Comparison of mechanisms of reproductive interference in Taraxacum.

Autor: Takemori A; Graduate School of Education, Okayama University, Kita-ku, Okayama City, Japan., Naiki A; Iriomote Station, Tropical Biosphere Research Center, University of the Ryukyus, Yaeyama-gun, Japan., Takakura KI; School of Environmental Science, The University of Shiga Prefecture, Hikone, Japan., Kanaoka MM; Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, Japan., Nishida S; Nagoya University Museum, Chikusa-ku, Nagoya, Japan.
Jazyk: angličtina
Zdroj: Annals of botany [Ann Bot] 2019 Jun 24; Vol. 123 (6), pp. 1017-1027.
DOI: 10.1093/aob/mcz007
Abstrakt: Background and Aims: Reproductive interference may reduce fitness of either of the involved species, with potentially important ecological and evolutionary consequences. Except for the effect of shared pollinators on reproductive success, however, mechanisms underlying reproductive interference have been little studied, even though the severity of its impact may depend on the specific mechanism. The aim of this study was therefore to explore the mechanisms of reproductive interference between Taraxacum japonicum (native to Japan) and Taraxacum officinale (alien).
Methods: In a field survey, the association between alien species density and seed set in T. japonicum, and whether pollinator behaviour indicated a preference for the alien, were examined. Effects of heterospecific pollen deposition were measured in a series of hand pollination experiments, including mixed pollination experiments in which the order of application of conspecific and heterospecific pollen was varied. Finally, to investigate hybridization frequency, the parentage of seedlings produced following natural, mixed or heterospecific pollination was compared.
Key Results: Alien species density did not negatively affect native seed set, nor did pollinators appear to have a preference for alien flowers. The hand pollination experiments showed that heterospecific pollen deposition adversely affected native seed set, especially when alien pollen was applied before conspecific pollen. No viable hybrids were found following natural pollination, which suggests that hybridization might be a rare event.
Conclusion: Among the examined mechanisms, heterospecific pollen deposition might have the largest deleterious effect on the native species. This effect is frequency dependent; thus, a positive feedback loop may cause the effect on the population dynamics to increase over time, with the result that the alien might eventually displace the native in a population. Effects of the examined mechanisms on population dynamics should be investigated further to improve understanding of the impact of reproductive interference on the structure of plant communities.
(© The Author(s) 2019. Published by Oxford University Press on behalf of the Annals of Botany Company.)
Databáze: MEDLINE
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