Pollen morphology of different species of Iris barbata and its systematic significance with scanning electron...

Forty-eight cultivars of Iris barbata were used as research materials, and observations of their pollen morphologies were made using scanning electron microscopy (SEM). The pollen of I. barbata consisted of a single grain, which was subspheroidal or subprolate and boat-shaped in equatorial view and oval or nearly round in polar view. The pollen was symmetrical or radially symmetrical on both sides, and there were five types of germination furrows: monocolpate, dicolpate, monocolpate-colpoidal, 2-syncolpate, and parasyncolpate. The exine ornamentation was mostly crass-reticulate and occasionally verrucate or pilate. Variation in the equatorial axis length of I. barbata pollen was the lowest, and variation in pollen morphology was stable. Q-type cluster analysis was conducted using seven indexes: polar axis length (P), equatorial axis length (E), P/E, mesh diameter (D), net ridge width (W), D/W, and germination furrow width (WG). The 48 cultivars were divided into three groups. Three dwarf cultivars were clustered in one group, and the degree of evolution of this group was higher than that of the other two groups. This paper systematically describes the characteristics of I. barbata for the first time, and thus provides important palynological insights into the classification and cross-breeding of I. barbata.