千金榆花序及花器官发育

在扫描电镜下首次观察了桦木科鹅耳枥属千金榆花序和花的形态发生过程。千金榆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2个花原基和2个次级苞片;每个花原基分化出2个心皮原基,形成1个二心皮雌蕊;次级苞片远轴面发育快于近轴面,呈不均等的联合状;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,并分化形成3朵小花,小花无花被,位于两侧的小花分别有2枚雄蕊,位于中央的小花有4枚雄蕊,雄蕊共8枚,稀为10枚,该3朵小花为二歧聚伞状排列,其花基数应为2基数。

Inflorescence and Floral Organ Development in Carpinus cordata

Morphogenesis of inflorescence and flowers in Carpinus cordata was observed under scanning electron microscope for the first time, which would provide micro-morphological evidence for the phylogeny and evolution in Betulaceae. The female inflorescence in C.cordata was composed of cymules arranged spirally; one primary bract and a group of cymule primordial meristem were differentiated from one cymule primordium, and two floral primordia and two secondary bracts were differentiated from the cymule primordial meristem; two carpel primordia were differentiated to form one bicarpellary pistil. The abaxial portion of secondary bracts developed faster than the adaxial one, which arranged in an unequal joint configuration. One layer circular perianth occurred in the base of pistil. The male inflorescences were catkin-like, composed of cymules arranged spirally. One primary bract and a group of cymule primordial meristem were differentiated from one cymule primordium, and three floral primordia were differentiated from the cymule primordial meristem, which differentiated into three small flowers without perianth, with two flowers laterally each having two stamens, and the small flower between them hasving four stamens. The total number of stamens of one cymule was eight, rarely ten. Three flowers are in a dichasial cyme, and the flower merosity is two.