Distribution Of Glandular Trichomes Research Articles

Glandular trichomes as a source of antifungal metabolites in a karyologically characterized population of Argyrochosma flava: Morphology and histochemistry

Argyrochosma, a xeric-adapted fern genus mostly from the New World, includes both farinose and non-farinose species. The yellow farina appears to be a synapomorphy of A. flava. The aims of this research were to study the morphology, location, distribution, and density of glandular trichomes; perform a histochemical analysis of the farina secretion; evaluate the biological activity of farinas against phytopathogenic fungi; and characterize the species genetically by making chromosome counts and building the karyotype of A. flava. Usual methods in plant anatomy and histochemistry were performed. Minimum Inhibitory Concentrations (MICs) and Minimum Fungicidal Concentrations (MFCs) of farina against four phytopathogenic fungi were determined by the broth microdilution technique. Chromosome counts and karyotyping metaphase plates were obtained from fiddleheads. The distribution of glandular trichomes in pinnules changes along the ontogenetic development of the frond. The histochemical study of the trichomes revealed the complex nature of the secreted material, including flavonoids and terpenes along with other metabolites. The farina was active against the four pathogenic fungi evaluated, with MICs between 31.25 and 125 μg/mL showing the highest inhibition for Monilinia fructicola. Botrytis cinerea displayed a MIC value of only one-fold dilutions more than the commercial fungicide Carbendazim. Cytogenetically, the base number proposed for the genus is x = 27, which is derived from aneuploidy of x = 29. The genus has diploid and tetraploid forms. The results obtained support the important role of glandular trichomes and farinous exudate secretion in the protection against phytopathogenic fungi. The obtained chromosome numbers support the taxonomic placement of A. flava.

Salinity Stress Influences the Main Biochemical Parameters of Nepeta racemosa Lam.

In this work, the effects of salt stress on Nepeta racemosa Lam. were studied to analyze the possibility of using it as a potential culture for salinity-affected soils. A total of nine concentrations of salts-NaCl (18, 39, and 60 mg/100 g soil), Na2SO4 (50, 85, and 120 mg/100 g soil), and a mixture (9 g NaCl + 25 g Na2SO4, 19 g NaCl + 43 g Na2SO4, and 30 g NaCl + 60 g Na2SO4/100 g soil)-simulated real salinity conditions. Environmental electron microscopy offered information about the size and distribution of glandular trichomes, which are very important structures that contain bioactive compounds. The chlorophyll pigments, polyphenols, flavonoids, and antioxidant activity were determined based on spectrophotometric protocols. The results have shown a different impact of salinity depending on the salt type, with an increase in bioactive compound concentrations in some cases. The highest polyphenol concentrations were obtained for Na2SO4 variants (47.05 and 46.48 mg GA/g dw for the highest salt concentration in the first and second year, respectively), while the highest flavonoid content was found for the salt mixtures (42.77 and 39.89 mg QE/g dw for the highest concentrations of salt in the first and, respectively, the second year), approximately 100% higher than control. From the Pearson analysis, strong correlations were found between chlorophyll pigments (up to 0.93), antioxidant activity and yield for the first harvest (up to 0.38), and antioxidant activity and flavonoid content for the second harvest (up to 0.95). The results indicate the possibility of growing the studied plants in salt-stress soils, obtaining higher concentrations of bioactive compounds.

Morphological Studies of Chamaecrista sect. Absus ser. Setosae (Leguminosae) With Emphasis on the Chamaecrista setosa Complex, Including a New Species

Abstract— Chamaecrista is one of the largest genera of Leguminosae, subfamily Caesalpinioideae. Traditionally, it has been divided into six sections, of which Chamaecrista sect. Absus is the largest, with 31 series. Chamaecrista sect. Absus ser. Setosae comprises nine species. Chamaecrista setosa is the most widely distributed species, comprising four varieties, distinguished by the type and distribution of glandular trichomes, and the leaflet venation. Given the importance of leaflet venation in the delimitation of the taxa, here we performed a study of leaflet architecture of all species of the series and a more detailed morphological study for the Chamaecrista setosa complex. For the study of leaf architecture, 2D images of the leaflets were made using the Faxitron x-ray technique. The morphological studies were based on herbarium specimens. We present the details of the leaflet architecture for the species of Chamaecrista sect. Absus ser. Setosae, and we propose nomenclatural changes for a variety of Chamaecrista setosa and some corrections to typifications. During our studies we also found a new species, Chamaecrista forzzae, which is morphologically similar to Chamaecrista setosa and Chamaecrista multiseta. It is here described and illustrated.

