Non-glandular Trichomes Research Articles

Anatomical traits of Artemisia umbelliformis subsp. eriantha (asteraceae) alpine glacial relict from Mt. Durmitor (Montenegro)

In this study, the vegetative anatomy of Artemisia umbelliformis subsp. eriantha, a Central European alpine glacial relict, wild-growing on Mt. Durmitor (Montenegro) was examined for the first time. The aim was to investigate the general anatomy and particular anatomical traits which might have possible taxonomic value. Microscopic slides were prepared according to the standard histological procedures. The adventitious young root showed a primary structure, while the older root showed a secondary structure with a well-developed periderm on its surface. The rhizome showed a primary structure with elements of a secondary structure (periderm). The stem cross section is characterized by a round shape with a well-developed periderm at certain stages, and collateral vascular bundles arranged in a circle. The petiole is concave in shape with a single-layered epidermis and parenchyma tissue with one large and two small vascular bundles. Druses and rhombohedral crystals are observed inside some petiole parenchyma cells. The leaf lobe cross section has an oblong-linear shape and is isolateral and amphistomatous in structure. The anticlinal walls of the leaf epidermal cells are sinuate. Secretory canals are present in the root cortex parenchyma (endodermal secretory canals) and the rhizome cortical parenchyma. The stem, petiole and leaf lack secretory canals. The stem and leaf are covered with T-shaped non-glandular and glandular trichomes. The taxonomic value of the analyzed characteristics is briefly discussed.

Structural Characterisation of the Leaf of Bauhinia monandra Kurz (Fabaceae - Cercidoideae)

HIGHLIGHTS Bauhinia monandra leaf is mesomorphous to xeromorphous. It has glandular navicular and uniseriate nonglandular trichomes. The petiole has differential anatomical characteristics within the genus. The pulvinus and the motile cushion have live pectic septate fibres.

Leaf anatomical adaptation of eighteen mangrove plant species from the Sundarbans in Bangladesh

Investigation on leaf anatomical adaptation of 18 mangrove plant species was carried out. Among the 18 species 13 were dorsiventral and five were isobilateral type. All the species had special stomatal structure and variable cuticle layer to minimize transpiration. Most of the species had succulent leaves with leaf thickness ranging from around 232 to 1363 μm. As an indication of salt secretion, both glandular and non-glandular trichomes were observed in several species. Although presence of single to multilayered hypodermis might effectively function as water storage tissue, several studied mangrove plant species e.g. Cynometra ramiflora L., Phoenix paludosa Roxb., Pongamea pinnata (L.) Pierre, Sonneratia apetala Buch. - Ham., S. caseolaris (L.) Engl. and Xylocarpus moluccensis (Lamk.) M. Roem. showed complete absence of hypodermis. This might be due to moderate saline condition. In addition, marked terminal tracheids in mesophyll tissue of a number of species might help with capillary water storage within the leaf. To enhance mechanical support several species were found to develop considerable amount of diverse sclereids within the mesophyll tissue and surrounding vascular bundle. Although maximum anatomical adaptations are common for plants growing in saline habitat it may be suggested that these features were differentially developed in plants specifically grown in mesohaline zone.

Assessment of Pharmacognostic and Preliminary Physicochemical Investigations of Ethnomedicinal Plant Leea Asiatica (L.) Ridsdale of Valmiki Tiger Reserve, West-Champaran District, Bihar

Leea asiatica (L.) Ridsdale is synonymously known as Phytolacca asiatica L. and Leea crispa L.. Leea asiatica is a perennial shrub or small tree in the family Vitaceae. According to a survey, any report was not available on macroscopic, microscopic, and physicochemical investigations of Leea asiatica (L.) Ridsdale. The present study was aimed to evaluate macroscopic, microscopic characters, and physicochemical investigations of Leea asiatica (L.) Ridsdale. All parameters were established according to the Pharmacognostical standards procedure. Leaves were found to be petiolate, leaflets 5-7, oblong or elliptic-ovate. Stems are soft wooded, erect, and pubescent. Transverse sections of the midrib of leaf displayed a single layer of the epidermis, glandular, and non-glandular trichomes. Powder microscopy of the leaf and stem showed the presence of rosette crystals of calcium oxalate, trichomes, and starch grains. Physiochemical studies like ash values, extractive values, and LOD of Leea asiatica leaves have also been established. The present studies have established parameters for the correct identification of Leea asiatica. The present investigation was carried out to focus on pharmacognostic and preliminary physicochemical investigations of plant, Leea asiatica (L.) Ridsdale., which will assist in standardization for authenticity, quality, and identification of herbal products.

