水份控制對柑橘碳水化合物含量及花芽形成的影響

Abstract

以盆栽之柑橘苗進行試驗，調查水份控制對碳水化合物含量及開花的影響。六個月的粗皮檸檬實生苗，在逐漸乾旱的過程中，澱粉在葉片發生萎凋現象前即迅速減少，而可溶性糖含量略增加。乾旱之後再充份灌水，碳水化合物含量即開始增加，可達13%至17%，高於對照區的含量，此可能與再灌水後之生長停滯現象有關。碳水化合物含量的變化，在葉片與莖中均呈相同的趨勢，顯示其增減並非由於轉運的結果。碳水化合物含量差異大時，對葉片單位面積之乾重將有明顯的影響，營養成份以乾重率為表示單位時，應注意其變化。二個月的水份控制，使柳橙幼株停止生長，可溶性糖在葉片中明顯累積，同時花芽大量形成。 Two experiments were conducted to investigate the effect of drought on carbohydrate content and flower formation of citrus. (1) Six months old Rough lemon seedlings were subjected to a water-stressed period of 28 days till 32% RWC of newly full expended leaves. (2) Liu-cheng orange buddlings of nine months old were water-controlled for 2 months. When Rough lemon seedlings were water stressed, alcohol soluble sugar increased slightly, and starch decreased before the mature leaves wilted. After rewatering there was a lag period of growth, and starch accumulated, its concentration reached 13% to 17% of dry weight. Because dry weight of leaf (g/m2) of water-stressed seedlings and DW/ FW ratio of rewatered seedlings changed in accordance with the content of total carbohydrate, it should be noticed that nutrient concentration may be influenced if dry weight is used as a basis. A significant effect of water control on flower bud formation was observed when container-grown Liu-cheng orange young trees were irrigated 150 ml/week for each tree. We found water-controlled trees produced 45.8 flowers per tree comparing with 2.0 flowers of well-irrigated trees after the treatment of 2 months. Soluble sugar content in water-controlled trees was 2.7 times higher than that of well-irrigated trees.