新疆小麦黑胚病主要病原的侵染特性研究

【目的】研究新疆小麦黑胚病主要病原的侵染特性。【方法】对采集的新疆小麦样品进行病菌分离鉴定,根据柯赫氏法则,通过田间回接试验,确定引致新疆小麦黑胚病的主要病原菌;并在小麦不同生长时期、不同部位进行病原菌的接种,观察其侵染特性。【结果】确定引致新疆小麦黑胚病的主要病原物是细链格孢Alternaria tenuis C.G.Nees.]和小麦根腐离蠕孢Biplaris sorokiniana(Sacc.)Shoem.]。两种主要病原物从小麦抽穗期至灌浆盛期均可侵染,以扬花末期和灌浆初期分别为细链格孢和小麦根腐离蠕孢的最适侵染时期,适宜的侵染部位为颖壳和小穗轴。细链格孢全疆都有分布,但在田间接种条件下致病力较小麦根腐离蠕孢弱。两种主要病原菌的萌发侵染方式不同,细链格孢孢子萌发产生附着孢,通过侵入钉侵染植物组织,而小麦根腐离蠕孢孢子则直接通过一端或两端萌发产生菌丝侵入植物组织。【结论】新疆小麦黑胚病的主要病原有两种,细链格孢分布广泛,田间分离率高,而小麦根腐离蠕孢致病力强。两种病原菌的侵染方式及适宜的侵染时期均不同。

Study on the Pathogenetic Fungi of the Black Point Disease of Wheat and Their Characteristics of Infestation in Xinjiang

【Objective】The fungal identification was determined from the 119 samples of 31 counties during 2003-2005 in Xinjiang.【Method】 Pathogen was isolated and confirmed by back inoculation as well as the Koch's postulates 【Result】Alternaria tenuis C.G.Nees.was the main pathogen in all grain-growing areas of Xinjiang;Biplaris sorokiniana(Sacc.) Shoem.was the second important pathogen that mainly occurred in some cetain areas.The pathogenicity of Biplaris sorokiniana(Sacc.) Shoem.was stronger than that of Alternaria tenuis C.G.Nees at inoculation condition in the field.The period of infection was from the heading date to middle filling of wheat,and the last phase of flowering and early filling of wheat was the fittest period of infection for A.tenuis C.G.Nees and B.sorokiniana(Sacc.) Shoem.The rachilla and glumes were suitable invasion part.There are different in spore geminating and infesting between the two pathogens.A.tenuis C.G.Nees.produced appressoria firstly,then invaded plant organism by penetration peg.B.sorokiniana(Sacc.) Shoem could geminate from one end or both ends to produce mycelium invading plant organism directly.【Conclusion】 Both Alternaria tenuis C.G.Nees.and Biplaris sorokiniana(Sacc.) Shoem.were the main pathogens.Alternaria tenuis C.G.Nees.was widespreaded and with high rate of isolation,whereas Biplaris sorokiniana(Sacc.) Shoem.with strong pathogenicity.Method of infestation and suitable invaded period are quite different between these two pathogens.