Phenology and pollen studies of some species of Annonaceae in Nigeria

Abstract

Phenology and pollen studies were investigated in some species of Annonaceae in Nigeria to help in  providing pollen data and record of flowering patterns of the species studied. Phenological data for   flowering and fruiting were tracked once a week for both rainy and dry seasons. Pollen grains from fresh anthers of the different species of Annonaceae were collected for pollen grain stainability and  morphological studies. The peak flowering period in all the species studied was between March and April. Flower production took place before flushing of leaves in M. tenuifolia, however, in A. reticulata and A. squamosa, flowering and flushing of leaves occurred at the same time. All the species have predictable annual fruiting periods; the harvesting of their fruits and seeds, and sustainable management is bound to be relatively easy. The percentage pollen stainability was higher than percentage pollen germination in the species studied. Low fertility was observed in A. reticulata and C. patens. Tetrad pollen observed in Annona, Monodora and Xylopia is an advanced character in Annonaceae and could have an advantage over the monad. The genus Cleistopholis now appears to be one of those genera which have retained the largest number of the characteristics of a primitive member of  Annonaceae. The evolutionary development is from Cleistopholis (monad) to Xylopia (tetrad) to Monodora (tetrad) to Annona (tetrad).

Keywords: Phenology, Pollen, Annonaceae, Evolution, Monad, Tetrad.