NANOSCALE SIMILARITIES IN THE SUBSTRUCTURE OF THE EXINES OF FAGUS POLLEN GRAINS AND LYCOPODIUM SPORES

The exine substructure of an angiosperm, Fagus sylvatica (beech) polle n and a pteridophyte, Lycopodium clavatum (a club moss) spore was inve stigated by scanning tunnelling microscopy. These pollen and spores, d espite their distinct differences in structure and morphology on a mic rometre scale, have very similar substructure on a nanometre scale. Th e substructure appears to consist of a multi-helix, i.e. a helical cha in in turn wound into a helix with a self-similarity at smaller and sm aller length scales, A simple Vectorial form is proposed to describe q uantitatively the multi-helical substructure. (C) 1998 Annals of Botan y Company.