Ground Tissue Research Articles

Antagonistic CLE peptide pathways shape root meristem tissue patterning.

Secreted CLAVATA3/EMBRYO SURROUNDING REGION (CLE) peptide ligands dimension the stem cell niche of Arabidopsis shoot meristems by signalling through redundant and cross-compensating CLAVATA1 (CLV1)-type receptor kinases. In the root meristem, the CLV1 homologues BARELY ANY MERISTEM 1 (BAM1) and BAM2 drive CLE13/16-mediated formative divisions that produce the ground tissue layers. Here we report that BAM1/2 are also required to initiate the vascular phloem lineage and that cross-compensation between CLV1-type receptors as observed in the shoot does not operate similarly in the root. Rather, we find that BAM3-mediated CLE45 signalling antagonizes BAM1/2-mediated CLE11/12/13 signalling in the phloem initials but not in the ground tissue. We further observe spatiotemporally contrasting CLE signalling requirements for phloem initiation and differentiation, which are shaped by the SHORT ROOT (SHR) pathway. Our findings thus suggest an intricate quantitative interplay between distinct and antagonistic CLE signalling pathways that organizes tissue layer formation in the Arabidopsis root meristem.

Glutathione accelerates the cell cycle and cellular reprogramming in plant regeneration.

The plasticity of plant cells underlies their wide capacity to regenerate, with increasing evidence in plants and animals implicating cell cycle dynamics in cellular reprogramming. To investigate the cell cycle during cellular reprogramming, we developed a comprehensive set of cell cycle phase markers in the Arabidopsis root. Using single-cell RNA-seq profiles and live imaging during regeneration, we found that a subset of cells near an ablation injury dramatically increases division rate by truncating G1. Cells in G1 undergo a transient nuclear peak of glutathione (GSH) prior to coordinated entry into S phase followed by rapid divisions and cellular reprogramming. A symplastic block of the ground tissue impairs regeneration, which is rescued by exogenous GSH. We propose a model in which GSH from the outer tissues is released upon injury licensing an exit from G1 near the wound to induce rapid cell division and reprogramming.

Three RLKs integrate SHR-SCR and gibberellins to regulate root ground tissue patterning in Arabidopsis thaliana.

Precise regulation of cell division is essential for proper tissue patterning in multicellular organisms. In Arabidopsis, the ground tissue (GT) comprises cortex and endodermis in the early stages of root development. During GT maturation, additional periclinal cell divisions (PCDs) occasionally occur of the endodermis, generating a middle cortex (MC) layer between the cortex and endodermis. Although several regulatory proteins and phytohormones were identified to mediate GT patterning, such as SHORT-ROOT (SHR), SCARECROW (SCR), CYCLIND6;1 (CYCD6;1), and gibberellins (GAs), the interrelationship among these factors is not elucidated. Here, we report that three closely related receptor-like kinases (RLKs), ARH1, FEI1, and FEI2, play crucial roles in mediating a signal transduction pathway from the SHR-SCR module to GA to regulate GT patterning. Two independent triple mutants of these RLKs (tri-1 and tri-2) exhibit increased MC formation compared with wild type. Genetic analysis indicated that all three RLKs regulate MC formation mainly in a cell-autonomous manner. The transcription levels of these RLKs are negatively controlled by SHR and SCR. The altered GT patterns in shr and scr can be partially complemented by tri-1. GA biosynthesis is significantly reduced in the roots of tri-1. The excessive MC formation in tri-1 can be greatly suppressed by the exogenous application of GA3 or by the mutation of CYCD6;1. Our results demonstrate a signaling pathway involving SHR/SCR-ARH1/FEI1/FEI2-GA-CYCD6;1 to govern GT patterning in Arabidopsis thaliana.

