Stem Epidermis Research Articles

A putative hemicellulose gene promoter drives high levels of expression in guard cells and stem epidermis of poplar and highlights hormone regulation of cell wall formation

Forest trees generate substantial quantities of organic carbon, recognized as a renewable and economically viable resource for applications in bioenergy and industry. This study specifically focuses on xylan, a major hemicellulose component in poplar, and on the role of PtrPARVUS2—a member of the glycosyltransferase 8 family genes involved in xylan biosynthesis. PtrPARVUS2 is hypothesized to exhibit tissue-specific activity, and here we assessed its promoter via bioinformatic analysis, revealing motifs associated with responsiveness to hormones including Gibberellic Acid (GA), Methyl Jasmonate (MeJA), Auxin, and Abscisic Acid (ABA), among others. Treatment with hormones, including ABA, 1-naphthaleneacetic acid, a synthetic auxin, MeJA, and GA, demonstrated a swift inhibition of PtrPARVUS2 transcription. Analysis of expression patterns in wildtype trees indicated heightened expression in vascular tissues, particularly the bark. Transgenic lines expressing Enhanced Green Fluorescent Protein and β-glucuronidase under the control of the PtrPARVUS2 promoter confirmed tissue-specific activity, particularly in guard cells, stem epidermis, and developing xylem. These results offer understanding into the potential functions of PtrPARVUS2 in terms of phytohormone response and the formation of guard cell walls. The investigation introduces a valuable promoter for specific biotechnological applications in guard cells and stem epidermal cells. Additional research is required to elucidate the precise regulatory mechanisms of PtrPARVUS2 in the future.

Effects of foliar application of two forms of selenium on anatomic features of Thymus daenensis Celak

To investigate selenium effects on anatomic features of Thymus daenensis, three concentrations of bulk and nanoparticles of the element (2, 4 and 8 ppm) along with distilled water, as a control, were sprayed on foliar of young seedlings of the plant species for six times with 2 weeks intervals. Transverse sections of stems, roots and leaves of the treated plants were manually produced and stained by Carmine and Methylene blue. Average of 5 readings was recorded for each treatment on several anatomic traits. Statistical analysis of the data revealed that the effects of selenium treatments were significantly different, at 1% of probability, on all of the studied anatomic characters. The first level of nanoparticles showed the most positive effects on several root characteristics. The highest level of selenium nanoparticles (8 ppm) showed the most positive effects on stem diameter and stem vascular cylinder diameter. The last two levels of nanoparticles had similar and the largest effect on stem epidermis thickness. The lowest level of bulk selenium (2 ppm) showed the most increment on leaf characteristics. Application of a low concentration of selenium by foliar spraying on young plants of the species is suggested for more vegetative growth and higher photosynthetic efficiency

3-ketoacyl-CoA synthase 19 contributes to the biosynthesis of seed lipids and cuticular wax in Arabidopsis and abiotic stress tolerance.

Very-long-chain fatty acids (VLCFAs) are essential precursors for plant membrane lipids, cuticular waxes, suberin, and storage oils. Integral to the fatty acid elongase (FAE) complex, 3-ketoacyl-CoA synthases (KCSs) function as crucial enzymes in the VLCFA pathway, determining the chain length of VLCFA. This study explores the in-planta role of the KCS19 gene. KCS19 is predominantly expressed in leaves and stem epidermis, sepals, styles, early silique walls, beaks, pedicels, and mature embryos. Localized in the endoplasmic reticulum, KCS19 interacts with other FAE proteins. kcs19 knockout mutants displayed reduced total wax and wax crystals, particularly alkanes, while KCS19 overexpression increased these components and wax crystals. Moreover, the cuticle permeability was higher for the kcs19 mutants compared to the wild type, rendering them more susceptible to drought and salt stress, whereas KCS19 overexpression enhanced drought and salt tolerance. Disrupting KCS19 increased C18 species and decreased C20 and longer species in seed fatty acids, indicating its role in elongating C18 to C20 VLCFAs, potentially up to C24 for seed storage lipids. Collectively, KCS19-mediated VLCFA synthesis is required for cuticular wax biosynthesis and seed storage lipids, impacting plant responses to abiotic stress.

