Palynological analysis of Annona muricata, A. squomosa and A. senegalensis

Abstract

Palynological analysis of Annona senegalensis Pers., Annona squamosa Linn. and Annona muricata Linn. was carried out to compare the pollen morphology of these species and to identify the differences, if any, that might warrant their re-classification. Fresh flowers of these plants were collected, dried and crushed to liberate the pollen grains. The liberated pollen grains were subjected to acetolysis treatment and then examined under the microscope. Photomicrograph of the pollen was taken using trinocular microscope fitted with a digital camera. Results showed that all the plants had tetrad, acalymate pollen that were inaperturate. Pollens of A. senegalensis and A. squamosa were tetragonal with a globose shape, rugulate exine ornamentation and an intectate exine inner structure. On the contrary, pollen of A. muricata was rhomboidal with an ellipsoidal shape, reticulate exine ornamentation and a semitectate exine inner structure. A. muricata had the highest pollen size with tetrad and monad diameter of 229 μm and 111 μm, respectively while A. squamosa had the least (tetrad diameter = 99 μm; monad diameter = 50 μm). Sexine was only present in A. muricata (5.5 μm). The observed differences in the pollen morphology of these three studied species do not warrant their re-classification.