| Cu和Cd胁迫下接种外生菌根真菌对油松根际耐热蛋白固持重金属能力的影响 |
| 摘要点击 2075 全文点击 1043 投稿时间：2013-07-23 修订日期：2013-09-25 |
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| 中文关键词 Cu Cd 菌根 耐热蛋白 固持重金属 |
| 英文关键词 Cu Cd mycorrhiza thermostable protein heavy metals sequestration |
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| 中文摘要 |
| 铜和镉是我国土壤重金属常见种类，生物固定过量重金属以降低其生理毒害是修复土壤重金属污染的有效方法之一. 外生菌根能够通过分泌大量有机物质来降低土壤中重金属的生物有效性. 在Cu或Cd胁迫下，外生菌根真菌接种油松幼苗根际分泌的耐热蛋白具有固持重金属的潜力. 结果表明，纯培养条件下接种并没有增加耐热蛋白的分泌，但是在Cu或Cd的胁迫培养下，接种幼苗耐热蛋白的分泌量增加. 不同Cu浓度处理下，接种油松幼苗总提取耐热蛋白（total thermostable protein，TTP）和易提取耐热蛋白（easily extracted thermostable protein，EETP）的分泌量为未接种油松的2.64~11.79倍；Cd处理下接种油松TTP和EETP的分泌量，分别是未接种油松的1.49~7.56倍. 虽然Cu处理下无论是接种还是未接种，根际耐热蛋白和根系细胞中固持的总Cu量显著大于空白对照，但接种显著增加了根际的重金属固持量，其Cu总相对含量是未接种的1.81~2.75倍，且绝大部分重金属固持在耐热蛋白中，使得根际耐热蛋白中的Cu相对含量是根系细胞含量的4.19~43.00倍. Cd处理下也得到了相似的结论. 说明接种菌根真菌促进了植物分泌耐热蛋白量，加强了根系对重金属的固持能力，从而达到减少过量重金属的生物有效性，缓解土壤重金属污染的目的. |
| 英文摘要 |
| Copper and cadmium in soil is a severe soil pollution problem in China. It is effective to remediate the soil by sequestrating Cu and Cd with tolerant plant and microorganism. Ectomycorrhizae could exude a large number of organic matter to reduce the biological effectiveness of heavy metals. Therefore, under Cu or Cd stress, thermostable protein in rhizosphere exuded by roots of pine seedling (Pinus tabulaeformis) associated with ectomycorrhizal fungi (Xerocomus chrysenteron) can have the potential of sequestration for heavy metals. The results illustrated that the association didn't impact on exudation of thermostable protein but treated with different concentrations of Cu,the total thermostable protein (TTP) and easily extracted thermostable protein (EETP) in mycorrhizal rhizosphere increased by 2.64 to 11.79 times compared with non-mycorrhizal one. While treated with Cd, it was 1.49 to 7.56 times. Further analysis of metal content in rhizosphere showed that association significantly increased the Cu sequestration in mycorrhizal rhizosphere where relative content of Cu was 1.81 to 2.75 times higher than those in non-mycorrhizal rhizosphere while most of Cu was sequestrated by thermostable protein, 4.19 to 43.00 times higher in protein than in root cell. Meanwhile results of Cd treatments showed a similar trend with Cu treatments. That indicated that under excessive heavy metals stress, ectomycorrhizal association facilitated the exudation of thermostable protein so as to extend the capacity of sequestration for excessive heavy metals and mitigate the phytotoxicity from heavy metals polluted soil. |