The effect of natural herbicide from Fusarium equiseti crude extract on the aquatic weed water hyacinth (Eichornia crassipes (Mart.) Solms)

In this study, Fusarium equiseti was isolated from the weed plant Tridax procumbens in an agricultural field and a crude extract produced with 75% ethanol for use as active ingredient material in natural herbicides. The herbicidal effect of F. equiseti extract was tested on water hyacinth (Eichornia crassipes), an invasive aquatic weed, by leaf disk assay at concentrations of 0.05%, 0.1%, and 0.2% w/v crude extract. Dose-dependent visual toxicity symptoms were evident after three days, namely chlorosis, yellow leaves surrounded by dark brown edges. Photosynthetic pigments (chlorophyll a, b, and carotenoids) and membrane integrity (as electrolyte leakage and malondialdehyde content) were evaluated following the leaf disk test. 3 days after treatment, photosynthetic pigment contents showed dose-dependent decreases, while both measures of membrane integrity showed dose-dependent increases with increasing extract concentration. In addition, a cytogenetic assay was conducted on Allium cepa L. root, in which mitotic index reduction and depigmentation were evident as early as 24 h after herbicide application. Finally, anatomical analysis of treated E. crassipes leaves revealed degradation or damage of the ground tissue. All told, our results support the F. equiseti crude-based natural herbicide cloud as a sustainable alternative in agriculture.

Outward askew endodermal cell divisions reveal INFLORESCENCE AND ROOT APICES RECEPTOR KINASE functions in division orientation.

Oriented cell divisions establish plant tissue and organ patterning and produce different cell types; this is particularly true of the highly organized Arabidopsis (Arabidopsis thaliana) root meristem. Mutant alleles of INFLORESCENCE AND ROOT APICES RECEPTOR KINASE (IRK) exhibit excess cell divisions in the root endodermis. IRK is a transmembrane receptor kinase that localizes to the outer polar domain of these cells, suggesting that directional signal perception is necessary to repress endodermal cell division. Here, a detailed examination revealed many of the excess endodermal divisions in irk have division planes that specifically skew towards the outer lateral side. Therefore, we termed them 'outward askew' divisions. Expression of an IRK truncation lacking the kinase domain retains polar localization and prevents outward askew divisions in irk; however, the roots exhibit excess periclinal endodermal divisions. Using cell identity markers, we show that the daughters of outward askew divisions transition from endodermal to cortical identity similar to those of periclinal divisions. These results extend the requirement for IRK beyond repression of cell division activity to include cell division plane positioning. Based on its polarity, we propose that IRK at the outer lateral endodermal cell face participates in division plane positioning to ensure normal root ground tissue patterning.

BIG coordinates auxin and SHORT ROOT to promote asymmetric stem cell divisions in Arabidopsis roots.

BIG regulates ground tissue formative divisions by bridging the auxin gradient with SHR abundance in Arabidopsis roots. The formative divisions of cortex/endodermis initials (CEIs) and CEI daughter cells (CEIDs) in Arabidopsis roots are coordinately controlled by the longitudinal auxin gradient and the radial SHORT ROOT (SHR) abundance. However, the mechanism underlying this coordination remains poorly understood. In this study, we demonstrate that BIG regulates ground tissue formative divisions by bridging the auxin gradient with SHR abundance. Mutations in BIG gene repressed cell cycle progression, delaying the formative divisions within the ground tissues and impairing the establishment of endodermal and cortical identities. In addition, we uncovered auxin's suppressive effect on BIG expression, triggering CYCLIND6;1 (CYCD6;1) activation in an SHR-dependent fashion. Moreover, the degradation of RETINOBLASTOMA-RELATED (RBR) is jointly regulated by BIG and CYCD6;1. The loss of BIG function led to RBR protein accumulation, detrimentally impacting the SHR/SCARECROW (SCR) protein complex and the CEI/CEID formative divisions. Collectively, these findings shed light on a fundamental mechanism wherein BIG intricately coordinates the interplay between SHR/SCR and auxin, steering ground tissue patterning within Arabidopsis root tissue.

An experimental study on low-temperature plasma tissue ablation and its thermal effect

