Reproductive biology and species geographical distribution in the Melastomataceae: a survey based on New World taxa |
| |
Authors: | dos Santos Ana Paula Milla Fracasso Carla Magioni Luciene dos Santos Mirley Romero Rosana Sazima Marlies Oliveira Paulo Eugênio |
| |
Institution: | Universidade Federal de Uberlandia, Instituto de Biologia, 38402-020 Uberlandia, MG, Brasil. |
| |
Abstract: | Background and AimsFloral variation, pollination biology and mating patterns were investigated in sunbird-pollinated Babiana (Iridaceae) species endemic to the Western Cape of South Africa. The group includes several taxa with specialized bird perches and it has been proposed that these function to promote cross-pollination.MethodsPollinator observations were conducted in 12 populations of five taxa (B. ringens subspp. ringens, australis, B. hirsuta, B. avicularis, B. carminea) and geographic variation in morphological traits investigated in the widespread B. ringens. Experimental pollinations were used to determine the compatibility status, facility for autonomous self-pollination and intensity of pollen limitation in six populations of four taxa. Allozyme markers were employed to investigate mating patterns in four populations of three species.Key ResultsSunbirds were the primary pollinators of the five Babiana taxa investigated. Correlated geographical variation in perch size, flower size and stigma–anther separation was evident among B. ringens populations. Experimental pollinations demonstrated that B. ringens and B. avicularis were self-compatible with variation in levels of autonomous self-pollination and weak or no pollen limitation of seed set. In contrast, B. hirsuta was self-incompatible and chronically pollen limited. Estimates of outcrossing rate indicated mixed mating with substantial self-fertilization in all species investigated.ConclusionsDespite the possession of specialized bird perches in B. ringens and B. avicularis, these structures do not prevent considerable selfing from occurring, probably as a result of autonomous self-pollination. In eastern populations of B. ringens, smaller flowers and reduced herkogamy appear to be associated with a shift to predominant selfing. Relaxed selection on perch function due to increased selfing may explain the increased incidence of apical flowers in some populations. |
| |
Keywords: | Babiana bird perch sunbird pollination floral variation mating pollen limitation relaxed selection |
本文献已被 PubMed 等数据库收录! |
|