Tempskya hailunensis sp. nov. (Tempskyaceae), a new tree fern with preserved leaf-like structures, from the Cretaceous of the Songliao Basin, Northeast China

A new tree fern of the family Tempskyaceae, Tempskya hailunensis sp. nov., is described herein based on a silicified trunk from the Cretaceous of Hailun City, Heilongjiang Province, Northeast China. The new species is composed of dichotomizing large stems surrounded by a mesh of adventitious roots, petioles, and leaf-like structures, constituting a solid and compact false trunk. The dorsiventral stems contain solenosteles that have long internodes with mostly two leaf traces. The stem cortex consists of a sclerenchymatous outer zone and a parenchymatous inner zone, and the stem pith is divided into a parenchymatous outer zone and a sclerenchymatous inner zone. Wide multicellular scales are attached to the stem epidermis. Leaf-like structures embedded among adventitious roots in the trunk are isobilateral, thick, and without distinct intercellular spaces. Also present are dispersed annuli of sporangia, which are only few cells long and apparently uniseriate. Though it cannot be fully ruled out that these vegetative and fertile remains belong to epiphytes that colonized the Tempskya trunk, the consistent and exclusive occurrence of these particular types of remains makes it likely that they belonged to the Tempskya plant itself. This new species represents only the second fossil record of Tempskya from China, increasing the known diversity of this genus during the Cretaceous both in Asia and globally. Moreover, it provided evidence for recognizing probable leaf structure and growth habit of Tempskya.

Evolution of vegetative morphoanatomical characters in Pabstiella (Pleurothallidinae: Orchidaceae)

The subtribe Pleurothallidinae encompasses approximately 48 genera, with Pabstiella standing out due to its 133 species, many of which are found in Brazil's Atlantic Forest. Molecular data strongly support the genus and its ten sections. However, only a few species have been anatomically described, and a comprehensive characterization of the genus for comparative purposes is still needed. Our study aimed to examine the main vegetative morphoanatomical characters of the root, stem, and leaves, and analyze their evolution based on the phylogeny of the genus. We analysed root, stem, and leaf samples from 57 species using light and scanning electron microscopy. We selected 35 characters and mapped them onto the molecular phylogeny. Pabstiella exhibits homogeneous leaf anatomy, with aquiferous tissue on both sides and chlorophyllous parenchyma in the middle, aligned with vascular bundles. The ramicaul anatomy displays a simple epidermis with primary or secondary walls, a simple to stratified hypodermis, a parenchymatous or aerenchymatous cortex, and a sheath of sclerenchyma surrounding the vascular bundles. The roots endovelamen cells are larger than those in the epivelamen, reticulated tilosomes of varying morphotypes, and giant cells in the cortex. Despite the common occurrence of homoplasy among vegetative traits, particularly in the leaves, our analyses revealed several synapomorphies for the genus. These include the presence of giant cells in the root cortex, endovelamen cells larger than those of the epivelamen, a specific distribution pattern of tilosomes, and 2–3 layers of aquifer tissue on the adaxial face of the leaf. Additionally, for the Pabstiella section, a lignified stem epidermis wall is a synapomorphic character state. Our findings demonstrate that vegetative morpho-anatomy is a useful diagnostic character for generic and infrageneric categories within the genus. When analysed from a phylogenetic perspective, it contributes to our comparative understanding of the genus.

Pathogen resistance was negatively regulated by the NAC transcription factor ScATAF1 in sugarcane

The NAC (NAM, ATAF, and CUC) is one of the largest transcription factor gene families in plants. In this study, 180, 141, and 131 NAC family members were identified from Saccharum complex, including S. officinarum, S. spontaneum, and Erianthus rufipilus. The Ka/Ks ratio of ATAF subfamily was all less than 1. Besides, 52 ATAF members from 12 representative plants were divided into three clades and there was only a significant expansion in maize. Surprisingly, ABA and JA cis-elements were abundant in hormonal response factor, followed by transcriptional regulator and abiotic stressor. The ATAF subfamily was differentially expressed in various tissues, under low temperature and smut pathogen treatments. Further, the ScATAF1 gene, with high expression in leaves, stem epidermis, and buds, was isolated. The encoded protein, lack of self-activation activity, was situated in the cell nucleus. Moreover, SA and JA stresses down-regulated the expression of this gene, while ABA, NaCl, and 4°C treatments led to its up-regulation. Interestingly, its expression in the smut susceptible sugarcane cultivars was much higher than the smut resistant ones. Notably, the colors presented slight brown in tobacco transiently overexpressing ScATAF1 at 1 d after DAB staining, while the symptoms were more obvious at 3 d after inoculation with Ralstonia solanacearum, with ROS, JA, and SA signaling pathway genes significantly up-regulated. We thus speculated ScATAF1 gene could negatively mediate hypersensitive reactions and produce ROS by JA and SA signaling pathways. These findings lay the groundwork for in-depth investigation on the biological roles of ATAF subfamily in sugarcane.

