Introductory Review on the Pollen Morphology of Citreae

Citrus is one of the most wide cultivated fruits in the world. Pollen morphology of citrus is one of the most important characteristics used in classification and reproductive biology studies. In this paper we reviewed the progress of palynological characters including pollen size, aperture, and exine ornamentation. Pollen grains of Citrus are usually circular in shape with 4-colporate aperture, and elliptical equatorial view. The exine thickness ranges from 1-3 μm. The size of grains is small to medium with polar axis ranging from 22-45 μm. This basic knowledge on citrus pollen morphology provides a fundamental information for understanding the development and fertility of citrus pollen.