Studies on Pollen Morphology and Activity of Pitaya(Hylocereus undatus Britt.& Rose)

本研究在探討不同紅龍果品種間花粉形態及生體外發芽之特性。本試驗觀察中發現'越白肉種'及'DR3 紅肉種'紅龍果(Pitaya, Hylocereus undatus Britt. & Rose)之花粉為為具3發芽溝(3-colporate)之橢圓形(oval-shaped)花粉，赤道面為扁球形，極面則為圓球形；花粉外璧紋飾之特色為呈短刺狀紋飾，具有小刺狀之突出，並與小孔穴相間。兩品種之花粉在形態上差異不顯著。最適合紅龍果花發芽之蔗糖濃度為25%，pH範圍為5~6，硼、鈣濃度均為100ppm，溫度範圍則在25~30℃之間。紅龍果之花粉發芽率隨著其在室溫下貯藏時間之延長而降低。花粉於開花24小時，'越白肉種'於開花後36小時喪失發芽能力。在調查中'DR3 紅肉種'之花粉發芽率均遠較'越白肉種'為低。Pollen of dragon fruit (Hylocereus undatus Britt. & Rose) was oval shaped with three colporate. Tropic face and polar face of pollen was flatted round and round shape, respectively. Small needle like obstacle within small holes were found on pollen surface. No significant difference was found on pollen morphology of red and white flesh dragon fruit. The best medium condition for dragon fruit pollen germination in vitro on sugar concentration, pH value, boric concentration, Ca concentration, and germination temperature were 25%, pH 5-6, 100ppm, and 25-30℃, respectively. Pollen germination percentage decreased as storage period increased under room temperature. Pollen germination of dragon fruit cv. ‘DR3'and ‘Vietnam White'loss 24 hours and 36 hours after anthesis. Pollen germination of ‘DR3'was far higher than that of ‘Vietnam White'in this study