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Bulletin of Botanical Research ›› 2016, Vol. 36 ›› Issue (6): 838-845.doi: 10.7525/j.issn.1673-5102.2016.06.006

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Plant Growth Characteristics and Ultrastructure of Megaspore of the Wild Cypripedium japonicum

YAN Xiao-Na1,2, TIAN Min1,3, WANG Cai-Xia1, ZHANG Ying1   

  1. 1. Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Fuyang 311400;
    2. Harbin Research Institute of Forestry Machinery, the State Forestry Administration, Harbin 150086;
    3. Key Laboratory of Tree Breeding of Zhejiang Province, Fuyang 311400
  • Received:2016-05-18 Online:2016-11-15 Published:2016-11-16
  • Supported by:
    National Natural Science Foundation of China "Studies on conservation biology of endangered species Cypripedium japonicum Thunb"(31370553)

Abstract: 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.

Key words: Cypripedium japonicum, bud development, growth cycle, ultrastructure of megaspore

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