我国南方桉树人工林菌根合成及其多样性研究(英文)

对我国南方部分地区桉树人工林菌根真菌资源和菌根类型进行了调查 .对采自广东、云南 15个桉树林地的根系样品进行了显微观察 ,结果证实了在自然土壤中桉树能形成不同类型的菌根 ,检查的根样在不同程度上均有菌根菌的感染 .其中 ,有 4个人工林的根系样品AM感染率在 50 %以上 ,另有 4个根样ECM感染根段长超过 50m .调查发现林分年龄大小对菌根形成及菌根类型有一定的影响 ,表现在幼林及过熟林菌根感染率均较低 ,而 4～ 7年生按树林菌根感染率相对较高 ,在同一根系上AM与ECM菌间存在一定的竞争性 .在菌根菌资源方面 ,从总体上来说 ,我国南方菌根菌资源较少 ,尤其是ECM菌 .调查结果表明 ,我国南方桉树人工林根际土壤中有AM菌 2 8种 ,隶属于 4个属 ,其中以球囊霉属真菌最多 ,占 6 4 % ;地球囊霉在所采集的土样中出现的频度最高 .南方 15个桉树人工林中发现有 17种ECM菌 ,隶属 10个属 ,其中彩色豆马勃、多根硬皮马勃、光硬皮马勃等菌种在两广地区许多桉林中较常见 ,云南地区则多以黄须腹菌、硬皮马勃等菌较多 .这些ECM菌通常生长于松树林中 ,能否与引进的桉属树种形成较好的菌根还有待于进一步研究 .本文对自然条件下混合菌根的形成及真菌间的竞争关系进行了讨论

Diversity and Colonization of Putative Mycorrhizal Fungi in Eucalyptus Plantations in Southern China

Based on a recent survey of putative mycorrhizal fungus diversity and distribution in 15 Eucalyptus plantations located in the South China,17 species representing 10 genera were collected and identified likely to be ectomycorrhizal(ECM)fungi according to the presence of fruiting bodies under Eucalyptus stands.Fungi in the genera Scleroderma,Laccaaria and Pisolithus were the most common species associated with Eucalyptus. Further confirmation of fungal comparability and persistence for exotic eucalypts is required as these fungi are commonly associated with native pine forests in southern China.There was a higher diversity of arbuscular mycorrhizal (AM) fungi than ECM fungi in eucalypt plantations.About 28 species(including 7 unnamed isolates)),belonging to four genera( Glomus,Acaulospora,Sclerocystis and Scutellospora) were observed in soil samples.Among them,18 species were identified to be Glomus fungi making up 64% of the total taxa collected. G.formosanum and G.geosporum were generally the most prevalent species in most plantations in the survey. G.mosseae, which was mainly restricted to alkaline soil in northern China,was also present in some soils from southern China.An additional survey on mycorrhizal colonization in roots of Eucalyptus over a range of plantation ages was undertaken from April to September.Roots from soil cores taken from 15 plantation sites were processed and examined under a microscope to assess mycorrhizal types and fungal colonization.Most root samples were associated with mycorrhizal fungi,either ECM or AM,or both.A general increase in root colonization with plant age by ectomycorrhizal fungi at the expense of AM fungal colonization indicated possible interaction between the two groups of fungi.