POLLEN MORPHOLOGY OF ONAGRACEAE IN IRAN

This study aims to assess the pollen characteristics of Iranian Onagraceae based on SEM techniques to evaluate the possibility of giving them a role in systematic analysis. Pollen grains of the studied taxa included radially symmetrical, tetrad tetra-hederal, isopolar, triangular to triangular-spheroidal, 3-zonoporate, with viscin threads, rugulate-granulate, granulate, verrucate and striate sculpturing. Polar axis ranged between 30 and 80 µm. Equatorial axis showed variation from 40 to 90 µm. Moreover, arm diameter ranged between 8.85 to 18.83 µm, pore diameter 8.72 to 21.69 µm. PCOA and Cluster analysis of pollen characteristics did not clearly show sectional divisions based on Flora Iranica as well as Flora of Iran. There are not significant differences in size, shape, pore structure and arm characteristics to delimit all species in Onagraceae. Moreover, Pollen grains are not efficient for generic delimitation in the studied taxa in Iran. Therefore, even though that the examined taxa cannot be distinguished exclusively by pollen, it may be a use­ful tool for delimitation some taxa in Onagraceae along with other evidence.