Foliar epidermal anatomy of Lamiaceae with special emphasis on their trichomes diversity using scanning electron microscopy

Abstract

Foliar epidermal features were based on the micromorphology of trichomes types, epidermal cells and stomatal complex. Even though each feature has its own limited taxonomic value but collectively these characteristics may be systematically important especially for the discrimination and identification of complex and problematic taxa. The systematics significance of nonglandular (NGTs) and glandular trichomes (GTs), stomatal complex and epidermal cells of Lamiaceous flora were analyzed by using the light microscopy (LM) and scanning electron microscopy (SEM). Variations on the observed epidermal appendages were divided into two basic types: glandular and nonglandular. GTs can be divided into subtypes: sessile capitate, subsessile capitate, and barrel and sunken. NGTs were also divided into subtypes: dendritic, stellate, conical, falcate, simple and 1–6 cells long having granulate and smooth surface ornamentation. NGTs were the most dominant features of both adaxial and abaxial surfaces of all observed taxa. Vitex negundo, Isodon rugosus, Colebrookea oppositifolia, and Marrubium vulgare could be demarked because of their twisted like appearance of NGTs at the abaxial surface. The Lamiaceae had both hypostomatic and amphistomatic leaf. Stomata were observed as diacytic, anisocytic, and anomocytic. Epidermal cells were found to be irregular, isodiametric, and rectangular. Based on these characters a taxonomic key was developed to delimit the closely related taxa. Distribution and morphology of the foliar epidermal trichomes through SEM highlight an important taxonomic tool used by the taxonomists as an aid to the correct identification of problematic Lamiaceae taxa.

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

“…The light microscopic analysis was performed for the investigation of foliar epidermal features. For LM both fresh and dried leaves were prepared using the technique of Gul et al (2018) with a little modification. The fresh leaves of collected samples were placed in water for about 2 hr to prevent them from drying.…”

“…Leaves of monocotyledonous taxa are mostly linear and have parallel venation although some taxa have broad leaves. Hence, foliar epidermal characters that is, trichomes and stomata have been used a taxonomic tool at various taxonomic ranks (Edeoga & Osawe, ; Gul et al, ). The foliar epidermal anatomy provides the taxonomic information of monocotyledonous taxa.…”

“…Hence, foliar epidermal characters that is, trichomes and stomata have been used a taxonomic tool at various taxonomic ranks (Edeoga & Osawe, 1996;Gul et al, 2018). The foliar epidermal anatomy provides the taxonomic information of monocotyledonous taxa.…”

Taxonomic study of one generic and two new species record to the flora of Pakistan using multiple microscopic techniques

“…Similarly, Hemcinschi et al, (Hemcinschi, Gales, Stanescu, & Toma, ) observed the anamocytic‐type stomata as well. Foliar epidermal traits of the Ajuga bracteosa and Ajuga parviflora in Pakistan were found significant in the correct identification and delimitation of the related species (Gul et al, ). Foliar epidermal features were found useful to elucidate the systematics of the Lamiaceae species (Gul et al, ).…”

“…Ajuga reptans has a total of nine vascular bundles, one big in the center and four at each corner (Akçin, Özyurt, & Şenel, ). The genus Ajuga belongs to family Lamiaceae and is represented in Pakistan by only two species (Gul et al, ; Perveen & Qaiser, ); till to date no third species were added to this genus in the flora of Pakistan and with the addition of Ajuga reptance the number of species will be three.…”