Effects of an ectomycorrhizal fungus on the growth and physiology of Pinus sylvestris var. mongolica seedlings subjected to saline-alkali stress

This research investigates the mechanism of increased salinity tolerance of ectomycorrhizal fungiinoculated P. sylvestris var. mongolica to provide a theoretical basis for the application of the fungus in saline soils.Growth effects due to inoculation of seedlings with Suillus luteus(a symbiotic ectomycorrhizal fungus), were determined in four kinds of saline–alkali soils. Growth and physiological indicators, including photosynthetic characteristics, plant height, biomass, photosynthetic pigments,catalase(CAT) and superoxide dismutase(SOD) enzyme levels, and malondialdehyde(MDA), an organic marker for oxidative stress, and soluble protein levels were determined. Mycorrhizal colonization rate decreased with increasing saline–alkalinity and growth of inoculated seedlings was significantly enhanced. Biomass and chlorophyll contents also increased significantly. SOD and CAT activities were higher than in non-inoculated seedlings. However, MDA content decreased in inoculatedseedlings. Soluble protein content did not increase significantly. Inoculation with a symbiotic ectomycorrhizal fungus could enhance the saline–alkali tolerance of P. sylvestris var. mongolica. Growth and physiological performance of inoculated seedlings were significantly better than that of uninoculated seedlings. The results indicate that inoculated P. sylvestris var. mongolica seedlings may be useful in the improvement of saline–alkali lands.

Promoting the Growth of Pinus sylvestris var.mongolica Seedlings and Improving Rhizosphere Fungal Community Structure through Interaction between Trichoderma and Ectomycorrhizal Fungi

In this study,pot experiments were conducted on the seedlings of Pinus sylvestris var.mongolica to study the influence of Trichoderma(Trichoderma harzianum E15)and Ectomycorrhizal fungi(Suillus luteus N94)on the growth of these seedlings.In particular,the effects of these fungi on the fungal community structure in the rhizosphere soil of the seedlings were investigated.Inoculation with Trichoderma harzianum E15 and Suillus luteus N94 significantly(P<0.05)promoted the growth of the Pinus sylvestris seedlings.The non-metric multidimensional scaling(NMDS)results indicated a significant difference(P<0.05)between the fungal community structures in the rhizosphere soil of the annual and biennial seedlings.In the rhizosphere soil of annual seedlings,the main fungi were Ascomycota,Basidiomycota,Zygomycota.Ascomycota,Basidiomycota,Mortierellomycota,and p-unclassified-k-Fungi were the main fungi in the rhizosphere soil of biennial seedlings.The dominant genus in the rhizosphere soil and a key factor promoting the growth of the annual and the biennial seedlings was Trichoderma,Suillus,respectively.Both of them were negatively correlated with the relative abundance of microbial flora in the symbiotic environment.Trichoderma had a significant promoting effect on the conversion of total phosphorus,total nitrogen,ammonium nitrogen,nitrate nitrogen,and the organic matter in the rhizosphere soil of the seedlings,while Suillus significantly promoted the conversion of organic matter and total phosphorus.

木霉菌生物防治及促进植物生长机制研究进展

木霉菌为适应能力较广的土壤腐生菌,在自然界中广泛存在于植物根系,是植物共生体,同时也是病原菌的强寄生者。木霉菌作为生物防治资源是近年来有害生物防治研究的热点,其生物防治机制包括竞争作用、重寄生作用、抗生作用、诱导植物抗性等,此外木霉菌还能通过改变土壤微生物群落结构、提高土壤有效养分含量等作用,在促进植物生长的同时间接地提高植物抗病性。文章主要从竞争作用、重寄生作用、抗生作用、诱导植物抗性及促进植物生长方面对木霉菌生物防治机制及其对植物的促生作用进行论述,以期为更合理地将木霉菌应用于生防领域,同时为木霉菌物开发及利用奠定基础。

外生菌根真菌对植物促生抗逆作用机制研究进展

外生菌根真菌(ECM)为土壤真菌与陆地植物根系形成的一种互惠共生体,是森林生态系统关键的组成部分。作为生态系统的重要组分,外生菌根真菌具有较强的适应能力,可适应干旱、盐碱、重金属污染等逆境条件,外生菌根真菌侵染宿主植物根系可促进宿主植物生长、土壤养分吸收与利用、提高抗逆和抗病能力、改善土壤环境微生物群落结构。林业生产与菌根关系密切,外生菌根真菌是林木生长必不可少的重要组成部分,森林的可持续经营离不开外生菌根真菌,菌根化育苗与造林可显著提高林木成活率、促进苗木对土壤中营养元素的吸收利用和植物生长、提高植物抗逆性。文中系统阐述了外生菌根真菌促进植物生长、增强宿主植物对重金属污染、干旱、盐碱以及病虫害胁迫抗性的机制及生物修复作用,同时对外生菌根真菌资源开发、环境因子对外生菌根真菌资源的影响及利用现代技术深入研究外生菌根真菌作用机制提出了研究建议与展望。

枯梢病感病和未感病樟子松根际土壤养分及真菌群落结构季节变化

樟子松具有抗逆性强,生长快等特点,是我国北方治沙工程的主要树种,近年来环境条件的变化导致辽宁省章古台地区樟子松人工林树势日益衰弱,樟子松枯梢病发生严重。以辽宁省章古台地区樟子松人工林枯梢病未感病樟子松(ck)和枯梢病感病樟子松(ss)为研究对象,利用高通量测序技术及qPCR技术分析不同季节感病和未感病樟子松根际土壤理化性质、真菌群落结构变化及土壤理化性质对真菌群落结构的影响。结果表明:门分类水平上Ascomycota、Basidiomycota、Mortierellomycota、Fungi-unclassified为主要的菌门,ck土样与ss土样菌群丰度具有显著差异(P<0.05),属分类水平上具有30个差异菌属,30个菌属在ck土样中的含量显著高于ss土样(P<0.05)且均为菌根真菌、深色有隔真菌、木霉菌等益生菌;冗余分析(RDA)表明,pH、OM、TN、NH_(4)^(+)、NO_(3)^(-)、AP、TP、AK、TK等环境因子是影响ck土样、ss土样春季、夏季菌群结构的主要环境因子,具有显著差异的30个菌属是影响秋季菌群结构的主要菌属。