多环芳烃对2种南方绿化树种生长的影响

Effects of PAHs Contamination on the Growth Of 2 Urban Afforestation Species

采用盆栽实验,研究了3种多环芳烃污染水平(重度L3:371.79 mg.kg-1)、(中度L2:186.35 mg.kg-1)、(轻度L1:77.79 mg.kg-1)下对1年生南方绿化树种广玉兰Magnolia grandiflora和马褂木Liriodendron chinense生长的影响.结果表明:2种绿化树种均能在多环芳烃污染的土壤中生长;经6个月和12个月的胁迫处理后,马褂木的茎高和地径在L1、L2污染水平下均比对照高,且马褂木地径生长变化率与多环芳烃L2污染水平呈显著差异关系,而广玉兰只有高生长在L2污染水平下比对照高;马褂木地径增长量与广玉兰相比,12个月后分别在L1和L2水平下表现为显著性差异.这说明马褂木对多环芳烃的耐受能力比广玉兰强.

Polycyclic aromatic hydrocarbons （PAHs） are a kind of organic pollutants existing accumulatively in the environment. Being highly persistent, they are potent toxins posing a carcinogenic risk to human beings. In this study, 2 urban afforestation species （Magnolia grandiflora and Liriodendron chinense） from subtropical China were selected and planted separately in pots whose soils were treated with diesel oil to three concentration levels of PAHs （L〈L2 〈L3）. A growth monitoring of their stem height and diameter during 180-d and 360-d experiments shows that the 2 species can grow in soils contaminated by PAHs; that the value of Liriodendron chinense＇s stem height and diameter under L2 and L1 is bigger than that of CK; that the change ratio of Liriodendron chinense＇s stem diameter displays a significant difference with PAHs concentration while the value of Magnolia grandiflora＇s stem height is bigger than that of the control only under L2 ; and that after a 360-d treatment under L1 and L2, Liriodendron chinense＇s stem diameter displays a significant difference with that of Magnolia grandiflora. All these illustrate that Liriodendron chinense can be regarded to be more tolerant to PAHs than Magnolia grandiflora.