• 关键词：Cd  苦楝  模拟酸雨  复合污染  生物量  叶绿素  丙二醛  可溶性糖

• 基金项目：国家自然科学基金（No.31470636）；四川省教育厅重点项目（No.12ZA116）；四川农业大学大学生创新性试验计划项目（No.201410626068）

• 苏明洁
• 四川农业大学风景园林学院, 成都 611130

• 蔡仕珍
• 四川农业大学风景园林学院, 成都 611130

• 邓辉茗
• 四川农业大学风景园林学院, 成都 611130

• 龙聪颖
• 四川农业大学风景园林学院, 成都 611130

• 叶充
• 四川农业大学风景园林学院, 成都 611130

• 宋会兴
• 四川农业大学风景园林学院, 成都 611130

• 廖源林
• 四川农业大学风景园林学院, 成都 611130

• 李璟
• 宜宾职业技术学院, 宜宾 644000

• 摘要：采用盆栽法研究了3个梯度模拟酸雨（pH=5.6、4.5、3.5）和不同剂量Cd²⁺（0、30、60、90、120、150、180 mg·kg^-1）单一及复合处理，对苦楝（Melia azedarach L.）幼苗生长、质膜透性和主要渗透调节物质含量的影响.结果表明，pH=4.5和30 mg·kg^-1 Cd²⁺复合处理对苦楝生物量的积累和幼苗的生长具有一定促进作用；pH=4.5和低剂量Cd²⁺（≤60 mg·kg^-1）单一及复合处理下，株高和干重变化不显著（p>0.05），叶色、叶绿素含量、相对电导率和丙二醛含量也无明显变化；而强酸雨（pH=3.5）和高剂量Cd²⁺（≥90 mg·kg^-1）处理下，叶片发黄卷曲，叶绿素含量下降，相对电导率和丙二醛含量增大，且酸雨和Cd²⁺复合处理较单一酸雨和单一Cd²⁺处理毒害作用更明显，表现为复合叠加效应；随酸雨强度和Cd²⁺剂量的增加，可溶性糖含量下降，可溶性蛋白和游离脯氨酸含量先升后降，二者峰值均出现在pH=4.5和60 mg·kg^-1 Cd²⁺处理，且Cd²⁺剂量≤120 mg·kg^-1时，各酸雨梯度下可溶性蛋白和脯氨酸含量均高于CK.综上认为，在Cd²⁺剂量≤60 mg·kg^-1、酸雨pH≥4.5的区域，苦楝可以正常生长且保持较大生物量，可将其作为Cd污染典型酸雨区的绿化和修复树种.

• Abstract：In this study, the single and combined toxic effects of acid rain and Cd²⁺ on growth, membrane permeability as well as main osmotic adjustment substance content in M. azedarach seedlings were investigated in a pot experiment. Results showed that the seedlings biomass accumulation and growth were enhanced with pH 4.5 and 30 mg·kg^-1 Cd²⁺ treatment. The treatment under pH 4.5 and low Cd content (≤60 mg·kg^-1) had no significant effects on the dry weights, plant height, leaf color, chlorophyll content, relative conductivity, and the malondialdehyde content compared with CK (p>0.05). While under the condition of severe acid rain (pH 3.5) and high concentration of Cd²⁺ (≥90 mg·kg^-1), the content of chlorophyll decreased and the relative electrical conductivity and the malondialdehyde content increased. The combined treatments of acid rain and Cd²⁺ show more obvious influence than single treatments. With the increase of acid rain intensity and Cd²⁺ concentration, the soluble sugar content reduced, and the soluble protein and free proline content increased first and then decreased, with maximum under pH 4.5 and 60 mg·kg^-1 Cd²⁺. when Cd²⁺ was below 120 mg·kg^-1, the soluble protein and the free proline content at each level of simulated acid rain were always higher than at CK treatment. Above all M. azedarach could grow well and maintain a large biomass in the range Cd²⁺ concentration ≤60 mg·kg^-1 and acid rain pH≥4.5, which could be used as the greening and soils restoration trees in the areas of contaminated with Cd and affected by acid rain.

• Key words：Cd  Melia azedarach L.  simulated acid rain  compound pollution  biomass  chlorophyll  malondialdehyde  soluble sugar

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