Energy dispersive x-ray (edx) investigations on some apocynaceae pollen

Abstract

Abstract Apocynaceae pollen and anthers (unacetolyzed) were analysed with a Cambridge S 200 scanning electron microscope equipped with an energy dispersive X-ray (EDX) unit. Pollen grains collected from herbarium sheets show a very similar distribution of their elemental content. In most cases, complete dried anthers and single pollen grains gave the same results. In all 21 species investigated, the presence and amount of P, S, Cl, K and Ca differs significantly in the three subfamilies of the Apocynaceae. Only, the Plumerioideae possess a distinct amount of Cl while all species of the Apocynoideae and Cerberoideae show a clear amount of S. Usually, the K peak is higher than the Ca signal in the Plumerioideae and Cerberoideae, which is reversal in the Apocynoideae. In neither case Si could be detected. It can be concluded that EDX derived characters of pollen grains may give valuable information to taxonomy. Advantages of this technique are the need for very little material (one pollen grain can be suffic...