矿区压实土壤接种AMF对柠条生长的影响模拟试验

Effects of AMF on the growth of Caragana in simulated compacted soil in mining area

土壤压实是露天矿区排土场土地复垦过程中面临的常见问题,对矿区植被恢复产生重要影响。为研究压实作用对植物根系发育和地上部养分吸收产生的影响,以及接种AMF对压实土壤中植物生长的效应,以矿区复垦常用植物——柠条为供试物种,采用室内模拟试验进行研究,结果表明:土壤紧实度影响植物根系构型发育,轻度压实(C1)促进柠条根系形态发育,重度压实(C2)抑制根系的生长,表现为根系总根长、根系平均直径、表面积和体积减小。接种AMF可促进压实土壤中柠条根系IAA,CTK,GA激素的分泌,且分泌量随压实程度增大有增加趋势,同时减少ABA的分泌,促进根系总根长、根系平均直径、表面积和体积增加。在重度压实(C2)下,接种AMF能显著提高柠条地上部N,P,Fe,Mn养分含量,提高柠条生物量,接菌柠条地上部分干重、地下部分干重和株高较对照分别增加48.08%,58.33%,6.91%。根系激素分泌与根系形态发育、地上部分各养分含量相互影响,根系IAA,CTK和GA的分泌与菌根侵染率、菌丝密度、地上部N,P,Zn养分含量显著正相关。紧实土壤中,接种AMF可以通过调节植物根系生理代谢活动,促进根系发育,提高宿主植物地上部对氮、磷、铁、锰、锌等矿质元素的吸收量,从而达到提高露天排土场压实土壤上植物生物量和抗压实胁迫的目的,实现高效生态恢复。

Soil compaction is a common problem in the process of land reclamation in mining area,which has a significant impact on vegetation restoration.In order to study the impact of soil compaction and the inoculation of AM fungi on plant root system development and the nutrient absorption in the aboveground,laboratory simulation experiments have been carried out on caragana.The results show that the soil compactness affected plant root system configuration,mild compaction(C1)promoted root morphological development,severe compaction(C2)inhibited the growth of root system,showing the total root length,average root diameter,root surface area and root volume decreased.The inoculation of AMF could promote the secretion of IAA,CTK and GA hormones in the caragana root system,and the secretion increased with the compaction degree,meanwhile,ABA secretion decreased.The synergy between hormones increase the total root length,average diameter,surface area and volume of the root system.The inoculation of AMF could significantly promote the absorption of nutrients N,P,Fe and Mn in severe compacted soil,and increase the biomass of caragana.Under the severe compaction gradient(C2),the inoculation of AMF could significantly promote the nutrient content of N,P,Fe and Mn in the aboveground part of caragana,and increase the biomass of caragana,compared with CK,the dry weight of the above ground and underground parts of caragana and plant height were increased by 48.08%,58.33%and 6.91%respectively.Root hormone secretion was correlated with root morphological development and nutrient content in the aboveground part.The secretion of root IAA,CTK and GA was significantly positively correlated with mycorrhizal infection rate,mycelium density,and the nutrient content of N,P and Zn in the aboveground.In the compacted soil,the inoculation of AMF could adjust plant root physiological activity,encourage more root growth,increase the host plants of N,P,Fe,Mn,Zn nutrient absorption,to reach the goal of improving plant biomass and soil compaction stress resistance in the compacted soil in mining area,achieving the purpose of efficient ecological restoration.