摘要
为了研究白桦和真桦对环境的适应性及对水分的调节能力,探讨两树种与适应干旱环境的生理学机制,选用1年生实生苗,采用LI-6400型光合仪,测试分析了光和速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)和水分利用效率(Wu)等生理指标的变化。试验结果显示:白桦的光合速率、气孔导度、蒸腾速率日变化呈"双峰"曲线,水分利用效率日变化呈"单峰"曲线;真桦的光合速率、气孔导度日变化呈"单峰"曲线,蒸腾速率和水分利用效率日变化呈"双峰"曲线。白桦的光合速率在8:00达到第一个峰值,10:00出现午休现象,在12:00出现第二个峰值;真桦在12:00出现峰值。白桦和真桦的蒸腾速率均表现为清晨最低。真桦的日平均光合速率、气孔导度、蒸腾速率和水分利用效率均高于白桦,真桦表现出高光合、高蒸腾、高水分利用效率的生理特性,其适宜干旱环境的能力要强于白桦。
An experiment was conducted to study the adaptability of one-year-old Betula platyphylla and Betula maximouicziana seedlings to dry enviroranent and their water adjustment abihties by the LI-6400 portable photosynthesis system, aiming to discuss the physiological mechanism of drought resistance of the two tree species. The photosynthetic rate, transpiration rate, stomatal conductance, and water use efficiency were measured and analysed. Result showed that the diurnal changes of photosynthetic rate, stomatal conductance, and transpiration rate of B. platyphylla seedlings exhibited double-peak curves, and the water use effciency displayed a single-peak curve; while the photosynthetic rate and stomatal conductance of B. maximowicziana seedlings presented single-peak curves, and the transpiration rate and water use efficiency manifested doable-peak curves. The first peak of photosynthetic rate of B. platyphylla seedlings was observed at 8 o＇ clock, midday depression phenomenon at 10 o＇ clock, and the second peak at 12 o＇ clock. The photosynthetic rates of B. platyphylla and B. maximowicziana seedlings all exhibited the lowest value in the early morning. The diurnal average values of photosynthetic rate, stomatal conductance, transpiration rate, and water use efficiency of B. maxirnowicziana seedlings were all higher than those of B. platyphylla seedlings. Therefore, the drought resistance of B. maximowicziana is stronger than that of B. platyphylla.
出处
《东北林业大学学报》
CAS
CSCD
北大核心
2009年第8期11-12,共2页
Journal of Northeast Forestry University
基金
哈尔滨市科学研究基金项目(2005AFXXJ019)
关键词
白桦
真桦
光合特性
生理指标
Betula platyphylla
Betula maximowicziana
Photosynthetic characteristics
Physiological indexes