Diversity of 17 Genotypes of Taro Based on Anatomy and Nutritional Value of Tuber

Indonesia is one of the countries with the greatest diversity of taro variety, while the study of taro's morphology and nutritional characteristics is limited. The aim of this study was to evaluate the anatomical of plant and nutritional value of taro tuber. This research observed fourteen genotypes of Colacasia esculenta (7 Eddoe types, 7 Dasheen types) and 3 Xanthosoma genotypes. In three blocks of replications, the eddoe and Xanthosoma genotypes were cultivated using cormel and the dasheen genotypes with sucker. Plant anatomy (leaf, stem, and root) and tuber nutritional characteristics were analyzed. From this research, explained that stomata and epidermis number, length from stomata and epidermis, number leaf epidermis, length of leaf and stem epidermis, also length of root epidermis, endodermis, cortex, and stele among 17 genotypes of taro were statistically different. The diversity of taro based on the nutrition content of tuber between 17 genotypes of taro was considered high, as represented by water, ash, fat, protein, carbohydrate, energy, and glucomannan, which were statistically different.

Drought stress-induced modification of morpho-anatomical and yield attributes of mung bean associated with the application of silicon and Moringa leaf extract

Mung bean (Vigna radiata) is the rich source of fiber and essential nutrients. They play a vital role in sustainable agriculture due to their ability to fix nitrogen in the soil and enhance soil fertility. Drought is characterized by limited water resources and severe arid climatic conditions, notably impair crop growth and yield. In the current experiment, two genotypes, Azri-M 2006 and NM-92, were studied against drought stress that was applied as 2 days and 4 days irrigation gap per week. Foliar application of magnesium-silicate (20 ppm and 30 ppm concentrations) and Moringa leaf extract (30% v/v solution) was applied as treatments. The results from the experiment morphology anatomical and yield components were recorded according to the prescribed methods. The result revealed that drought stress reduced the growth of plant. Foliar application of 30 ppm silicon against drought stress showed a highly significant (p<0.001) result compared with control group. Morphology parameters, including shoot and root length, shoot and root fresh weight, root dry weight, leaf area, leaf number, the anatomical structure included (stem epidermis, cortex, and stem vascular bundles,) and also yield components (pod length, and seed numbers). In contrast, MLE (30%) showed a significant impact (p<0.01) on leaf lamina thickness (Leaf anatomical parameters; midrib xylem and phloem, number of stomata on the adaxial and abaxial surface) and yield components included (100-grain weight, grains weight per plant, and numbers of pods,). The overall impact of 30 ppm Si was 39.9% more positive on Azri-M2006 than the NM-92 against the drought stress. The 30-ppm silicon and 30% MLE showed 90% similar results in all studied parameters. This study confirms that 30% MLE could be recommended to farmers to improve productivity under arid conditions than the silicon.

