Variation in floral morphology and plant reproductive success in four Ipomoea species (Convolvulaceae) with contrasting breeding systems
Por:
Delgado-Davila, R., Marten-Rodriguez, S., Huerta-Ramos, G.
Publicada:
1 nov 2016
Resumen:
This study tested the hypothesis that self-compatibility would be
associated with floral traits that facilitate autonomous
self-pollination to ensure reproduction under low pollinator visitation.
In a comparison of two pairs of Ipomoea species with contrasting
breeding systems, we predicted that self-compatible (SC) species would
have smaller, less variable flowers, reduced herkogamy, lower pollinator
visitation and higher reproductive success than their self-incompatible
(SI) congeners.
We studied sympatric species pairs, I. hederacea (SC)-I. mitchellae (SI)
and I. purpurea (SC)-I. indica (SI), in Mexico, over two years. We
quantified variation in floral traits and nectar production, documented
pollinator visitation, and determined natural fruit and seed set.
Hand-pollination and bagging experiments were conducted to determine
potential for autonomous self-pollination and apomixis.
Self-compatible Ipomoea species had smaller flowers and lower nectar
production than SI species; however, floral variation and integration
did not vary according to breeding system. Bees were primary pollinators
of all species, but visitation rates were seven times lower in SC than
SI species. SC species had a high capacity for autonomous
self-pollination due to reduced herkogamy at the highest anther levels.
Self-compatible species had two to six times higher fruit set than SI
species.
Results generally support the hypothesis that self-compatibility and
autonomous self-pollination ensure reproduction under low pollinator
visitation. However, high variation in morphological traits of SC
Ipomoea species suggests they maintain variation through outcrossing.
Furthermore, reduced herkogamy was associated with high potential for
autonomous self-pollination, providing a reproductive advantage that
possibly underlies transitions to self-compatibility in Ipomoea.
Filiaciones:
Delgado-Davila, R.:
Univ Nacl Autonoma Mexico, Escuela Nacl Estudios Super, Morelia, Michoacan, Mexico
Inst Ecol AC, Dept Biol Evolut, Xalapa, Veracruz, Mexico
Marten-Rodriguez, S.:
Univ Nacl Autonoma Mexico, Escuela Nacl Estudios Super, Morelia, Michoacan, Mexico
Huerta-Ramos, G.:
Univ Nacl Autonoma Mexico, Escuela Nacl Estudios Super, Morelia, Michoacan, Mexico
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