南岭杉木人工林光合-蒸腾作用特征研究

Photosynthesis and Transpiration Characteristics of Chinese fir Plantation in Nanling Mountains,Guangdong Province

应用便携式光合作用系统Licor-6400观测了南岭杉木人工林林冠层不同高度叶片光合作用-蒸腾作用日进程.结果表明:(1)处于林冠不同高度(林冠顶部、林冠中部和林冠下部,下同)的杉木叶光合作用速率及其日进程变化特征均存在差异,其日平均光合速率为(4.81±0.23)μmol.m-2s-1;(2)位于林冠不同高度的杉木叶的蒸腾作用速率及其日进程变化亦存在差异,其日平均蒸腾速率为(1.48±0.07)mmol.m-2s-1;(3)不同高度的杉木叶水分利用效率(WUE)差异不显著(p=0.05),叶片日平均WUE为(3.41±0.19)μmol/mmol;林冠内不同高度光合有效辐射在该杉木人工林中并非限制因子.

With a Lieor-6400 portable photosynthetic system, this paper conducted an observation study in situ of a Chinese fir plantation （Cunninghamia lanceolata） in Nanling Mountains, Guangdong Province in order to determine the characteristics of photosynthesis, transpiration rate and water-use efficiency in its diurnal course at a canopy level. The following results are obtained： （1） the photosynthetic rates and variation characteristics of the diurnal course, of its leaves at different canopy heights, differ from one another to the heights, the daily average photosynthetic rate being 4.81± 0. 23μmol · m^- 2 s^-1; （2） the transpiration rates and variation characteristics of the diurnal course also differ to the heights, the daily average transpiration rate being 1. 48 ±0. 07 mmol · m^-2s^-1; and （3）the water-use efficiency （WUE） of its leaves at different canopy heights does not differ obviously （p = 0.05）, the daily average WUE being 3.41 ± 0. 19 μmol/mmol. Photosynthetic active radiation （PAR） at different canopy heights is not a finite factor in the study of this plantation.