Morphological Characteristics and Similarity Analysis of Cassava (Manihot esculenta Crantz) in Wonosobo, Temanggung, and Magelang Regencies

The diversity of cassava in Wonosobo, Temanggung and Magelang districts must be investigated. The objective of the study was to analyze the diversity of cassava based on morphological characteristics. The cassava of each accession was planted in Bandongan, Magelang Regency. Morphological characters observed after six months of planting included apical leaf color, apical leaf hair, leaf lobe shape, petiole color, leaf color, number of leaf lobes, leaf length, leaf width, petiole length, vein color, petiole orientation, color epidermis of stem, color of outer appearance of stem, distance between nodes, stem growth, color of mature branch tip, branching type, tuber, tuber shape, outer tuber skin color, tuber flesh color, and tuber inner skin color. Analysis of the morphological characteristics of cassava is presented in the form of a dendrogram using the MVSP (Multi Variate Statistical Package) version 3.22. The results of the study obtained 39 accessions of cassava which showed different morphological characteristics. The lowest morphological similarity (0.735) was found in Group I only consisted of 2 acquisitions that did not have tubers, namely Red Vegetables and Green Vegetables and Group II ( Groups III and IV) have a similarity of 0.92. The highest similarity was in groups IIIa and IIIb and Groups IVa and IVb have a similarity coefficient value of 0.95. The morphological diversity of 39 accessions is a source of cassava germplasm: 37 accessions are harvested for tubers and 2 accessions areharvested explicitly for leaves as vegetables. This research was useful for the development of cassava-based food industry bioproducts.

Epicuticular wax accumulation and regulation of wax pathway gene expression during bioenergy Sorghum stem development.

Bioenergy sorghum is a drought-tolerant high-biomass C4 grass targeted for production on annual cropland marginal for food crops due primarily to abiotic constraints. To better understand the overall contribution of stem wax to bioenergy sorghum's resilience, the current study characterized sorghum stem cuticular wax loads, composition, morphometrics, wax pathway gene expression and regulation using vegetative phase Wray, R07020, and TX08001 genotypes. Wax loads on sorghum stems (~103-215 µg/cm2) were much higher than Arabidopsis stem and leaf wax loads. Wax on developing sorghum stem internodes was enriched in C28/30 primary alcohols (~65%) while stem wax on fully developed stems was enriched in C28/30 aldehydes (~80%). Scanning Electron Microscopy showed minimal wax on internodes prior to the onset of elongation and that wax tubules first appear associated with cork-silica cell complexes when internode cell elongation is complete. Sorghum homologs of genes involved in wax biosynthesis/transport were differentially expressed in the stem epidermis. Expression of many wax pathway genes (i.e., SbKCS6, SbCER3-1, SbWSD1, SbABCG12, SbABCG11) is low in immature apical internodes then increases at the onset of stem wax accumulation. SbCER4 is expressed relatively early in stem development consistent with accumulation of C28/30 primary alcohols on developing apical internodes. High expression of two SbCER3 homologs in fully elongated internodes is consistent with a role in production of C28/30 aldehydes. Gene regulatory network analysis aided the identification of sorghum homologs of transcription factors that regulate wax biosynthesis (i.e., SbSHN1, SbWRI1/3, SbMYB94/96/30/60, MYS1) and other transcription factors that could regulate and specify expression of the wax pathway in epidermal cells during cuticle development.

Heat shock-inducible clonal analysis reveals the stepwise establishment of cell fate in the rice stem.

The stem, consisting of nodes and internodes, is the shoot axis, which supports aboveground organs and connects them to roots. In contrast to other organs, developmental processes of the stem remain elusive, especially those initiating nodes and internodes. By introducing an intron into the Cre recombinase gene, we established a heat shock-inducible clonal analysis system in a single binary vector and applied it to the stem in the flag leaf phytomer of rice (Oryza sativa). With detailed characterizations of stem structure and development, we show that cell fate acquisition for each domain of the stem occurs stepwise. Cell fate for a single phytomer was established in the shoot apical meristem (SAM) by one plastochron before leaf initiation. Cells destined for the foot (nonelongating domain at the stem base) also started emerging before leaf initiation. Cell fate acquisition for the node began just before leaf initiation at the flank of the SAM, separating cell lineages for leaves and stems. Subsequently, cell fates for the axillary bud were established in early leaf primordia. Finally, cells committed to the internode emerged from, at most, a few cell tiers of the 12- to 25-cell stage stem epidermis. Thus, internode cell fate is established last during stem development. This study provides the groundwork to unveil underlying molecular mechanisms in stem development and a valuable tool for clonal analysis, which can be applied to various species.

