Breeding system of Anemone shikokiana and the influential factors of fruit-setting ratio in different habitats

Abstract

Anemone shikokiana (Makino) Makino is a rare perennial herb distributed only in China and Japan in restricted patches of two different habitats: the shrubs of mountaintop and the conifer and broadleaf mixed forest. Our data showed that the fruit-setting ratio is much lower in the latter than in the former. Given that the reproductive strategy is very crucial for fruit-setting, to reveal the main reasons that influence the fruit-setting ratio, breeding system must be known. Therefore, firstly, P/O and OCI were analyzed and results showed that breeding system of A. shikokiana was self-compatible and mainly outcrossed. Secondly, controlled pollination tests were carried out showing that neither apomixes nor wind pollination occurred. Further results on the type of the breeding system confirmed that A. shikokiana was self-compatible and mainly outcrossed by insects. Lastly, diameters of flowers and frequency of pollinators in two habitats were compared. Results showed that flowers were bigger and frequency of pollinators were higher in shrubs of mountaintop than those in conifer and broadleaf mixed forest, while numbers of pollens and ovaries had little difference. Thus, the overall analysis of the results indicates that the paucity of insect pollinators is the most important reason for the fruit-setting ratio of A. shikokiana lower in the conifer and broadleaf mixed forest than in the shrubs of mountaintop; however, such an implication needs to be further verified with additional work.