Dang Q L, Lieffers V J, Rothwell R L, Macdonald S E
Department of Forest Science, University of Alberta, T6G 2H1, Edmonton, Alberta, Canada.
Oecologia. 1991 Nov;88(3):317-324. doi: 10.1007/BF00317573.
The diurnal patterns of twig xylem water potential, net photosynthesis rate, water use efficiency of photosynthesis, and stomatal and mesophyll conductance to CO in tamarack, black spruce and swamp birch growing in a natural peatland in central Alberta, Canada, were examined. The relationships of photosynthesis to other ccophysiological parameters were investigated. Data were collected on three days with different weather and soil moisture conditions in the 1988 growing season. Day 1 was clear and warm and the ground water table was 7 cm above the average peat surface. Day 2 was clear and hot. Day 3 was cloudy but warm. On day 2 and day 3, the water tables were in the normal range for that season. Major findings were: 1) Soil flooding depressed photosynthesis in tamarack and black spruce. 2) Swamp birch was better adapted to flooding than tamarack or black spruce. 3) The trees experienced water stress in the afternoons of the two days with lower water table. 4) Changes in photosynthesis of the three species were primarily affected by changes in mesophyll conductance (g) and the response of photosynthesis to changes in g was similar for all three species.
对生长在加拿大艾伯塔省中部天然泥炭地的落叶松、黑云杉和沼泽桦树枝木质部水势、净光合速率、光合水分利用效率以及气孔和叶肉对二氧化碳的导度的日变化模式进行了研究。研究了光合作用与其他生理参数之间的关系。在1988年生长季节中，于三天不同天气和土壤湿度条件下收集数据。第1天晴朗温暖，地下水位比泥炭平均表面高7厘米。第2天晴朗炎热。第3天多云但温暖。在第2天和第3天，地下水位处于该季节的正常范围内。主要研究结果如下：1）土壤淹水抑制了落叶松和黑云杉的光合作用。2）沼泽桦比落叶松或黑云杉更能适应淹水。3）在地下水位较低的两天下午，树木遭遇了水分胁迫。4）这三个物种光合作用的变化主要受叶肉导度（g）变化的影响，并且所有三个物种光合作用对g变化的响应相似。