Low-temperature plasma ablation has been recently used for minimally invasive surgeries. However, more research is still needed on its generation process during tissue ablation and the underlying mechanism of tissue thermal damage. In this paper, high-speed camera footage, voltage–current signal collection, temperature analysis, and histological analysis were used to investigate the dynamic process of plasma tissue ablation and its thermal effect of dual-needle electrodes immersed in normal saline, which were driven by a high-frequency DC power supply with an output voltage ranging from 220 V to 320 V and a squire wave of 100 kHz. Microbubbles occurred around the ground electrode and merged to form a vapor layer that could completely cover the ground electrode. Plasma capable of ablating tissue would occur in the vapor layer between the ground electrode and tissue. The effect of electrical parameters on plasma generation and its thermal effect are analyzed by statistical results. The experimental results indicated that the voltage applied to the electrodes significantly influenced both the generation and stability of plasma, as well as the heat generation and tissue damage around the electrodes. Furthermore, under the same voltage, the existence of biological tissue promotes the formation of a vapor layer around the electrode, thereby facilitating the generation and stability of plasma. Notably, the temperature rise around the ground electrode is much higher than that around the powered electrode. These results have direct application to the design of plasma tissue ablation systems, which could achieve tissue ablation effects with minimal thermal damage.

Comparative morpho-anatomy of two sedges (<i>Cyperus cyperoides</i>(L.) Kuntze and <i>Cyperus rotundus</i. L.)

The research investigated the comparative morpho-anatomy of two sedges (Cyperus cyperoides (L.) Kuntze and Cyperus rotundus L.), members of the family Cyperaceae. They are perennial herbs and the former commonly known as commonflat sedge and the latter nut sedge or purple nutsedge. The epidermal peels were obtained by standard methods. The samples were fixed in formaldehyde, glacial acetic acid, 70% alcohol in the ratio of 1:1:18, dehydrated in alcohol solutions of 50%, 70%, 90%, absolute and sectioned, stained in 2% aqueous solution of Safranin O, counter stained in Alcian blue, mounted in glycerine.The result on epidermal studies showcased both kidney and dumbbell-shaped guard cells, graminaceous stomata which is amphistomatic for both species. The anatomical studies revealed scattered vascular bundies in ground tissues of stems, bulliform cells at adaxial foliar organs. The pith sections have large pith and a single row of barrel shaped endodermis prominently pronounced. The research findings here would assist in improving upon already existing knowledge about C. cyperoides and C rotundus.

Anatomical structure of leaves in Magnolia kobus, M. obovata, M. denudata in the first stages of ontogenesis

In the ontogenesis of woody plants in general, and magnolia species in particular, the virginal age is quite long, and therefore is critically important from the point of view of selecting optimal conditions for growing plants. The study was conducted on biennial plants of deciduous magnolias: Magnolia kobus Sarg., M. obovata Thunb., M. denudata Desr. The studied plants were at the beginning of the virginile stage of development. The material for the investigation is selected from plants, which were planted by us in the research area of A. V. Fomin Botanical Garden of the Taras Shevchenko National University of Kyiv. In this study, we used scanning electron and light microscopes to examine the ultrastructure of the surface of leaves of the studied species. The histological characteristics of the leaves of the studied species are similar. They are hypostomatic. Their stomata are of the paracytic type, they are evenly distributed on the abaxial surface of the leaves. The epidermal cells of the studied species of the genus Magnolia have tortuous (cells located on the periphery of the leaf) or straight (cells located on the veins) outlines and rectangular (cells located on the veins) or flattened (cells placed on the periphery of the leaf) projection. The cuticle is relatively thin, located on both the abaxial and adaxial surfaces of the leaves. Epicuticular wax is observed of three types in the studied species: films (M. denudata), crust (M. kobus, M. obovata) and wax granules (M. denudata, M. obovata). The amount of wax and pubescence is greater on the abaxial surface in M. obovata; very weak pubescence and waxy layer is observed only on the abaxial surface of the leaf in M. kobus, weak pubescence is present on both sides in M. denudata. In all species of the genus Magnolia pubescence is simple, formed by hairs that "accompany" the veins. There are two main types of lamina relief in the studied species: reticular (M. obovata, M. denudata (subtype reticular-collicular)) and pitted (M. kobus). The species clearly differ in this feature, so we believe that the type of relief of the lamina can be used as an additional diagnostic feature to distinguish species of the genus Magnolia. Magnolia denudata is characterized by a small number of stomata, while M. obovata and M. kobus are characterized by their average number. The Stomata Index varies from 2.8 in M. denudata to 1.02 in M. kobus. The lamina is the thickest in M. obovata, the thinnest is in M. kobus, but the total thickness of the epidermal tissue as a percentage of the thickness of the leaf is, in descending order: M. denudata (29%), M. kobus (24%), M. obovata (18%). The mesophyll varies from homogeneous-spongy (in M. kobus) to layered (in M. obovata, M. denudata) type. The number of layers of cells that form the mesophyll in all studied species is from 4 to 6. Thus, M. kobus is characterized by the least specialized type of mesophyll. The vascular system in the studied plants is represented by small central and lateral vascular bundles. The ground tissue is present only in the central and large side bundles. In the early stages of ontogenesis the studied plants are typical mesophytes with hypostomatic leaves adapted to exist in sufficiently moist conditions in soil and air. In practical terms, the results of investigation can be used to select optimal conditions for growing plants at the initial stages of ontogenesis.

