为明确大蒜（Allium sativum Linn.）的花芽分化进程，以不同特性的品种‘二水早’ （‘Ershuizao’）、‘太仓白’（‘Taicangbai’）、‘徐州白’（‘Xuzhoubai’）和‘美国大蒜’（‘American garlic’）为材料，采用石蜡切片技术对分化过程中花芽纵切面的解剖结构进行了研究，并观察了花芽形态特征变化，据此对花芽分化期进行划分，并比较了不同品种间花芽分化时间的差异。结果表明：依据花芽解剖结构的差异和形态特征变化，可将大蒜花芽分化过程划分为未分化期、总苞和花序原基分化期、小花原基分化期（包括小花原基、苞片和珠蒜原基分化）以及花器官原基分化期（包括花被片、雄蕊和雌蕊原基分化）4个时期，后3个时期共同构成花序形成期；在总苞和花序原基分化期，茎尖生长点形态开始改变，可作为大蒜花芽开始分化的指征。品种‘二水早’、‘太仓白’和‘徐州白’花芽分化各时期的解剖结构与形态特征基本一致，而品种‘美国大蒜’在小花原基分化期不分化苞片和珠蒜，故其小花原基分化期的解剖结构和形态特征与另3个品种略有不同。根据苞片和珠蒜的有无，可将供试4个品种的花序分为2类：一类花序中包含异常小花以及珠蒜和苞片，小花随珠蒜膨大而枯萎退化，导致无法正常开花，具有该类花序的为‘二水早’、‘太仓白’和‘徐州白’3个不开花品种；另一类花序中有小花但无珠蒜，小花可正常开花，具有该类花序的为开花品种‘美国大蒜’。田间自然条件下，品种‘二水早’花芽分化最早，而品种‘徐州白’花芽分化最晚；品种‘二水早’花芽分化持续时间最短（仅53 d），另3个品种的花芽分化持续时间在60 d以上；在花芽分化期间，以总苞和花序原基分化期历时最短（9～11 d），花器官原基分化期历时最长（31～37 d），表明不同大蒜品种花芽分化开始日期和分化持续时间存在差异，早熟品种花芽分化早于晚熟品种。

To figure out the flower bud differentiation process of Allium sativum Linn.， cultivar ‘Ershuizao’， ‘Taicangbai’， ‘Xuzhoubai’， and ‘American garlic’ with different characteristics were used as materials to study the anatomical structure of longitudinal section of flower bud during the differentiation process by using paraffin section technique， and to observe the change of morphological characteristics of flower bud. According to this， the flower bud differentiation stage was divided， and differences in differentiation time of flower bud among different cultivars were compared. The results show that the flower bud differentiation process can be divided into four stages of undifferentiation stage， spathe and inflorescence primordium differentiation stage， small flower primordium differentiation stage （including small flower primordium， bract and topset primordium differentiation）， and flower organ primordium differentiation stage （including tepal， stamen and pistil primordium differentiation） according to the difference in anatomical structure and the change of morphological characteristics of flower bud， and the latter three stages constitute together the inflorescence formation stage； morphology of shoot tip growth point begins to change at spathe and inflorescence primordium differentiation stage， and this can be used as the indication of differentiation initiation of flower bud of A. sativum. Anatomical structure and morphological characteristics of cultivar ‘Ershuizao’， ‘Taicangbai’， and ‘Xuzhoubai’ are basically identical at each stage， while cultivar ‘American garlic’ cannot differentiate bract and topset at small flower primordium differentiation stage， therefore its anatomical structure and morphological characteristics at small flower primordium differentiation stage are slightly different from other three cultivars. Inflorescence of four cultivars tested can be divided into two categories according to with or without bract and topset. One category of inflorescence contains abnormal small flower， bract and topset， and small flower perishes with the enlargement of topset， leading to failure of normal flowering， three unflowering cultivars of ‘Ershuizao’， ‘Taicangbai’， and ‘Xuzhoubai’ belong to this category. The other category of inflorescence contains small flower but without topset， and small flower can flower normally， flowering cultivar ‘American garlic’ belongs to this category. Under natural field condition， flower bud differentiation of cultivar ‘Ershuizao’ is the earliest， while that of cultivar ‘Xuzhoubai’ is the latest； duration of flower bud differentiation of cultivar ‘Ershuizao’ is the shortest （only 53 d）， while that of other three cultivars is longer than 60 d； during flower bud differentiation process， duration of spathe and inflorescence primordium differentiation stage is the shortest （9-11 d）， and that of flower organ primordium differentiation stage is the longest （31-37 d）， indicating that there are differences in initiation time of flower bud differentiation and duration of differentiation among different cultivars of A. sativum， and the flower bud differentiation of early-maturing cultivar is earlier than that of latematuring cultivar.