Características morfológicas dos grãos de pólen e mecanismos florais de polinização em Papilionoideae e Caesalpinoideae -Cassiinae (Leguminosae)

Abstract

The floral evolution in Leguminosae selected pollinators, making them more specialized. The highest expression of this occurs in Papilionoideae, with four pollen release mechanisms: piston, brush, valve and explosive. Considering that there are different strategies for pollen release among Leguminosae species, we hypothesize that there is a difference between the morphological characteristics of the pollen grains and the different floral mechanisms in the species of Papilionoideae and Caesalpinioideae s.l. poricides. To test the hypothesis, a database was built with information on the pollens of 121 species of Leguminosae pollinated by bees and with different presentation mechanisms, collected from published literature and material available in the Pollen Catalog Network. Statistical analyzes of variance were used to establish a relationship between the categories. From this, a significant relationship was noticed between: exine ornamentation and release strategies; Pollen/Exine (P/E) ratio, general average and general average diameter of the polar axis of the pollen grains, and the different pollen release strategies. It is concluded that, due to both diversity and the complex set of reproductive strategies, the evolution of Leguminosae systems has been building a strong relationship between pollen morphology and the mechanisms of pollen grains release.