Effects Of PCBs And PAEs Pollution On Rape(Brassica Compestris)Growth And Their Accumulation In Rape Plants

In the study, effects of PCBs (PCB28、PCB52、PCB101、PCB118、PCB153、PCB180)and PAEs (DOP、DBP、DIBP) on seed germination, growth and residual quantity of rape (Brassica campestris) were investigated. The germination potential, germination rate, plant height, leaf length, leaf width, fresh weight, moisture content of the over ground part, photosynthetic rate (Pn), relative content of leaf chlorophyll(SPAD), chlorophyll content, vitamin C content and residual were studied. The main results are as follows:1. Germination rate and germination potential of rape-seed were seriously inhibited with the treatments of PCBs and PAEs. With the increasing concentration of soil receiving PCBs, added, the germination rate and germination potential firstly decreased, then slightly elevated, finally drastically reduced. Germination rate and germination potential were seriously repressed at the higher concentrations (≥1mg/kg) of PAEs. The impacts of PAEs on germination rate and germination potential of rapes were different. With the treatments of DOP and DIBP, there was no significantly impact on germination rate and germination potential of rape compared with the blank control, and there was significant impact when the concentration of DBP at lOmg/kg concentration.2. With the treatments of PCBs, there was no significant hurt on rape’s height, leaf length, leaf width and fresh weight of aboveground part, and even played a promoting role at some concentrations. There was also no markedly effect on moisture content of aboveground part with the treatments of PCBs. Under the non-lethal conditions (DOP≥100mg/kg, DBP≥50mg/kg, DIBP≥5mg/kg),PAEs promoted leaf length and width of rape, and had no marked impact on moisture content of aboveground part. In addition, PAEs significantly inhibited rape’s height and aboveground biomass at high concentrations.3. Effects of PCBs on photosynthetic rate (Pn), relative content of leaf chlorophyll (SPAD) and chlorophyll content were different, on the whole, all of them were repressed. Contents of chlorophyll were promoted at low concentrations (<0.05mg/kg), and were repressed at higher concentrations. Experimental results also indicated that PAEs had on significant effect on rape’s photosynthetic rate (Pn), relative content of leaf chlorophyll (SPAD) of rape. In addition, with the treatments of PAEs, there were gradual downward trends on the contents of chlorophyll. 4. The results revealed that influences of PCBs on the content of rape’s reducing vitamin C were complexity and irregularity. DOP and DBP could improve the content of vitamin C at low levels, and repress it at higher levels. DIBP inhibited rape’s vitamin C.5. There were positive correlations between the accumulated concentrations of PCBs and PAEs in rapes’ stems and leaves and the concentrations of soil receiving PCBs and PAEs. From the toxicity of PCBs to the rape aspect, the degree of toxicity was PCB28>PCB52> PCB101>PCB118> PCB153> PCB180. When the concentrations of PCB28, PCB52and PCB101exceeded0.05mg/kg,0.1mg/kg and O.lmg/kg, respectively, the accumulated concentrations in rapes’ stems and leaves were higher than the national standards (0.1mg/kg). On the toxicity of PAEs to rape side, the degree was DIBP> DBP> DOP. Compared to the blank control, the accumulated concentrations of DIBP, DBP and DOP significantly increased when the soil receiving concentrations exceeded0.5mg/kg,5mg/kg and50mg/kg, respectively.