镉胁迫对欧美杂交杨(Populus deltoides×Populus nigra)光合作用与生物量生产的影响

Effects of Cadmium on Photosynthetic Characters and Biomass Production of a Poplar(Populus deltoides×Populus nigra)

采用盆栽实验研究了生长在四川盆地典型Cd污染冲积土和紫色土上的欧美杂交杨(Populus deltoides×Populus nigra)对国家土壤环境质量标准中Cd浓度梯度(0、0.3、1.0、2.0 mg/kg)的光合响应和生物生产量。Cd处理显著降低紫色土上生长的杨树叶绿素a和叶绿素总量,增加气孔导度与胞间CO2浓度,增加凋落叶生物量,降低茎生物量、根生物量和单株总生物量。但是,Cd处理对冲积土上生长的杨树叶绿素特征、光合生理指标和生物量生产并无明显差异。尽管同一生长基质上不同Cd处理间杨树光合生理指标与生物量生产均有一定程度的影响,但紫色土上生长的杨树生理和生长特征均显著低于冲积土上生长的杨树。这些结果表明,自然条件国家土壤环境质量标准内,Cd污染并不对杨树生长构成较大威胁,而生长土壤基质的选择可能对杨树的栽培更为重要。这为Cd污染土壤区域城市森林建设和速生丰产林建设提供了一定的科学依据。

A pot-experiment was arranged to study the photosynthetic responses and biomass production of a hybrid poplar （Populus deltoides ）4 Populus nigra ） at different levels of cadmium contaminations （0, 0.3, 1.0, 2.0 mg/kg） based on the national quality standards of soil environment. The typical cadmium-polluted alluvial and purple soils in Sichuan basin were used for culti- vated base. Cadmium treatment decreased the contents of chlorophyll a and tmal chlorophyll, in- creased stoma conductance and internal CO2 concentration, enhanced litter biomass, declined stem biomass, root biomass and whole biomass of the poplar growing in purple soil. In contrast, there were few variations of chlorophyll characters, photosynthesis and biomass production among the cadmium treatments when the polar grew in alluvial soil. However, the photosynthetic characters and biomass production of poplar growing in purple soil were lower than those of poplar growing in alluvial soil. The results indicate that under the natural environment and within the national quality standards of soil environment, cadmium contamination has little effect on the growth of poplar, while the choice of soil texture may play an important role in poplar plantation. Such results can provide certain scientific data for poplar plantation.