Palynology is the study of pollen grains produced by seed plants (angiosperms and gymnosperms) and spores (pteridophytes, bryophytes, algae and fungi). Pollen and spores differ in their function, but both result from cell division involving a reduction by half of the chromosome content (meiosis) (Moore et al. 1991). Pollen grains house the male gametes, but spores are usually the resting or dispersal phase of the fern, algae, etc. Because of the larger size and the importance of pollen in pollination and to insects, pollen will be emphasized.
Pollen grains vary in shape from spherical to elliptic to triangular. Most pollen grains range from about 4 to 250 ìm. Pollen grains often have openings (pores) or furrows (colpus = singular, colpi = plural). A pollen grain with one colpus is called monocolpate. A pollen grain with three pores is triporate and one with three pores within three colpi is termed tricolporate. The outside layer of the pollen grain can be smooth (psilate), net-like (reticulate), or looks like a ball of string (striate). Some pollen grains even have spine like projections (echinate).
It is common knowledge that pollen is a major cause of allergies. However, pollen can be used to determine insect migration, insect food sources, honey types and in forensics, climatic changes, etc. There are several reasons pollen is used in these studies. First, pollen grains are distinctive, easily recognizable and identifiable to the family, genus and often species rank. Thus, very specific information can be obtained. Second, pollen is made up of sporopollenin that is durable and does not easily decay. Third, from the identification of the pollen, the geographical origin of the plant from which the pollen came can be determined.
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