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The differential contributions of herkogamy and dichogamy as mechanisms of avoiding self‐interference in four self‐incompatible E pimedium species
Author(s) -
Li X.X.,
Zou Y.,
Xiao C.L.,
Gituru R. W.,
Guo Y.H.,
Yang C.F.
Publication year - 2013
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1111/jeb.12193
Subject(s) - biology , pollination , interference (communication) , botany , pollen , channel (broadcasting) , electrical engineering , engineering
Abstract Self‐interference is one of the most important selective forces in shaping floral evolution. Herkogamy and dichogamy both can achieve reductions in the extent of self‐interference, but they may have different roles in minimizing self‐interference in a single species. We used four self‐incompatible E pimedium species to explore the roles of herkogamy and dichogamy in avoiding self‐interference and to test the hypothesis that herkogamy and dichogamy may be separated and become selected preferentially in the taxa. Two species ( E . franchetii and E . mikinorii ) expressed strong herkogamy and weak protogyny (adichogamy), whereas another two species ( E . sutchuenense and E . leptorrhizum ) expressed slight herkogamy and partial protandry. Field investigations indicated that there was no physical self‐interference between male function and female function regarding pollen removal and pollen deposition in all species. Self‐pollination (autonomous or facilitated) was greater in species with slight herkogamy than in those with strong herkogamy. Artificial pollination treatments revealed that self‐pollination could reduce outcrossed female fertility in all species, and we found evidence that self‐interference reduced seed set in E . sutchuenense and E . leptorrhizum in the field, but not in E . franchetii and E . mikinorii . These results indicate that well‐developed herkogamy is more effective compared with dichogamy in avoiding self‐interference in the four species. In genus E pimedium , herkogamy instead of dichogamy should be selected preferentially and evolved as an effective mechanism for avoiding self‐interference and might not need to evolve linked with dichogamy.