Conical Trichomes Research Articles

Microstructural Feature of Salvia glutinosa L. vegetative and generative organs

 It has been studied perspective medicinal plant S. glutinosa  aboveground parts vegetative and generative organs internal diagnostic features. The aboveground vegetative and generative organs of the plant are lined with unicellular or multicellular, conical trichomes, glands, unicellular or multicellular, also conical, spherical, secretory trichomes; Basal layer cells of curved and curved wall epidermal tissue is characteristic feature for leaf. The leaf is bifacial, amphistomatic, dorsoventral structure. Folium and axial organs cover tissue are presented diacytic type stomata. Lentil-like Guard cells of stomata, subsidiary cells stomata are curvilinear structure.In the internal structure of aboveground part polygonal structure tissue and mechanical tissue are actively represented, fiber and collenchyma existence are particularly characteristic sign for mechanical tissue. The transport system is monocyclic, collateral vascular bundles reflected in the stem, leaf stalk, and midrib. Longitudinally arranged, spherically shaped vascular vessel and tracheid element is in the transport system cortex. The axis organs xylem vessel mainly is spiral type, rarely  porous wall thickening.

MICROSTRUCTURAL FEATURES OF THE VEGETATIVE ORGANS OF DELPHIUM FLEXUOSUM BIEB. COMMON IN GEORGIA

The genus Delphinium L. is rich in diterpene alkaloids, which exhibit a pronounced curare-like, anti-tumor, anti-inflammatory, analgesic, antidote and insecticidal action. The content of diterpene alkaloids in the aboveground and unde-ground vegetative organs of Delphinium flexuosum Bieb., a promising medicinal plant of the flora of Georgia, and diagnostic features of the internal structure were studied in order to determine the identity of the experimental raw material.GC/MS analysis revealed that the dominant alkaloid obtained from the vegetative organs of the plant is the pharmacologically active methyllicaconitine.  Other alkaloids have been identified as anthranoillocytonine, delcosine, lycotonine. As well, the underground organs contain also zongorine, delectine and norzongoramine. A set of diagnostic features of the internal structure of D. flexuosum was determined using the methods adopted in microtechnics. The leaf of D. flexuosum is bifacial, hypostomatic and has dorsoventral structure. It is very rarely covered with long conical trichomes, the underlying cells of the lower and upper epidermis of the leaf are non-wrinkled and curved. The differential stomatal apparatus in leaf-covering tissue is anomocytic.  Stomata are lenticular, and structure of the stomata is chaotic, in terms of the reciprocal location of the locking cells. The leaf pulp is differentiated into open, reverse-collateral conductive cones. The aboveground organs of D. flexuosum are characterized by an orderly aligned structural elements of the epidermal tissue, with linear and straight-walled stem cells and orderly arranged anomocytic stomata. Collenchymal and fibrous cells of the mechanical type and open-collateral type conducting cones with a thickening of the spiral and reticular membrane are actively reflected in the organs of the plant axis. The conductive tissue of the root system of D. flexuosum contains a number of polar rays of the wood with differentiated stepwise, spiral and ring-shaped tracheal elements.

Leaf Epidermal Morphology of Ten Wild Tree Peonies in China and Its Taxonomic Significance

This research reports for the first time the epidermal characteristics of 10 wild tree peonies belonging to the sect. Moutan group. The leaf micromorphology of 10 wild tree peonies—P. qiui, P. decomposita, P. jishanensis, P. ostii, P. delavayi, P. lutea, P. potanini, P. rockii, P. ludlowii and P. cathayana—were investigated by light and scanning electron microscopy. The characteristics of the leaf epidermis were found to be constant at the species level, but variable among species. Patterns of anticlinal walls were slightly wavy to wavy, very wavy, and straight to curved. All studied tree peonies presented stomata only on the abaxial surfaces of the leaves. The stomatal apparatus was elliptical or rectangular. Stomatal density was highest on the abaxial surface in P. qiui (300.25 per mm2), and lowest in P. jishanensiss (198.41 per mm2). Stomatal Index was highest on the adaxial surface of P. potanini (27.30%), and lowest in P. ludlowii (18.35%). Trichomes were observed in four studied peonies, which appeared only on the abaxial surface of the leaves, and three basic types of trichomes were identified. The long conical trichomes were distinctive of P. jishanensis, and the flat-shaped trichomes were characteristic of P. qiui, P. rockii and P. cathayana, and commonly occurred in the intervenous region and leaf veins. Stomatal shape, stomatal density, anticlinal wall patterns and trichomes may be of great value and significance for the classification of wild tree peonies. The principal component analysis showed that the component 1, component 2 and component 3 were the most components and nearly 79% of the observed variation. The key to the identification of wild tree peonies based on trichomes and stomata diversity was provided.

