Biodiv Sci ›› 2009, Vol. 17 ›› Issue (4): 406-413.DOI: 10.3724/SP.J.1003.2009.09046

Special Issue: 保护生物学: 现状和挑战

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Reproductive biology of an endemic orchid Cypripedium smithii in China and reproductive isolation between C. smithii and C. tibeticum

Peng Li1, Yibo Luo2*   

  1. 1 School of Life Sciences and Engineering, Southwest University of Science and Technology, Mianyang, Sichuan 621010
    2 State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Bei-jing 100093
  • Received:2009-03-02 Revised:2009-04-21 Online:2009-07-20 Published:2009-07-20

Abstract: Pollinator specificity has traditionally been considered as the main mechanism of reproductive isolation in orchids. Cypripedium smithii and C. tibeticum are two closely related species with similar characters and sympatric distributions. With the knowledge of reproductive biology of C. tibeticum, we studied the reproductive biology of C. smithii and compared the morphological characters between C. tibeticum and C. smithii. The results showed that a series of intermediate types occurred between typical C. smithii and typical C. tibeticum, indicating that no distinct taxonomic boundary existed between C. tibeticum and C. smithii. Pollination experiment showed that both C. smithii and C. tibeticum were pollinated by bumble queens. The hand-pollination experiments indicated that C. tibeticum and C. smithii were cross-fertilized, so that they could hybridize in the natural conditions and produced transitional types. It is better to combine them as one identical species rather than separate them as two distinct species.