暗褐网柄牛肝菌是外生菌根菌吗?--暗褐网柄牛肝菌与思茅松和栲树的菌根合成

摘要

在野外生态调查中，笔者从未发现暗褐网柄牛肝菌(Phlebopus portentosus)和任何树木根系形成外生菌根的结构。为了进一步证实暗褐网柄牛肝菌是否为外生菌根菌，在温室条件下，用暗褐网柄牛肝菌栽培种和液体种对思茅松(Pinus kesiya var.langbianensis)和栲树(Castanopsis sp.)进行菌根接种试验。接种5个月后，思茅松一、二级侧根及吸收根表面上，均有大量暗褐网柄牛肝菌菌丝缠绕生长；菌丝有锁状联合，但是并没有菌丝套和哈氏网发育的迹象。接种10个月后有大量暗褐网柄牛肝菌菌丝也缠绕在栲树根的表面，有发达的菌索；菌丝有锁状联合，呈结晶体状，但没有任何菌根结构形成。在同样的温室条件下，思茅松和印度块菌形成了典型的外生菌根。结果表明，暗褐网柄牛肝菌在室内接种条件下也不能与思茅松和栲树形成外生菌根。因此，暗褐网柄牛肝菌可能不是一种外生菌根菌。%Since ectomycorrhizal structures Phlebopus portentosus have never been found associated with tree roots in the field,the ectomycorrhizal status of the fungus has been evaluated using Pinus kesiya var. langbianensis and Castonopsis sp. grown under greenhouse conditions on substrates consisting of peat, vermiculite,cow dung and garden soil (1/1/1/1;v/v/v/v)(G1)and red loam,river sand and coconut bark powder (2∶2∶1;w/w/w)(G2).Five months following inoculation,the surfaces of lateral roots and rootlets of P.kesiya var.langbianensis were covered with abundant mycelia with clamp connections although microscopic examination of sectioned material revealed no development of either mantle or Hartig net.Ten months following inoculation,the surfaces of lateral roots and rootlets of Castonopsis sp.were covered with a dense fungal mycelium interspersed with rhizomorphs and crystal-containing hyphae. However, no ectomycorrhizal structures were evident whereas,under identical conditions,P.kesiya var.langbianensis formed ectomycorrhizas with Tuber indicum.Our data raise the possibility that P.portentosus may not be an ectomycorrhizal fungus.