杉木伐桩休眠芽萌发时的内源激素状况*
Status of Endogenous Hormones from Sproutiog Dormant Bud of Chinese Fir Stump
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摘要: 在南京林业大学下蜀实验林场杉木林采伐迹地上,对伐桩进行全光照、半遮荫、全遮荫3种处理,于1992年春季分别定期观测并从伐桩上取萌芽样品,进行内源激素含量分析.结果表明,在白天平均地表温度达到2O℃左右时,杉木休眠芽开始萌动,其萌发数量与内源激素的种类及数量有密切关系.在3种处理下,不同时期萌芽内CA3含量的变化均表现为形状相似的单峰曲线,只是达到峰值的时间不同,但却与各处理下休眠芽日均萌芽数达到高峰的时间基本相符,可见它对伐桩休眠芽破除休眠及持续萌发有重要促进作用.ZT对休眠芽的始萌发也有一定作用,而ABA和IAA含量低微,作用不大.Abstract: In the Chinese fir slasharea of the Xiashu Forest Experimental Centre,3 treatments of varied shading conditions (including full exposure,half shade and full shade) were conducted over the newly felling stumps in the late winter. From spring to early summer the sprouting processes of dormant buds were observed and the sprouted bud samples were collected for hormone analyses periodically. It was shown that the dormant buds on the stumps of Chinese fir began to sprout when the ground surface temperature rose up to around 20℃,and their sprouting amounts were closely related to the kinds and quantities of endogenous hormones within them. In all treatments the curves of GA3 contents in the sprouting buds collected on various dates were the single-peak curves of the same shape,only the time needed for the peak values to appear were different in different treatments.Nevertheless,in all treatments the peak values of GA3 content appeared at the time when the ground surface temperature reached 30.7~32.6℃,and were mainly in accordance with the dates when the daily sprouting amounts of bud in the treatments reached their peak points respectively. Thus it can be seen that GA3 exerted a great influence to break the dormancy of bud and to promote the continuous sprouting from the Chinese fir stump.ZT also play a part in facilitating the beginning of sprouting,while the contents of ABA and IAA were very low and unimportant for sprouting.