- 作者: 張和喜; 任慧超
- 作者服務機構: 中央研究院植物研究所
- 中文摘要: 利用葉面壓印法(Leaf impression method)和葉面直接分離法,所得到的葉表面菌類,依序如下:Rhodotorula sp., Cladosporiu“spp.,(特別是C. herbarum),未鑑定 white yeasts, Fusariu n sp.,pycnidium-fungi,Curvularia spp., AIternariaspp., Nigrospora oryzae 和Epicoccum sp. 以上所分離的菌株,對Helminthos; orium oryae的拮抗作用,實驗室PSAplates上所做的結果,顯示除了Rhodotorula spp.有拮抗作用之外,其他菌都不表現抑制作用”Rhodotorula spp.之大部份分離株,對H. oryzae均能形成抑制帶(inhibition zone)。在6.8 x 104∕ml的濃度,對胞子發芽與發芽管之生長都有抑制之現象。關於抑制作用之機構則尚不明暸,實驗室的證明,Rhodotorula並不產生對抗H. oryzae之抗生素。 用6.8 x 101/ml濃度之Rhodotorula sp.(isolate P:,)和H, oryzae同時接種到茭白葉片,或前者先24小時接到茭白葉片“H. oryzae接種後24小時,不論有沒有加Rhoiotorula到接種原,均表現典型病斑,此初步之實驗,顯示Rhoiotorula spp.雖在實驗之培養基(PSA)上對H, oryzae有拮抗作用,但在茭白之葉表面,並沒有減低H, oryzae的致病能力。
- 英文摘要: The microfungi (including yeasts) of rice and co ba leaves most frequ-ently isolated were Rhodotorula spp.,Cladosporium spp., unidentified whiteyeasts.,Fusarium sp.,pycnidium-fungi, Curvularia spp, Alternaria spp,NigrosporaOryzae and an Epicoccum sp. in order. Except Rhodotorula spp, the above mentioned. fungi did not show antag-onistic to Helminthosporium oryzae on potato sucrose agar plates. Most ofRhodotorula isolates inhibited H. oryzae and formed an inhibition zone onPSA plates. At 6.8 x 104/Ml conc. Rhodotorula sp. (isolate Ps) reduced theconidial germination of H. oryzae. The mechanisms of antagonism ofRhodotorula spp, to H. oryzae in vitro is remaineded to be disclosed. Experi-mental results revealed that antibiosis and competition were not involved. In vivo (on co ba leaves) Rhodotorula sp (isolate P9) did not decrease theinfectivity of H. oryzae. Symptom developed well within 24 hr after inocu-lation regardless with or without mixing Rhodotorula in inocula.
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