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花胡瓜光合作用特性之研究
The Studies on Photosynthetic Characteristics of Cucumber
摘要
本試驗調查光強度、二氧化碳濃度、溫度及設施內環境變化對二品種花胡瓜(Cucumis anguria L.)光合作用相關生理反應之影響，以供設施栽培管理之參考。由光反應曲線可知花胡瓜之光補償點、光飽合點及最大淨光合作用值(Pn)分別約為15～30 mol‧m^(-2)‧s^(-1)、1,000～1,200 mol‧m^(-2)‧s^(-1)及12～13 μmol CO_2‧m^(-2)‧s^(-1)。由CO_2反應曲線可知其CO_2飽合點約為1,000～1,200 mg‧L^(-1)，此時之Pn為16 μmol CO_2‧m^(-2)‧s^(-1)，較正常400 mg‧L^(-1)大氣濃度下增加約2倍。於25～40℃下植株Pn介於10～13 μmol CO_2‧m^(-2)‧s^(-1)，溫度間無顯著差異，45℃下Pn則降低約20%。夏作設施栽培花胡瓜植株Pn於上午6點後顯著上升，12點到達高峰值為18.4 μmol CO_2‧m^(-2)‧s^(-1)，此時設施內環境光強度約1,300 μmol‧m^(-2)‧s^(-1)、溫度達40℃、相對溼度54.9%、蒸氣壓差4 kPa，12點之後Pn則顯著下降。
並列摘要
In order to understand the photosynthetic characteristics of cucumber (Cucumis anguria L.) for its cultivated management under protected house, two cucumber cultivars 'Kappa Summer No. 11' and 'CU-87' plants were used as experimental materials. The effects of light intensity, carbon dioxide concentration, temperature, and diurnal changes of environment on photosynthetic related responses were studied. Light compensation point, light saturation point and maximum net photosynthetic rates (Pn) of cucumber were 15～30 mol‧m^(-2)‧s^(-1), 1,000～1,200 mol‧m^(-2)‧s^(-1), and 12～13 μmol CO_2‧m^(-2)‧s^(-1), respectively. The CO_2 response curve showed that the CO_2 saturation point was 1,000～1,200 mg‧L^(-1) while the Pn was 16 μmol CO_2‧m^(-2)‧s^(-1) and double higher than Pn was under 400 mg‧L^(-1). The Pn of cucumber plants grown under 25～40℃ were not different significantly, but decreasing about 20% under 45℃. The Pn diurnal changes of cucumber plants in protected house during summer cropping started elevated at 6:00AM and reached the peak 18.4 μmol CO_2‧m^(-2)‧s^(-1) at 12:00AM. In the meanwhile, the environmental factors was 1,300 μmol‧m^(-2)‧s^(-1) light intensity, 40℃, 54.9% relative humidity, and 4 kPa vapor pressure deficit. After 12:00 AM, Pn decreased significantly.