|Title:||由Pythium helicoides引起之巴西野牡丹根腐病||Other Titles:||First report of root rot of Tibouchina semidecandra caused by Pythium helicoides in Taiwan||Authors:||黃晉興
|Keywords:||巴西野牡丹;根腐病;Pythium helicoides;Tibouchina semidecandra;root rot;Pythium helicoides||Issue Date:||Mar-2009||Publisher:||中華民國植物病理學會||Journal Volume:||18||Journal Issue:||1||Start page/Pages:||51-56||Source:||植物病理學會刊||Abstract:||
2004年田間調查發現盆栽巴西野牡丹易發生根腐病，罹病株呈現葉片褪色、落葉及植株枯萎的病徵，而根部則褐化腐敗。自罹病植株根部可分離得一種腐霉菌(Pythium sp.)，在蔬菜汁培養基上，該菌菌絲透明無隔，直徑可達7µm，孢囊亞球形(subglobose)或卵形(ovoid)，平均人小為35×28 µm，有乳突，孢囊柄多分枝；游走子靜止子平均大小為12.0µm，孢囊釋放游走子後易內再生；藏卵器頂生或間生，平均人小為34.5 µm；每個藏卵器有1-4藏精器附著，藏精器呈延長形(elongate)，平均人小為20.8×5.6 µm，藏精器柄常纏旋藏卵器基部；卵孢子為球形(globose)或亞球形(subglobose)，淡褐色，非充滿型(aplerotic)，平均大小為29.0µm，依上述之形態特性，鑑定此菌為Pythium helicoides Drechsler。本菌菌絲於12-40℃可生長，最適溫為36℃，生長速率可達3.8 cm/day；於溫室經人工接種確定該菌對巴西野牡丹其病原性，乃25℃以上可造成嚴重之根腐，除了巴西野牡丹之外，本菌亦可危害迷你玫瑰，但不危害番茄、胡瓜、白菜及豌豆。
The potted Glory flower (Tibouchina semidecandra Cogn.) in the field was found to appear serious disease at Wufeng, Taichung in the summer of 2004. The main symptoms were leaf chlorosis followed by defoliation, and brown, water-soaked root rot. Pythium isolates were isolated from roots of disease plants. These isolates formed branched sporangial stalks and produced internal nested
proliferous ellipsoidal papillate sporangia, spherical smooth oogonia, elongate antheridia, and aplerotic oospores. The mycelia could grow on the media from 12-40℃. The optimum temperature for hyphal growth was 36℃ with a growth rate of 38 mm/day. The microorganisms were identified as P. helicoides based on these characteristics. In pathogenicity tests, the pathogen caused the root rot and blight symptoms on Glory flower as in nature and induced the same symptoms of miniature rose. But it didn't cause any symptoms of tomato, cucumber, Chinese mustard and pea. The disease was more serious at higher temperature (35℃) than at lower temperature (20-25℃). After inoculation, the leaves turned yellow and the roots were water-soaked rot on the third day, and followed by leaf blight and root dieback after 7 days. This is the first report of root rot of T. semidecandra caused by P. helicoides.
|Appears in Collections:||植物病理組|
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.