%0 Journal Article %A TIAN Min %A WANG Cai-Xia %A YAN Xiao-Na %A ZHANG Ying %T Plant Growth Characteristics and Ultrastructure of Megaspore of the Wild Cypripedium japonicum %D 2016 %R 10.7525/j.issn.1673-5102.2016.06.006 %J Bulletin of Botanical Research %P 838-845 %V 36 %N 6 %X We used two wild populations of Cypripedium japonicum from West Tianmu Mountain National Nature Reserve in Zhejiang Province to study the growth characteristics of C.japonicum. The dormant bud morphology, plant growth process and ovule development were observed regularly. The growth cycle of C.japonicum comprised budding, flowering and leaf stage, fruiting and decline stage, which lasted for one year. The division propagation was the main reproductive pattern, and the sexual reproduction was poor. Each plant of C.japonicum produced a dormant bud which grew above the ground within the first year of October. Dormant buds that developed fully would flower within the second year of April. While, dormant buds which could not develop well only produced fan-shaped leaves in the second year, and there were no floral organs. Ultrastructure of ovules showed that the archesporial cell's nucleus occupied most of the space, with dense cytoplasm and organelles. Megasporocyte located at the micropyle end, and the vacuoles, mitochondria and plastids densely distributed. In megasporangium, vacuole occupied a large space, and the nucleus was relatively small, with sparse cytoplasm and organelles. Mitochondria and plastids were visible. During the ovule developmental stage, protein and polysaccharide existed all the way. The staining of starch gradually deepened, without the presence of lipids. %U https://bbr.nefu.edu.cn/EN/10.7525/j.issn.1673-5102.2016.06.006