本研究主要目的在探討苜蓿組織培養中癒傷組織之分化是否受到乙烯荷爾蒙控制，試驗結果發現苜蓿葉柄組織培養過程中，在誘導癒傷組織培養基第28天時，部份分化能力較高之癒傷組織已有初期分化現象，此時之乙烯釋出量高於誘導之初，尤其是高分化品系RS-5，而移入分化培養基後6天內，乙烯釋出量漸減。此外，分化培養基中加20mgL-1 ethephon可略增加培植體的乙稀釋出量，乙烯增加會明顯降低中度分化能力品系RS-N1的分化能力，但對低分化能力的品系Hasavei則略有提高分化的效果。而添加10mg L-1 CoCl2˙ 2H2O對Hasavei則明顯抑制分化。試驗結果顯示，在誘導癒傷組織形成期間，乙稀會促進高分化品系RS-5之癒傷組織初期分化，但其後在分化培養基中，改變乙烯濃度似乎不會影響後續分化。至於中度分化能力RS-N1品系，乙烯會顯著抑制分化，而低分化品系Hasavei在抑制乙烯形成下，顯著抑制其分化，推測品系間分化能力對乙烯有不同敏感度。

Effect of ethylene on the callus differentiation of alfalfa ( Medicago sativa L.) was investigated. Experimental results showed that the inital differentiation of callus could be observed at the 28 the day after incubation of alfalfa leaf-petiole explants in callus induction medium. And the endogenous ethylene more increased than before, espeially for the high-differentiation line RS-5.In addition, a slight increase of ethylene under the application of 20 mg L ethephon in differentiation medium, significantly decreased differentiation of line RS-N1,the line with median-differentation ability. However, an increased ethylene might romote the differentiation of line Hasavei slightly, the line with low-differentiation ability. Further, it was found that the callus differentiation of the line Hasavei was significantly inhibited by a reduction of ethylene caused by CoCl2.2H2O,and inhibitor of ethylene biosynthesis. Therefore, the results showed that the effect of ethylene on callus induction and differentiation of alfalfa leaf-petiole explants was line-dependent.