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| The growth and physiological responses of Melia azedarach L. seedlings to cadmium stress |
| Received:July 18, 2016 |
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| KeyWord:Melia azedarach L., cadmium accumulation, biomass, photosynthetic characteristic, osmotic-regulating substance |
| Author Name | Affiliation | E-mail | | SU Ming-jie | College of Landscape Architecture, Sichuan Agricultural University, Chengdu 611130, China | | | LIAO Yuan-lin | College of Landscape Architecture, Sichuan Agricultural University, Chengdu 611130, China | | | YE Chong | College of Landscape Architecture, Sichuan Agricultural University, Chengdu 611130, China | | | CAI Shi-zhen | College of Landscape Architecture, Sichuan Agricultural University, Chengdu 611130, China | 415455088@qq.com | | LONG Cong-ying | College of Landscape Architecture, Sichuan Agricultural University, Chengdu 611130, China | | | DENG Hui-ming | College of Landscape Architecture, Sichuan Agricultural University, Chengdu 611130, China | |
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| Abstract: |
| 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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