打顶对烟草腋芽生长及植物激素含量的影响

Effects of Topping on Axillary Bud Growth of and Plant Hormone Contents in Tobacco

为揭示植物激素调控烟草腋芽萌发及生长的生理机制,以烟草K326(腋芽生长势强品种)和云烟87(腋芽生长势弱品种)为材料,测定和分析了打顶期、打顶后5,10,15,20和25 d的烟株上第1、第3腋芽(从上至下数)长度及腋芽内生长素(IAA)、脱落酸(ABA)、赤霉素(GA3)等植物激素含量的变化。结果表明:烟株顶的存在严重影响着腋芽的萌发与生长,打顶可以促进腋芽的萌发和伸长,且越靠近顶部的腋芽,萌发能力和生长势越强。打顶后上部腋芽较下部腋芽先萌发,且K326品种的腋芽长度在各个时期均显著高于云烟87;打顶后烟株腋芽内IAA,ABA和GA3含量显著低于打顶期,总体上呈现出先减少再增加的趋势。打顶后顶端优势削除,腋芽部位IAA和GA3含量迅速减少,从而促进了腋芽的萌发与生长。

To reveal the physiological mechanism that plant hormones regulates the germination and growth of axillary bud of tobacco, cv. K326 （the variety with axillary buds of strong growth vigor） and cv. Yunyan 87 （the variety with axillary buds of weak growth vigor） were taken as experimental materials. The lengths of the first and third axillary buds （counting from top to bottom of plant） were measured and the changes of IAA, ABA and GA3 contents in the axillary buds during topping and on the 5th, 10th, 15th, 20th, and 25th days after topping were analyzed. The results showed that the apex shoot of tobacco plants heavily affected the germination and growth of axillary buds, topping could promote the germination and growth of axillary buds. The germination ability and growth vigor of axillary buds increased with the ascent of stalk position. After topping, upper axillary buds germinated earlier than lower axillary buds, and the axillary buds of cv. K326 were longer than those of cv. Yunyan 87 at all stages. The contents of IAA, GA3 and ABA in axillary buds after topping were significantly lower than those during topping, generally, they decreased first and then increased. After topping, the apical dominance of tobacco plant was removed and the contents of IAA and GA3 at axillary bud site reduced rapidly, which promoted the germination and growth of axillary buds.