Plant Diversity ›› 2016, Vol. 38 ›› Issue (05): 253-258.DOI: 10.1016/j.pld.2016.09.003

• Articles • Previous Articles    

Reproductive biology of Magnolia sinica (Magnoliaecea), a threatened species with extremely small populations in Yunnan, China

Ye Chena,b, Gao Chena, Jing Yanga, Weibang Suna   

  1. a. Kunming Botanical Garden, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201 Yunnan, China;
    b. University of Chinese Academy of Sciences, 100049 Beijing, China
  • Received:2016-05-27 Published:2021-11-05
  • Contact: Jing Yang, Weibang Sun
  • Supported by:
    This study was supported financially by the NSFC-Yunnan joint fund to support key projects to W.B. Sun (Grant no. U1302262) and the Young Academic and Technical Leader Raising Foundation of Yunnan Province to G. Chen (2015HB091). The authors thank Guoyun Li, Zhiyong Yu and appreciate the cooperation of the Honghe and Wenshan forestry authorities. The first author wishes particularly to thank Rongli Liao and Bin Wang for helping carry out the experiments and Lingzeng Meng for the identification of the insects.

Abstract: Magnolia sinica is one of the most threatened trees endemic to Southeast Yunnan. Based on our investigations, only 52 individuals and eight populations are found in the wild. M. sinica has been categorized as Critically Endangered on the IUCN Red List and identified as a “Plant Species with Extremely Small Populations (PSESP)”. Its fruit/seed set is very low and seedlings are rarely found in the wild. It is hypothesized that it may encounter obstacles to reproductive success. This study, therefore, focuses on its reproductive biology, knowledge of which is essential for effective conservation. Flowers of this species are protogynous and nocturnal, and possess a two-day rhythm of sexual presentation. For the first night of anthesis, the flowers are in the pistillate stage during which tepals open at dusk and close approx. 1 h later (except for the open outer ones). They remain closed until the next afternoon, when flowers, now in the staminate stage, re-open and remain so until the tepals drop. Nocturnal beetles enter into the flowers and remain trapped throughout the night as the flower closes, during which time they feed on tepals. Pollen-gathering bees are found to visit the re-opened flowers and the beetles are released during this stage. Two species of Pleocomidae and Curculionidae beetles appear to be effective pollinators.M. sinica is a self-compatible, pollinator-dependent species, and its fruit/seed set can be significantly increased by hand-pollination. No functional seed dispersers have been found in its extant natural habitats. These findings suggest that it may face both pollination and seed disperser insufficiencies in its current fragmented habitats, which may account for its low regeneration. Here we propose conservation strategies based on our findings.

Key words: Magnolia sinica, PSESP, Flowering process, Pollination, Seed dispersal, Germination