穗花牡荆花芽分化过程中形态和生理指标变化

Study on the Changes of Morphological and Physiological Indexes during Flower Bud Differentiation of Vitex agnus-castus

为了解穗花牡荆花芽分化特性,为花期调控技术和栽培管理提供理论依据,以穗花牡荆为研究材料,采用物候期观察和石蜡切片方法,对花芽分化过程中形态发育变化及相关生理指标进行了测定,研究花发育过程中的形态和生理变化。结果表明,(1)穗花牡荆花芽分化为当年多次分化型,其进程可划分为七个时期:未分化期、总轴花序原基分化期、初级分轴花序原基分化期、次级分轴花序原基分化期、小花原基分化期、花器官分化前期和花器官分化后期。同一植株不同位置的花芽及同一花序中不同单花的分化进程不同,第一季花期后各阶段的花芽分化形态常存在重叠;(2)叶片和花芽中可溶性糖和可溶性蛋白质含量在花芽分化过程中均有上升下降的变化,总体上叶片中营养物质含量高于花芽来保证营养供应;(3)花芽分化过程中,IAA、ABA、CTK和GA_(3)整体水平上先升后降有利于花芽分化进行。研究认为,花芽中大量的可溶性糖和蛋白质积累及较高的碳氮比,有利于穗花牡荆花芽形态分化顺利完成。低水平的GA_(3)/ABA和IAA/CTK有利于花序的形成,ABA/CTK和ABA/IAA升高促进小花原基和小花萼片原基的分化,GA_(3)/CTK、GA_(3)/ABA和GA_(3)/IAA升高促进花瓣原基、雄雌蕊原基发育。

To understand the characteristics of flower bud differentiation and provide the theoretical basis for flowering regulation technology and cultivation management of Vitex agnus-castus,the morphological and physiological changes during flower development were studied.We observed the morphological characteristics of flower buds by combining phenophase observation with the paraffin section and measured the relevant physiological indexes during flower bud differentiation.The results showed that,(1)the flower bud differentiation process could be divided into seven stages:Undifferentiated stage,stage of total axis inflorescence primordial differentiation,stage of primary axillary inflorescence primordial differentiation,stage of secondary axillary inflorescence primordial differentiation,stage of microfloral primordial differentiation,stage of early and later floral organ differentiation,which were multiple differentiation types in one year.The process of flower bud differentiation in different positions of the same plant and single flowers in the same inflorescence was different.The flower bud differentiation formed at different stages after the first season of flowering and often overlaps.(2)The contents of soluble sugar and soluble protein in leaves and flower buds increased and decreased at different stages of flower bud differentiation.In general,the nutrient content in leaves was higher than that in flower buds to ensure nutrient supply.(3)During flower bud differentiation,the overall levels of IAA,ABA,CTK,and GA_(3)first increased and then decreased,beneficial to flower bud differentiation.In conclusion,the accumulation of a large amount of soluble sugar and protein in flower buds and the high carbon-nitrogen ratio was conducive to flower bud differentiation of V.agnus-castus.Low levels of GA_(3)/ABA and IAA/CTK were advantageous to inflorescence formation.The increase of ABA/CTK and ABA/IAA ratio promoted the differentiation of floret differentiation stage and sepal primordium.Petal primordium and stamen primordium differentiation needed higher GA_(3)/CTK,GA_(3)/ABA,and GA_(3)/IAA ratios.