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標題: 根溫處理對水耕萵苣生理之影響
Effect of root temperature on the physiology of solution cultured lettuce.
作者: 方怡丹
Fang, Yi-Dan
關鍵字: Lettuce
solution culture
root temperature.
出版社: 園藝學系
摘要: 萵苣"帥透"與"陛下"二品種處理根圈溫度25℃,30℃,35℃,高根溫處理使 地上部生長受阻,根生長與根長度在35℃處理後均受抑制,根部外觀偏褐 色,支根減少且根尖褐化或壞死;地上部乾重在35℃亦最低,生長停滯期 較25℃, 30℃處理者延長;根部生理活性隨根溫增加而升高,加速根部碳水 化合物消耗,使地上部往根部運移之還原糖,可溶性糖類增加.高根溫改變 植體內碳與氮之平衡, ;35℃處理者地上部全氮量,硝酸態氮均減少,並加 速蛋白質分解 ,致使可溶性蛋白質與游離胺基酸含量增加;另外,脯胺酸亦 隨根溫增加而累積,且植體內有轉運之現象,為逆境下出現之訊號物質;葉 片相對滲漏率以 35℃較嚴重,根部則差異不顯著.高溫處理對養液內大量 元素之吸收率有影響.二品種萵苣對養液中氮,鉀,鎂吸收皆隨根溫升高而 降低吸收率,磷,鈣則不受根溫影響.
Cultivars lettuce "Celture" and "Majesty" were grown in nutrient solution with root-zone temperature maintaining at 25℃, 30℃, and 35℃ . Root length as well as relative growth rate of the root were inhibited by 35℃ root-zone temperature. The affected plants had less secondary roots and brown root tips. Shoot dry weight was the least with 35℃ treatment. A longer lag phase was observed on the growth curve with 35℃ as compared with 25℃ o Increasing root temperature resulted in higher root activityas datermined by TTC test, Higher activity lead to more carbohydrates consumption in the root. This, in turn, induced the export of reducing r in the root. The balance of carbon and nitrogen in plant tissue was disturbed by the supra-optimal temperature. Total nitrogen and nitrate-N declined with 35℃ root temperature, which protein degradated with 35℃. Proline content in tissue accumulated in root with the enhancement of root temperature. Translocation of proline between tissue was observed, which might be used as an index of environmental stress.The most severe with 35℃ treatment. In the root tissue, hundred percent leakage was detected due probably to the impact of high temperature treatment (35℃). Macroelements uptake by lettuce plants were also affected by the supra-optimal temperature. For both cultivar tested, the increasing root temperature reduced the absorption of N, K, and Mg, while levels of P and Ca were not affected.
Appears in Collections:園藝學系



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