Análise morfométrica floral em três populações de Prosopis Affinis Spreng. (mimosoideae – fabaceae) no bioma pampa brasileiro

Abstract

Pampa biome, degraded by intensive exploitation, including Fabaceae as one of mostly represented families in Savanna-Park formations. Mimosoideae contains species characteristic of Pampa and presents diverse sexual and reproductive systems among inflorescence with floral specialization in Prosopis species. Therefore, its paper researches floral biology and differentiation between P. affinis flowers through inflorescence and relation between those traits and Pampa fragmentation. Then, pollen/ratio and morphological variations among base, middle and apex of inflorescence collected in São Vicente do Sul, Cacequi and Quaraí-RS. Floral biology was accessed with outcrossing index (OCI), seed/ovule ratio, flowers per inflorescence and 1,000-kernel weight. Spikes have in average 117.13±29.50 yellowish tubular flowers, including 23.33% of basal flowers with tendency to auto-pollination unrelated to flower position. Seed/ovule ratio (0.503±0.189) was similar to outcrossing although OCI was characteristic to facultative autogamy species, appointing reproductive flexibility. 1,000-kernel weight obtained was 9.98g. There was reproductive reduction in basal flowers without reproductive differentiation since mostly anthers were higher than sigma. Its strategy contributes to rise of frequency of visitors‟ rates and flexibility of reproductive system facilitates establishment of individuals in fragmented landscapes as Pampa.