Lychnis alba pollen possesses 0.73–0.79% elemental silicon (dry weight), and levels at least as high as in pollen exines have been indicated in tapetal orbicules upon maturation. Even higher levels of elemental silicon (1.30–1.37%) were recorded from Impatiens sultanii pollen. This may indicate that silicon is an important elemental component of exine materials characteristic of many types of pollen, in which silicate compounds may aid in the high degree of pollen resistance to geological weathering, microbial decay, and acetolysis treatments. Further, the data for the incorporation of silicon in L. alba pollen in this report support the concept that exine materials are derived from tapetal cell secretions during pollen ontogeny.