Floral Nectary and Trichome Structure of Hoya cagayanensis, Hoya lacunosa, and Hoya coriacea (Apocynaceae, Marsdenieae)

Hoya R.Br. is a genus of ornamental plants with an attractive flower shape and unique scents. Anatomical studies are required to understand their structure that produces, and stores, the metabolites released by plants. The present study was conducted to determine the type and position of floral glands in three Hoya species: Hoya cagayanensis C.M Burton, Hoya lacunosa Blume, and Hoya coriacea Blume. The investigations were carried out using light microscopy (LM), scanning electron microscopy (SEM), and histochemical staining tests. Secondary nectaries were present in the corona lobe portion, while simple trichomes (unicellular) were found in the petals’ adaxial epidermis of all the studied species. Conical trichomes were found in H. cagayanensis, cylindrical trichomes in H. lacunosa, and falcate trichomes in H. coriacea. In the cells of secondary nectaries, this study revealed proteins, lipids, polysaccharides, and starch grains; however, only lipids and proteins were observed in simple trichomes. Secondary nectaries and simple trichomes were described for the first time in all the studied species, contributing new insight into Hoya’s anatomical and micromorphological floral glands.

Taxonomic Characteristics of Vegetative Organs for Invasive Species of Reynoutria Hook.

Species of the genus Reynoutria Hook. were originally intentionally introduced from East Asia and in the twentieth century, three of them were successfully naturalized in Europe: R. sachalinensis (F. Schmidt) Nakai, R. japonica Houtt. and their cultigenous hybrid R. × bohemica Chrtek & Chrtkova, which arose in the secondary distributional range of the parent species. As the taxa of the genus Reynoutria bloom very late, in late September-October, the characteristics of their leaves – shape, and type of pubescence – are mainly used as diagnostic ones. Identification of the species is often difficult, so this paper aims to identify diagnostic characters of their leaves in the secondary distribution range. Spontaneous invasive populations in Luxembourg, the Czech Republic, and Russia have been investigated. Comparisons have been made with plants growing in the natural range in Japan. Morphological characters were studied using a Keyence VHX-1000E digital microscope and an LEO 1430 VP scanning microscope. R. sachalinensis was found to be well distinguished from other species by its larger leaves with a heart-shaped base and a non-retracted apex. On the underside of the leaf, there are long uniseriate filiform trichomes along the lateral veins or outside the veins and peltate glands with 4-, 6- or 8-cell heads. For R. × bohemica, the presence of unicellular conical trichomes on the midrib was found to be a diagnostic feature in plants growing in Middle Russia (but not always) and is not applicable to plants from Czech populations, from which this species was actually described! In the taxonomic description of R. japonica, it has been suggested that the maximum height of the shoots should be significantly reduced (from 3 m to 1 m), as in the natural range this taxon has prostrate shoots. Plants of the secondary range with tall shoots are likely to be really R. × bohemica hybrids. It has been suggested that in Eastern Europe R. japonica grows generally very rare and predominantly in culture, and the information about most plants from invasive populations described in the literature as R. japonica should in fact be attributed to the hybrid complex R. × bohemica.

Trichome diversity studies in selected species of Sida

Sida (Family: Malvaceae) belongs to the genus of flowering plants that possess high medicinal value and is used traditionally in almost all parts of the world. There were about 18 species reported from the state of Kerala (India). Among these, some are with taxonomic controversies. Hence micro-morphological characters of leaves such as trichomes can be used as a taxonomic tool for the identification of plants. Their type, presence, absence and distribution are important diagnostic characters in plant identification and plant taxonomy. Plant samples were collected from different localities of Kerala. Foliar epidermal studies were carried out in order to identify the diversity and distribution of trichomes in the selected species of Sida viz., S. acuta, S. alnifolia, S. beddomei, S. cordata, S. cordifolia, S. fryxelli, S. ravii, S. rhombifolia and S. rhomboidea. Six types of trichomes were identified; they were stellate, conical, forked, capitate (short stalked), uniseriate multicellular and peltate. Stellate trichomes were observed in all the species. Conical trichomes were observed in S. beddomei, S cordata and S. fryxelli. Forked trichome was observed in S. acuta, S. cordata, S. cordifolia, S. ravii, S. rhombifolia and S. rhomboidea. Capitate (short stalked) trichomes were observed in S. acuta, S. alnifolia, S. rhombifolia and S. rhomboidea. Uniseriate multicellular trichomes were observed in S. cordifolia, S. fryxelli and S. ravii. Peltate trichomes are observed in all species except S. beddomei, S. cordifolia and S. fryxelli. However, these species could be easily distinguished by their conical trichomes. A bracketed dichotomous key was prepared for the identification of the species considered for the study.