Defoliation by Gypsy Moth (Lepidoptera, Erebidae) Induces Differential Delayed Induction of Trichomes in Two Birch Species.

Outbreaks of the gypsy moth (Lymantria dispar japonica Motschulsky) cause serious defoliation in birch. A single year of defoliation has no significant impact on the trees, whereas continuous defoliation events could be fatal. How birch species avoid serious damage caused by gypsy moth outbreak is yet to be revealed. Trichomes on leaf surfaces of birch trees are an effective antiherbivore defense strategy. We examined a 1-yr delayed induction of glandular (GT) and nonglandular trichomes (NGT) on leaf surfaces caused by stress in white birch (Betula platyphylla Sukaczev var. japonica [Miq.] Hara) and monarch birch (Betula maximowicziana Regel). Saplings were subjected to four treatments in June 2009: herbivory (50% of the leaf area was grazed by gypsy moths), mechanical cutting (50% of the leaf area was cut using scissors), shading (50% light shading with a black sheet), and control (covered with a net to prevent herbivory). Then, the density of GT and NGT on early leaves was determined in April 2010. In both birch species, the density of GT was higher in herbivory than in other treatments. The density of GT due to mechanical cutting was higher than that in the control, but only for white birch. However, the density of NGT was lower after mechanical cutting than in other treatments for white birch. There were no differences in the density of NGT among treatments for monarch birch. These results show that 1-yr delayed induction of GT by herbivory was stronger in white birch than in monarch birch.

Comparative Studying of Leaf Trichomes, Teeth and Glands in Populus nigra L., Populus deltoides W. Bartram ex Marshall and Their Hybrids

Poplars from Aigeiros Duby section are very widespread in the world. A range of morphological characters were studied in such species of this section as Populus deltoides Bartram ex Marshall, P. nigra L. and their hybrid P. × canadensis Moench. However, there is little information about micromorphological characters of their leaves. The aim of this work was to study these characters and understand their species-specific potential. Thus, the morphological features, density and distribution of non-glandular trichoms, marginal glandular trichomes (salicoid teeth or coleters), epiglandular trichomes and basilaminar nectaries-glands were ontogenetically examined by both light and scanning electron microscopy in the certified by molecular markers P. deltoides, P. nigra and P. × canadensis samples. Non-glandular trichomes belong to the uni-, multicellular, uniseriate category. Marginal glandular trichomes can be classified as coleter types. Other morphological and anatomical trichome features are discussed with regard to their possible function. In summary, some variations in leaf morphology may be useful for the P. nigra, P. deltoides and their hybrid P. × canadensis species identification. These species differ in shape and number of basilaminar glands, as well as non-glandular trichome types and their distribution on the leaf.

Tools to Tie: Flower Characteristics, VOC Emission Profile, and Glandular Trichomes of Two Mexican Salvia Species to Attract Bees.

A plant can combine physical and chemical tools to interact with other organisms. Some are designed for pollinator attraction (i.e., colors and volatile organic compounds-VOCs); others can act to discourage herbivores (i.e., non-glandular trichomes). Few studies fully address available tools in a single species; notwithstanding, this information can be pivotal in understanding new interactions out of the home range. We characterized flower traits, emission profiles of constitutive compounds from flowers and leaves, micro-morphology of the glandular trichomes, and listed flower visitors of two Mexican bird-pollinated Salvia species (S. blepharophylla and S. greggii), growing in an Italian botanical garden. Flowers were highly variable in their morphometric characteristics. In both species, four trichome morphotypes with similar histochemistry and distribution were documented for leaves and flowers except the calyx abaxial side. The vegetative emission profiles were qualitatively more complex than the floral ones; however, common compounds occurring in high relative percentages were β-caryophyllene and germacrene D. Floral bouquets were dominated by limonene and β-pinene in S. greggii and by 1,8-cineole in S. blepharophylla. Two potential (non-bird) pollinators were especially abundant: small bees belonging to the genus Lasioglossum and large bees belonging to the species Xylocopa violacea. Our study highlights the plasticity of these plants, as well as tools that can be conveniently used to establish novel interactions.

