Palynology and meiotic behavior of Genipa americana L., a species native to the Amazon

Genipa americana L., commonly known as genipap, belongs to the Rubiaceae family. This study aimed to describe the pollen morphology of the species, evaluate its meiotic behavior and pollen viability, and provide information to help the maintenance and conservation of the species in its natural habitat. Flower buds were collected from 20 individuals in Alta Floresta and Matupá municipalities, Mato Grosso, Brazil. Pollen morphology was characterized using acetolysis and compared to existing literature. Meiotic and post-meiotic phases were analyzed using 2% acetocarmine stain, and pollen viability was estimated using Sudan IV, Alexander's stain, Lugol's solution (1%), and 2% acetocarmine stain. G. americana has medium-sized, 3-colporate pollen with reticulated exine and few meiotic irregularities. Acetocarmine stain showed the highest mean percentage of pollen viability (97.96%). Stain tests revealed significant differences, indicating high pollen viability and meiotic regularity. However, conservation and recovery of degraded areas are still necessary as there is no guarantee of successful reproduction due to factors associated with fragmentation, genetic drift, reduced gene flow, and inbreeding.