Type of stomata and peel structure associated with programmed cell death of senescent spotting in banana

Senescent spotting or brown spot on bananas, is regarded as a form of programmed cell death (PCD). These spots appear in areas where stomata are present on the banana peel, there is no report describing the relationship between these spots and stomata on peel. This research aims to investigate whether senescent spotting in banana is involved in the PCD of stomata on peel. Three banana cultivars, ‘Khai-Kasetsart 2’ (KK2), ‘Dwarf Cavendish’ (CVD), and ‘Hom Thong’ (HT) bananas were examined for senescent spotting. KK2 banana exhibited more severe senescent spotting than CVD banana, while HT bananas did not display brown spot. Electrolyte leakage and DNA degradation increased before the spotting was observed in KK2 and CVD bananas. The peel structure revealed compact cells in CVD and HT bananas, whereas KK2 banana had a loose cell structure. Notably, KK2 banana had a high stomata density correlate with weight loss. Interestingly, the stomata type of KK2 banana was the same as CVD banana, being the typical type, while HT had a sunken type. The spotting zone of KK2 and CVD bananas revealed that stomata were more open than in the healthy zone. Additionally, the outer ground tissue of spotting zone flattened and collapsed, while the healthy zone did not exhibit this flattening and collapsing. Observations of cell morphology in the spotting zone of KK2 banana showed a detached plasma membrane, organelle destruction, and the presence of cell corpse with an absence of cytoplasm clearance. In conclusion, the result provides an evidence that stomata type on the banana peel involve in PCD, resulting in senescent spotting.

Physio-Biochemical, Anatomical, and Molecular Analysis of Resistant and Susceptible Wheat Cultivars Infected with TTKSK, TTKST, and TTTSK Novel Puccinia graminis Races.

Stem rust, caused by Puccinia graminis f.sp. tritici, is one of the most dangerous rust diseases on wheat. Through physiological, biochemical, and molecular analysis, the relationship between the change in resistance of 15 wheat cultivars to stem rust disease and the response of 41 stem rust resistance genes (Sr,s) as well as TTKSK, TTKST, and TTTSK races was explained. Some cultivars and Sr genes, such as Gemmeiza-9, Gemmeiza-11, Sids-13, Sakha-94, Misr-1, Misr-2, Sr31, and Sr38, became susceptible to infection. Other new cultivars include Mir-3 and Sakha-95, and Sr genes 13, 37, 40, GT, and FR*2/SRTT3-SRTT3-SR10 remain resistant. Some resistance genes have been identified in these resistant cultivars: Sr2, Sr13, Sr24, Sr36, and Sr40. Sr31 was not detected in any cultivars. Reactive oxygen species such as hydrogen peroxide and superoxide, enzymes activities (catalase, peroxidase, and polyphenoloxidase), and electrolyte leakage were increased in the highly susceptible cultivars, while they decreased in the resistant ones. Anatomical characteristics such as the thickness of the epidermis, ground tissue, phloem tissue and vascular bundle diameter in the midrib were decreased in susceptible cultivars compared with resistant cultivars. Our results indicated that some races (TTKSK, TTKST, and TTTSK) appeared for the first time in Egypt and many other countries, which broke the resistant cultivars. The wheat rust breeding program must rely on land races and pyramiding genes in order to develop new resistance genes that will survive for a very long time.

