- 作者: 謝式坢鈺
- 作者服務機構: 國立中興大學植物病理學研究所
- 中文摘要: 水稻白葉枯病菌在感病性品種嘉農秈11號維管束內之移動比在抵抗性品種臺中秈216號快很多。在感病性品種內,白 葉枯病菌移動迅速, 一直到大都數維管束被佔據?止。在抵抗性品種內,病菌被限制在接種部位附近,而不會到達生長點。 當病菌由感病性品種之幼苗葉片侵入後,迅速在維管束內向下移動和繁殖。接種後第十天,病菌到達莖基部之生長點,然後向上移動至其他葉片之維管束。接種後第十七天,生長點及大都數維管束被病菌佔據時,幼苗?萎凋-表現典型的急 性萎凋病徵。如病菌由根部侵入幼苗,病菌向上移動與繁殖,接種後第九天,病菌?可佔據整個生長點及新長出葉片之葉鞘。 白葉枯病菌在感病性品種體內之繁殖也比在抵抗性品種快,到病害發展末期,約接種後第十六天,嘉農秈11號,每苗約有1 X 10^12病菌,而臺中216號則每苗只有5 X 10^8病菌。 引起嘉農秈11號急性型萎凋最少病菌數目?:經葉片須60個病菌,如經由根尖部侵入,則須較多病菌?1,000個。
- 英文摘要: The translocation of Xanthomonas oryzae in the vascular bundles of a susceptible variety (Chianung sen 11) was quicker than that of resistant variety (Taichung sen 216). In the susceptible variety, the pathogen moved freely until most of the vascular bundles were occupied by the bacterium. In the resistant variety, the bacterium was limited to certain portion of the inoculated leaves and never reached the meristem of the plant. After the pathogen invaded into the rice seedlings of a susceptible variety through the leaf tissue, it moved downward and multiplied in the vascular bundles rapidly. It reached the meristem of the plant 10 days after inoculation, and then was translocated to other upper vascular bundles of the leaves. Finally when the meristem and all the lower portion of vascular bundles of the leaves were filled with the bacterium, about 17 days after inoculation, the rice seedlings wilted and showed typical symptoms of kresek. If infection occurred on a root of a susceptible variety, the pathogen migrated upward and eventually occupied the whole crown and newly emerged leafsheath 9 days after inoculation. The multiplication of X. oryzae in vivo was also faster in the susceptible va'riety than in a resistant one. At the end of disease progress, 16 days after inoculation, the number of bacterial cells in Chianung sen 11 was 1*1012/seedling, but only 5 x 108/seedling in Taichung sen 216. The lowest number of X. oryzae cells needed to infect and induce kresek on Chianung sen 11 was 60 cells when the bacterium infects through wounded leaves and 1,000 cells are needed when the bacterium infects through wounded roots.
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