遮陰與生長調節劑對九重葛生長及開花之影響

Effects of Shading and Growth Regulators on the Growth and Flowering in Bougainvillea

本試驗以九重葛「台北紅」品種二年生扦插盆栽植株為材料，分別探討光線和生長調節劑對其生長和開花之影響。遮陰處理下，九重葛枝條生長受到抑制，其第一花序出現所需的時間較長，開花節位提高、開花數較少，不利於開花。生長調節劑試驗中，施用BA（benzyladenine）500ppm有抑制營養生長、縮短第一花序出現所需的天數、降低開花節位的效果；BA 1000ppm在試驗期間發生藥害現象，故促進開花效果反不如BA 500ppm；施用PP 333（paclobutrazol）250、500ppm則嚴重抑制營養生長，但無促進開花的效果；而在隔年降低PP333的施用濃度為25、50ppm，不但具有抑制營養生長的效果，並可有效地提早開花、降低開花節位及增加開花數，達明顯的促進開花效果，可見生長調節劑施用濃度為影響九重葛開花效果之重要關鍵。

Two-year-old potted plants bougainvillea 'Taipei Red' from cutting were treated with shading and plant growth regulators to investigate the growth and flowering responses in Taipei. The results indicated shading treatment inhibited the shoot growth of bougainvillea. The shaded plants need more time to initiate first inflorescence, and had higher node number to first inflorescence and less number of flowers than control plants. Plants treated with 500ppm BA had less growth rate, lower node number to first inflorescence and flowering earlier. However, plants treated with 1000ppm BA had chemical injury. Application of paclobutrazol 250, 500ppm severely inhibited the vegetative growth, and had not any promotive effect of flowering. In the sescnd, reducing the concentration of paclobutrazol to 25, 50 ppm, the vegetative growth treated plants were still inhibited but the days to flowering were shortened and the number of flowers were increased, remarkably. Therefore, the dosage of plant growth regulators are the key factor of flower forcing.