铝胁迫下千年桐内生真菌对根际土壤不同铝形态的影响

Effects of Endophytic Fungi in Aleurites montana on Different Aluminum Forms in Rhizosphere Soil under Aluminium Stress

【目的】了解不同浓度铝胁迫下内生真菌对根际土壤不同铝形态的影响。【方法】将5种分离自千年桐的优势内生真菌菌株配置为菌液,分别施入不同浓度铝胁迫的千年桐盆栽苗,外源铝浓度设置为0 mmol/L (A0)、0.555 mmol/L (A1)、0.745 6 mmol/L (A2)、1.111 mmol/L (A3)和1.852 mmol/L (A4)。通过测定不同菌液处理的土壤活性铝含量以及千年桐根系活力,探讨内生真菌对根际土壤活性铝含量及比例变化的影响。【结果】在非铝胁迫(A0)的条件下,不同内生真菌对千年桐根际土壤活性铝含量均有不同程度的升高。施加链格孢属菌液处理后,根际土壤交换性铝含量在A2铝浓度时较未施菌处理降低了20.58%,单聚体羟基铝含量在各铝浓度下均低于未施菌处理,降幅分别为7.19%(A1)、19.56%(A2)、6.27%(A3)和4.01%(A4)。盾壳霉属和嗜热真菌属菌液处理后,千年桐根际土壤活性铝含量均高于未施菌处理。不同菌液处理对千年桐根系活力的作用各异,其中盾壳霉属处理后的根系活力较未施菌提升了11.27%,而拟盘多毛孢属处理后根系活力与未施菌处理无显著差异。【结论】接种内生真菌能改变植株根际土壤活性铝含量和比例。链格孢属能有效降低根际土壤单聚体羟基铝含量,而盾壳霉属和嗜热真菌属提升了根际土壤活性铝含量。内生真菌的作用效果受到铝浓度、内生真菌基因型和宿主种类的影响。研究结果拓展了内生真菌对于宿主根际土壤影响的探索,可为林木-微生物互作的深入研究提供参考。

【Objective】This study aims to investigate the effects of endophytic fungi on different forms of aluminum in rhizosphere soil under different aluminium stress levels.【Method】Five dominant endo-phytic fungal strains isolated from Aleurites montana were cultured as fungal solutions and applied to pot-ted A.montana seedlings under different aluminum levels,including 0 mmol/L(A0),0.555 mmol/L(A1),0.7456 mmol/L(A2),1.111 mmol/L(A3)and 1.852 mmol/L(A4).The effects of endophytic fungi on the contents and proportions of different forms of active aluminum in rhizosphere soil were inves-tigated by measuring the contents of active aluminum in soil and the root activity of A.montana treated with different fungal solutions.【Result】Under non-aluminum stress(A0)condition,various endo-phytic fungi caused different levels of increase in the active aluminum contents in the rhizosphere soil of A.montana.The inoculation with Alternaria sp.led to a 20.58%reduction in exchangeable aluminum content in rhizosphere soil under A2 aluminum level compared to the non-inoculated treatments.Mean-while,the content of monomeric hydroxyl aluminum in Alternaria sp.-inoculated treatments was lower than that of the non-inoculated treatments across all aluminum levels,with reductions of 7.19%,19.56%,6.27%and 4.01%for A1,A2,A3 and A4,respectively.For Coniothyrium sp.and Thermomy-ces sp.treatments,the active aluminum contents in the rhizosphere soil were higher compared to the non-inoculated treatments.Different fungal inoculation treatments had varying effects on the root activity of A.montana,among which the root activity inoculated with Coniothyrium sp.was 11.27%higher than that of the non-inoculated treatments,while the root activity inoculated with Pestalotiopsis sp.showed no signifi-cant difference compared with that of non-inoculated treatments.【Conclusion】These findings show that inoculation with endophytic fungi could change the content and proportion of active aluminum in rhizo-sphere soil.Alternaria sp.could effectively reduce the content of monomeric hydroxy aluminum in rhizo-sphere soil,while Coniothyrium sp.and Thermomyces sp.increase the active aluminum contents.The ef-fectiveness of endophytic fungi are influenced by aluminum level,the genotype of endophytic fungi,and the types of hosts.The research results expand the exploration of the impacts of endophytic fungi on host rhizosphere soil,providing a reference for the in-depth study on tree-microorganism interaction.