Abstract Detail

Reproductive Processes

Nishida, Sachiko [1], Hashimoto, Yusuke [2], Yamamoto, Akane [3], Kanaoka, Masahiro [4], Naiki, Akiyo [5], Takakura, Ko-Ichi [6].

Pollen-pistil interactions in reproductive interference.

Reproductive interference, an interspecific mating interaction that reduces fitness in one or more species, has been gaining attention as a notable factor for exclusive distribution, habitat segregation, and character displacement among closely-related species. Reproductive interference has been considered a type of “interspecific mating error” rather than as interspecific competition in its original sense as applied to animals.   Outbound reproductive interference with exported pollen has been intensively studied and is commonly referred to as interspecific pollen transfer, which can lead to reduced siring success or hybridization.  However, the negative consequences of heterospecific pollen receipt have been much less thoroughly explored.
We have focused on reproductive interference between native dandelion and its alien congener, and have recently revealed that heterospecific pollen receipt, i.e., deposition of alien pollen onto focal stigmas, exerts a deleterious effect on some of the natives. To clarify what happens after the alien pollen is deposited onto the native stigma, and to evaluate consistency of inbound reproductive interference across taxa, we conducted hand-pollination experiments in six populations of three native Taraxacum species that receive different amounts of reproductive interference from the alien congener, T. officinale, and compared pollen-pistil interactions among the populations. We also compared the interactions among different T. japonicum individuals whose reproductive success against alien pollen deposition were previously measured, to assess consistency of the interaction at the individual level. Our results revealed that following heterospecific pollen receipt, heterospecific pollen tubes often penetrated the native ovary in the populations vulnerable to the reproductive interference, whereas they seldom penetrated in the population impervious to it. However, association between the relative frequency of the heterospecific pollen tube penetration and the strength of the alien’s reproductive interference was not significant. At the individual level, the native pistils did not always accept or refuse the alien pollen tubes, but sometimes accepted and sometimes refused, which indicates that the native pistils’ recognition of pollen identity is not consistent within an individual. Our results partly support the assumption that reproductive interference from the alien to the native dandelions occurs when native flowers lack interspecific incompatibility and “mistakenly” accept the alien pollen tubes, which causes the ovules to be usurped. However, some variation in the acceptance within the native individual, and/or the other factors during the heterospecific pollen transfer are likely to be involved, and the details should be clarified in future research.

1 - Nagoya Univ. Museum, Furo-Cho, Chikusa-Ku, Nagoya, 464-8601, Japan
2 - Nagoya University, Graduate School of Environmental Studies, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8601, Japan
3 - Okayama University, Graduate School of Education, Tsushima-naka 1-1-1, Kita-ku, Okayama, Okayama, 700-8530, Japan
4 - Nagoya University, Graduate School of Science, Furo-cho, Chikusa-ku, Nagoya, Aichi, 484-8601, Japan
5 - University of the Ryukyus, Iriomote Station, Tropical Biosphere Research Center, Taketomi-cho, Yaeyama-gun, Okinawa, 907-1541, Japan
6 - The University of Shiga Prefecture, Yasaka-cho, Hikone, Shiga, 552-0057, Japan

heterospecific pollen transfer
reproductive interference

Presentation Type: Oral Paper
Session: REP3, Reproductive Processes 3
Location: Virtual/Virtual
Date: Thursday, July 30th, 2020
Time: 11:00 AM
Number: REP3005
Abstract ID:364
Candidate for Awards:None

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