修剪及環剝對荔枝開花的影響

Abstract

本研究目的在探討枝葉修剪與環剝處理對荔枝開花率、抽穗時期及花穗性狀的影響。試驗方法是以‘玉荷包’荔枝進行修剪與環剝單獨及複合處理。在未修剪及弱剪處理者環剝，對開花率沒有影響；但強剪處理者若不配合環剝則開花率顯著降低。弱剪處理不會延後花穗抽出時期，而強剪處理則會延後15天。環剝處理不會延後抽穗時期。修剪與環剝單獨及複合處理均會影響花穗發育。花穗長度隨著修剪程度的增加而顯著縮短，而環剝處理則會更加縮短；強剪處理會提高花穗之偏雌花比率而弱剪處理則無此效應；環剝處理亦會提高花穗之偏雌花比率，但不會受到修剪程度的影響。本試驗結果顯示，修剪處理會因延遲枝條成熟時間或延後抽穗日期之效應，而使花芽誘導及花穗發育時期所處的微氣候環境不同，進而影響荔枝開花及花穗性狀。但環剝處理對開花及花穗性狀的影響，則與改變植體的生理機制有關。在本文中亦討論了修剪與環剝處理對荔枝結果的影響。 The separated and combined effects of pruning and girdling branches on flower initiation and flower development were investigated in ‘Yu Her Pau’ litchi (Litchi chinensis Sonn.). Light pruning and girdling did not influence the flowering, but flowering in heavy pruning was very little in the absence of girdling. Light pruning did not delay the date of panicle emergence, but heavy pruning delayed 15 days. Girdling pre se did not influence the date of panicle emergence. Pruning and girdling did influence the panicle development. Pruning reduced panicle length and the response was stronger in heavy pruning. Combined treatments of pruning and girdling reduced panicle length more than spearated treatment. Heavy pruning increased the proportion of female flowers, but not in light pruning. The proportion of female flowers increased by girdling but the response had no relations to pruning. The results of this experiment indicated that the effects of pruning on flower initiation and flower development are related to environmental factors, especially air temperature, during flower induction and early stage of flower development. However, the effects of girdling on flower initiation and flower development depend relatively on the changes of physiological mechanism in plant. The effects of pruning and girdling on fruit set were discussed in this report.