Floral biology and reproductive system of enantiostylous Senna corymbosa (Caesalpiniaceae)

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Auteur principal: Cecilia Laporta
Format: Artículo científico
Langue:en
Publié: Universidad de Costa Rica 2005
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author Cecilia Laporta
author_facet Cecilia Laporta
contents Floral biology and reproductive system of enantiostylous Senna corymbosa (Caesalpiniaceae) Cecilia Laporta Biología buzz Senna Cassieae pollination enantiostyly The genus Senna (K.Bahuin) Miller (Cassieae) is represented in Argentina by 35 species and several varieties distributed in temperate, tropical and subtropical regions, and presents a high degree of endemism. Some taxa are used for medicine, animal foraging and ornamental purposes. Floral morphology, phases, rewards, attractants, visitors, pollen, reproductive system, P/O ratio, OCI and ISI indexes of enantiostylous Senna corymbosa were analyzed for morphological androecial differentiation and possible related functional differences between stamens groups. The study was carried out over three consecutive flowering seasons in March of 1999, 2000 and 2001, in two populations near the city of Buenos Aires, Argentina. The species has a buzz-pollination syndrome. The pollinators are Bombus atratus that vibrate the stamens, leading to nothotribic or sternotribic deposition of pollen. P/O ratio and pollen production were high thanks to the precise pollinating mechanism that needs a large delivery of pollen to ensure effective pollen deposition. P/O ratio also indicates that the species is xenogamous, although geitonogamy and autogamy (only induced, not spontaneous)were also recorded. The species is self-compatible. There were differences in hand-pollination treatments between long and medium stamens in fruit set, as well as in vitro differential fertility between their pollen grains. Hence, there are morphological and functional androecium differences: the medium stamens play a nutritional role while the long ones play a reproductive one. These differences are reflected in the breeding system. Moreover, differential fertility and enantiostyly may diminish the effects of self-compatibility by partially reducing the contribution of geitonogamy to selfing. 2005 artículo científico 0034-7744 https://www.redalyc.org/articulo.oa?id=44918946006 en http://www.redalyc.org/revista.oa?id=449 Revista de Biología Tropical application/pdf Universidad de Costa Rica Revista de Biología Tropical (Costa Rica) Num.1-2 Vol.53
format Artículo científico
id redalyc_44918946006
institution Redalyc
language en
publishDate 2005
publisher Universidad de Costa Rica
spellingShingle Floral biology and reproductive system of enantiostylous Senna corymbosa (Caesalpiniaceae)
Cecilia Laporta
Biología
buzz
Senna
Cassieae
pollination
enantiostyly
Floral biology and reproductive system of enantiostylous Senna corymbosa (Caesalpiniaceae) Cecilia Laporta Biología buzz Senna Cassieae pollination enantiostyly The genus Senna (K.Bahuin) Miller (Cassieae) is represented in Argentina by 35 species and several varieties distributed in temperate, tropical and subtropical regions, and presents a high degree of endemism. Some taxa are used for medicine, animal foraging and ornamental purposes. Floral morphology, phases, rewards, attractants, visitors, pollen, reproductive system, P/O ratio, OCI and ISI indexes of enantiostylous Senna corymbosa were analyzed for morphological androecial differentiation and possible related functional differences between stamens groups. The study was carried out over three consecutive flowering seasons in March of 1999, 2000 and 2001, in two populations near the city of Buenos Aires, Argentina. The species has a buzz-pollination syndrome. The pollinators are Bombus atratus that vibrate the stamens, leading to nothotribic or sternotribic deposition of pollen. P/O ratio and pollen production were high thanks to the precise pollinating mechanism that needs a large delivery of pollen to ensure effective pollen deposition. P/O ratio also indicates that the species is xenogamous, although geitonogamy and autogamy (only induced, not spontaneous)were also recorded. The species is self-compatible. There were differences in hand-pollination treatments between long and medium stamens in fruit set, as well as in vitro differential fertility between their pollen grains. Hence, there are morphological and functional androecium differences: the medium stamens play a nutritional role while the long ones play a reproductive one. These differences are reflected in the breeding system. Moreover, differential fertility and enantiostyly may diminish the effects of self-compatibility by partially reducing the contribution of geitonogamy to selfing. 2005 artículo científico 0034-7744 https://www.redalyc.org/articulo.oa?id=44918946006 en http://www.redalyc.org/revista.oa?id=449 Revista de Biología Tropical application/pdf Universidad de Costa Rica Revista de Biología Tropical (Costa Rica) Num.1-2 Vol.53
title Floral biology and reproductive system of enantiostylous Senna corymbosa (Caesalpiniaceae)
topic Biología
buzz
Senna
Cassieae
pollination
enantiostyly
url https://www.redalyc.org/articulo.oa?id=44918946006