接种AMF对海绵结构重构土层的玉米根系分布及水分利用特征的影响

Effects of Arbuscular Mycorrhiza Fungi Inoculation on Maize Root Distribution and Water Use Characteristics in Spongy Reconstructed Soil Layer

[目的]露天煤矿区生态脆弱,水资源短缺,利用微生物复垦已成为矿区生态重建的研究热点。探究露天矿排土场重构土层海绵生态结构条件下接种丛枝菌根真菌(arbuscular mycorrhiza fungi,AMF)对玉米根系生长及水分利用特征的影响,为矿区生态农业建设提供科学依据。[方法]在室内布设土柱模拟试验,设置裸土柱(CK)、玉米不接菌(NM)和玉米接菌(AM)3个处理,采用氢氧稳定同位素示踪技术研究玉米根系水分利用特征。[结果]①接种AMF处理促进了玉米根系的生长,改变了玉米根系分布。AM处理玉米的总根长、总根表面积、总根体积和根尖数分别比NM处理高19.3%,14.8%,9.1%和34.0%,AM处理小于0.3mm的细根及大于0.7mm的粗根比例分别比NM处理高3.2%和3.5%。②AMF改变了玉米的水分利用特征,AM处理玉米利用的水分来源于0—20cm土层的比例较NM处理提升5.5%。③AM处理土柱0—20cm土层含水率显著低于NM处理,饱和黏土层含水率:CK处理>NM处理>AM处理。AMF提升了玉米根系吸收水分的能力,影响黏土层中水分的释出。[结论]在矿区排土场海绵结构重构土层上接种AMF能促进玉米根系发育,改善水分利用策略,使其充分利用海绵结构中涵水层保蓄的水分。

[Objective]The ecology of open-pit coal mine areas is fragile and water resources are scarce.Therefore,the use of microorganisms for mine reclamation has become a research hotspot with regard to ecological reconstruction of mining areas.The effects of soil inoculation with arbuscular mycorrhizal fungi(AMF)on maize root growth and water use charateristics under the conditions of a reconstructed soil sponge ecological structure in an open-pit mine dump were determined in order to provide a scientific basis for the implementation of ecological agriculture in mining areas.[Methods]A soil column simulation experiment was conducted in a laboratory.Three treatments were evaluated:a bare soil column(CK),maize without bacterial inoculation(NM),and maize with bacterial inoculation(AM).The stable hydrogen and oxygen isotope tracer technique was used to study water use characteristics by maize roots.[Results]①The AMF treatment increased maize root growth and changed maize root distribution.Total root length,total root surface area,total root volume,and number of root tips for the AM treatment were 19.3%,14.8%,9.1%,and 34.0%,respectively,higher than observed for the NM treatment.The proportions of fine roots smaller than 0.3 mm and coarse roots larger than 0.7 mm for the AM treatment were 3.2%and 3.5%,respectively,higher than for the NM group.②AMF changed water use characteristics by maize roots by depth.The proportion of water used by maize for the AM treatment from the 0—20 cm soil layer was 5.5%higher than for the NM treatment.③The moisture content of the 0—20 cm soil layer of the AM treatment was significantly lower than for the NM treatment.The moisture content of saturated clay layer of the CK treatment was higher than for the NM treatment,which was higher than for the AM treatment.AMF improved the ability of maize roots to absorb water,and affected the release of water in the clay layer.[Conclusion]AMF inoculation of a reconstructed soil sponge structure in an open-pit mine dump can promote maize root development,improve maize water utilization strategy,and make full use of the water stored in the water layer in the sponge structure.