ANATOMY OF THE ENDEMIC ALYSSUM PATERI SUBSP. PATERI

Objective: Alyssum pateri Nyár. subsp. pateri is an endemic plant known as "kanatlı kevke" in Türkiye. The plant is perennial and in semi-shrub form. The plant is traditionally used externally in the treatment of rheumatism in Bingöl (Türkiye). Microscopic analysis of the anatomical structures of plants can provide useful information for taxonomic classification. Light microscopy analysis is a widely used and effective method for the identification of medicinal plants. In this study, the anatomical features of the A. pateri subsp. pateri were examined. Material and Method: The plant material was collected from Ankara (Türkiye). The samples were protected in 70% alcohol. The cross and surface sections were cut by hand with a razor blade into microscopic preparation form. A Leica DM 4000B microscope was used for anatomical analysis and micro photographs. Result and Discussion: The anatomical characters of the leaf, petiole and stem of the Alyssum pateri subsp. pateri were revealed. The leaf is dorsiventral and contains 1-2 rows of palisade parenchyma. Cruciferous stomata and stellate hairs are located on the lower epidermis. The petiole cross-section is sulcate and stellate hairs are observed in the epidermal layer. The main vein is arc-shaped and is accompanied by lateral veins. The stem is disc-shaped. Stem epidermis contains stellate hairs. The interfascicular tissue between the xylem strands of the vascular bundles is composed lignified cells. Vascular bundles are surrounded by a pericyclic sclerenchymatous cap.

Phenotypic Characterization, Evaluation, and Classification of Cassava (Manihot esculenta Crantz) Accessions in Ethiopia

Cassava has a crucial role in benefiting smallholder farmers as the main food and income source in southern Ethiopia. Characterization accessions are crucial for assessing variation, classifying, and identifying desirable accessions for crop improvement and conservation. In this regard, there needs to be more information on the morphological characterization and classification cassava accessions. Thus, the aim of this research was to systematically characterize, evaluate, and classify cassava accessions using qualitative characters to provide useful information for breeding program and conservation. A total of 64 accessions were planted using a simple lattice design during the 2020-2021 cropping season. Thirty qualitative data were collected at 3, 6, 9, and 18 months after planting and analyzed using the SAS and R-software packages. The high variable characteristics were the shape of the central leaflet, petiole color, leaf retention, branching habit, the color of the stem epidermis, the color of the stem exterior, the external color of the storage root, and the color of the root pulp towards frequency distribution analysis. The Shannon–Weaver diversity index ranged from 0.24 to 1.47, with an overall mean of 0.84. The first three dimensions in the multiple correspondent method explained approximately 39.39% of the total variation, with Dim 1 accounting for 20.77% and Dim 2 accounting for 9.98%, while petiole color and texture of the root epidermis were the leading contributors to the total variation, respectively. In clustering analysis, 64 accessions were classified into 4 clusters of varying sizes. The distribution of accessions in each cluster revealed that 52 accessions were in cluster I, 6 in cluster II, 5 in cluster III, and 1 in cluster IV. Each cluster was varied by a major group characteristic that it represented. Furthermore, the study identified the desirable accessions for desired storage root characteristics such as root constrictions, the external color of the storage root, the color of root pulp, the color of the root cortex, and cortex peeling tendency. In conclusion, the various analyses performed indicated the existence of sufficient genetic variability for the characteristics evaluated, which could be attributed to the dissimilar genetic backgrounds of the evaluated accessions. Thus, these could be utilized for breeding work and conservation.

Anatomical Study for Vegetative Organs of Pelargonium graveolens L.'Hér Cultivated in Iraq

The current investigation concluded an anatomical study of the cultivated species Pelargonium graveolens L. 'Hér belong to the Geraniaceae family and which cultivated as an ornamental plant, fresh specimen were collected from different region in Baghdad ,the study vegetative parts (leaf, stem and petiole) in details ,the upper and lower epidermis of leaf and epidermis of stem also studied, ordinary epidermal cells and stomatal complexes studied in term of shapes and dimensions ,the result showed that stomatal in leaf and stem is anomocytic type, the cross sections of the vegetative parts prepared by microtome and free hand sectioning. The tissues of these parts include the number and the type of layers and thickness of each one , the result showed the presence of druses crystals in parenchyma cells of the petiole, stem and leaf. Vistur type of this organs also studied and it comprises of glandular and non-glandular trichomes which occur in different types and lengths.

