滇重楼与丛枝菌根的共生对重金属元素吸收的影响

Effects of symbiosis of Paris polyphylla var. yunnanensis with arbuscular mycorrhizal fungi on absorption of heavy metals (Cd,Hg,As,Cu,Pb)

通过室温盆栽接种试验,研究在灭菌土壤中,不同丛枝菌根(arbuscular mycorrhizal,AM)真菌处理对滇重楼生长过程中根际土壤和药材中5种重金属(Cd、Hg、As、Cu、Pb)吸收累积的影响.结果表明,与对照组(CK组)相比,人工栽培条件下接种28种不同AM真菌,滇重楼根际土壤及其对应药材中5种重金属残留量差异显著,不同重金属在滇重楼生长不同时期含量变化的差异较大,具体影响效果不同.除Spe、Asc、Asp处理组果熟期的根际土壤Cd元素含量超标外,其余处理组根际土壤及其对应药材均低于国家限量标准.同时,28种AM真菌对滇重楼根茎5种重金属元素的富集能力存在显著差异,滇重楼对Cd、Hg、As、Cu具有较强的生物积累作用,但均显著低于超富集植物的临界含量标准(1000 mg·kg^(-1)).对不同AM真菌处理组滇重楼栽培土壤重金属残留量进行风险评估及分级发现,土壤尚处于"无污染"状态,但有个别处理组的Cd已接近轻微污染.实验结果表明,人工接种AM真菌能保证滇重楼根茎重金属残留量在安全范围内,为推动滇重楼绿色种植建设开辟一条新的途径,但在大田栽培时应根据实际情况,选择合适的AM真菌菌株与滇重楼进行共生栽培,应重视滇重楼自身特性对重金属吸收和累积的影响.

Through potted inoculation test in sterile soil at room temperature,the effects on the adsorption and accumulation of 5 heavy metals（ Cd,Hg,As,Cu,Pb） in the rhizosphere soil and Paris polyphylla var. yunnanensis were investigated after different arbuscular mycorrhizal（ AM） fungi were injected. The results showed that there were significant differences in the residues of the5 heavy metals in the rhizosphere soil and its corresponding host after 28 AM fungi were injected under artificial cultivation condition compared with the control group（ CK group）. The heavy metals contents varied significanty in different periods of Paris polyphylla var. yunnanensis growth,but the effects were different. The metal contents in the rhizosphere soil and its corresponding host in the other AM fungi groups were below the national standard limit. Except for the Cd contents in rhizosphere soil of the AM fungi groups（ Spe,Asc,Asp） during the fructescence. Meanwhile,28 AM fungi showed significant differences in collection capacity of 5 heavy metals on Paris polyphylla var. yunnanensis rhizome,a higher bioaccumulation of Cd,Hg,As,Cu was found in Paris polyphylla var. yunnanensis,however,these values were still significantly lower than the threshold concentrations for hyperaccumulators（ 1000 mg·kg^-1）. According to the risk assessment and classification of the residues of heavy metals,the soil of all AM fungi groups was still at pollution-free level,but Cd contents of some AM fungi groups were close to micro-pollution level.The experimental results showed that inoculation of AM fungi could help residues of heavy metals in the Paris polyphylla var. yunnanensis rhizome in a safe range and provide a new way to green agriculture,but it should choose the suitable AM fungi species for cultivating Paris polyphylla var.yunnanensis under field condition according to the actual situation,considering the effects of Paris polyphylla var. yunnanensis on absorption and accumulation of heavy metals is also important.