兰州市交通干道路侧土壤重金属积累对碧冬茄生理特性的影响

Effects of heavy metal accumulation in the soil on the physiological properties of Petunia×hybrida along an arterial road in Lanzhou City

采集兰州市交通干道"黄河风情线"的土壤及绿化植物碧冬茄(Petunia×hybrida)叶片,分析土壤重金属污染程度、植物叶片对重金属的富集特征及其抗氧化反应和渗透性调节等生理特性,以期揭示碧冬茄对重金属的耐受性及富集能力,为城市重金属污染的治理及绿化提供理论参考。结果表明:交通干道路侧土壤中镉(Cd)、铬(Cr)、镍(Ni)和锌(Zn)含量均显著高于对照采样点,且交通干道路侧土壤中重金属Cd达到重度污染;对照采样点和路侧采样点土壤中铜(Cu)、Ni和铅(Pb)为轻度污染,Cr和Zn未达到污染水平。与Cr、Ni和Pb相比,碧冬茄对Cd、Cu和Zn积累作用较强。与对照采样点(b_(1)除外)相比,路侧采样点(B_(2)除外)的碧冬茄叶片总叶绿素、叶绿素a和类胡萝卜素含量均显著升高,脯氨酸、可溶性糖和可溶性蛋白含量显著增加。此外,相较于对照采样点,路侧采样点的碧冬茄叶片丙二醛(MDA)含量以及超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性显著升高。该研究表明,城市交通会导致道路土壤重金属含量增加,碧冬茄叶片Cr和Zn含量增加、叶绿素含量升高;碧冬茄可通过增加抗氧化酶活性与渗透性调节物含量来抵抗重金属胁迫。

The soil and leaves of the green plant petunia(Petunia×hybrida)along an arterial road,Yellow River Custom Line,in Lanzhou City were collected to analyze the degree of soil pollution due to heavy metal accumulation,characteristics of heavy metal accumulation in plant leaves,and their antioxidant response and osmotic adjustment.Our research reveals the heavy metal tolerance and enrichment capacity of petunia,providing a theoretical reference for the treatment and greening of heavy metal pollution in urban area.The results show that compared to the control sampling points,the levels of cadmium(Cd),chromium(Cr),nickel(Ni),and zinc(Zn)on the side of the arterial road were significantly increased in soil,with Cd reaching heavy pollution level.The levels of copper(Cu),Ni,and lead(Pb)in the soil at the roadside sampling points were slightly higher than those at the control sampling points,whereas levels of Cr and Zn did not reach the pollution levels.Petunia had a stronger effect on the accumulation of Cd,Cu and Zn than Cr,Ni and Pb.The contents of total chlorophyll,chlorophyll a,carotenoids,proline,soluble sugar,and soluble protein in petunia leaves at the roadside sampling points(except sampling point B_(2))were significantly enhanced compared to those at the control sampling points(except sampling point b_(1)).In addition,the content of malondialdehyde(MDA)and activities of superoxide dismutase(SOD),peroxidase(POD),and catalase(CAT)of leaves were significantly increased at the roadside than at the control sampling points.Our study shows that urban traffic increases the levels of heavy metals in road soil and the levels of Cr,Zn and chlorophyll in petunia leaves.Petunia can resist heavy metal stress by increasing the activities of antioxidant enzymes and osmotic regulators.