秦艽斑枯病病原菌鉴定及生物学特性研究

The Pathogen Identification of Leaf-spot and Its Biological Characteristics on Gentiana spp.

目的:明确引起甘肃省秦艽斑枯病的病原,为深入研究和防治提供依据。方法:通过症状观察,病原菌鉴定,并以悬液法和固体法分析测定不同因子对秦艽斑枯病菌菌丝生长和产孢的影响。结果:甘肃栽培区秦艽斑枯病的病原为Septoria gentianae。PSA、PDA均利于菌落扩展和产孢;菌落扩展、产孢和菌丝干重的最适温度分别为25、20、20℃,最适pH 7;12 h光暗交替、8 h紫外线照射+16 h光照利于菌落扩展和产孢,菌丝干重以全黑暗和8 h紫外线照射+黑暗最佳。木糖、蔗糖、可溶性淀粉等3种C源利于菌落扩展,蔗糖最利于产孢,菌丝干重以棉子糖最佳;N源以丙氨酸利于菌落扩展和产孢,而尿素和NaNO2不能被利用,产孢及菌丝干重以NH4H2PO4最好。

Objective ： To clear the pathogen of leaf-spot on Gentiana spp. in Gansu province, and to control the disease theoretically. Methods： The symptoms were observed and described in the field. The pathogen was identified on the base of morphology. The factors influencing the colony growth, mycelium gross and sporulation were studied by the suspension and solid media. Results： The pathogen was identified as Septoria gentianae. PDA and PSA were benefitial for colony growth and sporulation. The optimum temperature for colony growth, sporulation and mycelium gross were 25℃, 20℃and 20℃ respectively. The optimum pH was 7 for the pathogen growing and sporulation. 12h light plus 12h dark, 8 hours UV plus 16h light were beneficial to colony growing and sporulation. All-dark, 8 hours UV plus 16 hours dark were good for mycelium gross. Among 11 carbon sources, xylose, sucrose and soluble starch were very good for colony growth. Sucrose was best for sporulation, while raffilose best for mycelium gross. Among nitrogen sources, colony growth and sporulation quantity reached highest on alanine, urea and NaNO2 were not utilized very well. NH4H2PO4 was the best for sporulation and mycelium gross.