Differences in Leaf Area, Trichome Density, and Xylem Structure between the Two Types of Theobroma cacao L. Cultivation: With or without Shade Plants

This study aimed to analyze the structure and density of non-glandular trichomes and the area of cocoa leaves, and the differences of xylem vessel structures on various shade tree composition. The leaf area and length, and trichomes were observed. The xylem vessel structure was observed from the root system. The result showed the area of cocoa plots without shade tree has more varied leaves size, in which upper canopy was smaller than the bottom. The area with various shade had a relatively equal size between the upper and the lower of the canopy. The three stellate-shaped non-glandular trichomes were found on the leaf venations only with the density in two plots increased with time. The xylem width area to the whole root width area ratio (k) in various shade trees was lower (k = 0.641) than that of without shade trees (k = 0.718). The higher k values indicated xylem structure without the shade tree had more xylem cells, and the pores was smaller compared to the plot with various shade trees.

Tomato hairless on stems mutant affects trichome development

Trichomes are hair-like structures derived from plant epidermal cells. Trichomes exist in most plant species and are categorized as either glandular or non-glandular. Glandular trichomes function as chemical protection against herbivores, while non-glandular trichomes serve as physical barriers to various biotic and environmental stresses. Here, we describe a novel recessive mutation named hairless on stems (host) which was identified based on the absence of trichomes on stems. host plants exhibited lower density of trichomes on leaves, stems, and hypocotyls, compared with the wild-type (WT) plants. Types I, III, and V trichomes, especially, were not developed at all on the stems of the host plants. In addition to trichome initiation, the length of Type I trichomes was shorter in the host plants than in the WT plants. The growth of host plants under greenhouse conditions showed that the mutant has shorter stems and fewer leaves than the WT plants. Genetic mapping of the host locus using the map-based cloning approach positioned the locus within 4.4 cM interval flanked by markers, Solyc09g074280 and Solyc09g075360, on chromosome 9. The identification of the Host gene will provide a clue for understanding multicellular trichome development in tomato and the Host gene can be used as a useful genetic resource to develop insect-resistant tomato.

Constitutive and Inducible Resistance to Thrips Do Not Correlate With Differences in Trichome Density or Enzymatic-Related Defenses in Chrysanthemum

Western flower thrips (WFT), Frankliniella occidentalis, is a serious insect pest of Chrysanthemum [Chrysanthemum × morifolium Ramat. (Asteraceae)]. Here we have investigated whether genotypic variation in constitutive and inducible resistance to WFT correlates with phenotypic differences in leaf trichome density and the activity of the defense-related enzyme polyphenol oxidase (PPO) in chrysanthemum. Non-glandular and glandular leaf trichome densities significantly varied among ninety-five chrysanthemum cultivars. Additional analyses in a subset of these cultivars, differing in leaf trichome density, revealed significant variation in PPO activities and resistance to WFT as well. Constitutive levels of trichome densities and PPO activity, however, did not correlate with chrysanthemum resistance to WFT. Further tests showed that exogenous application of the phytohormone jasmonic acid (JA) increased non-glandular trichome densities, PPO activity and chrysanthemum resistance to WFT, and that these effects were cultivar dependent. In addition, no tradeoff between constitutive and inducible resistance to WFT was observed. JA-mediated induction of WFT resistance, however, did not correlate with changes in leaf trichome densities nor PPO activity levels. Taken together, our results suggest that chrysanthemum can display both high levels of constitutive and inducible resistance to WFT, and that leaf trichome density and PPO activity may not play a relevant role in chrysanthemum defenses against WFT.

