SO_2对三种园林绿化苗木叶片膜脂过氧化和保护酶的影响

EFFECT OF SULFUR DIOXIDE STRESS ON MEMBRANE LIPID PEROXIDATION AND PROTECTIVE ENZYMES OF THREE ORNAMENTAL TREE SEEDLINGS

采用自己设计的开顶式熏气装置对三种盆栽园林绿化幼树进行SO2熏气,并对其质膜透性、MDA含量和保护酶活性的变化进行比较研究,结果表明,随SO2胁迫浓度的增大,三个树种质膜透性和MDA含量增大,SOD、POD、CAT活性没有测到规律性变化。其中质膜透性与MDA含量呈正相关,朴树的三种保护酶的活性与质膜透性呈显著正相关,梓树和鹅掌楸的保护酶活性与质膜透性的关系不一致,但相关关系显著。随着胁迫时间的延长,三个树种质膜透性和MDA含量增大,抗性强的朴树能维持较高的保护酶活性,质膜透性小,MDA含量低;而抗性弱的梓树则相反。在5.4mg·m-3SO2胁迫条件下处理4～8小时,以上测定指标均可作为幼树对SO2抗性的鉴定指标。

The potted seedlings of three ornamentat tree species were fumingated by sulfur dioxide in a specially designed fumigation equipment and the changes of protective enzyme activity, MDA content and permeability of plasma membrane were compared. The results showed that as the concentration of sulfur dioxide increased, permeability of plasma membrane and MDA content also increased, but activity of CAT, SOD and POD varied irregularly. The permeability of plasma membrane was positively related to MDA content. The activity of three protective enzymes had remarkably positive correlation with permeability of plasma membrane in leaves of Celtis sinensis, but relationship between protective enzymes and permeability of plasma membrane was different in Liriodendron chinense and Catalpa ovata, although correlation between them was remarkable. As sulfur dioxide treatment extended, permeability of plasma membrane and MDA content increased in leaves of three potted tree seedlings. Resistant tree of Celtis sinensis could maintain a higher protective enzyme activity, and its permeability of plasma membrane and MDA content were relatively low. The result of susceptible tree of Catalpa ovata was contradictory. These items evaluated under 4 -8 hours of sulfur dioxide treatment （5.4 mg·m^-3） may be used as the index for evaluating the responses of tree species to sulfur dioxide stress.