Is Silene acaulis (Caryophyllaceae) a trioecious species? Reproductive biology of two subspecies

• Published in: Canadian Journal of Botany
• Main Authors: Maurice, Sandrine, Desfeux, Christine, Mignot, Agnès, Henri, Jean-Pierre
• Other Authors: Institut des Sciences de l'Evolution de Montpellier (UMR ISEM), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École Pratique des Hautes Études (EPHE), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Montpellier (UM)-Institut de recherche pour le développement IRD : UR226-Centre National de la Recherche Scientifique (CNRS), Ecologie Systématique et Evolution (ESE), Ecole Nationale du Génie Rural, des Eaux et des Forêts (ENGREF)-Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 1998
• Subjects: breeding systems; trioecy; subdioecy; Silene acaulis; [SDE.BE.BP]Environmental Sciences/Biodiversity and Ecology/domain_sde.be.bp
• Online Access: https://hal.science/halsde-00350052; https://doi.org/10.1139/cjb-76-3-478

International audience Based on morphological characters, Silene acaulis subsp. exscapa and Silene acaulis subsp. cenisia have been previously described as dioecious and trioecious, respectively. Here we examine whether these subspecies are truly dioecious (subsp. exscapa) and trioecious (subsp. cenisia) based on individual seed and pollen production. Nine populations of subsp. cenisia and five populations of subsp. exscapa were studied in the French Alps. The ratio of staminate to female plants within populations did not in general differ from 1:1, the sex ratio expected in dioecious populations. Staminate plants of both subspecies were found to set fruits. In subsp.exscapa, the ratio of fruit production in female versus staminate plants is around 900; in subsp. cenisia, this ratio is around 10. The advantage of female plants in fruit production is not always sufficient to explain their frequencies in natural populations. Staminate plants cannot be divided in two distinct categories: males and hermaphrodites. The two subspecies can be best described as subdioecious, although S. a. exscapa is effectively closer to exhibiting true dioecy than S. a. cenisia.