We might consider plant reproduction as commencing when a pollen grain lights on the female part of a flower. Thus the role of pollen is critical. But, being a pollen grain is challenging, particularly for pollen distributed by wind. Subjected to the vicissitudes of weather and physical shocks during a journey that may encompass scores of miles or more, it's not for the weak or timid.
The pollen grain's success at surviving its ordeal may be due in
part to the matter making up its outermost, protective wall. This material,
sporopollenin, is one of the most resistant organic substances known, and like the
mineralized animal material known as enamel, fossilizes well, lasting for millions upon
millions of years. Over much of the northern hemisphere, fossil pollen from the Ice Age
gives us a glimpse of times past. Falling into ponds and lakes to be preserved in their
bottom mucks, pollen reveals the past regional vegetation. What a boon for our
biological history—except, alas, our desert conditions appear too harsh even for
sporopollenin, and pollen survival is rare.
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.
Erdtman, G. 1969. Handbook of palynology. Munksgaard, Copenhagen. 486 pp.
Faegri, K., and J. Iversen. 1964. Textbook of pollen analysis. 2nd ed., Munksgaard, Copenhagen. 237 pp.
Pollen, Owen Davis.