Morphological diversity of glandular trichomes in Urticalean Rosids

Glandular trichomes are epidermal structures that produce, store and release a variety of chemical compounds. Their high morphological diversity allows their taxonomic use at various levels. Therefore, their description and standardization of terminology become challenging. Cannabaceae is a well known family of Urticalean Rosids because of the presence of cannabinoid-secreting trichomes in Cannabis sativa. Other Urticalean Rosid families (Moraceae, Ulmaceae and Urticaceae) are neglected in this regard. Thus, the morphology and distribution of glandular trichomes were studied in Cannabaceae and Ulmaceae species and compared with published data for Moraceae and Urticaceae. Surface and anatomical analyses were performed on vegetative and floral organs. Urticalean Rosids show at least 15 types of glandular trichomes, 12 of them capitate and three filiform. In particular, Trema micrantha, a Cannabaceae species, has six different types. A trichome with biseriate stalk and pluricellular head, found in Trema micrantha and Pteroceltis tatarinowii, was not previously reported. Glandular trichomes are widely distributed in the plant body, which may be related to protection against herbivory. The greatest difficulty was the large quantity of terms and the lack of morphological details of the glandular trichomes in previous studies. A standardization of the terminology of glandular trichomes was therefore proposed.

Foliar anatomy of Rhynchosia spp. (Leguminosae, Papilionoideae) from Roraima state, northern Brazilian Amazon

ABSTRACT Comparative studies on the structure of foliar anatomy in four species of Rhynchosia from Roraima state (northern Brazilian Amazon) were carried out to identify additional morphological characters to support the definition of the systematic boundaries among the species. Fully expanded leaves, including the petioles, were collected from the upper nodes of a plant’s stem. Anatomical characters were observed in cross-sections of the middle portion of leaflets and petiole segments. Presence and distribution of glandular trichomes, continuity of sclerenchyma around the vascular bundles in leaflet blades and the conformation of the area between the two ridges of petioles were important characters to distinguish among the species of Rhynchosia. For the first time we report a distinct multicellular gland-like structure which we found in the petioles of three species.

Bioactive farina of Notholaena sulphurea (Pteridaceae): Morphology and histochemistry of glandular trichomes

The morphology and distribution of glandular trichomes in fronds at different developmental stages were investigated in Notholaena sulphurea, and the main components of the secreted material (farina) were identified. In addition antifungal and molluscicidal activities of farinose exudate were tested. Trichomes were examined using conventional light and scanning electron microscopy (SEM). The histochemical studies were conducted using the following tests on hand-sections: Toluidine Blue, Calcofluor White, Ruthenium Red, Phloroglucinol/HCl, NADI reagent, Sudan black B, Sudan IV, Nile Blue, Neutral Red, ferric chloride, Vainillin/H2SO4, Vainillin/HCl, alumimium chloride and Benedict reagent. Antifungal activity was evaluated by broth microdilution techniques and molluscicidal activity by Adenusi, 2008. One type of glandular trichomes was found in both the adaxial and the abaxial surfaces. Young fronds were densely covered with trichomes; however, the density decreased progressively with frond maturity. Secretions flowed by diffusion through cuticle micropores, and no rupturring mechanism to release secretions was observed. Histochemical reactions revealed that the main components of the materials secreted by trichomes include polysaccharides, lipids, terpenes, phenols and flavonoids. The farina showed antifungal and molluscicidal activity. Our results strongly support an ecological role of farina as herbivore deterrent and resistance to fungi. Since N. sulphurea is a xeric adapted fern, flavonoids present in farinous secretions may also function as stress protection against harsh environmental conditions.

