| 苏明洁,廖源林,叶充,蔡仕珍,龙聪颖,邓辉茗.镉胁迫下苦楝(Melia azedarach L.)幼苗的生长及生理响应[J].农业环境科学学报,2016,35(11):2086-2093. |
| 镉胁迫下苦楝(Melia azedarach L.)幼苗的生长及生理响应 |
| The growth and physiological responses of Melia azedarach L. seedlings to cadmium stress |
| 投稿时间：2016-07-18 |
| DOI：10.11654/jaes.2016-0929 |
| 中文关键词: 苦楝，镉积累，生物量，光合特性，渗透调节物质 |
| 英文关键词: Melia azedarach L., cadmium accumulation, biomass, photosynthetic characteristic, osmotic-regulating substance |
| 基金项目:四川省教育厅重点项目(12ZA116)；四川农业大学大学生创新性实验计划项目(201410626068) |
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| 中文摘要: |
| 采用盆栽试验研究不同浓度Cd(0、30、60、90、120、150、180 mg·kg-1)处理对苦楝(Melia azedarach L.)幼苗生长、Cd积累、光合、质膜透性以及渗透调节的影响。结果表明，当Cd2+浓度≤60 mg·kg-1时显著促进苦楝幼苗生物量的积累(P<0.05)，Cd2+浓度>60 mg·kg-1时抑制作用逐渐增强，但≤120 mg·kg-1 Cd处理对株高影响不显著(P>0.05)，植株能正常生长且保持较大的生物量，苦楝对Cd具有一定的积累能力，其根、茎、叶中Cd含量随Cd处理浓度的增加而增加，且根系是主要积累部位，随着Cd处理浓度的增加，叶绿素(Chla+b)含量和光合速率(Pn)下降，相对电导率(REC)和丙二醛(MDA)含量增大，但≤60 mg·kg-1 Cd处理时均无明显变化，随Cd浓度的升高，可溶性糖含量下降，可溶性蛋白和游离脯氨酸呈先升后降趋势，游离脯氨酸含量始终高于CK，苦楝通过增加可溶性蛋白和游离脯氨酸的含量来维持Cd胁迫下的渗透平衡，从而降低Cd毒害。上述结果表明，苦楝对Cd具有一定耐性，其耐Cd胁迫的阈值浓度大约是120 mg·kg-1，可以将其应用于土壤Cd污染区域，在美化环境的同时修复土壤Cd污染。 |
| 英文摘要: |
| Melia azedarach L. is a garden tree that can grow in poor soil, and has high ornamental and medicinal value. In this study, the effects of cadmium(Cd) on growth, cadmium accumulation, photosynthetic characteristic, membrane permeability as well as osmotic adjustment in Melia azedarach L. seedlings were investigated in a pot experiment. Results showed that the biomass accumulation was enhanced when ≤60 mg·kg-1 Cd treatments, whereas >60 mg·kg-1 Cd2+ inhibited plant growth and biomass accumulation, however, ≤120 mg·kg-1 Cd treatments had no significant differences on plant height compared with CK(P>0.05), plants could grow normally and keep large biomass. Melia azedarach L. showed capacity in Cd accumulation, and the Cd content in roots,stems and leaves increased when Cd content increased in soil, and root was the main accumulation area. With increased Cd concentration, Chlorophyll a+b content and net photosynthetic rate were reduced but relative conductivity(REC) and malondialdehyde(MDA) content were increased, however, no significant difference with Cd treatments(≤60 mg·kg-1) was found. Cd stress caused the content of soluble sugar decreased, the contents of soluble protein and free proline were increased at first then decreased when Cd concentration increased, free proline content was always higher than CK. By increasing soluble protein and free proline contents Melia azedarach L. maintained the osmotic balance under Cd stress, thus alleviated Cd toxicity. These results suggests that Melia azedarach L. has strong tolerance for Cd2+, the threshold concentration is about 120 mg·kg-1.Therefore Melia azedarach L. can be used in Cd contaminated soil, which remediate Cd contaminated soil. |
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