Biologia floral de tacinga inamoena (K. Schum.) N. P. Taylor & Stuppy (cactaceae)

Abstract

Caatinga is the predominant vegetation in northeastern Brazil, composed of seasonal dry tropical forests, and presents a diversity of species of the Cactaceae family with high ecological importance. The phenological monitoring of reproductive stages, floral biology, reproductive system and pollination biology of the species Tacinga inamoena (K. Schum.) NP Taylor & Stuppy (Cactaceae) were studied in three communities of Caatinga in the state of Paraíba, Brazil. To define the phenophases, the description of the intensity of the phenological event was adopted and the flowering synchrony index was calculated for each population. To assess the relationship of phenological events with climatic variables, Spearman's correlation coefficient was applied. Analyzes of floral and reproductive biology were carried out, as well as the observation and recording of the richness, abundance and frequency of floral visitors. The species showed low synchrony flowering and fruiting events and significant correlation with environmental factors. The flowers of T. inamoena have diurnal anthesis, red color, actinomorphic with an inferior ovary and epigina, offering nectar as a resource. The pollen grains had 96.87% viability and the pollen:ovule (P:O) ratio was 998.72. There was a significant difference in fruit morphometry between populations. The reproductive system is mixed and can happen by self-pollination and by cross-pollination. There was a significant difference in fruit morphometry between populations. The reproductive system can happen by self-pollination and by cross-pollination. There was no significant difference in the quality of fruits from pollination treatments. Seed germination is low. The main pollinator is the hummingbird (Chlorostilbon lucidus) that visits the flowers only in the morning, corroborating the ornithophilia syndrome presented by the flower. Butterflies and bees were registered as looters. The species showed continuous flowering and fruiting and correlated with climatic variables, with a mixed reproductive system that guarantees the reproductive success of the species.