链格孢菌对银海枣的趋向性与其对寄主识别和侵染的联系  

Tropism of Alternaria alternata f. sp. phoenix to Phoenix sylveseris Associated with Its Recognition and Infection

作　　者：孙思[1] 王军[1] 

机构地区：[1]华南农业大学林学院,广州510642

出　　处：《林业科学》2009年第1期107-111,共5页Scientia Silvae Sinicae

基　　金：广州市花木病(虫)害调查及重要病害控制技术研究

摘　　要：以银海枣褐斑病的病原菌链格孢刺葵专化型为材料,研究其对寄主和非寄主叶片伤口的趋向性及其特异性。结果显示病菌对寄主叶片伤口具有强烈的趋向性,对非寄主伤口则基本缺乏定向性生长。趋向性的存在和强度与病菌对供试植物的识别和成功侵染有密切联系。病菌的趋向性受到伤口与孢子之间距离的影响,在500μm范围内,趋向性反应最强,但当距离超过1000μm后,趋向性下降甚至消失。伤口新鲜度是影响趋向性强度的另外一个因素,新鲜伤口对真菌芽管具有较强的吸引力,但24h的伤口对芽管吸引力大幅下降,48h或以上时间的伤口基本失去了吸引力。沾染了非寄主叶片汁液的寄主伤口的吸引力下降;而沾染寄主叶片汁液的非寄主伤口的吸引力却上升。病菌在寄主叶片汁液中生长旺盛,但在非寄主叶片汁液中生长贫弱。链格孢刺葵专化型对寄主伤口的趋向性生长具有明显的特异性,趋向性是该病理系统病菌与寄主识别的首发事件,对于启动病菌对寄主植物的成功侵染起着关键作用。This paper investigated the tropism and its specificity of Alternaria alternata f. sp. phoenix, a pathogen of brown leaf spot of Phoenix sylveseris, to the leaf wounds of host and nonhost trees. The results showed that the germ tubes of the fungus had strong tropic growth toward the fresh wounds of hosts, but had little or no such direetional growth to those of nonhosts. The existence and intensity of tropism of the pathogen were strongly associated with the recognition and successful infection to tested plants. Tropism of the fungus was affected by the distance between the wounds and spores, strong tropic response was observed within the range of 500 μm, and it decreased or even lost when the distance exeeeded 1 000 ,μm. The freshness of wound is another major factor that affects the intensity of tropism, the fresh wound had stronger attraction to the fungal germ tubes, but the attraction of 24 hours old wound decreased dramatically, and the attraction almost lost when a wound was 48 hours or elder. The wounds of host tainted with non host leaf juice reduced their attraction, on the other hand, the wounds of non host tainted with host leaf juice increased their attraction. The fungus developed vigorously in host leaf extract liquids, but grew poorly in non host leaf extract liquids. The results of experiment demonstrated that there existed significant specificity of tropic growth of A. alternata f. sp. phoenix to wounds of hosts. Tropism is the first event in fungus-host reeoguition in this pathosystem and plays a crucial role in initiating a sueeessful infection to host plants.

关 键 词：链格孢刺葵专化型 银海枣 趋向性 识别 

分 类 号：S763.15[农业科学—森林保护学]