紫穗槐接种AM真菌对红壤林下侵蚀劣地的影响研究

Study on the Effect of Amorpha fruticosa L. Inoculated with AM Fungi on Erosion-Degraded Forestland in Red Soil

为探究植被接种丛枝菌根(AM)真菌对南方红壤区林下侵蚀劣地恢复的影响机制,本研究以马尾松退化林地为对象,设置引种灌木不接菌(S)和引种灌木接菌(S+AMF)两种处理,研究土壤AM真菌群落、土壤肥力及植物生长对紫穗槐(Amorpha fruticosa L.)接种AM真菌的响应。结果表明,接菌一年后,S+AMF处理菌根侵染率(MIR)极显著大于S处理(P<0.001),而接菌三年后MIR在两处理间无显著差异。接菌三年后,与S处理相比,S+AMF处理AM真菌的多样性和丰富度无显著差异,但其在种水平上的网络复杂性有所提高,其中Rhizophagus manihotis、Glomus cf.clarum Att894-7、fungal sp.Kamogawa和Rhizophagus neocaledonicus丰度具有显著性差异;土壤有机碳(SOC)、全氮(TN)、总球囊霉素相关土壤蛋白(TG)、土壤微生物生物量碳(SMBC)和土壤微生物生物量氮(SMBN)含量均显著或极显著提高,土壤团聚体变化不显著;植物叶片中全氮(TN)和全磷(TP)含量以及地上生物量(AGB)均显著或极显著提高,而地下生物量(UGB)显著降低(P<0.05);植物根系构型中,根系总根长(TRL)、总体积(TRV)、比根长(SRL)、比表面积(SSA)和根冠比(R-S R)均显著或极显著降低,而根组织密度(RTD)则极显著提高(P<0.001)。线性回归分析表明,SOC、土壤TN、TG、SMBC、SMBN、AGB与MIR间存在显著或极显著正相关关系,TRL、TRV、R-S R、UGB和MIR间存在显著或极显著负相关关系,说明紫穗槐接种AM真菌能够有效改善土壤肥力,同时改变植物地上地下部的生长情况。本研究结果为林下劣地土壤质量提升和植被恢复提供了技术参考。

To investigate the mechanism of plant inoculation of arbuscular mycorrhizal(AM)fungi on the restoration of forestlands which have been damaged by erosion in the red soil region of South China,this study took the degraded pine forest as the object.Two treatments were implemented,namely shrub planting(S),and shrub planting with AM fungi(S+AMF).The objective was to examine the impact of Amorpha fruticosa inoculated with AM fungi on soil AM fungal community,soil fertility and vegetation growth.The results showed that the mycorrhizal infestation rate(MIR)was significantly higher in the S+AMF than S after one year of inoculation(P<0.001),but there was no significant difference after three years of inoculation.After three years of inoculation,there were no significant difference in the diversity and richness of AM fungi between the two treatments.The inoculation of AM fungi increased the complexity of the network:four microorganisms were identified,i.e.Rhizophagus manihotis、Glomus cf.clarum Att894-7、fungal sp.Kamogawa and Rhizophagus neocaledonicus.Although soil aggregate did not change,soil organic carbon(SOC),total nitrogen(TN),total glomalin-related soil protein(TG),soil microbial biomass carbon(SMBC),and soil microbial biomass nitrogen(SMBN)were significantly higher in the S+AMF than S(P<0.05).The TN and total phosphorus(TP)in plant leaves and above-ground biomass(AGB)were significantly higher in the S+AMF than in the S(P<0.05),whereas under-ground biomass(UGB)was significantly lower than that in the S(P<0.05).In plant root architecture,the total root length(TRL),total root volume(TRV),specific root length(SRL),specific surface area(SSA),and root-shoot ratio(R-S R)were significantly lower in S+AMF(P<0.05),whereas root tissue density(RTD)was significantly higher in S+AMF,compared to that in S(P<0.001).Linear regression analysis showed that SOC,soil TN,TG,SMBC,SMBN,and AGB had significantly or extremely significantly positively correlated.However,TRL,TRV,R-S R,UGB and MIR had a significantly or extremely significant negative correlation.These results indicated that inoculation with AM fungi could significantly improve soil fertility and change the growth of aboveground and underground parts of vegetation.The results of this study provide technical reference for improving soil quality and restoring vegetation in erosion-degraded forestland.