Tolerance of the Australian halophyte, beaded samphire, Sarcocornia quinqueflora, to Pb and Zn under glasshouse conditions: Evaluating metal uptake and partitioning, photosynthetic performance, biomass, and growth

Saltmarsh sediments are susceptible to accumulation of excessive concentrations of anthropogenically elevated metals such as lead (Pb) and zinc (Zn). The resident salt tolerant plants of saltmarsh ecosystems form the basal underpinning of these ecosystems. As such, metal-associated adverse impacts on their physiology can have detrimental flow-on effects at individual, population, and community levels. The present study assessed the accumulation and partitioning of ecologically relevant concentrations of Pb, Zn, and their combination in a dominant Australian saltmarsh species, Sarcocornia quinqueflora. Plants were hydroponically maintained under glasshouse conditions for 16 weeks exposure to either Pb (20 µg l–1), Zn (100 µg l–1), or their mixture. We evaluated the chronic toxicological effects of single and mixed metal treatments with reference to metal uptake and partitioning, photosynthetic performance, photosynthetic pigment concentration, biomass and growth. Lead was more toxic than Zn, and Zn appeared to have an antagonistic effect on the toxicological effects of Pb in S.quinqueflora in terms of metal uptake, photosynthetic performance, photosynthetic pigment concentrations, and growth. Indeed, the tolerance index was 55 % in plants treated with Pb compared to 77 % in Zn treated plants and 73 % in Pb+Zn treated plants. Finally, Sarcocornia quinqueflora primarily accumulated both Pb and Zn in roots at concentrations exceeding unity whilst translocation of these metals to above ground tissues was restricted regardless of treatment. This suggests that S. quinqueflora may be suitable for phytostabilisation of Zn, and of Pb particularly in the presence of Zn.

Investigation of the Morpho-Anatomical and Epidermal Properties of Commelina erecta L.

In traditional medicine, Commelina erecta L. has been used as antiviral, for the treatment of hemorrhages, skin rashes and sores, and for the treatment of infections. It is also used as a wild edible plant in salads, preserves or decorating the dishes. Hence, the objective of this paper was to investigate the morpho-anatomical and epidermal properties of Commelina erecta L of Commelinaceae using appropriate standard methods. Results revealed C. erecta as a Broadleaf and vivacious branching up to 20 to 55 cm in length as it trails and roots at nodes, having leaves which are elliptical, oval to lanceolate and sub sessile about 2.5 ± 0.5 cm long and 1.5 ± 0.5 cm wide; the leaf sheath is closed and united at base. The stomata are anomocytic, tetracytic and paracytic stomata with pentagonal to heptagonal epidermal cells and trichomes (piloses) including glandular trichomes which are amphistomatic. Anatomical sections showcased root pith, vascular bundles scattered and concentrated towards the ground tissues. These information would assist for further delimitation of the species.

PpSCARECROW1 (PpSCR1) regulates leaf blade and mid-vein development in Physcomitrium patens.

In plants, asymmetric cell divisions result in distinct cell fates forming large and small daughter cells, adding to the cellular diversity in an organ. SCARECROW (SCR), a GRAS domain-containing transcription factor controls asymmetric periclinal cell divisions in flowering plants by governing radial patterning of ground tissue in roots and cell proliferation in leaves. Though SCR homologs are present across land plant lineages, the current understanding of their role in cellular patterning and leaf development is mostly limited to flowering plants. Our phylogenetic analysis identified three SCR homologs in moss Physcomitrium patens, amongst which PpSCR1 showed highest expression in gametophores and its promoter activity was prominent at the mid-vein and the flanking leaf blade cells pointing towards its role in leaf development. Notably, out of the three SCR homologs, only the ppscr1 knock-out lines developed slender leaves with four times narrower leaf blade and three times thicker mid-vein. Detailed histology studies revealed that slender leaf phenotype is either due to the loss of anticlinal cell divisions or failure of periclinal division suppression in the leaf blade. RNA-Seq analyses revealed that genes responsible for cell division and differentiation are expressed differentially in the mutant. PpSCR1 overexpression lines exhibited significantly wider leaf lamina, further reconfirming the role in leaf development. Together, our data suggests that PpSCR1 is involved in the leaf blade and mid-vein development of moss and that its role in the regulation of cell division and proliferation is ancient and conserved among flowering plants and mosses.

