The Exogenous Hormonal Control of the Development of Regenerated Flower Buds in Hyacinthus orientalis
The Exogenous Hormonal Control of the Development of Regenerated Flower Buds in Hyacinthus orientalis
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发表时间：
2000
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通讯作者：
L. Wen
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作者：
L. Wen
进一步证明了外源激素在诱导再生花芽中不同花器官的发生和控制其数量方面的关键作用。以风信子的花被为外植体，首次诱导了花芽的发生。CV.用2 mg/L 6-BA和0.1mg/L 2，4-D组合诱导，继之以100片以上的花被片（一个花蕾）的连续诱导，形成白色珍珠; orientalis in situ只有6片花被片）通过维持这样的激素浓度成功地控制。而改变激素浓度（2 mg/L 6_BA和0- 0.0001mg/L2，4_D）则使花被片的连续分化停止，但诱导了雄蕊的分化。保持改变后的激素浓度，可成功地控制20多个雄蕊（一个花蕾）的连续发生。orientalis in situ只有6枚雄蕊）。实验表明，一定浓度的外源激素可以控制再生花芽中相同花器官的数量，而诱导的相同花器官的数量对再生花芽中不同花器官的分化顺序没有影响。在系统研究了外源激素对花被外植体和再生花蕾花器官分化的调控作用的基础上，对花器官分化的调控机制进行了初步探讨。orientalis花发育过程中不同花器官的自动分化和有序分化的调控机制，提出了植物激素调控花发育过程中不同花器官自动分化和有序分化的新观点。主要内容如下：1.植物花芽的发育是花器官从花分生组织中自动、有序分化出来的过程。2.离体实验表明，外源激素控制不同花器官的发生具有严格的浓度依赖性，一种花器官可以从花分生组织连续和重复地发生，只要它保持在适合于该特定种类花器官发生的特定浓度的外源激素。3.这表明，在一轮花器官分化完成后，原位花芽必须能够自动调节内源激素浓度，以适应下一轮花器官的分化。因此，不同浓度的植物激素承担着器官分化的多次转换开关，在花器官每两轮分化之间起着连接和调节作用。也就是说，在不同花器官从花芽相继发生的过程中，这些转换开关起着抑制控制第一轮花器官发生的基因表达，同时激活控制第二轮花器官发生的基因表达的作用。它导致花的各种器官从花分生组织中自动和顺序地发生。
The critical role of exogenous hormone on inducing the initiation of different floral organs in the regenerated flower bud and controlling their numbers was further evidenced. The initiation of the flower buds was first induced from the perianth explants of Hyacinthus orientalis L. cv. White pearl by a combination of 2 mg/L 6_BA and 0.1 mg/L 2,4_D, and then a continuous initiation of over 100 tepals (a flower bud of H. orientalis in situ has only 6 tepals) was successfully controlled by maintenance of such a hormone concentration. However, a change of hormonal concentration (2 mg/L 6_BA and 0-0.000 1 mg/L 2,4_D) caused cessation of continuous initiation of the tepals but gave rise to induction of stamen initiation. Keeping the changed hormone concentrations could successfully control the continuous initiation of over 20 stamens (a flower bud of H. orientalis in situ has only 6 stamens). The experiment showed that the number of identical floral organs in the regenerated flower buds can be controlled by certain defined concentrations of the exogenous hormones, and the amount of the induced identical floral organs has no effect on the differentiation sequence of the different floral organs in the regenerated flower bud. Based on a systematic research on controlling the differentiation of the floral organs from both the perianth explants and the regenerated flower buds by the exogenous hormones in H. orientalis over the past decade, the authors put forward here a new idea on the role of phytohormone in controlling the automatic and sequential differentiation of the different floral organs in flower development. The main points are as follows: 1. the development of flower bud in plant is a process in which all of the floral organs are automatically and sequentially differentiated from the flower meristem. 2. Experiments in vitro showed that the effect of exogenous hormones in controlling the initiation of different floral organs is strictly concentration dependent, i.e., one kind of the floral organ can continuously and repeatedly initiate from the flower meristem as long as it is maintained in that specific concentration of the exogenous hormone which is suitable for the initiation of that particular kind of floral organ. 3. It shows that the flower buds in situ must be automatically able to adjust the endogenous hormonal concentrations just after the completion of the differentiation of one whorl of floral organ to suit the differentiation of the next whorl. Thus, the phytohormone in different concentrations takes after many change_over switches of the organ differentiation and plays a connective and regulatory role between the differentiation of every two whorls of the floral organ. In other words, these change_over switches play the roles of inhibiting the expression of the genes which control the initiation of the floral organs in the first whorl, meanwhile, activating the expression of the genes which control the initiation of the floral organs in the second whorl during the successive initiation of the different floral organs from the flower bud. It results in the automatic and sequential initiation of the various floral organs from the floral meristem.