落葉性果樹萌芽前芽內抑制物質的變化

Changes of Naturally Occurring Inhibitory Substances in the Buds of Deciduous Fruit Trees before Sprouting

本試驗是以梨樹20世紀品種為材料，分別於海拔2, 200公尺的高山（梨山）及海拔15公尺的平地（臺北），於萌芽前採取枝條，將芽切下，進行抽出及濾紙分離法分離，並用綠豆苗發根法之生物測定，求知同一種植物在不同環境生長下，在萌芽前的芽中，有關抑制物質的變化，試驗結果如下：1.臺灣高山區梨樹之芽，於3月25日頃，芽中的抑制物質完全消失而萌芽。頂芽與側芽中抑制物質的消失情形也一致。該地元月到三月在10℃以下的氣溫累積有1,797小時，足夠完全休眠的需要。2.臺北區梨樹之芽，由於元月到四月的氣溫，在10℃以下累積僅有253小時，不足休眠完成的需要。所以，梨樹的側芽中的抑制物質，到四月上旬仍有大量的出現，其後即逐漸消失。而在頂芽中，到四月下旬仍有大量抑制物質的存在，但隨即也突然消失。不論頂芽及側芽，均在四月底到五月初開始萌發。

Buds, on the trees, of ”Twenty Century” pear were collected from high mountain area (Lishan, 2,200 meters above sea level) and plain ground (Taipei, 15 meters above sea level) to determine the levels of naturally occurring inhibitory substances in buds at different period of time before sprouting. Methanol extracts of buds were chromatographed for separating of chemical components, and were subsequently bioassayed, using the Mung bean test, to determine the zones of inhibition. Results of this experiment are summariged as follows: 1. Inhibitory substances both in the lateral and terminal buds taken from high mountain area were totally disappeared on March 25. In that place about 1,797 hours with temperatures below 10℃ from January to March were recorded. This is believed to be enough to satisfy the chilling requirements of the pear buds during rest period. 2. In Taipei area, or the plain ground, with temperatures below 10℃ during the same period, there was only 253 hours which is not enough to meet the chilling requirement of the pear buds needed. Inhibitory substances which extracted from the lateral buds showed a large amounts in early April and decreasing gradually there after. Those extracted from the terminal buds occurred large quantities in late-April and disappeared abruptly later on. All the pear buds tested in Taipei area began to sprout from late-April to early-May.