Structure and distribution of glandular trichomes in three species of Bignoniaceae

Glandular trichomes play a major role in the morphological characterization of the Bignoniaceae. Due to their great diversity of forms and functions, this study aimed to inventory the glandular trichomes present in the aerial vegetative axis of Amphilophium magnoliifolium, Martinella obovata and Stizophyllum riparium, analyze their structure and register the participation of ants in these plants. Fresh samples from the nodal region, petiole and from medium to apical regions of the leaflet blade were fixed and processed according to usual methods in light and scanning electron microscopies. The glandular trichomes found were: peltate, capitate, stipitate, and patelliform/cupular. Peltate trichomes are the most abundant ones and present the most uniform distribution. Patelliform/cupular trichomes occur at specific regions, such as prophylls, leaflet blade and nodal regions. Martinella obovata is the only species that presents capitate and stipitate trichomes, which are widely distributed along the entire aerial vegetative axis. Ants were found in all species, mainly at nodal regions. The occurrence of the capitate-type trichome is reported for the first time to the genus.

Chemical traits and antimicrobial activity of endemic Teucrium arduini L. from Mt Biokovo (Croatia)

Abstract Chemical composition of the essential oil (analysed by GC-FID and GC-MS), the content of macroelements and trace elements (analysed by ICP-AES), and antimicrobial activities were investigated in Teucrium arduini L. from Mt Biokovo (Croatia). Additionally, a study on the types and distribution of glandular trichomes which produce essential oils was investigated. The oil was characterized by a high concentration of sesquiterpene hydrocarbons (68.5%) of which β-caryophyllene (32.9%) and germacrene D (16.4%) being the major compounds. Among the macroelements, the content of calcium was the highest (9772 mg/kg), while the content of sodium was the smallest (117.74 mg/kg). Among the micronutrients, the most represented element was iron (72.07 mg/kg). The content of each investigated toxic metal (As, Hg, Pb, Cd and Cr) was below permissible levels. The essential oils showed antimicrobial activity against bacterial species tested, with MIC values ranging from 6.25 mg/mL to 37.50 mg/mL. Fungal species were susceptible with MIC values from 7.81 mg/mL and 25.00 mg/mL.

The structure and distribution of glandular trichomes on the stems and leaves of drug eyebright (Euphrasia stricta D. Wolff ex J. F. Lehm.)

<i>Euphrasia stricta</i> is a medicinal plant being one of the ingredients of "Herba Euphrasiae". Many studies have been devoted to the identification of biologically active substances in the herb of eyebright, but much less research has been done on the constitution of glandular structures of this taxon. This paper relates to glandular trichomes located on the stems and leaves of <i>E. stricta</i>. The trichome structure was examined using light and scanning electron microscopy. It was shown that the stems of <i>E. stricta</i> were mainly covered by non-glandular trichomes, whereas glandular trichomes were rarely found on them. However, clusters of short capitate trichomes were found to occur in specific epidermal regions on both surfaces of the leaf blades and bracts. On the adaxial leaf surface, glandular trichomes grew only in the grooves above the vascular bundles, while on the abaxial surface in the depressions located in the expanded part of the teeth. The glandular hairs consisted of 1-2 cells of the stalk and a two-celled head. Trichomes with 3- or 4-celled heads were found sporadically. The glandular trichomes functioned non-synchronously, since they differed in head size and the colour of cell protoplasts. The presence of a light secretion was found on the surface and around the trichomes in both fresh and dry plant material.

Structural investigation of the glandular trichomes of endemic Salvia smyrnea L.

The morphology, anatomy and distribution of glandular trichomes on the aerial organs of Salvia smyrnea L. endemic to Turkey have been investigated with light microscopy (LM) and scanning electron microscopy (SEM). This species is evaluated in endangered (EN) category. Two morphologically distinct types of glandular trichomes were determined. Various types of capitate glandular trichomes consist of a 1–4 celled base, a 1–8 stalk celled or no stalk and a uni- or bicellular head. In capitate trichomes the neck cell that has an important role especially for xeromorfic plants, acting to prevent the backflow of secreted substance through the apoplast, has been distinctively observed in the investigated species. The capitate trichomes were present abundantly on all aerial organs of S. smyrnea. Peltate glandular trichomes had a large secretory head comprising 1–2 central and 4,6, 8–10 peripheral cells. This study pointed out that S. smyrnea was of rich glandular trichomes in point of diversity and quantity.

