Sporopollenin: A review of its chemistry, palaeochemistry and geochemistry

Sporopollenin, the tough resistant biopolymer that coats the outer walls of pollen grains, spores and related microorganisms, considered “the most resistant organic material known”, accounts for the morphology and microstructure and for geological preservation of palynomorphs. The stability of sporopollenin is thus the raison d'etre of the science of palynology. Although sporopollenin is such a unique and interesting material, very few chemical studies had been made on it until research started at the University of Bradford in the 1960's. In 1968, we discovered the relationship between the chemical nature and properties of sporopollenin and those of oxidative polymers of carotenoids, and shed some light on the chemical structure of sporopollenin. This review describes some of the chemical, biochemical and geochemical studies on sporopollenin during the last ten years.