|Title:||瓜類露菌病菌胞子囊之存活||Other Titles:||Survival of Sporangia of Pseudo peronospora cubensis Causing DownyMildew of Cucurbitst||Authors:||蔡武雄
|Issue Date:||7-Mar-1989||Publisher:||農業試驗所||Journal Volume:||38||Journal Issue:||1||Start page/Pages:||80-87||Source:||中華農業研究||Abstract:||
瓜類露菌病菌（Pseudoperonospora cubensis）胞子囊在30°C l天後，放同15°C，需經4小時後始可發芽，其發芽率為20.87％，24小時發芽率達63.11％。若在35°C l天後，放同15°C時則需經24小時後始可發芽，其發芽率僅7.01％，48小時後發芽率亦僅22.42％。若將病葉放在30°C l天後，再放同15°C，則其上之胞子囊，需經4小時始可發芽，病葉放在35°C l天後再放回15°C其上之胞子囊亦需經24小時始可發芽。胞子囊之發芽率隨著相對濕度之增加而增加，在相對濕度55、81、95及100％時，其發芽率分別為29.85、66.30、80.02及97.53％。在水瓊脂培養基中瓊脂之含量亦影響胞子囊之發芽率，瓊脂含量2.0時發芽率在15°C 24小時後高達99.30％，瓊脂含量3.0％時發芽率亦達96.91％，但瓊脂之含量高至8.0％時胞子囊不發芽。胞子囊在洋香瓜葉汁不發芽，在V－8汁濃度越高，發芽率越低，當V－8汁濃度達35％時胞子囊不發芽。胞子囊在土壤含水量30％，經24小時尚不發芽，4天後發芽率僅2.66％，其發芽率隨含水量之增加而增加，50％含水量時24小時後之發芽率為20.38％。另胞子囊在30％含水量之土壤中可存活至少14天。胞子囊製成胞子懸浮液後經6及24小時接種，植株均可發病，但存放48小時者不發病。
The sporangia of Pseudoneropospora cubensis were incubated at 30°C for one day, and then transferred to 15°C, additional four hours were necessary to germinate, the germination percentage at this time was 20.87%. As long as at 15°C for 24 hrs the germination percentage increased to 63.11%. If the sporangia were incubated at 35°C for one day first and then transferred to 15°C, another 24 hrs were needed for germination, and the germination percentage was only 7.01%. Even at 15°C for 48 hrs, the germination percentage was also increased to 22.42% only. If the infected leaves with sporangia were incubated at 30°C for one day and then moved to 15°C, the sporangia also took 4 hrs for germination. While the infected leaves with sporangia were incubated at 35°C, it required 24 hrs for germination. On the other hand, the germinability increased with increasing relative humidity, at the RH of 55, 81, 95 and 100% the germination percentage were 29.85, 66.30, 89.02 and 97.53%, respectively. The agar content in water agar medium also influenced the germination of the sporangium. When the agar contents were at 2.0% and 3.0% the germination percentage were 99.30 and 96.9%, respectively, after 24 hrs of incubation at 15°C. As agar content reached 8.0% no germination was observed. The sporangia also did not germinate on the leaf juice of Cucumis melo. When the sporangia were incubated on V-8 juice, it indicated that the higher the concentration of V-8 juice, the lower the germinability was observed, and 35% of V-8 juice, germination didn’t occur. On the other hand, the results also indicated that in the soil with 30% of water content the sporangia did not germinate even after 24 hrs of incubation. After 4 days of incubation, the germination percentage was only 2.66%. Therefore, the germinability increased with increasing water content. The sporangia could survive at least 14 days under 30% of water content in the soil. The fungus of downy mildew of cucurbits maintained its infectivity in spore suspension after 6 or 24 hrs preparation , however, after 48 hrs, no infectivity was observed.
|Appears in Collections:||1.台灣農業研究(1950～迄今)|
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