Format: ORAL

Clesnan Mendes-Rodrigues1, Rafaela Cabral Marinho1, Diana Salles Sampaio1, Gastn O. Carvallo2, Luciana Nascimento Custdio1, Ana Paula de Souza Caetano3, Renata Carmo-Oliveira1, Paulo Eugnio Oliveira1

1 Universidade Federal de Uberlândia, Uberlândia, MG, Brazil 2 Pontificia Universidad Catolica de Valparaíso, Valparaiso, Chile 3 Universidade Federal de Mato Grosso, Cuiabá, Brazil

Polyembryony involves multiple, either sexual or asexual embryos in the same seed. Asexual embryos are commonly the result of apomixis processes. Although sexual systems and monoembryony predominate among Cerrado plants, the Neotropical savannas in Central Brazil, recent studies have shown increasing numbers of apomictic species, many of them polyembryonic. Here we surveyed the polyembryony among Cerrado plants and connected its occurrence with apomixis. We compiled records of embryonic patterns - monoembryony or polyembryony (216 species) and breeding systems (139 species) from literature, and also gathered original data (91 species). We observed the rate of polyembryony either by dissecting seeds or evaluating the emerging seedlings per seed after germination experiments. Plant species were classified as exhibiting monoembryony, low polyembryony (5%) or higher polyembryony rate (5%). Polyembryony was observed in 72 species (31.8%). Surveyed species were either self-incompatible (66 species; 47.5%), self-compatible (33 species; 23.7%), apomictic (28 species; 20.1%) or dioecious (12 species; 8.6%). Among apomictic species, 89.3% (N = 25) were polyembryonic. Percentage of polyembryonic seeds ranged from 0.09% to 98.4%, with sporophytic apomicts exhibiting usually higher rates of polyembryony. Polyembryony and apomixis in Cerrado plants seem to be linked to dioecy and polyploidy, and widely distributed woody species. Although apomixis and polyembryony are common in taxa such as Bignoniaceae, Fabaceae, Malvaceae and Melastomataceae, we did not find any clear phylogenetic signal for the distribution of these traits. Polyembryony rate higher than 5% proved to be a good indicator of apomixis. However, polyembryony was absent in some apomictic specie and, in several cases, was even linked to sexual reproduction. Polyembryony associated with apomixis seems to be a common reproductive alternative in savanna plants rather than a reproductive abnormality. Moreover, these traits will be important for plant conservation strategies in this threatened biome. (We acknowledge CAPES, FAPEMIG and CNPq funding)