Plant Diversity ›› 2009, Vol. 31 ›› Issue (1): 8-14.DOI: 10.3724 SP.J.1143.2009.07329

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The Floral Syndrome and Its Pollination in Cynanchum otophyllum (Asclepiadaceae)

WANG Ding-Kang1 , 2 , SUN Gui-Fang3 , ZHAI Shu-Hua2 , GUO Li-Hong2 , XIAO Feng-Hui1   

  1. 1 Institute of Chinese Medicinal Materials of Yunnan Agricultural University, Yunnan Provincial Center for Chinese Medicinal Material GAP Technology , Kunming 650201 , China ;
    2 Biology Department , Kunming University , Kunming 650031 , China ;
    3 Skill Center, Kunming Medical College, Kunming 650032 , China
  • Received:2008-02-11 Online:2009-02-25 Published:2009-02-25
  • Contact: 萧凤回


This paper studied on the floral syndrome of Cynanchum otophyllum, visiting insects and their foraging behavior. The results showed that the floral morphologies were complex . Two separate ovaries were united by their styles to form a gynostegium with anthers . The stigmatic surfaces were enclosed by the tightly abutting wings of adjacent anthers to produce five stigmatic chambers . C. otophyllum possessed pollinia , which permited the transfer of hundreds of pollen grains at a time . Honeybees ( Apis cerana Fabricius) were primary pollinators . The process of C. otophyllum pollination was : ( 1) removal of a pollinarium: when the groove in the corpusculum catched on mouthparts or legs of honeybees and was forcibly pulled from the flower, and (2) insertion of a pollinium: when a pollinium lodged in a stigmatic chamber . Following successful
insertion , the pollens germinated within the stigmatic chamber and pollen tubes subsequently grew down the stylar
canal and finally entered the ovaries . The durable covering of pollinia allowed a long residence time on pollen viability , so
the pollen could remain a relatively high viability in the flower period . Stigma receptivity , however , decreased gradually
over the seven-day life span of flowers .

Key words: Cynanchum otophyllum

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