Leaflet blade epidermis and its taxonomic significance in 13 species of Bignonieae (Bignoniaceae) from Pico do Jabre, Paraíba, northeast of Brazil

Bignonieae is the largest tribe of Bignoniaceae, with 21 genera and 393 species of lianas and shrubs that are 1–3-foliolate with the terminal leaflet modified as tendrils. We examined the micromorphologies of the epidermis from the leaflet blade of 13 species of Bignonieae belonging to Amphilophium, Anemopaegma, Bignonia, Cuspidaria, Dolichandra, Fridericia, Pyrostegia, Tanaecium, and Xylophragma, from Pico do Jabre, Paraíba, Brazil. These are lianas except for Tanaecium parviflorum (shrub). We sought to identify the epidermal leaflet parameters to support their taxonomy, subject to great similarities between their vegetative characters, mainly in species of the same genus and related genera. Analyses were performed using light and scanning electron microscopy, and showed five types of epicuticular waxes, four cuticle types, three epidermal cell anticlinal wall types, and nonglandular and glandular trichomes. Hypostomatic leaves showed 10 different types of stomata, with stomatal indices from 6.21% (Bignonia ramentacea) to 23.52% (Tanaecium parviflorum), and stomatal densities from 76 stomata/mm2 (Pyrostegia venusta) to 752.9 stomata/mm2 (T. parviflorum). The presence of raphides in Amphilophium crucigerum and styloids in Fridericia pubescens constitute the first records for these genera. Epidermal micromorphology provided a set of distinctive characters with which to separate these species, representing an additional tool to support their taxonomies, as well as that of tribe Bignonieae.

Foliar micromorphology, ultrastructure, and histochemical analysis of Barleria albostellata C.B. Clarke

Barleria albostellata (Acanthaceae), is a valuable medicinal plant with a broad spectrum of antibacterial and anti-inflammatory activities. This study aimed to characterize the micromorphology, distribution, and chemical composition of the trichomes present on the leaves and stems of B. albostellata using light and electron microscopy and histochemistry. Morphological observations using stereo and scanning electron microscopy (SEM) revealed a dense indumentum bearing numerous non-glandular trichomes on the leaves and stems of B. albostellata. The histochemical and SEM analyses revealed the presence of five morphologically distinct glandular capitate trichome types, multangulate-dendritic branched (MDB) non-glandular trichomes and a glandular head attached to a branched non-glandular trichome. Transmission electron micrographs showed that numerous plastids, mitochondria, and endoplasmic reticulum cisternae were actively involved in the secretory process. The stained leaf and stem sections indicated the presence of alkaloids and phenolics as the major medicinal compounds in glandular and non-glandular trichomes. To our knowledge, this study represents the first detailed report describing the key micromorphological features of the foliar structures of B. albostellata as well as the preliminary chemical composition of the secretions produced by these structures.

A new taxon within Biscutella laevigata L. (Brassicaceae) endemic to calamine areas in southern Poland.

A new taxon Biscutella laevigata subsp. woycickii (Brassicaceae) is described from southern Poland. The taxon is similar to B. laevigata subsp. gracilis, but differs in having thin, light-green rosette leaves very densely covered by simple non-glandular trichomes, smaller seeds and the ability to tolerate and accumulate high amounts of heavy metals. This new taxon is supported by results of cultivation experiments, as well as genetic and paleobotanical evidence.

Morphological and Physiological Adaptation of Synedrella nodiflora (L.) Gaertn. in Various Altitudes

Nodeweed (Synedrella nodiflora (L.) Gaertn.) is a widely distributed tropical plant species. Nevertheless, it has taxonomically been the only member of genus Synedrella. Hence, it is interesting to study the morphological and physiological adaptation in different altitudes. Three altitudes were selected in this study, i.e. 0, 130, and 820 m above sea level (asl). The parameters examined included number of stomata and trichomes per leaf area unit, size of glandular and non-glandular trichomes, size of peripheral and central seeds, number of peripheral and central seeds. It was found that seed number and length, leaf structure, chlorophyll content show differences among altitudes. S. nodiflora from 0 m asl show lowest central seed number and length, non glandular trichomes number, but highest non-glandular trichomes length and chlorophyll a and carotene contents.

