A biologia reprodutiva da Leucaena leucocephala (Lam.) de Wit (Fabaceae - Mimosoideae): Estratégias reprodutivas de uma espécie invasora

Abstract

Leucaena leucocephala is a perennial legume characterized by rapid seed germination and fast plant growth. In addition, the species has low nutritional requirements, which favors its establishment as a pioneer species in different environments. Its white flowers are grouped into globular heads ranging from 1.5 cm to 3 cm in diameter. The inflorescences produce clusters of narrow and flattened pods, approximately 20 cm long and 2 cm wide, containing 15 to 30 brown-colored seeds. These morphological characteristics may directly influence the reproductive biology of the species, contributing to its ecological success and wide dissemination in anthropized areas.

This study aimed to investigate reproductive aspects of Leucaena leucocephala during the transition period between the end of the dry season and the beginning of the rainy season in 2012, generating information to explain the wide dominance of this species in anthropized areas in Trindade.

Experiments related to the reproductive biology of the species were carried out, including floral senescence observations, analysis of floral resources, pollen viability tests, floral anthesis evaluation, and focal observations to record floral visitors and their visiting schedules. First and second visit tests were also conducted, as well as self-pollination and cross-pollination experiments, in order to evaluate fruit and seed production resulting from the applied treatments.

The results demonstrated a higher frequency of visits by Apis mellifera and Trigona spinipes to leucena flowers. However, the tests performed to evaluate reproductive efficiency showed low fruit production rates, even after the third floral visit. Likewise, self-pollination and cross-pollination experiments presented lower results than expected.