三种观赏海棠花芽分化进程的形态解剖特征

采用常规石蜡切片法,对原产于我国的垂丝海棠和引自北美的观赏海棠‘印第安魔力’、‘春雪’花芽分化的形态发育进程进行观察分析。结果表明:垂丝海棠花芽形态分化始于7月中上旬,分化进程可划分为6个阶段:花芽分化前期、花序原基分化期、萼片原基分化期、花瓣原基分化期、雄蕊原基分化期、雌蕊原基分化期,同朵小花各轮原基发育顺序严格,各分化期时间上存在重叠现象。初步判断垂丝海棠营养芽向花芽转变的生理分化期发生在6月上旬至7月中上旬之间,持续时间短于42天。物候观察和切片观察的结果表明垂丝海棠花序类型更偏向于伞形花序而非伞房花序。‘印第安魔力’的花序原基分化期约比‘春雪’晚1个月,这可能是导致‘印第安魔力’的花期相对于‘春雪’较滞后的原因之一。

Observation on the processing of flower bud differentiation for three cultivars of Malus

This article studied the internal anatomical structure of three cultivars of Malus during their flower development by paraffin section.Three cultivars of Malus included traditional M.halliana in China and M.’Indian Magic’,M.’Spring Snow’from North America.The results were as follows:The differentiation of M.halliana flower bud started at the beginning of July.The process of flower bud differentiation could be divided into 6 stages: flower bud pre-differentiation,inflorescence primordium differentiaon,petal primordium differentiaon,sepal primordium differentiaon,stamen primordium differentiaon and pistil primordium differentiaon,the primordium differentiaon of same flower is strictly in each round and could have overlap in every stages.By preliminary judgment,the physiological differentiation stage of M.halliana begins at early June to middle July,the duration less than 42 days.Phenology observation and anatomy observation indicate that the inflorescence type of M.halliana is umbel but corymb.The flower buddifferentiation process of M.’Indian Magic’is about one month later than M.’Spring Snow’,this may cause flowering later than M.’Spring Snow’.