Palynological analysis some species of Chenopodiaceae and its systematic implications using scanning electron microscopy

Chenopodiaceae is a large, diverse and cosmopolitan family within the order Carophyllales. The majority of Chenopodiaceae species are adapted to saline, hypersaline, xerophytic and xerohalophytic communities or ruderal habitats. The family Chenopodiaceae is stenopolinous the pollen grains are monad and exclusively polypantoporate with tiny spinules on both tectum and operculum. Pollen morphology of six genera of Chenopodiaceae (Seidlitzia, Atriplex, Bassia, Salsola, Krascheninnikovia and Spinacia) have been studied in details. These plant species were collected from different phytogeographical regions of Iran. The palynological investigation was done using scanning electron microscopy (SEM) techniques. Pollen characters studied in this study include pollen and pore diameters, number and density of apertures, interporal distance (chord), chord/pollen diameter ratio, pore diameter/pollen diameter ratio as well as spinule density on tectum and operculum. We used different multivariate statistical methods to reveal the species relationships. Ward clustering analyses have been done to check out the relationship among the species. The shapes of pollen grains were radially symmetrical, isopolar, pantopolyporate and spheroidal. Their exine structure is similar. In the Chenopodiaceae, three pollen types have been defined, mainly on the basis of pollen grain size, pore number, number of microechinae on pore membrane, the density of spinules, and pore edge shape.