Comparative anatomy and achene micromorphology assessment of two Cousinia Cass. (Asteraceae) species in view of taxonomy

Comparative anatomy and achene micromorphology assessment of two Cousinia Cass. (Asteraceae) 
 species in view of taxonomy
 Deniz ULUKUŞ 1, Osman TUGAY 2
 ORCID: 0000-0002-9627-5492; 0000-0003-3980-7648
 
 1 Department of Biotechnology, Faculty of Sciences, Selçuk University, Konya, Turkey
 2 Department of Pharmaceutical Botany, Faculty of Pharmacy, Selçuk University, Konya, Turkey 
 
 Abstract
 Cousinia is a member of the monophyletic tribe Cardueae, which is traditionally subdivided into four taxonomic groups; however, the rank and boundaries of these taxa are highly controversial. The purpose of this study was to contribute to the genus taxonomy by determining the comparative anatomical and achene micromorphological features of C. aintabensis Boiss. & Hausskn. and C. birecikensis Hub.-Mor. that are morphologically similar to each other. In anatomical studies, stem, leaf, and midrib features were determined. Paraffin embedding, microtome sectioning, and safranin-fast green staining were used for the samples. The obtained sections were photographed, and the leaf, stem, and midrib characters were measured. The importance of anatomical characters between species was determined by applying Independent sample T-test test to quantitative characters. In addition, box plot and heatmap analyses of the studied species were carried out. Our results showed that the stem epidermis, inner sclerenchyma and phloem layer; For leaves; lower and upper epidermis mesophyll thickness, palisade parenchyma; In midrib; number of vascular bundles, collenchyma, and phloem are important characters that can be used in the differentiation of species. SEM microscope was used for achene micromorphological examinations. C. aintabensis achene surface ornamentation is identified as striate-retipylate. It was observed that C. birecikensis had striate and irregular reticulate-faveolate surface ornamentation.
 
 Keywords: Asteraceae, Anatomy, Cousinia, micromorphology, Türkiye

Comparative anatomy and pollen morphology of two endemic Noccaea species (Brassicaceae) and their taxonomic significance

This study was conducted for extensive and systemic investigation of anatomical, palynological and seed morphological properties of two endemic Noccaea species, naturally growing in Turkey. Independent sample T-test and box plot were carried out using quantitative characters of the studied species. The anatomical results showed that the species had similar characteristics, though there were significant differences in root cortex cells and trachea; stem epidermis, cortex cell and endodermis; leaf upper and lower epidermis, lower cuticle, mesophyll and palisade parenchyma. Pollen grains of two endemic species were observed as radially symmetric, isopolar, with tricolpate aperture, prolate pollen shape and had small size. Pollen surface ornamentation was micro-reticulate in both species. Considering palynological characters, equatorial axis, AMB exine and intine have taxonomic importance. Seeds of N. birolmutlui were ovate to orbicular in shape and orange-brown in color, with colliculate ornamentation; however, the seeds of N. camlikensis were ovate to oblong in shape and brown and shiny in color, with colliculate-reticulate ornamentation.

Anatomical and palynological comparison of three endemic species of Teucrium sect. Teucrium of Turkey

Teucrium ekimii, T. pestalozzae and T. semrae are three endemic species of Turkey belonging to Teucrium sect. Teucrium. These species grow in the western Mediterranean region of the country and are morphologically similar to each other. In the present study, the three species underwent anatomical examination of the stems, leaves and palynological studies for a better characterization of the species and in search of additional diagnostic characters. Quantitative characters were subjected to one-way analysis of variance (ANOVA) and boxplot. In general, these species are anatomically similar, though there are significant differences in stem cuticle thickness, stem epidermis length and width, leaf lower epidermis width and midrib parenchyma width. Pollen grains of all three species are prolate, medium-sized and tricolpate. The exine ornamentation is microverrucate-perforate in T. ekimii, verrucate in T. pestalozzae and microverrucate in T. semrae. Considering palynological characters, polar axis and t (apocolpium) were identified as taxonomically significant characters.

