Pollen Morphology of Some Species of the Genus Amelanchier Medik.

Abstract

Pollen grain structure is one of the diagnostic taxonomic and phylogenetic parameters. Study of morphology and morphometry of pollen grains of Amelanchier spp. allows found new additional diagnostic parameters of species. We determined that pollen of Amelanchier spp. is variable both in size and morphology. SEM investigations showed that the pollen grains various species of Amelanchier are prolate and perprolate, the surface sculpture and shape index of the species vary. The average length of the polar axis varied from 27.38 to 47.14 μm and the width of the equatorial axis was in the range from 14.33 to 28.95 μm. Shape index (P/E) of tested species varied from 1.77 to 2.09. The most average length of pollen was Amelanchier spicata (43.24 μm) and the least length was Amelanchier arborea (13.69 μm). The most average width pollen was Amelanchier canadensis (23.04 μm), and the least width was Amelanchier arborea (16.07 μm). Cluster analysis showed that the relationships of the tested Amelanchier species according to morphological features are represented by two main groups. It is evidently that A. arborea which has the smallest parameters is really separated from other species. A. lamarki, A. spicata and A. canadensis are similar according to morphometric sizes. Studies via scanning electron microscope have established characteristic differences in the morphometric and microsculptural features of pollen for each of the studied Amelanchier spp. which can be used to identify the representatives of species. Differences in the size of pollen grains in comparison with other authors may be the result of many environmental factors specific to the geographical area, climatic conditions of the country such as constantly increasing atmospheric temperature, alternation of rainfall with a dry season and others, which could be the subject of further research.