Structural investigation of the glandular trichomes of Salvia argentea

The morphology, anatomy and distribution of glandular trichomes on the aerial organs of Salvia argentea L. has been investigated. Two morphologically distinct types of glandular trichomes were determined. Capitate glandular trichomes forming a base 1-7 celled, a stalk 1-5 celled or no stalk and a head uni- or bicellular had various types. In capitate trichomes, the neck cell that has an important role especially for xeroformic plants, acting to prevent the backflow of secreted substance through the apoplast has been distinctively observed in the investigated species. The capitate trichomes were present abundantly on all aerial organs of S. argentea. Peltate glandular trichomes had a large secretory head forming 1-5, 8 central and 8-10, 12, 14 peripheral cells. Peltate trichomes are present on all aerial organs, except petiole, being the most abundant on calyx and corolla. Results were shown by tables and photographs.

Montanoa tomentosa glandular trichomes containing kaurenoic acids chemical profile and distribution

Montanoa tomentosa has been used in traditional medicine in Mexico to treat diverse female health disorders; it is particularly useful in inducing childbirth. Microscopic analysis of leaf surfaces of M. tomentosa revealed the presence of glandular trichomes. The chemical profile and distribution of glandular trichomes from different developmental stages of M. tomentosa leaves were investigated. Two diterpenic acids, kaurenoic and grandiflorenic were detected in glandular trichomes through the glandular microsampling technique and GC/MS analysis. In the glandular trichomes of the leaves also up to twenty-six volatile terpenes were identified, where beta-eudesmol and valencene were the most abundant terpenes.

Nutlet morphology and anatomy of the genus Lycopus (Lamiaceae: Mentheae)

Nutlet morphology and pericarp structure of 16 species in the genus Lycopus were studied by light microscopy (LM) and scanning electron microscopy (SEM), and a detailed description of nutlet morphological features for all examined taxa is provided. The nutlets of all taxa in the genus Lycopus are well adapted to typical hydrochory (or nautochory) with an air-filled pericarp, and myxocarpy was not at all found. It is noteworthy that the nutlet morphology (in particular the shape of corky crests and corky ring and the distribution of glandular trichomes) and pericarp anatomy of Lycopus are unique and are well distinguished from the other genera in the tribe Mentheae. We also found some groups of the species within the genus Lycopus by the present nutlet morphological and anatomical data that appear to be useful as diagnostic characteristics for delineation purposes at the specific/interspecific levels. The earlier infrageneric classification for the genus Lycopus is, however, not well supported by the present results. In addition, the systematic and biological implications of the nutlet characteristics investigated are briefly discussed.

Morphology, Anatomy, and Distribution of Capitate Glandular Trichomes on Selected Trifolium Species

Glandular trichomes may impart insect resistance to crops. This study was conducted to determine the morphology, anatomy, and distribution of glandular trichomes on Trifolium pratense L., T. medium L., T. hybridum L., and T. repens L. Fluorescence microscopy, scanning electron microscopy, and transmission electron microscopy were used to facilitate this study. Procumbent and erect glandular trichomes were found on cultivars of these species. Both procumbent and erect glands arose from epidermal cells, were capitate, and had thick‐wailed stalks. The heads of the procumbent glands were long and thin, consisting of four to eight layers of cells, each layer consisting of one to four cells. By contrast, the heads of the erect glands were globose and not organized in layers, although they were multicellular. Leaves, stems, peduncles, and sepal surfaces had procumbent and erect glands. All floral organs, other than sepals, were devoid of procumbent glands, except in alsike clover (T. hybridum L.) specimens, where these glands were found on the gynoecium. Tissue‐culture grown white clover (T. repens L.) leaflets showed the greatest density of procumbent glands, these being located abaxially only. Erect glands frequently appeared on petioles and on foliar margins, near vein endings, and in association with simple (vegetative) hairs. On the basis of previous evidence, it is proposed that the two kinds of glandular trichomes present on these Trifolium species may be involved in plant defense.