荔枝胚囊發育觀察

Observation of Embryo Sac Development of Litchi (Litchi chinensis Sonn.)

荔枝（Litchi chinensis Sonn.）胚囊之發育屬於蓼型（polygonum type）。在’玉荷包’中，開花後大多數胚囊才逐漸發育，柱頭完全平展時始有胚囊發育成熟，至柱頭反轉後，發育完整之比例達平衡，約佔45%,但受精現象需到柱頭呈彎鉤狀時才發生。偏雌花胚囊之發育較早且完整，同時受精現象亦較早發生。糯米糍偏雌花胚囊發育烏三品種中最快，在柱頭尚未展開時，已有60%胚囊發育完整，而異常比例明顯較低。顯示荔枝胚囊開始發育與花之開放無絕對之關係。在玉荷包中，發育完全胚囊比例維持在30%-50%；在黑葉與糯米糍中維持在40%以上及50%以上，顯示胚囊異常並非低著果率之主因。在玉荷包可能是胚囊發育成熟後快速退化及發育太晚所造成，而在糯米糍可能是其他原因。

The'Yu Her Pau' litchi embryo sac, which develops according to the polygonum type, will not differentiate until the anthesis. Well-development embryo sac was present when stigma turn flat and about 45% when stigma opens downward. Fertilization occurred when stigma opened into a hook shape. In·Haak Yip', embryo sac development and fertilization was earlier than that of 'Yu Her Pau'. In'No Mi Tsz·. the embryo sac development was the fastest of the three cultivars, and 60% of the embryo sac were not well development before the stigma opened. This indicated that there was no absolute relationship between the embryo sac development and anthesis in litchi. In'Yu Her Pau', the percentage of well-developed embryo sac was about 30%--50%, and in'Haak Yip' and'No Mi Tsz' the percentage was about 40% and 50%, respectively. This indicated that abnormal embryo sac was not the main factor for low yield of Taiwan litchi A quick degeneration or late development of the embryo sac might be the main reason for low yield or·Yu Hr Pau'. It's probable that there were other factors causing low yield of'No Mi Tsz'.