Taxonomic significance of foliar epidermal morphology in Lamiaceae from Pakistan.

Foliar micromorphological features are useful to elucidate the taxonomy and systematics of the Lamiaceae species. Leaf epidermal morphology using scanning electron microscopy and light microscopy of 22 Lamiaceae species from 15 genera have been investigated with an aim to solve its taxonomic problem in the correct identification. Various foliar micromorphological features were observed to explain their importance in resolving the correct identification of Lamiaceae taxa. Two main types of trichomes were observed; glandular trichomes (GTs) and nonglandular trichomes (NGTs). GTs were further divided into seven subtypes including the capitate, subsessile capitate, sessile capitate, sunken, barrel, peltate, and clavate. Similarly, NGTs were also divided into simple unicellular and multicellular including conical, falcate, cylindrical, dendrite, papillose, and short hook shape. Quantitative measurement includes the length and width of the trichomes, stomatal complex, epidermal cells, stomata, and trichomes index. Based on the foliar micromorphological characters, a taxonomic key was developed to delimit and correctly identify studied taxa. Further molecular, other anatomical and phylogenetic studies are recommended to strengthen the systematics of Lamiaceae.

Taxonomic study of subfamily Nepetoideae (Lamiaceae) by polynomorphological approach.

The present study is insight into pollen morphology for characterizing species and their utility in the taxonomic separation of certain taxa of subfamily Nepetoideae (Lamiaceae) from Pakistan. The pollen micromorphology of 11 species of the Nepetoideae was analyzed and documented using light microscopy and scanning electron microscopy (SEM) for both qualitative and quantitative characteristics. Most species have hexazonocolpate pollen grains but trizonocolpate and tetrazonocolpate pollen with circular and oval amb were also rarely observed in Mentha spicata. The basic pollen shape in most of the studied species was subspheroidal but prolate grains were also observed in M. spicata, S. coccinea, and S. plebeia. The exine sculpturing of Nepetoideae pollen was taxonomically very informative particularly at subfamily level. Observations of exine sculpturing with SEM revealed various types of pollen grains: reticulate, bireticulate, microreticulate, perforate, aerolate, and gammate. The bireticulate type further subdivided into three subtypes based on the number of secondary lumina in each primary lumen and is characterized by varying characteristics of the secondary reticulum and primary muri. A significant variation was observed in colpus surface ornamentation. The maximum polar diameter was found in O. americanum (58 ± 5.8 µm) and the maximum equatorial diameter observed in O. basilicum (50.25 ± 1.37 µm). Pollen features of the studied species were discussed and compared based on the current taxonomical concepts. The results showed that pollen traits of the subfamily Nepetoideae was found significant to classify the taxa. Furthermore, pollen features provide additional evidence to distinguish macromorphologically similar taxa from each other.

Palyno-anatomical studies of monocot taxa and its taxonomic implications using light and scanning electron microscopy.

Palyno-anatomical study of monocots taxa using Light and Scanning Electron Microscopy (SEM) was first time conducted with a view to evaluating their taxonomic significance. Studied plants were collected from different eco-climatic zones of Pakistan ranges from tropical, sub-tropical, and moist habitats. The aim of this study is to use palyno-anatomical features for the correct identification, systematic comparison, and investigation to elucidate the taxonomic significance of these features, which are useful to taxonomists for identifying monocot taxa. A signification variation was observed in quantitative and qualitative characters by using the standard protocol of light microscopy (LM) and SEM. Epidermal cell length varied from maximum in Allium griffthianum (480 ± 35.9) µm at the adaxial surface to minimum in Canna indica (33.6 ± 8.53) µm on abaxial surface. Maximum exine thickness was observed in Canna indica (4.46) µm and minimum in Allium grifthianum (0.8) µm. Variation was observed in shape and exine ornamentation of the pollen, shape of the epidermal cell, number, size, and type of stomata, guard cell shape, and anticlinal wall pattern. Based on these palyno-anatomical features a taxonomic key was developed, which help in the discrimination of studied taxa. In conclusion, LM and SEM pollen and epidermal morphology is explanatory, significant, and can be of special interest for the plant taxonomist in the correct identification of monocots taxa.