Taxonomic significance of palyno-morphic markers for the delimitation of some Brassicaceous taxa in Balochistan Province (Pakistan)

The pollen morphology of Brassicaceous taxa was analyzed to investigate their reliability as operational taxonomic units (OTUs) down to species level. The derived formula for all observed pollen was N3P4C3 based on NPC classification. Documentation of quantitative parameters via statistical analysis included dendrogram, correlation, and loading plots. The studied taxa belong to 15 tribes, Brassiaceae, Alysseae, and Euclidieae being the dominant, including the endemic species Pseudodraba hystrix. The assessment of qualitative and quantitative features of pollen grains using LM and SEM aided in the discrimination of closely related species. The size of polar axis ranged from a minimum of 15.85 µm in Eruca vesicaria to a maximum of 33.05 µm in Dilophia salsa. Values of equatorial axis range from a minimum of 14.75 µm in Diplotaxis griffithii. to a maximum of 33.2 µm in Dilophia salsa. Exine sculpturing types were reticulate, coarsely reticulate, and scabrate. Lumen was prominent in polygonal and amorphous shapes with irregular and regular types. Lobate round, and triangular ambs were observed in the polar view of pollen. The Polar axis, equatorial axis, and length of colpi in equatorial view exhibited a highly positive correlation. This study describes the micromorphological characteristics of pollen which can aid in accurate identification and delineate boundaries among Brassicaceous members at different taxonomic ranks.