The Micromorphology and Histochemistry of Foliar Mixed Indumentum of Leucas lavandulaefolia (Lamiaceae)

Abstract

Leucas lavandulaefolia Sm. (Lamiaceae) is an important medicinal plant with a broad spectrum of pharmacological activities. This study aimed at characterizing the morphology, distribution, and chemical composition of the secretions of trichomes at different developmental stages on the leaves of L. lavandulaefolia, using light and electron microscopy. Morphological observations revealed the presence of bicellular non-glandular, glandular peltate, and capitate trichomes on both adaxial and abaxial leaf surfaces. The density of both non-glandular and glandular trichomes decreased with the progression of leaf development. Heads of peltate and short-stalked capitate trichomes were between 20.78–42.80 µm and 14.98–18.93 µm at different developmental stages. Furthermore, long-stalked capitate trichomes were rare and infrequent. Leaf sections revealed the presence of important secondary metabolites in glandular trichomes, i.e., terpenoids. This study represents the first report on the morphology and histochemistry of trichomes of L. lavandulaefolia; therefore, there is a great scope for further research in this field.

Applying quantitative spatial phenotypes analysis to the investigation of peltate glandular trichomes development pattern in Perilla frutescens

“…3 ). These GTs in P. frutescens were structurally analogous to those present in other Lamiaceae plants, displaying a tripartite organization consisting of basal, stalk, and head cells [ 20 , 42 , 43 ]. In this study , we found P. frutescens PGTs are spheroid structures that accumulate oily substances during their maturation stages.…”

“…It is worth noting that the distribution of GTs on only one side of the leaf is not a universal phenomenon in plants that possess abundant glandular trichome tissue. More commonly, GTs are found on both the abaxial and adaxial surfaces of leaves [ 42 , 44 , 45 ]. Hence, when investigating species with GTs distributed on both sides of the leaf, the model proposed in this study requires spatial information of the GTs on both sides of the leaf, along with a cross-surface correction.…”

“…Moreover, our study provides a snapshot of the developmental stage of PGTs on leaves at a similar time point. Previous studies have suggested that GTs undergo a rapid maturation process, and that the developmental stage of GTs on mature leaves tends to be consistent [ 22 – 24 , 42 ]. Therefore, we chose juvenile leaves as the research object to obtain PGTs at various developmental stages.…”

Glandular Trichomes and Essential Oils Variability in Species of the Genus Phlomis L.: A Review

“…Glandular trichomes are considered true "natural biofactories" [2] essential oils but are also for other secondary metabolism compounds, their secretion being polymorphic, depending on the species and their structure [26]. Although there are numerous studies on the morphology and histochemistry of glandular trichomes in species of the Lamiaceae family [27][28][29][30][31][32], the number of research works that refer to the Phlomis genus remains quite limited.…”

Comparative microscopic investigations of leaf epidermis in four Ajuga species from Korea

“…Lamiaceae includes a considerable number of species that produce essential oils, secreted by glandular trichomes on leaves as well as some reproductive organs (Ascensão et al, 1999; Hanlidou et al, 1991). The structure and function of these trichomes, along with other leaf morphological characters can be used to differentiate closely related species in a systematic as well as biochemical context (Abu‐Asab & Cantino, 1987; Autunes & Sevinate‐Pinto, 1991; Cantino, 1990; Dunkić et al, 2017; Hu et al, 2012; Maurya et al, 2019; Moon et al, 2009; Naidoo et al, 2021; Xiang et al, 2010; Zhang et al, 2014). Leaf epidermal morphology, analyzed using light and scanning electron microscope (LM and SEM), also provides important systematic traits in Lamiaceae species in Korea (Jang & Hong, 2007; Jeon & Hong, 2006).…”