毛白杨杂种无性系BL107光合和蒸腾特性研究

本文研究了光强和CO_2浓度对毛白杨杂种无性系BL107光合速率和蒸腾速率的影响,比较了毛白杨BL107与易县雌株及大官杨不同叶子光合特性和光合耗水量.结果表明BL107光合光补偿点为18μmol·m~(-2)·s~(-1),光饱和点为950μmol·m~(-2)·s~(-1).光饱和时光合速率为16.15μmol·m~(-2)·s~(-1),表观量子效率为0.033.蒸腾速率随光强增加而增大.增加CO_2浓度在一定范围内光合速率增加,在光强为1000μmol·m~(-2)·s~(-1),温度为25℃时,CO_2饱和点为650ppm,大于1000ppm产生抑制作用.CO_2饱和时光合速率为22.26μmol·m~(-2)·s~(-1).增加CO_2浓度会降低气孔导度和蒸腾速率,在100ppm气孔导度和蒸腾速率最大.BL107最大光合速率在第20片叶,易县雌株和大官杨在第10片叶,BL107光合速率随叶衰老在第20片叶前不降低,由于叶面积较大表现较高的总光合速率.光合耗水量与光合速率有关,BL107最低光合耗水量84、易县雌株113、大官杨139.大官杨、易县雌株表现随叶衰老光合耗水量增加,BL107则略有下降,老叶增加也不明显.

A Study on the Characteristics of Photosynthesis and Transpiration in Hybrid Aspen Leaves (BL107)

Photosynthesis and transpiration of hybrid aspen leaves in different light intensities and CO2 concentrations were measured. The photosynthetic rate and water use efficiency of hybrid aspen, Populus tomentosa f. yixianensis and P. dakuanensis leaves were also compared. Results showed, the photosynthetic light compensation point of mature hybrid aspen (BLl07) leaves was 18μmol·m-2·s-1, the light saturation point was 950μmol·m22·s-1. The photosynthetic rate under light saturation was 16.15μmol·m-2·s-1. The apparent quantum efficiency was 0.033. The transpiration rate increased with increasing light intensity. Increasing the CO2 concentration could increase the photosynthetic rate. The CO2 saturation point was 650 ppm, and CO2 inibition was 1 000 ppm at a light intensity of 1000μmol·m22·s-1, and an air temperature of 25℃. The photosynthetic rate at the CO2 saturation point was 22.26μmol·m22· s-1. The maximum transpiration rate and stomatal conductance was at the CO2 compensation point, i. e. 100ppm. Increasing CO2 concentration could decrease the transpiration rate and stomatal conductance. The leaves with the maximum photosynthetic rate of hybrid aspen (BL107) , P. tomentosa f. yixianensis and P, dakuanensis Hsu were the 20th, 10th and 10th leaf from top of seedlings, respectively. The leaves with maximum photosynthetic rates also had maximum water use efficiency. Water use efficiency of the leaves with maximum photosynthetic rates in hybrid aspen, P. iomentosa f. yixianensis and P .dakuanensis Hsu were 1/84, 1/113 and 1/139, respectively. The best variety for water use efficiency of whole seedlings was BLl07>P. tomentosa f. yixianensis> P. dakuanensis.