強剪與溫度對四季橘花芽形成與開花之影響

Abstract

本試驗利用不同月份強剪及溫度處理，探討其對花芽形成與開花的影響。四季橘（Citrus microcarpa Bunge; syn. C. mandurensis Lour.）在未修剪的狀態下，一年有三次抽梢期，分別於二至三月、六至七月與十至十一月，開花期為二至三月、六至七月與十至十二月，每次抽梢均會開花。強剪後之四季橘植株，第ㄧ次梢皆為營養芽，在第二次抽梢時才產生花芽，顯示強剪對第一次梢的花芽形成有抑制作用。不同月份強剪處理的結果顯示，元月、二月、三月、十一月及十二月強剪組，於五至六月抽出第二次梢時方開花。四月與五月強剪組，在九月抽出第二次梢，始花期為十月；六月與七月強剪者，在十月抽出第二次梢，始花時間為十至十一月。八至十月強剪處理者，至次年二月萌出第二次梢時開花。 將於三月、六月、九月強剪處理者之第一次梢頂芽，以石蠟切片觀察後，發現其分別於六至七月、九月、次年一月開始花芽分化。亦即在台北之環境下，強剪後之第一次梢，約會維持在營養狀態下二至三個月。而在十二月強剪後之植株，經過日/夜溫27.5/22.5℃處理3週，即可觀察到花芽分化初期階段。以四種日/夜溫度，30/25，25/20，20/15及15/13℃處理下，以日/夜溫30/25℃處理者於處理後第2週開花為最早，25/20℃處理者於處理後第8週開花，20/15℃及15/13℃處理開花時間則需處理後22週，才開始開花。

Abstract Calamondin (Citrus microcarpa Bunge; syn. C. mandurensis Lour.) has three flushes per year, which occur in February to March, June to July and October to November, under natural condition in Taipei. Normally, each flush simultaneously formatted flower, so will flowering three times, which are February to March, June to July and October to December. In this experiment, we treated potted calamondin plants with heavy pruning time and temperature to discuss how they effect flower formation and flowering time. The first flushes of calamondin after heavy pruning were all vegetative flushes, and flower buds occurred after the second flashes sprouting. The result had show that treatment of heavy pruning suppress generative buds of the first flushes, which sprouted after heavy pruning. Plants of heavy pruning in January, February, March, November and December flowering in May and June when the second flashes sprouted. Plants of heavy pruning in April and May flowering in October when the second flashes sprout in September. Plants of heavy pruning in June and July flowering in October to November when the second flashes sprouted in October. Plants of heavy pruning in August to October came to sprout and flower in February of next year. Anatomic observation of the first flushes of plants after heavy pruning in March, June and September were found that flower differentiated in June to July, September and next January respectively. It means that first flushes after heavy pruning maintain vegetative buds for two to three month in Taipei. However, after heavy pruning in December, the plants treated with day/night temperature 27.5/22.5℃ for 3 weeks, flower differentiation was observed. After two month heavy pruning, plants were treated with four night/day temperature, 30/25，25/20，20/15 and 15/13℃. The plants in 30/25℃ and 25/20℃ bloomed after 2 and 8 weeks respectively, and while those in 20/15℃ and 15/13℃ bloomed after 22 weeks.