Pollen morphology of some genera selected tribe Alysseae (Brassicaceae)

Abstract

The tribe Alysseae (Brassicaceae) contains the genera Brachypus, Clastopus, Fibigia, Irania, Physoptychis, and Straussiella. Little is known about the pollen morphology in these taxa. In this study, pollen from 11 species and one variety representing some of the genera in the tribe Alysseae were examined using light microscopy (LM) and scanning electron microscopy (SEM). The size of pollen is the smallest in Brachypus tabriziana (30.23 µm), conversely, the largest in Irania umbellata (47.17 µm) and Clastopus vestitus (46.60 µm) in the Alysseae. The pollen morphology of Irania umbellata deviated from I. multicaulis and was distinct in having perprolate, ornamentation reticulate, the thickest exine, and the polar axis length. In this study, the pollen morphology of some species of Fibigia, Brachypus, and Irania, was previously placed in the Fibigia genus in order to determine the significance of pollen features as taxonomic characters. In addition, our results indicated that Clastopus differs from the related genera Physoptychis and Straussiella, and pollen morphology conforms to the separation of the three genera. These results support research phylogenetic studies in the Alysseae. Based on the above evidence, the three new combinations such as Brachypus kermanshahensis, B. khoshyelaqensis, and B. tabriziana proposed.