The specialized parenchyma in the Paspalum vaginatum stem as a strategy to water deficit and salinity

Abstract Paspalum vaginatumis a halophyte plant found along coastal plains, which presents cells with atypically thickened walls in the ground tissue of the stem stele (GTS). The tolerance of this species to high salinity and water stress led us to investigate whether the thickened walls could be related to adaptation to the coastal environment. Thus, we sought to characterize the cell walls that make up the GTS ofP. vaginatum, describe the tissue, and verify the influence of the water resource on the thickening of the walls and a possible function related to the reserve of substances. For this, analyses were carried out using light microscopy, transmission electronic microscopy, and histochemical tests. The samples were collected in the field during low and high rainfall periods.Paspalum vaginatumGTS cells have pectic-cellulosic primary walls. In most basal internodes, these cells presented thickened walls formed in two to three layers. Statistical analysis demonstrated that the level of precipitation is directly related to cell wall thickening. The data suggest the storage and mobilization of substances through the cell wall of the specialized parenchyma.

A precise balance of TETRASPANIN1/TORNADO2 activity is required for vascular proliferation and ground tissue patterning in Arabidopsis.

The molecular mechanisms guiding oriented cell divisions in the root vascular tissues of Arabidopsis thaliana are still poorly characterised. By overlapping bulk and single-cell transcriptomic datasets, we unveiled TETRASPANIN1 (TET1) as a putative regulator in this process. TET1 is expressed in root vascular cells, and loss-of-function mutants contain fewer vascular cell files. We further generated and characterised a CRISPR deletion mutant and showed, unlike previously described mutants, that the full knock out is additionally missing endodermal cells in a stochastic way. Finally, we show that HA-tagged versions of TET1 are functional in contrast to fluorescent TET1 translational fusions. Immunostaining using HA-TET1 lines complementing the mutant phenotype suggested a dual plasma membrane and intracellular localisation in the root vasculature and a polar membrane localisation in the young cortex, endodermal and initial cells. Taken together, we show that TET1 is involved in both vascular proliferation and ground tissue patterning. Our initial results pave the way for future work to decipher its precise mode of action.

First megafossil occurrence of Cryosophileae (Arecaceae) in Asia: anatomy, systematics, and biogeography

ABSTRACT Cryosophileae, one of eight tribes within the palm subfamily Coryphoideae, is now restricted to tropical-subtropical areas of Central America with a few megafossil records in Europe and America. However, no megafossil of the tribe has been reported from Asia. Here, we describe Cryosophiloxylon indicum Kumar et Khan sp. nov. assigned to Cryosophileae based on permineralized palm stem from the latest Maastrichtian (Late Cretaceous) to earliest Danian (early Paleocene) sediments (c. 63–65 Ma old) of the Deccan Intertrappean Beds of Madhya Pradesh, Central India. Cryosophiloxylon indicum is characterized by a Cocos-type general stem pattern, the presence of well-preserved vaginata fibrovascular bundles (fvbs) with 2–>4 elongated metaxylem vessel elements and one phloem strand, tabular parenchyma, fibrous bundles, uniform distribution of fibrous part of fvbs from the periphery towards the centre, and compact ground tissue with oval to elongated parenchymatous cells. The present finding represents the oldest reliable megafossil record of Cryosophileae from India supporting its Gondwanan occurrence and so is important for tracing its migration pathways from India to other continents (North and South America, Europe). The extinction of modern members of the tribe from fossil locality may be related to the intensification of the East Asian monsoon.

Exploring Morpho-Anatomical Attributes, Phytochemical, and HPTLC Profile of Enicostema axillare (Poir. ex Lam.) A.Raynal

Enicostema axillare (Lam.) A. Raynal, known as the Indian whitehead, is member of Gentiaceae family and has been used medicinally for a very long time both in India and around the world. The objective of the present work comprises collection, identification, macroscopical, microscopical, and phytochemical evaluation and HPTLC fingerprint analysis on Leaves of E. axillare. The surface studies of the leaf are amphistomatic, with anisocytic stomata and trichome complex absent in both surfaces. The T.S of Leaf is slightly flat adaxially and ribbed on abaxially at midvein, presence of one layered epidermis. Mesophyll is heterogenous, differentiated into palisade and spongy tissues, and interspersed with sphaerocrystaliferous idioblasts. The ground tissue of the mid vein consists of palisade 1-2 layered and parenchyma 1-3 layered. The midvein consists of a single oval-shaped vascular bundle, at the center. The microscopic and organoleptic characters of the powder are provided. The phytochemical analysis following hot continuous and successive extraction by Soxhlet apparatus on various extracts indicates the presence of alkaloids, phenolic glycosides, tannins, steroids and terpenoids flavonoids, saponins, phytosterols, fixed oils, gums and mucilage’s, etc., It is discovered that the number of spots, and Rf values of HPTLC are distinct diagnostic features of the plant for identification. The information accumulated through the combination of chemical and botanical screening could potentially be utilized for establishing pharmacopeial standards as well as creating a standard for the identification and authentication of E. axillare.

