Flowering behaviors of the inflorescences of an alien plant (Plantago asiatica), an alpine plant (Plantago hakusanensis), and their hybrids on Mt. Hakusan,Japan |
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| Authors: | Saki Sano Yuichiro Nakayama Kentaro Ohigashi Tatsuya Nogami Atsushi Yagyu |
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| Institution: | 1. Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, JapanPresent address: Division of Safety and Environment, Fukui Prefecture Government, Fukui, Japan.;2. Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, JapanPresent address: Graduate School of Humanities and Sustainable System Sciences, Osaka Prefecture University, Sakai, Japan.;3. Ecosystem Informatics Division, National Institute for Agro‐Environmental Science, Tsukuba, Japan;4. Hakusan Nature Conservation Center, Hakusan, Japan;5. Ishikawa Prefectural Kanazawa Commercial High School, Kanazawa, Japan |
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| Abstract: | In the subalpine zone on Mt. Hakusan, Japan, Plantago asiatica, an alien plant, and Plantago hakusanensis, a native alpine species, grow sympatrically along with their putative hybrids. Here, their flowering behavior, which affects the frequency of hybridization and the colonizing ability of P. asiatica and its hybrids, is described. The flowering behavior of each species and of two F1 hybrids from different seed parents was determined based on the position of the flower in the inflorescence by using a generalized linear mixed model. The percentage fruit set of individually bagged inflorescences was calculated to corroborate the assumptions of the opportunities for self‐pollination. All the flowers were protogynous; however, many P. asiatica anthers dehisced before browning of the stigma in the flower and the sex presentations in the inflorescence were asynchronous. The percentage of fruit set was high. Consequently, P. asiatica has the opportunity for self‐pollination within the flower and in the inflorescence. In contrast, the P. hakusanensis anthers dehisced after browning of the stigma in the flower; their sex presentation was synchronous in the inflorescence, showing negligible opportunities for self‐pollination, and the fruit set was low. Accordingly, in the field, P. hakusanensis might require pollination among the inflorescences for seed production and be actively outcrossed, while P. asiatica is able to outcross in the early flowering phase. Therefore, P. asiatica and P. hakusanensis have opportunities for hybridization. The F1 hybrids exhibited intermediate flowering behavior and produced fruits, demonstrating the potential to reproduce by selfing. |
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| Keywords: | alien plant alpine plant flowering behavior Plantago protogyny |
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