Blueprinting morpho-anatomical episodes via green silver nanoparticles foliation

Abstract Traditional fertilization not only enhances the acidification of soil but also leads toward eutrophication. Here stimulatory and inhibitory effects of foliar fertilization of Cordia based silver nanoparticles (AgNPs) were studied on lettuce (Lactuca sativa L.) biomass accumulation, antioxidant activity, and morphological and anatomical modifications. The AgNPs were foliar supplied with a concentration of 25, 50, and 100 ppm along with control (deionized water) and negative control AgNO3 for consecutive 25 days. The L. sativa fresh and dry biomass accumulation were significantly higher by 53%, leaf area by 25%, and leaf water holding capacity by 207% for foliar sprayed at 25 ppm concentration of AgNPs. The application of AgNPs and AgNO3 had significantly shortened the shoot length (52%), while foliar spray of AgNPs promoted the root length (40%). Among different concentrations of AgNPs, the 50 ppm improved the thickness of stem epidermis (44%), hypodermis (130%), and cortex cell area (372%). For antioxidant studies, the 25 ppm of AgNPs depicted the highest anti-oxidative activity for 2,2-diphenyl-1-picryl hydrazyl radical scavenging activity (75%), total antioxidant capacity (167%), total phenolic content (292%), and total reducing power (60%), while 50 ppm showed the maximum activity for total flavonoid content (243%) as compared to control. Thus, we may conclude that the AgNPs have both stimulatory and inhibitory effects on L. sativa. These effects were dependent on the concentration of the nanoparticles and have varied for different growth, antioxidants, and anatomical traits of the plant.

Hemp Stem Epidermis and Cuticle: From Waste to Starter in Bio-Based Material Development.

Nowadays, hemp farmers are facing an urgent problem related to plant stem disposal after seed harvesting. In this work, the commonly discarded epidermis and cuticle of hemp stems were valorized, turning them towards a sustainable recycling and reuse, contributing to the circular economy concept. Cellulose deprived of amorphous regions was obtained by a green process consisting of an ethanolic ultrasound-assisted maceration followed by mild bleaching/hydrolysis. The obtained hemp cellulose was esterified with citric acid resulting in a 1.2-fold higher crystallinity index and 34 °C lower Tg value compared to the non-functionalized hemp cellulose. Green innovative biocomposite films were developed by embedding the modified cellulose into PLA by means of an extrusion process. The structural and morphological characterization of the obtained biocomposites highlighted the functionalization and further embedment of cellulose into the PLA matrix. Attenuated Total Reflectance–Fourier Transform Infrared spectroscopy (ATR-FTIR) results suggested physical and chemical interactions between PLA and the organic filler in the biofilms, observing a homogeneous composition by Field Emission-Scanning Electron Microscopy (FESEM). Moreover, some increase in thermal stability was found for biocomposites added with 5%wt of the hemp cellulose filler. The obtained results highlighted the feasible recovery of cellulose from hemp stem parts of disposal concern, adding value to this agro-waste, and its potential application for the development of novel biocomposite films to be used in different applications.

Phytochemical, Histochemical and In Vitro Antimicrobial Study of Various Solvent Extracts of Costus speciosus (J. Koenig) Sm. and Costus pictus D. Don

Costaceae family comprises many ornamental and medicinal plants used for different diseases. This investigation includes the phytochemical, histochemical, and in vitro antimicrobial study of Costus speciosus (J. Koenig) Sm. and C. pictus D. Don. Solvents such as methanol, ethyl acetate, and hexane were used to extract the leaves and rhizomes of both plants. The antibacterial study was executed using the agar well diffusion technique. Phytochemical study confirmed that alkaloids, flavonoids, quinones, and saponins were present in solvent extracts of both plants. The macromorphological studies including size, shape, texture, surface characters, and color, were analyzed. Salmonella typhi, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus were used for the antibacterial study. Agar well diffusion and agar disk diffusion methods were performed to determine the susceptibility of bacterial strains to various extracts of these plants. Histochemical analysis revealed alkaloids, proteins, and phenols in the vascular bundles, the cortex, and epidermis of stem, root, and leaves of the plants. Inhibition zones caused by the methanol and hexane extracts showed better antibacterial activity compared to those of other extracts. Future work on the isolation, purification, and characterization of the active constituents and the elucidation of possible mechanisms can be executed.