Micromorphological Characterization of Seeds of Dicot Angiosperms from the Thal Desert (Pakistan)

Abstract

Micromorphological and ultrastructural data have been helpful in determining the evolution, classification, ecology, and phylogeny of seed plants. Taxonomic utility of seed characters has been explored, although the value of micro-structure in selected dicot angiosperms from desert areas has not been adequately addressed. We conducted a comparative morphometric analysis of internal and external seed features in the 16 dicot species representing 10 families from the Thal desert (Pakistan) using scanning electron microscopy. Seeds were mostly minute and small and slightly larger than 1 mm in length except for Acacia nilotica, Astragalus hamosus and Prosopis juliflora. Seeds varied in shape from elliptical to obovate, D-shaped, reniform, rhomboid, and ellipsoidal. The cell outline, periclinal boundaries, and sculpture pattern of the anticlinal wall were generally rugulate, reticulate and striate, papillate and rugose, or rarely undulating granulate. The seed coat also comprises diverse forms of epicuticular projections and texture. The phenetics of 84 character-states using principal component and dendrogram statistics supported the affinities among desert species. Here, we identified micromorphological similarities and differences among dicot angiosperms to determine their systematic relationships.