| dc.description.abstract | 本省中南部於1982 年第二期作之乳熟期水稻發現一種穀粒新病害。被害穀粒初呈蒼白色漸變為灰白色或淡黃褐色，內外穎先端或基部呈紫褐色，護穎常呈紫褐色至暗紫褐色，穗軸及枝梗則健全而呈綠色；罹病穀多呈不稔，若能稔實，其糙米大多萎縮畸形，一部分或全部變為灰白色、黃褐色或濃褐色，患部與健全部界限明顯。由病穀上共分離得到13 個細菌菌株，依照柯氏法則( Koch’s Postulates ) ，經二次接種及再分離之結果證實確為本病之病原。選取B9、O1及P4 等3 個菌株進行形態及生理試驗，本菌呈革蘭氏陰性、桿狀、鞭毛單極生、好氣性、在NA 培養基上呈白色稠狀菌落，可液化白明膠，可還原litmus milk 及nitrate ，可產生氨，可水解Tween 80 ，有卵磷脂酵素作用，略可在4%食鹽下生長，Koras’ oxidase activity 測試觀察20秒後呈正反應；methyl red test 及arginine dihydrolase 為負反應，不產生瑩光色素、H2S 、indole及leavan 。本菌最好的生長溫度為28℃，最高生長溫度在40℃ 以上，最低溫度為8~12℃。根據以上諸特性，本病原菌應屬Pseudomonas glumae Kurita et Tabei .
In central and shouthern Taiwan, a new disease of rice was found at the milky stage of second crop in 1982. Eased on the smptomology, morphology and physiology of the pathogen, the disease is identified as bacterial grain rot of rice caused by Pseudornonas glumae. The diseased grains scattered on the panicles, but in severe cases more than half of the grains may be attacked. The sterile lemmas of infected grains were purplish brown to deep purplish brown, however, the branches remained green. Infected grains were shrunk and pale green first, then became dirty grey with age and finally turned to yellowish brown to deep brown and dried up. The infected part of hulled rice was grey, yellowish brown, or deep brown with a clear cut from the health part. Thirteen isolates of bacteria were isolated from diseased grains collected at different locations. According to the results of inoculation and reisolation tests, all isolates were considered the pathogen of grain rot as suggested by Koch’s Pospulates. Three (i. e., B9, O1 & P4) out of the 13 isolates were selected and used for physiology and morphology studies. The three isolates were all Gram-negative, rod shaped, monotrichous and aerobic. They formed white viscid colonies on nutrient agar, liquefied gelatin, reduced litmus milk and nitrate, produced ammonia, hydrolyzed Tween 80, produced lecithinase, grew on 4% salt slightly, delayed the reaction of oxidase activity 20 seconds after treament, and not reacted to methyl red test. No arginine hydrolase, fluorescin, H2S, indole, or leavan production was observed. The maximum temperature for the growth is higher than 40°C; optimum, 28°C; minimum, 8-12°C. | en_US |
