摘要
在黄土半干旱地区，利用LI-6400便携式光合仪的Li-6400—02B红蓝光源设定从0～2000μmol／（m^2·s）的光强，通过人工控水的方法取得不同的水分梯度，对白榆的各生理生长参数的光响应规律进行研究，结果表明：光辐射强度和土壤含水量对白榆的净光合速率，蒸腾速率和水分利用效率有十分显著的影响。白榆光合速率Pn在土壤含水量为17．68％左右时达到最大，光合利用率在光强为1200～1600μmol／（m^2·s）时较高。蒸腾速率Tr在各水分梯度下随光强的增大有增大的趋势，水分利用效率WUE在土壤含水量为14．86％左右达到最大，在光强为8001500μmol／（m^2·s）时较高。因此．白榆生长的适宜水分条件为14．86％～17．68％，光强为1200～1500μmol／（m^2·s）时，光能和水分利用效率都较高。
Controlling soil moisture by men , under the simulated photosynthetic radiation （SPR） of portable photosynthesis system（LI-6400） , physiological index of Ulmus pumila was conducted in this study in a semi-arid region of loess plateaus. The result shows that photosynthetic rate （Pn）, transpiration rate （Tr） and water use efficiency of leaf（WUE） have clear threshold value response to soil moisture and photosynthetic active radiation. The soil water content and photosynthetic active radiation cause photosynthetic rate of Ulmus pumila highest is about 17.68% . Photosynthetic active radiation of keeping higher sunshine use efficiency under fitting soil water content is 1 200-1 600 μmol/（m^2·s） , transpiration rate is higher as higher photosynthetic active radiation under soil moisture. The soil water content cause water use efficiency highest is about 14.86%, keeping higher water use efficiency under fitting soil water content is 800-1 500 μmol/（m^2· s）. so the fitting soil water content management range of Ulmus pumila is about14.86% -17.68 %, photosynthetic active radiation cause higher sunshine use efficiency and water use efficiency of Ulmus pumila is 1 200-1 500 μmol/（m^2· s）.
出处
《水土保持研究》
CSCD
北大核心
2007年第2期92-94,共3页
Research of Soil and Water Conservation
基金
国家自然科学基金(30371172)
教育部科学技术研究重大项目(10407)项目内容
关键词
白榆
净光合速率
蒸腾速率
光响应
Ulrnus purnila
photosynthetic rate
transpiration rate
sunshine response
