Cu胁迫下兴安落叶松菌根苗生长和Cu积累特性

Growth and Copper Accumulation Characteristics of Larix gmelinii Mycorrhizal Seedlings Under Copper Stress

外生菌根真菌(ECMF)能够提高宿主植物对外界环境胁迫的抵抗力,促进植物生长。为了解重金属Cu胁迫下外生菌根真菌对兴安落叶松(Larix gmelinii)生长及土壤修复的影响,采用盆栽试验,对兴安落叶松幼苗进行美味牛肝菌(Boletus edulis,Be)、血红铆钉菇(Gomphidius rutulus,Gr)和Be+Gr的混合接种处理,研究不同菌根真菌在重金属Cu(0、40、80、160、320 mg/kg)胁迫下兴安落叶松生长、根系发育、营养元素及重金属Cu吸收分配的作用机理。结果表明,2种ECMF均能与兴安落叶松形成良好的共生关系,且Cu胁迫质量分数对根系外生菌根真菌侵染率有显著影响;在不同Cu质量分数处理下,接种ECMF能显著促进幼苗的生长,增加根系和植株生物量,增强对营养元素以及重金属Cu的吸收,并随Cu胁迫质量分数的增加改变其地上、地下部分分配格局。随着Cu施加质量分数的增加,各接种处理植株地上、地下生物量,氮磷钾营养元素的吸收均呈先升高后下降的趋势,Cu积累量升高,且菌根结构通过吸收固持Cu,减少Cu向地上部分的迁移,从而缓解重金属Cu胁迫。与单接种处理相比,混合接种Be+Gr对兴安落叶松抗Cu胁迫的效果最显著。因此,兴安落叶松接种外生菌根真菌在重金属Cu污染土壤生态修复中有一定的应用价值。

Ecmycorrhizal fungi(ECMF)can improve the resistance of host plants to external environmental stress and promote the growth of plants.In order to understand the effects of ECMF on the growth and soil remediation of Larix gmelinii under heavy metal copper(Cu)stress,pot experiment was conducted to inoculate L.gmelinii seedlings with Boletus edulis(Be),Gomphidius rutulus(Gr)and Be+Gr.The mechanism of growth,root development,nutrient elements and copper absorption and distribution of different mycorrhizal fungi under heavy metal copper(0,40,80,160,320 mg/kg)stress was studied.The results showed that both ECMFs could form a good symbiotic relationship with L.gmelinii,and copper concentration had a significant effect on the infection rate of root ectomycorrhizal fungi.Under different Cu concentrations,inoculation of ECMF can significantly promote the growth of seedlings,increase the biomass of roots and plants,enhance the absorption of nutrient elements and heavy metal Cu,and change the distribution pattern of aboveground and underground parts with the increase of copper stress concentration.With the increase of Cu application concentration,the aboveground and underground biomass and the absorption of N,P and K nutrients of each inoculation treatment plant showed a trend of first increasing and then decreasing,and the copper accumulation increased,the mycorrhizal structure reduced the migration of Cu to the aboveground part by absorbing and holding copper,thus alleviating the heavy metal Cu stress.Compared with single inoculation,mixed inoculation of Be+Gr had the most significant effect on the copper stress resistance of L.gmelinii.Therefore,ectomycorrhizal fungi inoculated with L.gmelinii have certain application value in ecological remediation of Cu contaminated soil.