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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.
Copper and cadmium are common species of soil heavy metals in China, and biological immobilization of excess heavy metals to reduce their physiological toxicity is one of the effective methods to repair heavy metal pollution in soils.Extrema mycorrhiza can reduce the bioavailability of heavy metals in soils by secreting a large amount of organic matter. Under Cu or Cd stress, the ectomycorrhizal fungi inoculated with rhizosphere secreted heat-tolerant protein has the potential of holding heavy metals.The results showed that in pure culture conditions did not increase the heat-resistant protein inoculation, but in Cu or Under Cd stress, the secretion of heat-resistant protein increased in inoculated seedlings.Under different Cu concentrations, total thermostable protein (TTP) and easily extracted thermostable protein EETP) was 2.64 ~ 11.79 times of that of Pinus tabulaeformis.The secretion of TTP and EETP under Pinus tabulaeformis was 1.49 ~ 7.56 times that of Pinus tabulaeformis respectively.Although Cu treatment did not result in inoculation or not Inoculation, rhizobacteria, and root cells retained significantly more total Cu than blank control, but the inoculation significantly increased the amount of heavy metals in rhizosphere, The amount of non-inoculated 1.81 ~ 2.75 times, and most of the heavy metals are retained in the heat-resistant protein, so that relative content of rhizosphere heat-resistant protein is 4.19 ~ 43.00 times the root cell content.Cd also get similar The results showed that inoculation of mycorrhizal fungi promoted the secretion of heat-resistant protein and enhanced the ability of roots to fix heavy metals, thus reducing the bioavailability of heavy metals and alleviating heavy metal pollution in soils.