Wood structural diversity in fynbos, chaparral, and maquis: a preliminary estimation

Summary Fynbos, a shrubland from the Cape Floristic Region in South Africa, is one of five Mediterranean-climate biomes alongside maquis in the Mediterranean Basin, chaparral in California, matorral in Central Chile and kwongan in Southwestern Australia. We compiled the available information on the wood anatomy of 226 species belonging to 65 genera of 14 families that occurred in fynbos and compared this dataset with the published data on wood diversity in Californian chaparral and Israeli maquis. “Carlquist’s Law”, i.e., the association between the ground tissue made of fibre tracheids and low vessel grouping, has been confirmed for the fynbos plants. The lack of ring porosity and very low incidence of semi-ring-porous woods is the most prominent difference of the fynbos from the other two vegetation types. These features are attributed to the paucity of deciduous plants in fynbos which is probably associated with the poor-nutrient soils in this biome. The fynbos differs from chaparral and maquis also in the greatest percentage of the species having no tracheids in their wood as well as with the lowest incidence of helical thickenings on the vessel walls. These differences could be explained by the lower tolerance of fynbos shrubs to seasonal drought due to the relatively mild dry season in this biome. We also found that some differences between fynbos, chaparral, and maquis in the incidences of fibre tracheids and vasicentric/vascular tracheids associated with large vessel groups can be at least partly explained by different systematic compositions of their floras. The higher percentage of distinct growth rings, greater vessel diameter, and lower vessel frequency in maquis compared with fynbos and chaparral can be attributed to a common occurrence of relatively tall trees in this vegetation.

Potentially toxic metals in irrigation water, soil, and vegetables and their health risks using Monte Carlo models

Food safety has become a serious global concern because of the accumulation of potentially toxic metals (PTMs) in crops cultivated on contaminated agricultural soils. Amongst these toxic elements, arsenic (As), cadmium (Cd), chromium (Cr), and lead (Pb) receive worldwide attention because of their ability to cause deleterious health effects. Thus, an assessment of these toxic metals in the soils, irrigation waters, and the most widely consumed vegetables in Nigeria; Spinach (Amaranthushybridus), and Cabbage (Brassica oleracea) was evaluated using inductively coupled plasma-optical emission spectroscopy (ICP-OES). The mean concentration (measured in mg kg−1) of the PTMs in the soils was in the sequence Cr (81.77) > Pb(19.91) > As(13.23) > Cd(3.25), exceeding the WHO recommended values in all cases. This contamination was corroborated by the pollution evaluation indices. The concentrations (measured in mg l−1) of the PTMs in the irrigation water followed a similar pattern i.e. Cr(1.87) > Pb(1.65) > As(0.85) > Cd(0.20). All the PTMs being studied, were found in the vegetables with Cr (5.37 and 5.88) having the highest concentration, followed by Pb (3.57 and 4.33), and As (1.09 and 1.67), while Cd (0.48 and 1.04) had the lowest concentration (all measured in mg kg−1) for cabbage and spinach, respectively. The concentration of the toxic metals was higher in spinach than in cabbage, which may be due to the redistribution of the greater proportion of the metals above the ground tissue, caused by the bioavailability of metals in the aqueous phase. Expectedly, the hazard index (HI),and carcinogenic risk values of spinach were higher than that of cabbage. This implies that spinach poses potentially higher health risks. Similarly, the Monte Carlo simulation results reveal that the 5th percentile, 95th percentile, and 50th percentile of the cumulative probability of cancer risks due to the consumption of these vegetables exceeds the acceptable range of 1.00E−6 and 1.00E−4. Thus, the probable risk of a cancerous effect is high, and necessary remedial actions are recommended.