Epidermal morphology of the cordaitalean leaf Noeggerathiopsis brasiliensis nom. nov. from the southern Paraná Basin (Lower Permian, Rio Bonito Formation) and paleoenvironmental considerations

A Brazilian cordaitalean leaf is reassigned and redescribed based on cuticular analysis. The new name Noeggerathiopsis brasiliensis is erected as a replacement for Rufloria gondwanensis Guerra-Sommer. The leaf adpressions come from a tonstein layer within a Sakmarian coal seam of the Faxinal Coalfield, southern Parana Basin, Brazil (U–Pb SHRIMP mean age 291 ± 1.3 Ma, Rio Bonito Formation). The leaf micromorphological pattern, observed under optical transmitted light and field emission gun — scanning electron microscopy, is distinct from the Euramerian Cordaites Unger and very similar to the Angaran Rufloria Meyen. The lower epidermis has conspicuous longitudinal stomatiferous furrows typical of Noeggerathiopsis (Feistmantel) McLoughlin & Drinnan covered by tightly interwoven trichomes, epidermal and probably also hypodermal highly cutinized sheaths at the borders of furrows, and haplocheilic stomatal apparati surrounded by long conical trichomes. The xeromorphic cuticle structures are similar to those of Glossopteris pubescens (Guerra-Sommer) Degani-Schmidt & Guerra-Sommer, the dominant leaf species preserved in the tonstein layer, indicating convergent ecological adaptations to abiotic stress factors in distinct plant groups in the peat-forming paleoenvironment.

Anatomía del rizoma y de la parte basal, media y distal del vástago de Solidago chilensis var. chilensis (Asteraceae)

Solidago chilensis var. chilensis “goldenrod” is a rhizomatous perennial herb native to Argentina. It is used in popular medicine as antilithic, diuretic and vulnerary; it also has pharmacological activity as a gastroprotective, antibacterial, anti-inflammatory and anti - oxidant. The objective of this study is to characterize the anatomy of the basal or proximal, middle and distal zones of the stem and the rhizome of Solidago chilensis var. chilensis in vegetative state to study future relations between parts of the plant and the production of phytochemicals, and to contribute to its characterization as a crude drug. The stem, rhizome and adventitious roots of vegetative individuals collected in the province of Buenos Aires were divided into three zones (distal, middle and basal or proximal) and studied by conventional histological techniques for optical and scanning electron microscopy. The results show that non-glandular whip and conical trichomes are located mainly in the leaves. The density of whip trichomes is higher in the leaves of the distal and middle stem. Biseriate glandular trichomes are only present in the distal leaves and stem and in the scales of the rhizome. The stomata are located in both foliar epidermis, but its density is lower in the basal leaves. There are schizogenous secretory spaces in all analyzed organs. In the leaves are associated with xylem and phloem, and in the scales, only with phloem. In the stem, rhizome and roots, they are located in the cortex associated with phloem; they are very well developed in the distal leaves and stem. Stems, rhizomes and roots have aerenchyma in the cortex, which develops larger intercellular spaces towards their basal or proximal zones. Calcium oxalate crystals in the form of needles, styloids and prisms are abundant in the aerenchyma and pith of the stem upper distal zone.

