重金属胁迫对小叶丁香叶片解剖结构的影响

以小叶丁香(Syringa microphylla Diels)为研究对象,研究了6种重金属锌(Zn)、铜(Cu)、铅(Pb)、汞(Hg)、铬(Cr)、镉(Cd)在不同质量分数(a,b,c)胁迫下小叶丁香叶片解剖学特征,并应用石蜡切片法配合显微摄影技术,对叶片栅栏组织厚度、海绵组织厚度、栅栏与海绵组织厚度比值、上下表皮厚度、角质层厚度以及叶片总厚度的影响进行分析。结果表明:随着施加6种重金属质量分数的升高,小叶丁香栅栏组织的厚度在逐渐变厚,海绵组织的厚度逐渐变薄,且栅栏组织与海绵组织的比值也随之增加,上下表皮厚度、角质层厚度以及叶片总厚度变化不大。小叶丁香在不同质量分数重金属胁迫下均表现出抗性,对重金属Zn抗性作用大小为Zn(100 mg.kg-1)>Zn(200 mg.kg-1)>Zn(150 mg.kg-1);小叶丁香随着重金属Cu的质量分数增加抗性越来越强,Cu(300 mg.kg-1)>Cu(200 mg.kg-1)>Cu(100 mg.kg-1);小叶丁香只对Pb(50 mg.kg-1)产生了抗性,随着Pb质量分数的增大,小叶丁香对重金属Pb的抗性逐渐减弱,说明浓度越低抗性越强(Pb(50 mg.kg-1)>Pb(100 mg.kg-1)>Pb(150 mg.kg-1));小叶丁香对重金属Hg的抗性大小为Hg(2.00 mg.kg-1)>Hg(1.10 mg.kg-1)>Hg(0.20 mg.kg-1);小叶丁香对重金属Cr抗性作用为Cr(100 mg.kg-1)>Cr(150 mg.kg-1)>Cr(200 mg.kg-1);小叶丁香对重金属Cd抗性作用大小为Cd(1.75 mg.kg-1)>Cd(1.00 mg.kg-1)>Cd(0.25 mg.kg-1),研究结果为在重金属污染区选择抗性强的绿化树种提供科学依据。

Effect of Heavy Metal Stress on Leaf Anatomical Structure of Syringa microphylla

An experiment was conducted to study the leaf anatomical features of Syringa microphylla Diels under heavy metal(Zn,Cu,Pb,Hg,Cr,Cd) stress at three different concentrations.The thickness of palisade tissue and spongy tissue,thickness ratio of palisade tissue to spongy tissue,thickness of upper and lower epidermis,cuticle thickness and total leaf thickness were analyzed by paraffin section combined with photomicrography.Results showed that S.microphylla exhibited resistance to heavy metals at different concentrations.The resistance of S.microphylla leaves to 100 mg·kg-1 Zn was highest,followed by 200 mg·kg-1 and 150 mg·kg-1;the resistance gradually increased with increasing concentrations of Cu(100,200,300 mg·kg-1),Hg(0.20,1.10,2.00 mg·kg-1) or Cd(0.25,1.00,1.75 mg·kg-1);while the resistance decreased with increasing concentrations of Pb(50,100,150 mg·kg-1) or Cr(100,150,200 mg·kg-1).