability of relict plant Tetraena mongolica under the condition of ex-situ conservation, instantaneous photosynthetic efficiency is analyzed by applying the LI-6400 photosynthes measurement system and the T. mongolica in the ex-situ conservation area and the diurnal photosynthesis changes of Nitraria tangutorum as well as the growth are determined. The results show that:the growth of T. mongolica seedlings crown is in the order of the core area of Wuhai T. mongolica seedlings (26.48 cm×27.26 cm)>Ordos seedlings (21.27 cm×21.75 cm)>Alxa seedlings (19.25 cm×18.27 cm). There are significant differences (P≤0.01) in growth between the original habitat Alashan seedlings and the Wuhai T. mongolica in the core area planted and also there is a significant difference among the growth of Ordos seedlings (P≤0.05). Under the conditions of ex situ conservation, the photosynthetic rate of T. mongolica seedlings leaves shows diurnal variation of“bimodal” curve. T. mongolica diurnal variation of photosynthesis (Pn) in different test areas, transpiration rate(Tr), stomatal conductance(Gs), intercellular CO2 and concentration show a clear difference. Under the condition of ex-situ conservation, photosynthetic rate of T. mongolica in the original habitat>photosynthetic rate of Ordos T. mongolica seedlings>Alxa T. mongolica seedlings. Furthermore, relict plant T. mongolica, with a higher physiological habitat adaptability and eco-suitability, can be carried eastward from the former ex-situ conservation. But in order to realize “seed to seed” ex-situ to “conserve and represent”, and ultimately to achieve“retention and prevention”of T. mongolica ex situ conservation, the ultimate success of ex-situ conservation of T. mongolica remains to be continued to further research.