title: Stigma receptivity over the lifetime of the hermaphroditic flower of Elsholtzia rugulosa was negatively correlated with pollen viability.
abstract: Dichogamy is generally thought to be a mechanism that prevents self-fertilization in flowering plants. This study aims to investigate the relationships between floral age and stigma receptivity, style length and pollen viability, and define how floral characters avoid self-pollination in a gynodioecious Chinese plant, Elsholtzia rugulosa. We assessed the relationships between flower age and style length, stigma receptivity, and pollen viability in E. rugulosa. This species produces 2 forms with plants bearing either hermaphrodite flowers (H) or female flowers (F). Corolla length in F flowers was shorter than the corolla length of H flowers and produced no pollen. H flowers were protandrous, pollen release of H flowers occurred before stigma receptivity. Stigma receptivity was significantly positively correlated with style length in both F flowers and H flowers. Pollen viability in H flowers declined significantly with floral age. Our results suggest that self-pollination in H flowers is likely reduced by dichogamy because stigma receptivity and pollen viability were effectively separated in time. However, because H inflorescences typically have multiple flowers open at the same time means that geitonogamous selfing is not avoided.
authors.affiliation: a Key Laboratory of Disaster Warning and Control in Yunnan Province, Colllege of Forestry, Southwest Forest Forestry University , Kunming , Yunnan , China.
authors.forename: Xin-Min
authors.initials: XM
authors.lastname: Zhang
authors.affiliation: b Kunming Institute of Botany, Chinese Academy of Sciences , Kunming , Yunnan , China.
authors.forename: Lorne M
authors.initials: LM
authors.lastname: Wolfe
mesh_terms: D035264:Flowers / Q000378:metabolism* / Q000502:physiology*; D019684:Magnoliopsida / Q000378:metabolism* / Q000502:physiology*; D011058:Pollen / Q000378:metabolism* / Q000502:physiology*; D054817:Pollination / Q000502:physiology
keywords: Dichogamy; gynodioecy; pollen viability; pollen-stigma interference; stigma receptivity