Palyno-Anatomical and Seed Morphology of Lamiaceous Taxa from Northern Pakistan

Abstract

This project is the first comprehensive taxonomic information on Lamiaceous plant species Northern Pakistan. The study is confined to pollen micromorphology, seed micromorphology, and foliar epidermal anatomy. The Lamiaceae is not previously documented regarding recent taxonomic trends (palynology, anatomy and seed morpology) from the Northern Pakistan. The present research was aimed at the documentation of significant taxonomic markers to identify the Lamiaceious species. From different parts of Northern Pakistan, 104 Lamiaceae plant species comprising 40 genera and 6 sub families were collected. Among them genus Nepeta species dominating the family (19 species), followed by genus Salvia (12 species), genus Mentha (8 species) and Ocimum (6 species) were reported. The pollen micromorphological characterization was carried out via light microscopy (LM) and scanning electron microscopy (SEM). The foliar epidermal anatomical attributes were examined via LM and SEM. Seed micromorphological features were documented through stereomicroscope and SEM. The data of quantitative measurements of the palynological and anatomical traits was collected into a matrix and analyzed statistically via SPSS (2016), Past (2021), and XLSTATE (2018). Lamiaceae species showed variation in pollen size and shape, aperture type and exine sculpturing. Nepeta exine sculpturing were found as reticulate, reticulate perforate, bireticulate perforate, reticulate perforate-verrucate, fine reticulate perforate and reticulate-perforate/ foveolate. The largest polar diameter was found in Nepeta distans (86.5µm), and smallest in Nepeta praetervisa (20.3 µm). The microanatomy of the stomata, epidermis, anticlinal wall pattern, and variety of trichomes were different on both surfaces of the leaves. In the current study four main types of stomata were observed: anomocytic, diacytic, anisocytic, and paracytic. The largest stomata length at the adaxial surface was observed in Ajuga reptans (35 µm) and the lowest in Scutellaria prostrata (20 µm). Variation in seed shape was observed from semi-spheroid, spherical, oblong, globose oblong, trigonous, obovate, fusiform, spheroid, oval, elliptic, rhomboid, broad elliptic and broad obovate. The Lamiaceae seeds ranged in size from (1 mm) in Anisomeles indica to (4 mm) in Phlomoides vicaryi in length and from (0.75 mm) in Phlomoides vicaryi to (3.5 mm) in Vitex agnus-castus in width. The taxa of the family were successfully divided by the Principal Component Analysis (PCA), dendrogram, correlation. XXVIII The construction of taxonomic keys also revealed micromorphological markers for accurate identification. Micromorphological characteristics that have been established serve as a foundation for the accurate identification of Lamiaceous taxa and their systematic significance.