科尔沁草原主要牧草冷蒿和差不嘎蒿的生理生态学特性与竞争机制

一日内冷蒿和差不嘎蒿的光合速率（Pn）、蒸腾速率（E）和水分利用效率（WUE）在早或晚出现了最高值，而其余时间则变化低缓，原因归结于沙地环境因子和植物内部因子的共同作用。冷蒿的Pn和WUE日均值高于差不嘎蒿，E的日均值却低于差不嘎蒿，说明冷蒿在干旱环境下具有较高的物质生产量和节约用水的能力。自然状态下冷蒿各生长季的水势（ψω）和充分膨胀时的渗透势（ψπ^100）远低于差不嘎蒿，水分相对亏缺（RWD）、束缚水含量（BWC)、缚水与自由水的比值（BWC／FWC）元高于差不嘎蒿，表明其具有更强的抗旱性；干旱和旱后复水条件下差不嘎蒿的RWD、BWC和BEW／FWC产生大幅度波动；长期极端干旱条件下两才RWD、EWC和ψω终极植相近；长期淹水对冷蒿生理过程的影响更大些。干旱使两种牧草蛋白质发生分解，脯氨酸和可溶性糖大量累,其中冷蒿的累积量远远超过差不嘎蒿，这种累积特征可能正是两种牧草竞争机制的本质所在。

Ecophysiological Characteristics and Their Competition Mechanism of the Two Dominant Grasses in Horqin Sandy Land: Artemisia halodendron and Artemisia frigida

It is revealed that the maximum Pn, E and WUE of the two concerned grasses appears at both dawn and dusk time, comparing to a slow variation at other time due to the co-action of sandy environment factors and the inter-factors of the grass. %A. halodendron% has a higher daily average Pn and WUE but lower daily average E than %A. frigida.% It suggests that %A. halodendron% has a relatively higher primary productivity and water saving capability in aridity situation. At natural conditions, %A. frigida% has mu...