Determining the quality of the powders of Xanthium Strumarium and Xanthium Spinosum by microscopic examination and preliminary tests

Xanthium strumarium and Xanthium spinosum are found in many parts of the world and they are used in traditional medicine in many countries. Several studies have shown some medicinal effects for X. strumarium parts (leaves–seedlings–flowers–roots–fruits), and of the leaves of X. spinosum to treat some diseases. This paper is designed to set standards in determining the quality of the powders of these two plants. The standards include microscopic examinations and preliminary tests, which can be considered as identification tests for the purity of the powders. Contamination can occur during the collection of the plant, such as the presence of fruit elements among the powder of the leaves. Additionally, toxic substances in the fruits of the plant could be present that need special treatment before using them. Furthermore, these species of Xanthium are invasive to fields, so microscopic examination revealed the contamination of other plant powders with parts of these Xanthium species. The microscopic examination of X. strumarium leaves showed a distinctive nonglandular trichomes different from the ones in X. spinosum leaves. Seedling powder gives more glandular trichomes than the leaf powder, and the flower powder can be distinguished by the presence of distinctive pollen grains. The root powder is characterized by the presence of stone cells, while the presence of fibers indicates the elements of stems or fruits, depending on the shape of the fibers. The preliminary tests showed that all parts of X. strumarium contain alkaloids, but not in the leaves of X. spinosum. The type of flavonoids was different between the leaves of Xanthium species. The two species did not contain anthraquinones or saponins, while the leaves of X. spinosum contained tannins.

Metabolite Profiling and Transcriptome Analysis Revealed the Chemical Contributions of Tea Trichomes to Tea Flavors and Tea Plant Defenses.

Tea trichomes contain special flavor-determining metabolites; however, little is known about how and why tea trichomes produce them. Integrated metabolite and transcriptome profiling on tea trichomes in comparison with that on leaves showed that trichomes contribute to tea plant defense and tea flavor and nutritional quality. These unicellular, nonglandular, and unbranched tea trichomes produce a wide array of tea characteristic metabolites, such as UV-protective flavonoids, insect-toxic caffeine, herbivore-defensive volatiles, and theanine, as evidenced by the expression of whole sets of genes involved in different metabolic pathways. Both dry and fresh trichomes contain several volatiles and flavonols that were not found or at much low levels in trichome-removed leaves, including benzoic acid derivatives, lipid oxidation derivatives, and monoterpene derivatives. Trichomes also specifically expressed many disease signaling genes and various antiherbivore or antiabiotic peptides. Trichomes are one of the domestication traits in tea plants. Tea trichomes contribute to tea plant defenses and tea flavors.

Growth Response of Thunbergia grandiflora (Roxb. ex Rottler) Roxb. (Skyflower) on Shading and Anatomical Characteristics Under Various Soil Series

Thunbergia grandiflora Roxb. (Acanthaceae) or “skyflower” is an exotic species that was reported to be aggressively spreading out of control in the tropical and subtropical ecosystems. This study assessed the invasive characteristics of the species by analyzing its growth characteristics on varying shading intensity and soil series, as well as anatomical characteristics in varying soil series. Growth characteristics include the height and root collar diameter (RCD), while anatomical parameters include the thickness of all dermal, ground, and vascular tissues. Based on the results of the shading experiment, T. grandiflora grew significantly in terms of height and RCD under full light conditions (1784.75 lx). The species can survive intense light condition but is suppressed under partial to fully shaded treatments. In the soil series experiment, the highest growth and RCD were observed in the Luisiana soil series with strongly acidic soil (4.1 pH). The leaf and stem anatomical structures of T. grandiflora have the characteristics typical of invasive species that can adapt to certain harsh conditions. This includes the presence of dense non-glandular trichomes, cystolith, multi-layered collenchyma cells in the hypodermis, sclerenchymatous tissues, wider xylem pores, and closely pack parenchyma cells in the stem. Therefore, anatomical structures of this species suggest its ability as an invasive species. Consequently, the invasive characteristics can be suppressed by controlling the shade and soil conditions during the wildling stage of the species. The species can be bioinvasive and the extent may depend on the prevailing conditions in the site. However, further researches on the species’ root physiological and anatomical responses to other biotic and abiotic factors in the environment are recommended. Also, knowing the invasiveness of T. grandiflora will help us identify possible strategies to limit the spread of the species, including early detection of the occurrence of species, avoiding disturbance in the area, and identifying species as biocontrol.

