蕹菜白?袢葙瀁R菜植株光合作用與醣類代謝之影響

柯如營

指導教授 ： 周雪美博士

國立臺灣師範大學/理學院/生物學系/碩士(2001年)

摘要

本研究以蕹菜（Ipomoea aquatica Forsk）作為實驗材料，探討蕹菜白?袢?(Albugo ipomoeae-aquaticae)對其植株形態與光合作用生理上的影響，並驗證“蔗糖轉化酵素活性提高是造成感病植株光合作用下降的主要因子”之假說。根據光學與電子顯微鏡觀測之孢子囊與卵孢子的形態與大小，鑑定實驗菌種為蕹菜白?袢腄C蕹菜植株感病7天之後，開始出現形態與生理上的變化；子葉與成熟葉之上表皮出現黃褐色病斑，下表皮形成白色孢子囊堆。接種後7-14天，呼吸速率以及蔗糖轉化酵素、ADP-葡萄糖焦磷酸酵素、b-澱粉酵素活性提高，葡萄糖、果糖、以及海藻糖含量大幅上升，澱粉堆積，蔗糖合成酵素活性降低，蔗糖、葉綠素a、類胡蘿蔔素的含量下降，氣孔導度、蒸散速率、以及光合作用同化速率下降。根據感病過程中，光合作用與醣類代謝變化發生的時間順序顯示，支持上述假說。

關鍵字

蕹菜白?袢 ； 光合作用 ； 醣類代謝 ； 蔗糖轉化酵素

並列摘要

The aim of this study was to investigate the impact of white rust on the morphology and photosynthetic physiology of Ipomoea aquatica, a very common vegetable in Taiwan, and to examine the hypothesis that increasing the activity of invertase was the primary factor responsible for the reduction of photosynthesis in diseased leaves. According to the morphology and size of sporangia and oospores examined by light and electronic microscopes, the studied pathogen was identified to be Albugo ipomoeae-aquaticae. Changes in morphology and physiology of infected leaves occurred 7 days after infection. Yellow-brown patches and white rust pustules appeared respectively on the upper and lower surfaces of locally infected cotyledons and leaves. Elevation of respiratory rates and the activities of invertase, ADP-glucose pyrophosphorylase and b-amylase, increase in the amounts of glucose, fructose, starch and trehalose, decrease in the contents of chlorophyll a, carotenoids and sucrose, and in the activity of sucrose synthase, and decline in the rates of assimilation, transpiration, and stomatal conductance were observed in the infected tissues during the infection (7-14 days after infection). The timing of the changes in the photosynthetic and carbohydrate metabolism of the infected tissues described above suported the hypothesis.

並列關鍵字

Albugo ipomoeae-aquaticae ； photosynthesis ； carbohydrate metabolism ； invertase