论文部分内容阅读
以盆栽枫杨实生幼苗为研究对象,设置0mg/kg,10mg/kg,20mg/kg,50mg/kg和100mg/kg(以纯镉计)5个不同条件处理组,研究了枫杨实生苗的镉积累、生物量、光合色素含量及光合特性.结果发现,枫杨幼苗吸收的镉95.92%~96.70%积累在根部,最高干质量浓度达240.97mg/kg,地上部分干质量镉积累最高仅为9.24mg/kg;10mg/kg镉胁迫下枫杨幼苗仍能进行正常的生长和生物量生产,具有较强的生长适应性.4个镉胁迫组枫杨幼苗叶绿素a/b的比值与对照相比无显著差异,有助于枫杨对镉的耐受性,且枫杨幼苗净光合速率(Pn)在10mg/kg镉胁迫下依然具有对照的83.09%,仍能表现出较高的光合能力,具有一定的光合适应性;枫杨幼苗胞间CO2浓度(Ci)逐渐下降,气孔限制值(Ls)逐渐上升,可以确定其净光合速率(Pn)的下降主要是由气孔限制因素引起的.枫杨幼苗的Fv/Fm,Fv′/Fm′,ΦPSⅡ,ETR,qP及NPQ随着镉浓度的增加逐渐降低,尤其以Fv′/Fm′,ΦPSⅡ,ETR下降幅度大,说明枫杨Pn的下降与非气孔限制因素也有一定的关系,镉胁迫显著抑制了枫杨幼苗开放的反应中心捕获激发能的效率和电子传递速率.研究证实枫杨幼苗在10mg/kg镉胁迫下,虽然Pn有所下降但生物量生产仍然正常,具有较强的生长适应性和光合适应性,考虑到枫杨幼苗吸收的镉95%以上积累在根部,可以将之用于限制污染地区重金属镉向地下水层的渗透(植物固定).
The potted seedlings of Pterocarya stenoptera seedlings were used as research objects. Five different treatments including 0mg / kg, 10mg / kg, 20mg / kg, 50mg / kg and 100mg / kg Accumulation, biomass, photosynthetic pigment content and photosynthetic characteristics were studied.The results showed that 95.92% ~ 96.70% of the cadmium absorbed by Pterocarya stenoptera seedlings accumulated in the roots with the highest dry weight concentration of 240.97mg / kg and the highest accumulation of dry mass cadmium in shoots was only 9.24 mg / kg. Under the stress of 10 mg / kg cadmium, the seedlings of Populus simonii were still able to grow normally and produce biomass with strong growth adaptability. Compared with the control, the ratio of chlorophyll a / b The Pn of Pterocarya stenoptera seedlings was still 83.09% of the control under 10 mg / kg cadmium stress, which still showed higher photosynthetic capacity, (Ci) decreased gradually and the stomatal limitation value (Ls) increased gradually, which indicated that the decrease of Pn was mainly caused by the stomatal limitation. The Fv / Fm, Fv ’/ Fm’, ΦPSⅡ, ETR, qP and NPQ of young seedlings decreased with the increase of cadmium concentration, especially Fv ’, ΦPSⅡ and ETR decreased greatly, indicating that the decline of Pn of Pterocarya stenoptera also had a certain relationship with the non-stomatal limitation factors. Cadmium stress significantly inhibited the efficiency and electron transfer rate of capture excitation energy in the open reaction center The results showed that under the stress of 10mg / kg cadmium stress, the Pn of Populus simonii seedlings reduced the Pn, but the biomass production was still normal, and had strong growth adaptability and photosynthetic adaptability. Considering that more than 95% cadmium absorbed by Populus simonii seedlings accumulated At the root, it can be used to limit the infiltration of heavy metal cadmium into the groundwater layer (phytoremediation) in contaminated areas.