Plant Diversity ›› 2017, Vol. 39 ›› Issue (01): 52-59.DOI: 10.1016/j.pld.2017.01.001

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Floral characteristics and pollination ecology of Manglietia ventii (Magnoliaceae), a plant species with extremely small populations (PSESP) endemic to South Yunnan of China

Bin Wanga,b,c, Gao Chena,b, Congren Lia, Weibang Suna,b   

  1. a. Kunming Botanical Garden, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, Yunnan, China;
    b. Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, Yunnan, China;
    c. University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2016-06-17 Revised:2016-12-26 Online:2017-02-25 Published:2021-11-05
  • Contact: Weibang Sun
  • Supported by:
    Funding (No. U1302262) to W.B. Sun from the NSFC-Yunnan joint fund on key projects and Survey and Germplasm Conservation of PSESP in Southwest China (2017e2020, 2017FY100100) are particularly acknowledged. This study was also partly supported by the Young Academic and Technical Leader Raising Foundation of Yunnan Province (2015HB091) and the Science and Technology Research Program of Kunming Institute of Botany, the Chinese Academy of Science (KIB2016005) to G. Chen. We gratefully thank Drs Z.L. Dao & C.Y. Han, J.Y Liu, Z.Y. Yu, Z.L. Liang, X.W. Li, W.Q. Yao, S.X. Zhu, J. Bai and J. Qian for their help during fieldwork; the local forestry authorities of Pingbian, Hekou and Jinping for assistance in field work. We also thank Z. Yu for floral scents analysis; Dr Y.P. Ma for giving valuable advice for data processing; Drs T. and J. Marczewski for reviewing the text; Dr W.C. Gong for drafting Fig. 4, and Y. Qin for photographing insects and for their identification. We are also grateful to Prof. Sergei Volis and four anonymous reviewers for their valuable comments on the manuscript.

Abstract: Manglietia ventii is a highly endangered plant species endemic to Yunnan province in China, where there are only five known small populations. Despite abundant flowering there is very low fruit and seed set, and very few seedlings in natural populations, indicating problems with reproduction. The causes of low fecundity in M. ventii are not known, largely because of insufficient knowledge of the species pollination ecology and breeding system. We conducted observations and pollination experiments, and analyzed floral scents to understand the pollinator–plant interactions and the role of floral scent in this relationship, as well as the species breeding system. Like the majority of Magnoliaceae, M. ventii has protogynous and nocturnal flowers that emit a strong fragrance over two consecutive evenings. There is a closing period (the pre-staminate stage) during the process of anthesis of a flower, and we characterize the key flowering process as an “open-close-reopen” flowering rhythm with five distinct floral stages observed throughout the floral period of this species: pre-pistillate, pistillate, pre-staminate, staminate, and post-staminate. Flowers are in the pistillate stage during the first night of anthesis and enter the staminate stage the next night. During anthesis, floral scent emission occurs in the pistillate and staminate stages. The effective pollinators were weevils (Sitophilus sp.) and beetles (Anomala sp.), while the role of Rove beetles (Aleochara sp.) and thrips (Thrips sp.) in pollination of M. ventii appears to be minor or absent. The major chemical compounds of the floral scents were Limonene, β-Pinene, α-Pinene, 1,8-Cineole, Methyl-2-methylbutyrate, p-Cymene, Methyl-3-methyl-2-butenoate and 2-Methoxy-2-methyl-3-buten, and the relative proportions of these compounds varied between the pistillate and staminate stages. Production of these chemicals coincided with flower visitation by weevils and beetles. The results of pollination experiments suggest that M. ventii is pollinator-dependent, and low seed set in natural populations is a result of insufficient pollen deposition. Thus, conservation of the species should focus on improving pollination service through the introduction of genetically variable individuals and increase in density of reproducing trees.

Key words: Floral scent, Weevil, Beetle, Pollination, Breeding system, Conservation