Biologia floral, da reprodução e da polinização de Desmodium affine Schltdl (Fabaceae)

Abstract

Desmodium affine is a Fabaceae native to Brazil that has potential forage. For forage species breeding and pollination studies are primordial since they are species destined to the production of seeds. This work had as objectives: 1. To describe the morphology and floral biology to define the pollination system of the species. 2. Determine the mode of reproduction and verify if there is dependence of pollen vectors for the formation of fruits and seeds. 3. Check the flower visitors and set the pollinators. 4. Analyze the effect of different pollination modes on the reproductive success of the species. 5. Identify among the pollinators, which contribute most positively to the reproduction of D. affine. The study was carried out in a natural population in the municipality of Cerro Largo, Rio Grande do Sul. The floral biology was verified in the field through the events of anthesis. The reproductive system was verified through three tests: spontaneous self-pollination, manual self-pollination and cross-pollination, flowers were still marked for open pollination (control). The frequency of floral visitors was recorded and the pollinators efficiency was defined. The flowers of D. affine are papilionadas and present an explosive mechanism of pollination. Even though they are fruit by self-pollination, the indexes indicate that D. affine is autoincompável. Open pollination showed the highest fructification (69%), indicating that these plants need pollinators and that these influence on the greater reproductive success of this species. Regarding the efficiency of pollinators, Ephantidium bicoloratum, Exomalopsis aureopilosa, Megachile sp. 2, and Augocloropsis sp. were considered the most efficient pollinators for D. affine, since they presented the best results for the evaluated variables. Mainly by pollination of these species results in higher fruiting rates. Being a species destined to fruit production, pollination by bees plays an important role in increasing the productivity of D. affine.