施用Chlormequat Chloride、Uniconazole及Paclobutrazol矮化劑以控制盆栽迷你型馬拉巴栗之生長

Effect of Growth Retardants-Chlormequat Chloride, Uniconazole, and Paclobutrazol-on Potted Miniature Pachira macrocarpa

馬拉巴栗（Pachira macrocarpa Walp.）綠苗編為一新興且具潛力的外銷作物。因其容易快速長大，商業生產上需要控制株高之技術。本試驗以三種迷你型馬拉巴栗—單幹、綠苗編及重新修剪後之苗編—作為植物材料，灌注或噴施Chlormequat Chloride（CCC）1000、2000及4000 mg‧L^(-1)，Uniconazole（UCZ）15、20及25 mg‧L^(-1)，以及Paclobutrazol（PBZ）100、200及300 mg‧L^(-1)，以測試其控制株高及株型的效果。結果顯示無論灌注或噴施UCZ或PBZ皆能有效抑制三種迷你型馬拉巴栗之株高，但CCC則無效。藥劑濃度相同時，因灌注與噴施的藥量有差異，會造成結果有差異。故噴施矮化劑時若提高噴藥量可提高抑制生長之效果。施用矮化劑不會造成或影響綠苗編的失編（braid loss）情況。藥劑造成之捲葉情況則可藉由降低濃度而改善。將生長過大的苗編進行修剪後再噴施UCZ 15 mg‧L^(-1)或PBZ 100 mg‧L^(-1)，可使苗編恢復良好株型，產生較緊密之植冠，使原株重新成為適合外銷之商品。 Braided miniature Pachira macrocarpa Walp. is a new product which has a great export potential. Due to its rapid-growth nature of the plant, a method to control the plant size is essential for commercial 244-production. In this study, effects of growth retardants on plant height and shape control in this crop were investigated. Three types of mini Pachira macrocarpa plant namely: single cane, green braided, and braided and pruned by heading back, were treated, either by soil drenching or spraying, with chlormequat chloride (CCC; 1000, 2000, or 4000 mg‧L^(-1)), uniconazole (UCZ; 15, 20, or 25 mg‧L^(-1)), or paclobutrazol (PBZ; 100, 200, or 300 mg‧L(-1))solutions. The results showed that drenching or spraying with either UCZ or PBZ retarded the plant height effectively, but CCC did not. When the concentration of a growth retardant was fixed, regular drenching and spraying consumed different volumes of the liquid per plant or pot, and therefore generated different efficacies in retarding plant growth. The effect of spraying could be substantially improved by increasing the application volume. Application of growth retardants did not affect the occurrence of braid loss. Leaf curling, a side effect of growth retardants, could be lowered by using lower concentrations of the chemicals. Over-sized braided Pachira macrocarpa could be pruned by heading back and then applied with UCZ at 15 mg‧L(-1) or PBZ at 100 mg‧L(-1) in order to reshape the plants for suitable height, compact canopy, and having acceptable quality for export.