植物学报2011，Vol.46Issue(5)：489-497,9.DOI:10.3724/SP.J.1259.2011.00489
基部被子植物雪香兰(金粟兰科)单性花的形态发生和发育
Characterization of Unisexual Flower Development in the Basal Angiosperm Hedyosmum orientale (Chloranthaceae)
摘要
Abstract
Chloranthaceae are a family of basal angiosperms with very simple unisexual or bisexual flowers. Hedyos-mum orientals Merr. Et Chun is a dioecious species with unisexual flowers. The floral morphology and structure of H. Orientate conspicuously differ from that of other species and are important in the study of floral origin and phytogeny, especially of the perianth, in angiosperms. We investigated the organogenic processes and anatomical characters related to unisexual flower development in H. Orientate Merr. Et Chun by scanning electron and light microscopy. Male and female flowers are in the axil of bracts and are usually formed in a thyrse. The staminate flower is subtended by two leaf-like bracts. 150-200 stamens spirally arranged along the spike axis and the phyllome are located at the base of the spike axis. The bract primordium with its axillant flower primordia is dome-shaped in the beginning and then elongates. The bract primordium grows faster than the floral primordium during male flower development. The male floral primordium expands longitudinally and the phyllome primordia are established around the base. Stamen primordia are formed and further develop at the axis from bottom to top. Two female flowers, composed of trifid perianth and inferior ovary, cluster into a cymule with the adjacent floral bracts. The floral primordium grows faster than the bract primordium during the female floral development process. Three perianth primordia are initiated along the sides of the trilateral floral apex. Simultaneously, a concave floral apex appears, which differentiates into an ovary primordium. The floral development of H. Orientate Merr. Et Chun is unisexual from inception. The floral meristem initiates only androecial or gynoecial organs and does not go through a hermaphroditic stage. Our studies support the view that the flower of H. Orientate Merr. Et Chun is a primitive character. The trifid perianth of the female flower is homologous to the phyllomes at the bottom of the male flower. They may be the origin of the perianth (sepal and petal).关键词
金粟兰科/花器官发生/雪香兰/单性花Key words
Chloranthaceae/floral organogenesis/Hedyosmum orientate/unisexual flower引用本文复制引用
崔永坤,徐启江,孙永华,孟征..基部被子植物雪香兰(金粟兰科)单性花的形态发生和发育[J].植物学报,2011,46(5):489-497,9.基金项目
中国博士后科学基金(No.20080440556) （No.20080440556）
