Morpho-palynological evaluation of family Poaceae from arid and semi-arid regions of Pakistan

This study marks the first investigation into the palynomorphic documentation of grasses from the arid to semiarid regions of Baluchistan, Pakistan. The objective of the current study was to examine the morphological traits of the pollen of 38 species of the family Poaceae. The pollen micromorphological characterization was carried out utilising light microscopy (LM) and scanning electron microscopy (SEM). The features analysed qualitatively (such as symmetry, polarity, size, aperture count, harmomegy, exine sculpting, and the NPC formula) and quantitative data on palynological traits were compiled into a matrix and analysed using SPSS and Past software. Grasses have homogeneous stenopalynous pollen, characterised by consistent aperture number, symmetry, and polarity. Most taxa possess large peritreme, ulcerate type pollen with a single pore and radial symmetry. The NPC formula for these pollen types is N1P0C4. The significantly varied palynological features among poaceous pollen were stenopalynous when characterized, although there were differences in the shape (prolate spheroidal, oblate spheroidal, suboblate, subprolate, and prolate), degree of harmomegathy, annulus appearance, and pore orientation. The NPC formula N1P0C4 was drevied for all grasses. The Principal Component Analysis (PCA), dendrogram, and correlation plot effectively distinguished the taxa based on the polar axis, equatorial diameter, exine thickness, pore length, and pore width. The pollen micromorphological traits were used as taxonomic markers to develop the taxonomic key for the delimitation of studied Poaceae flora. The distinguished palynological characters provide the base for the identification of grasses.