台灣檫樹(Sassafras randaiense)種子經低溫層積、雙氧水前處理,在剔除種皮與子葉後,取其胚軸培養於MS培養基及25℃恆溫環境,發芽率可提高至58.3%。取用試管內種子苗之莖梢(shoot tip)及單芽節為培植體,莖梢培養顯示其接種於WPM補充lmg/L BA之增殖效果較佳,每個培植體平均可增殖為3.7個芽。培養基若添加L-glutamine,雖可提高其平均芽數至4.2,卻使多芽體之形成率下降。當培養基添加adenine時,多芽體形成率及平均芽數都較添加lmg/L BA者明顯下降。取用單芽節為培植體,多芽體之形成情形欠佳,但是卻有促進腋芽萌長之現象。若將芽體繼代培養,第一次繼代培養的芽體增殖率為1:4.7,持續之繼代培養亦顯示穩定的增生效率,平均每世代增殖的芽數皆維持在3.6個以上。截取小枝梢進行微扦插之不定根誘導,以培養在Ms培養基補充1mg/L IBA之效果較佳,發根率為80%,平均根數為每個芽體3.3個不定根。試管內發根之小值株移植至穴植管,當進一步移值至溫室之健化過程中,成活率可達80%以上。健化之組培苗與種子苗栽至造林地,3年後調查苗木存活率、苗高及胸徑,兩者之間雖無顯著統計差異,但其生長勢仍以組培苗較佳。
Cold-stratified and H2O2-pretreated seeds of Sassafras randaiense were used. After detaching the seed coat and cotyledon, germination of the embryo axis on MS medium increased to 58.3% at constant 25℃. In vitro multiple shoot proliferation of shoot tip culture was optimal on woody plant medium (WPM) containing 1mg/L BA, which achieved 100% proliferation and 3.7 shoots per explant. With the addition of 50-100mg/L L-glutamine, the shoot number per explant increased to 4.2, but the percentage of multiple shoot formation dropped. If adenine was supplemented, multiple shoot formation and shoot number per explant decreased as compared to those using 1mg/L BA. When nodal explants were cultured, the formation of multiple shoots was poor, but the sprouting of axillary buds was distinct. In the first subculture, 4.7 shoots per explant proliferated, and a stable multiplication rate of 1:3.6 was maintained from 1 subculture to the next. Root induction of microcutting was optimal on MS medium containing 1mg/L IBA, which obtained 80% rooting and 3.3 roots per microcutting. In vitro plantlets were successfully transplanted to plug plates placed in a culture room. The survival rate was 100% for all plantlets grown on 3 combinations of different growth media. During the process of hardening in the greenhouse, mortality of plantlets was less than 20%. Both acclimated plantlets and seedlings were out-planted with the same field conditions. Tissue-cultured trees main tamed better growth vigor than did sexually derived trees by the third year in the test plantation, although no statistical differences were found in survival, tree height, or diameter at breast height (DBH) between the 2 groups of trees.