| 摘要: | 1997年5月到1998年3月，利用斷根、修枝，以及兩者混合等三種育林作業，每個月處理24年生台灣肖楠2個營養系。1999與2000連續兩年只促進0-2.4%的植株開花，育林作業處理對本樹種開花促進效果不佳。1998年3月樹幹基部剝皮後每株施用激勃素A3(GA3)200、400、600、800mg，在1999年促進開花的植株分別達66.7、83.3、83.3及100%，至2000年分別下降為16.7、16.7、0及33.3%，四個劑量間開花率並無顯著差異；控制組及含酒精溶劑的對照組(0mg)之開花率為0%，與前者呈極顯著差異。1999年經GA3處理植株之開花枝條佔所有枝條的9.2%，2000年下降到0.47%。1999年每一開花枝條雄花分化數量在20-152，445之間（平均12,573, SD 33,915）；雌花芽分化數量在0-5，332之間（平均423, SD 1,218），四種劑量對雄花與雌花花芽分化的差異並不顯著。GA3運轉促進開花效果分布於植株各枝條，但23.9%集中在處理點之上方2m位置，顯著高於其它部位。
To produce flowers in 24 year-old grafts of 8 clones in 2 clonal orchards of Calocedrus formosana, cultural practices including pruning of roots, branches, and roots plus branches were carried out once every month for 9mo during the period from May 1997 to March 1998. Only 2.4% of grafts treated with root or branch pruning produced flowers in 1999 and 2000. Although the control grafts never flowered, these pruning treatments in different months did not significantly differ from the control ones. GA3 at 200, 400, 600, and 800 mg/tree injected into the bark of basal trunks of grafts on March 1998 induced 66.7, 83.3, 83.3, and 100% of them to flower in 1999, respectively. There still were 16.7, 16.7, 0, and 33.3% of trees flowering in 2000. The percent of flowering grafts among GA3 concentrations did not significantly differ, however, all of them were very significantly greater than those of the control and solvent treatments. An average of 9.2% of branches per grafts treated with GA3 produced flowers in 1999, while 0.47% of branches per grafts flowered in 2000. The number of pollen cones per branches ranged from 20 to 152,445 (12,573±33,915, mean±standard deviation), while the number of female cones ranged from 0 to 5,332 (423±1,218). GA3 concentrations did not significantly affect the differentiation and development of pollen and seed cones. Flowering branches were scattered in the crowns of grafts, however, 23.9% of them were found in areas up to 2m above the GA3 application sites, which was significant greater than numbers flowering in the crown areas ranging from 2 to 9 m high. |
