台灣十字花科蔬菜黑斑病的病原菌特性

Characteristics of Cruciferous Black Spot Pathogens, Alternaria Brassicicola and A. Brassicae

黃振文(J. W. Huang) ； 鍾文全(W. C. Chung)

《植物病理學會刊》 2卷3期 (1993/09) Pp. 141-148

https://doi.org/10.6649/PPB.199309_2(3).0005

摘要

本省十字花科蔬菜黑斑病主要是由Alternaria brassicicola與A. brassicae等兩菌所引起，其中以A. brassicicola的出現頻率較高。A. brassicicola的分生孢子具縱橫隔膜，暗褐色，有或無口喙，長串鏈生，大小為7.7-46.3×7.7-19.3μm；A. brassicae的分生孢子亦具縱橫隔膜，淡褐色，有15.4-115.5μm長的口喙，單生或短鏈生，大小為77.0-231.2×15.4-30.8μn。這兩種病原菌具有相同的寄主範圍，除為害白花芥藍、蘿蔔、芥菜、油菜、甘藍、包心白菜與青江白菜等十字花科蔬菜外，亦可為害細葉碎米薺。比較兩菌菌株間的致病毒力，發現A. brassicicola菌株間的致病毒力差異顯著，而A. brassicae菌株問則差異不明顯。利用掃描式電子顯微鏡觀察兩菌在白花芥藍葉表的侵入方式，發現大部分的A. brassicicola先形成附著器，再行侵入寄仁，惟A. brassicae主要是經由氣孔侵入。此外，在白花芥藍葉表，A. brassicicola與A. brassicae發芽的最適溫度分別是16-32 C與12-24 C；形成附著器的最適溫度分別是24-28 C與24 C；而兩者侵入葉片造成病斑的最適溫度則分別為28 C與24 C。

關鍵字

十字花科蔬菜黑斑病 ； 分生孢子形態 ； 寄主範圍 ； 致病毒力 ； 侵入寄主方式

並列摘要

Black leaf spot of crucifers in Taiwan was found to be caused by Alternaria brassicicola and A. brassicac. These two pathogens showed the same host range among eight cultivated species and cultivaes of crucifers, and six species of cruciferous weeds tested. However, on Chinese kale A. brassicicola displayed greater variation in pathogenicity among isolates tested than A. brassicae. Obsercation with the scanning electron microscope revealed that A. brassicicola penetrated leaves of Chinese kale directly via formation of appressoria, while A. brassicae invaded the leaf tissue through the openings of stomata. The optimum temperatures for germination of conidia and formation of appressoria on detached leaves of Chinese kale were 16~32 C and 24-28 C, respectively, for A. brassicicola; and 12-24 C and 24, respectively, for A. brassicae. In general, A. brassicicola required about 4 C higher than A. brassicae for the optimum growth.

並列關鍵字

Alternaria brassicicola ； A. brassicac ； morphology ； host range ； virulence ； cruciferae