铁木属(桦木科)花序及花的形态发生

Morphogenesis of Inflorescence and Flower in Ostrya(Betulaceae)

在扫描电镜下观察了桦木科(Betulaceae)铁木属花序和花的形态发生过程。结果显示,铁木雌花序由多个小聚伞花序螺旋状排列组成。每个小花序原基分化出1枚初级苞片和一团小花序原基分生组织,由小花序原基分生组织分化形成1对次级苞片和2个花原基,每个花原基分化出2个或3个心皮原基,形成二心皮或三心皮雌蕊,雌蕊基部有1层环状花被原基。雄花序为柔荑状,由多个小聚伞花序螺旋状排列组成。每个小花序原基分化出1枚初级苞片和一团小花序原基分生组织,由小花序原基分生组织分化出3个花原基分区,位于中央的花原基分区,分化形成5–6枚雄蕊原基,两侧的花原基分区,分别分化形成3–4枚雄蕊原基,雄蕊原基分化形成四药囊雄蕊。雄蕊原基纵裂,但花丝纵裂没有达到基部。

The morphogenesis of inflorescence and flowers of Ostrya was observed by scanning electron microscopy. The female inflorescence of Ostrya japonica is composed of multiple cymules arranged in a spiral configuration. Each cymule primordium differentiates one primary bract and one cluster of cymule primordium meristem. One secondary bract and two flowers were differentiated from each cymule meristem. Each flower primordium differentiated into two or three carpels, forming a bicarpellary or tricarpellary pistil. Each flower has one layer perianth at the base of the pistil. The male inflorescences were catkin-like, composed of multiple cymules arranged in a spiral configuration. Each cymule primordium differentiated into one primary bract and one cluster of cymule primordium meristem. Three flower partitions differentiated from each cymule primordium. The central partition was differentiated into five or six stamens, and each side partition differentiated into three to four stamens. In the process of the stamen differentiating into four anther sacs, the young stamen began a longitudinal fissure, but the filament was not divided into the base.