Investigation of pollen morphology of the genera Grammosciadium, Vinogradovia and Caropodium (Apiaceae)

Abstract

In this study, detailed light microscopy (LM) and scanning-electron microscopy (SEM) analyses of pollen grains belonging to 11 taxa of genera Grammosciadium, Vinogradovia and Caropodium were performed. The pollen is radially symmetrical and generally isopolar with the exception of Grammosciadium macrodan ssp. nezaketiae where 65% of the grains have asymmetrical appearance. All the taxa are tricolporate. Ectoapertures are discontinuous (colpus length: 14.7 ± 0.8 and colpus width: 21.20 ± 2.28) with narrow and acute at the ends extending to the subpolar region. Endoapertures are in the mid-section of the ectoapertures, which is lolangate, prolate-spheroidal in Grammosciadium scabridum, while lalongate, ellipsoidal, oblate or suboblate in the other taxa. Pollen shape is triangular and semi-triangular in polar-view. Pollen outline in equatorial view is subrectangular-straight in G. scabridum and Caropodium platycarpum, however, those were subrectangular and slightly constricted in equatorial region in all others. Based on the P/E ratio, it is prolate in G. macrodon ssp. macrodon while it is perprolate in the other taxa. Ornamentation variation (i.e. psilate, psilate-perforate, psilate-rugulate, rugulate and rugulate-perforate) was observed around the apertural, equatorial and polar regions. This character has been found as taxonomically important for the studied taxa.