Cuticular Striations Research Articles

MORPHOMETRIC AND SCANNING ELECTRON MICROSCOPE-BASED IDENTIFICATION OF Taenia hydatigena PARASITES IN STRAY DOGS

Taenia hydatigena, an intestinal parasite of domestic and wild canids which can cause medical problems and economic losses in animals. Thirty T. hydatigena recovered from the intestine of stray dogs after T. hydatigena based on morphological characters and morphometric observations involving Scanning Electron Microscopy (SEM) and the scoleces were stained by Semichon's acid carmine and viewed on a light microscope. High-quality SEM photographs were shown the blade dimensions of both large and small hooks (83.89 µm and 48.16 µm) respectively, which was close to measurements by a digital camera. The number of hooks around the rostellum were 30 hooks, and both were equal in number (15 hooks), while the average length of the large hooks was 220.11 ±28.07 µm, and was 88.58 ±7.92, and the average length of small hooks was142.37 ±12.52 µm and was 65.73 ±6.94 µm. body surface of Taenia hydatigena presence of characteristic transverse cuticular striations.

COMPARATIVE LEAF ANATOMY AND MICROMORPHOLOGY OF ASYSTASIA GANGETICA T.ANDERSON SUBSP. MICRANTHA (NEES) ENSERMU AND RHINACANTHUS NASUTUS (L.) KURZ (JUSTICIINAE, ACANTHACEAE) FROM PENINSULAR MALAYSIA

Acanthaceae family has been used traditionally for medicinal purposes, especially amongst the native communities in Peninsular Malaysia. Nowadays, many taxonomists have difficulties in the identification of the Acanthaceae species due to its morphological similarities and when there is an incomplete part of plants obtained from the field sampling. But until now, there is no comprehensive study that has been documented especially on the Acanthaceae family, specifically for A. gangetica subsp. micrantha and R. nasutus. To avoid incorrect species identification, a systematic study that involved the leaf anatomy and micromorphology parts is being used for the identification and classification of plants in the Acanthaceae. Therefore, the main objective of this present study is to identify the leaf anatomical and micromorphological characteristics that can be used in plant identification and for supportive data in plant classification. The leaf anatomical and micromorphological studies that are conducted on species studied involve several procedures such as cross-section using a sliding microtome, and observation under a light microscope and scanning electron microscope. The anatomical and micromorphological characteristics observed that have been used to identify each species studied include patterns of petiole and midrib vascular bundles, leaf margin, leaf lamina, presence of cuticular striae, and the presence of trichomes. The results of this study showed that the cystolith cells can be found only in midrib of A. gangetica subsp. micrantha while it also recorded in petiole, midrib, and the leaf lamina of R. nasutus. Observation under the light microscope revealed nine types of trichomes in R. nasutus meanwhile seven trichomes were recorded in A. gangetica subsp. micrantha. Other than that, the present of cuticular striae only recorded at the abaxial epidermis of A. gangetica subsp. micrantha. In conclusion, results showed that anatomical and micromorphological characteristics have taxonomic significance that can be used in the identification and classification, especially at the species level

Comparative taxonomy and evolutionary significance of foliar epidermis in Jasminum L. (Oleaceae) based on light and scanning electron microscopy

Jasminum L. is an important genus of the Oleaceae family with nearly 200 species cultivated or distributed wild in almost all parts of the world. A comparative taxonomy and evolutionary relationship on the basis of foliar epidermal quantitative and qualitative micro-morphological characters of nine species of the genus Jasminum were assessed using light microscopy (LM) and scanning electron microscopy (SEM) techniques. Foliar epidermal anatomical attributes like number and size of cells, stomata, stomata complex, granular and non-granular trichomes along with the abaxial to adaxial cell ratio and stomata index were assessed as distinguished characters of the Jasminum foliar epidermis. Results displayed irregular types of cells, anomocytic, cyclocytic, anisocytic and giant stomata, peltate glands and unicellular or uniseriate trichomes in Jasminum species. The presence of domatia at the vein axil, glabrous, hairy, or spiny leaf margin, midrib, anticlinal view of the cells, cuticular folds and striations appeared as valuable micro-morphological attributes in Jasminum. The cluster analysis based on micro-morphology divided Jasminum species into two major clusters. The first cluster (C1) displayed four white flowering Jasminum species from section Unifoliolata with shared characters like simple opposite leaves with spinose and cuticular striations. The second cluster (C2) showed five white and yellow flower-bearing Jasminum species having compound leaves with cuticular folds or striations and spinose at their leaf margins. Conclusively, micro-morphological attributes are crucial to characterize and infer evolutionary relationships and the direction of character evolution from yellow to white flowering Jasminum.

