3种地被植物对二氧化硫胁迫的生理响应

该研究以3种地被植物蜂斗菜、峨眉附地菜和绵毛水苏为材料,采用人工模拟熏气方法,在0、5.71、11.43和17.14mg·m-3 SO2浓度水平下,测定了参试植物的外观受害症状以及和生理生化指标对SO2的反应,明确供试植物对大气污染的反应特性,为选择景观效果良好同时具有更好生态效应的地被植物提供依据。结果表明:(1)随着SO2浓度的增加,3种地被植物受伤害症状从重到轻依次为绵毛水苏峨眉附地菜蜂斗菜,它们的叶片叶绿素含量、叶液pH值不同程度下降,丙二醛含量、相对叶片电导率、可溶性糖含量、游离脯氨酸含量均不同程度上升,同时其SOD、POD、CAT活性被激活并显著增强。(2)隶属函数和主成分分析综合评定结果显示,3种地被植物对SO2抗性能力由强到弱的顺序为:蜂斗菜峨眉附地菜绵毛水苏,与其受伤害症状顺序相反。(3)依据SO2胁迫下叶片含硫量的分析发现,各植物对SO2的净化能力由高到低的顺序为:蜂斗菜绵毛水苏峨眉附地菜。研究表明,3种地被植物中的蜂斗菜对SO2的抗性及净化能力最强,能够通过自身应激保护系统来提高对SO2的抗性,维持正常生长,适宜在城市园林绿化中推广。

Physiological Responses of Three Ground Cover Plants under Sulfur Dioxide Stress

Ground cover plants are one of the essential landscape plant species among the current urban greening,and understanding the physiological mechanism of these plants resistance to sulfur dioxide (SO₂) can help us choose the suitable species.In this study,three ground cover plant species (Petasites japonica,Stachys lanata and Trigonotis omeiensis) growing under the greenhouse condition were selected and screened for tolerance to acute SO₂ injury.Four SO₂ treatments including 0,5.71,11.43,and 17.14 mg·m^-3 were used in this study,and release of SO₂ were achieved using the artificial simulated fumigation method.Differential response to SO₂ injury among these three species was manifested through the phenotypic injuries and the various physiological indexes.Our results showed that:(1)the phenotypic injury of three species is ordered in sequence from severe to light as S.lanata>T.omeiensis>P.japonica.The content of chlorophyll and the value of leaf pH decreased gradually with the increase of SO₂ concentration,while the levels of MDA content,the electrolyte leakage rate,and the contents of soluble sugar and the proline rose in the varying degree among the three species.Furthermore,the activities of superoxide dismutase(SOD),peroxidase(POD),catalase(CAT) were activated dramatically.(2)Through the subordination function and principal component analysis,we concluded that the resistance to SO₂ among these three species is ordered in sequence from high to low as P.japonica>T.omeiensis>S.lanata.(3)The purification ability to SO₂ is ranked in order from high to low as P.japonica>S.lanata>T.omeiensis by analogizing sulfur accumulation within leaf under SO₂ stress.The results shows that P.japonica has the strongest capacity of resistance and purification of SO₂ and it can also has no obvious phenotypic injury through its own stress protection system to improve resistance to SO₂.This conclusion can guide us in respect of large-scale use of P.japonica in heavily SO₂-polluted urban areas.