脱落酸（ABA）在蒜苔衰老中的作用

蒜苔在切除珠蒜后可减少贮存中干物质的损失，延缓衰老，在切口处施加外源ABA可加速苔干叶绿素的破坏和组织的老化，气相色谱与色质联用法检测完整蒜苔和无珠蒜蒜苔各部分组织中ABA含量在衰老过程中的变化，发现无珠蒜苔干上，中，下各段ABA含量在衰老进程中是逐步减少的，变化幅度小，而带有珠蒜的苔干各相应段和珠蒜的ABA含量均有一迅速增加而后减少的过程，珠蒜的ABA含量最大，ABA含量高峰出现时间最早，苔干各段ABA含量按上，中，下顺序依次减少，高峰出现的时间也是由上至下依次推迟，没有发现蒜苔在衰老过程中有乙烯放出，外加乙烯对其衰老进程影响不大，本文认为珠蒜是蒜苔衰老的关键部位，能加速苔干衰老的ABA主要是在珠蒜中合成的，并自上向下极性运往苔干组织，进而动员物质的再分配，起着信息传递作用，蒜苔的衰老过程可分为“准备期”和“活跃期”两个阶段。

EFFECTS OF ABSCISIC ACID IN SENESCENCE OF GARLIC(ALLIUM SATIVUM)SCAPE

Removing the apical cloves from the excised garlic scapes could delay the senescence of scape and decrease the rate of dry matter loss during storage.The ABA content of all the portions of the scapes with apical cloves is decreased as the prolongation of storage period; but its content of all the portions of the scapes with the cloves reaches their peak one after an- other within the first 6 days of the experiment period.The peak of ABA in the apical cloves appears earliest;the ABA content of any portion of the scapes is lower than that of the cloves, and gradually decreases from upper to lower portions,and the peak of ABA content appears in the sequence as above.Exogenous ABA which is added to the top of the scapes without cloves would simulate the function of the apical cloves in part and accelerates the chlorophyll des- truction and senescence of the scapes.No ethylene can be detected by the G.C.,in the process of senescence.The authors suggest that ABA is mainly synthesized in the cloves,and then transported into the scapes from there.In the senescence of garlic scapes and in the redistribu- tion of material between the apical cloves and the scapes(the relation between the sink and source),ABA functions as transporting information and promoting senescence but ethylene has not such a function.The senescence of garlic scape could be divided into two stages:first the static phase and second,the active phase.