Morphoelastic modelling of pattern development in the petal epidermal cell cuticle.

We use the model system Hibiscus trionum as a vehicle to study the origin and propagation of surface nano-ridges in plant petal epidermal cells by tracking the development of the cell shape and the cuticle. In this system, the cuticle develops two distinct sub-layers, (i) an uppermost layer which increases in thickness and in-plane extension and (ii) a substrate, composed of cuticular and cell wall material. We quantify the pattern formation and geometrical changes and then postulate a mechanical model assuming that the cuticle behaves as a growing bi-layer. The model is a quasi-static morphoelastic system and it is numerically investigated in two- and three-dimensional settings, using different laws of film and substrate expansion and boundary conditions. We recreate several features of the observed developmental trajectories in petals. We establish the respective roles of the layers' stiffness mismatch, the underlying cell-wall curvature, the cell in-plane expansion and the thickness growth rates of the layers in determining the observed pattern features, such as the variance observed in the amplitude and wavelength of the cuticular striations. Our observations provide evidence which justifies the growing bi-layer description, and provide valuable insights into why some systems develop surface patterns and others do not.

Development and Biomechanics of Grewia lasiocarpa E. Mey. Ex Harv. Trichomes Exudate.

Grewia lasiocarpa E. Mey. Ex Harv., Malvaceae (forest raisin) is a tropical small tree or shrub valued for its ecological importance as well as its nutritional, antioxidant, antibacterial, and anti-cancer properties as well as its ecological and ornamental importance. Glandular and non-glandular trichomes are present on the fruits, stem bark and leaves of G. lasiocarpa and these trichomes are the first line of defense. They are important structures that plants use to combat biotic and abiotic stress. The development of G. lasiocarpa trichomes and the biomechanics of the exudates present in the glandular (capitate) trichome were investigated for the first time using advanced microscopy techniques [Scanning electron microscope (SEM) and Transmission electron microscope (TEM)]. The pressurized cuticular striations may play a role in the exudates' biomechanics, i.e., releasing secondary metabolites present in the capitate trichome, which was observed to be multidirectional. The presence of many glandular trichomes on a plant implies an increase in the amount of phytometabolites. A common precursor for the development of trichomes (non-glandular and glandular) was observed to be DNA synthesis associated with a periclinal cell division, thus the final fate of the cell is determined by cell cycle regulation, polarity, and expansion. The glandular trichomes of G. lasiocarpa are multicellular and polyglandular, while the non-glandular (glandless) trichomes are either single-celled or multicellular. Since, trichomes 'house' phytocompounds of medicinal, nutritional, and agronomical benefits; the molecular and genetic study of the glandular trichomes of Grewia lasiocarpa will be beneficial to humanity.

A new plant-parasitic nematode species associated with coffee, Rotylenchus bunae n. sp. (Nematoda: Hoplolaimidae) from Jimma, Ethiopia

Summary Rotylenchus bunae n. sp. was discovered in the coffee rhizosphere in Gera district of Jimma, Ethiopia, and has been morphologically and molecularly characterised. The new species is identified by a female body length of 725-876 μm, hemispherical lip region with 4-5 lip annuli, stylet length of 28-30 μm, lateral field areolation only in the pharyngeal region, no cuticular striations, pharyngeal gland overlapping intestine dorsally by 15-26 μm, double epiptygma, no clear spermathecae, vulva position at 54-58% of body length from anterior end, prominent fasciculi in mid and posterior body, rounded or sometimes slightly truncated, coarsely crenated tail with 11-13 annuli, and phasmids located at 7-16 annuli anterior to anus. No males were detected. This species was found closely related to other African Rotylenchus species, such as R. unisexus and R. wimbii; however, it could be well separated from them by both morphology and molecular data (D2-D3 of 28S and partial 18S of rDNA).

