科尔沁沙地主要植物种的生理生态学特性

Physioecological characteristics of four dominant plant species in Kerqin sandy land.

对科尔沁沙地主要植物种小叶锦鸡儿、差不嘎蒿、冷蒿和杂交杨进行了光合和水分生理生态学特性的研究 .结果表明 ,小叶锦鸡儿、差不嘎蒿和杂交杨的光合速率在 6 0 0最高 ,至 8 0 0剧降 ,在 8 0 0～ 16 0 0内处于低水平 ,16 0 0以后有回升现象 ;冷蒿由于 6 0 0光合速率低 ,下降幅度较小 .一日内光合速率降低冷蒿在6 0 0～ 8 0 0、小叶锦鸡儿在 8 0 0～ 10 0 0、杂交杨和差不嘎蒿在 6 0 0～ 10 0 0以气孔限制为主 ,其余时间均以非气孔限制为主 .4种植物对干旱适应机制有所不同 ,其中小叶锦鸡儿和冷蒿蒸腾低、水势低、束缚水含量高、束缚水 /自由水比值大 ,自身潜在的抗旱性强 ;杂交杨虽然水势高 ,但在干旱时气孔导度大幅度降低使蒸腾降到较低水平 ,同时体内束缚水含量较高 ,束缚水 /自由水比值亦大 ;差不嘎蒿则为高蒸腾、高耗水 ,水分利用效率最低 ,抗旱性最差 .

The photosynthetic and water physioecological characteristics of four dominant species, Caragana microphylla,Artemisia halodendron,Artemisia frigida and Populus spp(a hybird),in Kerqin sandy land were compared.The photosynthesis rates of C.microphylla,A.halodendron, and Populus spp. reached highest at 600,rapidly fall at 800 ,remained at low level from 800 to 1600,then rose slowly after 1600.The photosynthesis rate of A.frigida was comparatively low at 600,so the range of declining speed was small.Diurnal photosynthesis rate of Artemisia frigida decreased at 600～800, C.microphylla at 800～1000, Populus spp and. A.halodendron at 600～ 1000 ,and was controlled by stomatal limitation;in rest time,it was controlled by non stomatal limitation.The four species also adapted different ways to resist drought stress. C.microphylla and A.frigida resisted drought stress through their low transpiration,low water potential and high ratio of bound water to free water(BW/FW); Populus spp.resisted drought stress through its rapid fall of stomatal conductivity to reduce its transpiration in spite of its high water potential and high BW/FW,while A.halodendron resisted drought stress weakly because of its high transpiration,high water consumption and low water use efficiency.