摘要:
以小麦为供试植物,山西工矿区生黄土为供试土壤,进行了土壤中二氧化硫(SO2)与多环芳烃(PAHs)单一及复合污染对小麦种子萌发率及小麦幼苗株高、根伸长和地下生物量影响的研究,以期考察复合污染的生态毒性效应。结果表明,小麦种子萌发对SO2与PAHs单一及复合污染均不敏感;SO2和PAHs单一污染时,小麦幼苗的株高与根伸长均受到一定程度的影响,低浓度SO2或PAHs处理对小麦生长起促进作用,高浓度则为抑制作用;小麦幼苗株高与SO2浓度呈显著负相关(r=-0.954,P < 0.05),但与PAHs浓度的相关性不显著;SO2与PAHs复合污染条件下,对小麦幼苗株高或根伸长的联合作用多体现为协同作用,在低浓度情况下(SO2 < 500 mg·kg-1)表现为协同促进;当SO2达到500~1 000 mg·kg-1时,对小麦幼苗株高或根伸长的联合作用均体现为协同抑制。SO2和PAHs单一污染时,小麦幼苗地下生物量与SO2、PAHs浓度均为显著负相关(rPAHs=-0.953,rSO2=-0.916,P < 0.05);复合污染条件下,在SO2浓度为10 mg·kg-1时,对地下生物量的联合作用多体现协同促进作用;而在SO2浓度为1 000 mg·kg-1,PAHs为50~100 mg·kg-1时,对地下生物量的联合作用均体现为协同抑制作用。多元逐步回归分析进一步表明,SO2与PAHs复合污染条件下,小麦幼苗株高、根伸长都受到了SO2及PAHs的共同影响,而SO2是影响小麦幼苗地下生物量的主要因素。
Abstract:
Seed germination, plant height, root elongation and underground biomass of wheat seedlings in fresh mixed-loess soils contaminated by sulfur dioxide (SO2) and polycyclic aromatic hydrocarbons (PAHs) with different concentrations were studied to reveal the ecotoxical effects of combined pollution of SO2 and PAHs. The results indicated that seed germination was not sensitive to single or combined pollution of PAHs and SO2. Root elongation and plant height were affected by single pollution of PAHs or SO2 to different extents. Wheat seedlings growth was slightly improved at lower concentrations, while inhibited at higher concentrations. Plant height of wheat seedlings were correlated well with SO2 concentrations (r=-0.954, P < 0.05), but the correlation was not well with the concentrations of PAHs. Under combined pollution conditions, the joint action of SO2 and PAHs on plant height or root elongation reflected multiple synergism. Specifically, in the case of low concentration (SO2 < 500 mg·kg-1), it showed synergistic stimulation, while the concentration of SO2 ranged from 500~1 000 mg·kg-1, it showed synergistic inhibition. By single pollution of PAHs or SO2, underground biomass of wheat seedlings significantly correlated with concentrations of PAHs or SO2 (rPAHs=-0.953, rSO2=-0.916, P < 0.05). The combined effects of PAHs and SO2 on underground biomass of wheat seedlings showed synergistic stimulation when the concentration of SO2 was at 10 mg·kg-1. It was showed synergistic inhibition when the concentration of SO2 was up to 1 000 mg·kg-1 and the concentration of PAHs was up to 50~100 mg·kg-1. By using the stepwise regression method, it was showed that plant height or root elongation of wheat seedlings were subject to the combined effect of PAHs and SO2. Meanwhile, SO2 was the main factor which affected the underground biomass of wheat seedlings under combined pollution conditions.
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