Pollen morphology and taxonomic implications of Zingiberaceae in Eastern India

Abstract

The present study investigated the pollen morphology of 29 species in nine genera of the family Zingiberaceae collected from natural habitats of Odisha, Eastern India. The fresh flower buds were collected and pollen preparation was done using standard methodology. The morphology of the pollen was examined using light and scanning electron microscopy. The sizes of the pollen grains ranged from 26-117 mu m and were apolar and inaperturate. The pollen grains of this family were classified into three, five and five types based on pollen size, shape and surface ornamentation, respectively. There were 17 species from Odisha with large pollen grains, i.e. magnae, followed by mediae (six species) and permagnae (six species). The five categories of pollen shape were per-prolate, prolate, sub-prolate, prolate-spheroidal and spheroidal. The five pollen ornamentation types were echinate (Alpinia, Amomum, Boesenbergia, Globba, Kaempferia, and Meistera); rugulate (Curcuma); psilate (Hedychium); and cerebroid and spiro-striate (Zingiber). We also provide a dendrogram of the family Zingiberaceae created by the unweighted pair-group method with arithmetic mean (UPGMA) to show the phenetic relationships among the species. The observed differences in pollen morphological traits provide important taxonomic information that is useful for delimitation of the taxa of Zingiberaceae. The taxonomic groupings inferred from palynological traits represent the first comprehensive palynological assessment of Zingiberaceae species from Odisha. The novel integration of details of sexine ornamentation with phenetic clustering offers a unique framework for resolving long-standing taxonomic ambiguities and advancing future pollination-biology research.