Nutlet micro‐morphology of the genus Microula (Boraginaceae) from the Qinghai–Tibetan Plateau, and its systematic implications

The micro‐morphology of nutlets in 30 taxa (28 species and 2 varieties) of Microula Benth. (Boraginaceae) was surveyed by light and scanning electron microscopy. A principal coordinate‐based ordination analysis (PCO) (8 morphological and 14 micro‐morphological characters) was applied to explore whether taxa clustered according to the current sectional taxonomy. The nutlet epidermis showed three major features: trichomes, papillae and lamellae. Two basic trichome types could be identified: branched and unbranched. Stellate trichomes (STT) and stipitate stellate trichomes (SST) can be considered as two subtypes of branched trichomes based on shape and branching location. Three kinds of unbranched trichomes were recognized by their shapes: slender trichomes (SLT), spear‐like trichomes (SPT) and conical trichomes (CT). Four types of papillae were revealed in this genus: central apiculate papillae (CAP), debris‐covered convex papillae (DCP), rugous papillae (RP) and tabular papillae (TP). The lamellae was classified in five types: glossy lamellae (GL), thread‐like lamellae (TL), rugous lamellae (RL), interrupted lamellae (IL) and debris‐covered lamellae (DCL). The variation in the nature of surface sculpturing, nutlet shape and size, dorsal aperture shape, and attachment scar positions proved useful diagnostic characters. Taxa belonging to the same section generally clustered together in the PCO analysis. A key based on the morphology and micro‐morphology of nutlets is provided to distinguish the sections of Microula. The presence of SLT, STT, DCP and DCL is consistent with the macro‐morphological classification and provides additional evidence for the subgeneric delimitations. The SST, SLT, CAP, DCP, RP, DCL, GL and RL are useful in discriminating species in Microula. Additionally, the distribution of some trichomes, papillae and lamellae types is correlated with the altitudinal distribution of the species.

Morphology and density of trichomes and stomata of Trichosanthes cucumerina (Cucurbitaceae) as affected by leaf age and salinity

We investigated the relationship between leaf age and trichome/stomata densities in the snake tomato (Trichosanthes cucumerina L.). In a second experiment, the effects of different salinity levels on trichome and stomatal densities and their micromorphology were investigated. The leaf age investigation utilised young, semiold, and old leaves, while the salinity study utilised 0, 60, 120, and 180 mM NaCl for the investigation. Two morphotypes (Variant --Green and Variant B-Light Green) of T. cucumerina were used for the salinity experiment while only Variant B-Light Green was used for the leaf age investigation. This study identified 2 discernible types of trichomes in T. cucumerina, namely conical trichomes and globular-headed trichomes, which are segmented into 3 or more distinct sections. A major observation in this study was that while salinity did not significantly (P ≥ 0.05) affect the densities (abaxial and adaxial) of the conical trichomes in Variant A, the same parameter was significantly reduced in Variant B due to salinity treatment. Results showed that there were significantly (P ≥ 0.05) more stomata on the abaxial surface than the adaxial surface, irrespective of the morphotype and salinity treatment. Under the control treatment (no salinity), Variant B-Light Green had significantly more stomata on the abaxial side than Variant A-Green, while on the adaxial side, the reverse was found to be true. Results also showed that the conical and globular-headed trichomes’ densities decrease as leaf age increases. The leaf petioles of the 2 variants are dominated by globular-headed trichomes. On the abaxial surface, analyses showed that there were 28% and 58% more stomata on the young leaf compared to semiold and old leaves, respectively. Further studies into the physiologically mediated mechanisms that are responsible for these observations in T. cucumerina are crucial.

LEAF TRICHOMES OF SOME PARTHENIUM SPECIES

Guayule (Parthenium argentatum), a native shrub of the Chihuahuan desert, contains rubber. Guayule has been crossed with other Parthenium species in an attempt to improve its agronomic characteristics. The resulting hybrids show intermediate morphologies. Each Parthenium species has a characteristic combination of leaf trichomes. In order to recognize the contribution of each parent in future studies of hybrids, characteristics of leaf trichomes of the following Parthenium species were studied: P. tomentosum, P. fruticosum, P. Schottii and P. rollinsianum. All species studied had two or more types of trichomes, and, in some species, trichomes of upper and lower epidermal surfaces were different. The prominent trichomes on upper epidermis of P. tomentosum and P. fruticosum were simple, uniseriate, conical trichomes, which also were observed on both epidermal surfaces of P. Schottii. Extremely long, narrow, simple, whiplike, trichomes formed a dense cover on both surfaces of P. rollinsianum and on the lower surfaces of P. tomentosum and P. fruticosum. Simple, uniseriate, cylindrical trichomes, and biseriate, glandular trichomes were observed in all four species.