Susceptibility of some new strawberry genotypes to infestation by western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) in the nursery

Strawberries are infested with Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) in Egypt. This study evaluated the effects of the biochemical components and leaf surface characteristics of ten new strawberry cultivars (Fortuna, Festival, Sahary, Forintaris, Red Merlin, Winter Star, Winter Dawn, Eliana, Montary and Florida) on the levels of infestation by F. occidentalis. There were significant differences in the susceptibility of strawberry cultivars to infestation by F. occidentalis. Fortuna, Sahary, Festival and Forntaris were the most susceptible cultivars. Red Merlin, Winter Star, Winter Dawn and Eliana had intermediate infestations. Montary and Florida were the most resistant cultivars. The relationship between mean number of F. occidentalis and leaf nitrogen was not significant. There was a significant relationship between mean numbers of F. occidentalis and phosphorus, potassium and total phenols content of leaves. The highest mean numbers of F. occidentalis were found on leaves of the Fortuna cultivar with high levels of phosphorus and low levels of potassium and total phenol. The lowest mean numbers of F. occidentalis were found on the leaves of the Montary and Florida cultivars with low levels of phosphorus and high levels of total phenols and potassium. Cultivars with higher density of non-glandular trichomes had significantly fewer F. occidentalis than cultivars with lower densities of non-glandular trichomes on the upper leaf surface. Similarly, cultivars with thicker leaves had significantly fewer thrips than cultivars with thinner leaves. The proper choice of strawberry cultivar is an important component of integrated pest management programs for controlling thrips in strawberry nurseries.

Leaf anatomy of Varronia polycephala Lam. (Cordiaceae)

Varronia polycephala is a medicinal plant used as a substitute of V. curassavica (the popular “erva baleeira”) in some traditional communities. This paper aims to describe and illustrate the leaf anatomy of V. polycephala. The results show that V. polycephala presents a distinct type of non-glandular trichome in abundance on the abaxial leaf surface, as well as a single type of glandular trichome on the same surface. Other characteristics observed in V. polycephala include non-glandular trichomes with cystoliths, crystal sand idioblasts, shape of the petiole in cross section, type of vascular bundles and ring collenchyma in the petiole. Histochemical results suggest similarities with V. curassavica, showing the pharmacological potential of V. polycephala. Possible ecological functions of structures and substances are discussed.

Pharmacognostic Profile of Ageratum conyzoides L Plant and Simplicia

Ageratum conyzoides Linn. is known as billy goat weed, including the family Asteraceae. This plant has been used empirically as a medicine for diarrhea, scratches, antinflammatory, snakebite, insecticide and nemasiticide. This study aims to identify plants based on pharmacognitive profiles including macroscopy, microscopy and non-parametric characters from plant parts of Ageratum conyzoides to determine the standardization of herbs. The results showed that the leaves were ovoid, pale green, soft hairy and purple, bluish or white flowers flowers. Microscopic observations of cross section of stem and leaf showed the presence of parenchyma cells, collenchyma cells and multicellular non-glandular trichomes, upper and lower epidermal cells, stomata in the upper and lower epidermis of the leaf. The highest value of water content was in the radix. The highest value of ash content was in the stem. The highest value of acid soluble ash content was in the radix. The highest value of water-soluble extract was in the folium. The highest value of ethanol-soluble extract was in the flower. The results of this study can be used as authentication of plant parts and a basis for the analysis of the standard pharmacopoeia A. conyzoides.