南澳大利亚麦田茄丝核菌抑病土中木霉菌的特性和鉴定

从抑制Rhizoctonia solani的麦田土中分离到木霉菌，依据形态特征，鉴定为Trichoderma pseudokoningii，T.parceramosum,T longibrachianum和T.harzianum。取样土壤为灰质砂壤土，pH8．4(H2O)，位于南澳大利亚的埃文。研究了与生物防治作用机制相关的生理学特性包括几丁质酶活性、β-1，3-葡聚糖酶活性、内切葡聚糖酶活性、抗菌活性以及重复寄生能力。T。pseudokoningii生长速度快但是产分生孢子少，但是T.parceramosum产分生孢子多。与其他种类相比，Trichoderma pseudokoningii的分离频率高，在盆载条件下对小麦Rhizoctonia solani根腐病以及全蚀病防治效果高，对R．solani的重复寄生能力强。Trichoderma pseudokoningii菌株问的重复寄生能力差异不明显，但在几丁质酶活性和β-1，3-葡聚糖酶活性上有明显差别。依据平板抑菌能力，可将木霉菌株分为3个组。菌株在不同pH培养基上的生长速度不同，但没有发现特别能适应碱性条件而快速生长的菌株，虽然这些菌株都分离自碱性土壤。

Characterisation and identification of Trichoderma isolates from a South Australian soil suppressive to Rhizoctonia solani on wheat

Trichoderma pseudokoningii, T. parceramosum, T. longibrachiatum and T. harzianum were identified based on morphological characterisation of isolates from a Rhizoctonia solani suppressive wheat field soil. The soil, a calcareous sandy loam, pH 8.4 (H2O) was collected from Avon, South Australia. Physiological characters which are possibly connected to biocontrol mechanisms including chitinase,β-1,3-glucanase and endoglucanase activity, antibiosis and mycoparasitism were investigated.T. pseudokoningii was fast growing and poor in conidiation, but T. parceramosum isolates were good conidium producers.Compared to the other species,Trichoderma pseudokoningii showed much higher isolation frequency, was better in controlling Rhizoctonia solani root rot and take-all of wheat in a pot experiment, and had stronger mycoparasitic ability toward R. solani. No remarkable difference was found among Trichoderma pseudokoningii isolates in their mycoparasitic ability, but differences were found in their chitinase and β-1,3-glucanase activity.Based on an inhibition rating, Trichoderma isolates tested were categorised into 3 groups. In addition, Trichoderma spp. grew at different rates on media of different pH, but all isolates tested were not specially more adapted to alkaline media in overall growth rate, even though they were isolated from alkaline soil.