Two new species of genus Perspiria (Desmodoridae: Nematoda) from the Bohai Bay of China

ABSTRACT Two new species of genus Perspiria were discovered from the subtidal sediments of Bohai Bay of China and described as Perspiria macramphida sp. nov. and Perspiria major sp. nov. Perspiria macramphida sp. nov. is characterised by the large and longitudinal loop-shaped amphidial fovea, partially surrounded with cuticular striations; conical buccal cavity with a dorsal tooth; spicules arcuated with enlarged proximal end and ventral velum, 53–61 µm long; 15–16 papillary precloacal supplements; and tail conico-cylindrical with prominent transverse striations except its terminal end. Perspiria major sp. nov. is characterised by its small unispiral amphidial fovea looking like a double circle in outline, partially surrounded with cuticular striations; conical buccal cavity with a small dorsal tooth; pharynx with a pear-shaped terminal bulb; tail short, conico-cylindrical; spicules strongly curved with heart-shaped proximal end, without ventral velum; and lacking precloacal supplements. An updated key for valid species of Perspiria is provided. http://www.zoobank.org/urn:lsid:zoobank.org:pub:AB1A7D19-1030-4FF8-8882-3F79C9080597

Eugenol; Effective Anthelmintic Compound against Foodborne Parasite Trichinella spiralis Muscle Larvae and Adult.

Trichinosis is a foodborne parasitic infection that results from ingestion of raw or under-cooked pork meat infected by parasitic nematode Trichinella spiralis with cosmopolitan distribution. Anthelmintic drugs are used to eliminate intestinal adult parasites and larvae as well as tissue-migrating newborn and in-turn encysted larvae. However, eliminating the infection or averting it from transmission is rarely possible using anthelmintic groups of benzimidazole derivatives. Eugenol (EO) is the main extracted constituent of clove oil (80-90%) and is responsible for its aroma. Therefore, this study aims to investigate the effect of eugenol on both adult and muscle larvae of Trichinella spiralis in vitro. IC50 for different concentrations of eugenol were calculated for both muscle larvae (187.5 µM) and adults (190.4 µM) to determine the accurate dose range. Both the nematode stages were cultured in the commonly used RPMI-1640 media in 24-well plates. Different concentrations of eugenol (122, 305, 609, 1218, and 3045 µM) were administered in different groups of larvae/adults. The parasitological parameters were monitored after 1, 3, 6, 10, 24 h for each EO concentration in concomitant with the control groups. Reference chemotherapeutic anthelminthic drug "albendazole" (at dose 377 µM) was experimentally grouped in triplicates as positive control and the untreated as negative control, respectively. Mortality was observed where time-dependent adult stages were less susceptible than muscle larvae. Eugenol achieved 100% efficacy against T. spiralis larvae and killed the total larvae after 10 and 24 h at concentrations of 1218 and 3045 µM, the same as albendazole's effect on the positive control group. In regard to adults, resembling muscle larvae (ML), a significant effect of both concentrations at p < 0.0001 was obtained, and the concentration × time interaction was significant at p < 0.0001. Furthermore, the treated/untreated adult and muscle larvae were collected and processed for scanning electron microscopy (SEM). Massive destruction of parasite burden was observed, especially at high concentrations (1218 and 3045 µM). In addition, complete and mild loss in cuticular striation in both the treated and positive controls were confirmed by SEM, respectively, in comparison to the control untreated group.

Leaf Epidermal Traits of Selected Euphorbiaceae and Phyllanthaceae Taxa of Hainan Island and Their Taxonomic Relevance

Euphorbiaceae and Phyllantaceae are two of the most taxonomically complex and diverse families among angiosperm. Therefore, this study aims to identify the common, variation, and diagnostic traits of foliar anatomy and micromorphology of selected Euphorbiaceae and Phyllanthaceae taxa collected from Hainan Island. A total of 42 individuals of 38 species belonging to these two families were examined under light microscopy (LM) and scanning electron microscopy (SEM). A multivariate detrended correspondence analysis (DCA), principal component analysis (PCA), and chord diagram analysis were performed to visualize the variations and relationships between the species. The nonglandular trichomes were further classified into long falcate and short conical with papillae on their surface, and stellate and lepidote subentire, while the glandular trichomes were divided into capitate, subsessile capitate, sessile capitates, and peltate. The paracytic-type stomata were found in most of the species. The prominent continuous or discontinuous cuticular striations radiating from the guard cells in parallel, horizontal, or reticulate patterns were analyzed in most of the taxa. Variation was also found in epidermal cells and anticlinal wall patterns. Together, these traits are useful for identification, discrimination, and to define species boundaries at various levels. Our study will provide a basis for future studies to strengthen the systematic of Euphorbiaceae taxa.

Morphometry, molecular identification and histopathology of Passalurus ambiguus Rudolphi, 1819 in domestic rabbits (Oryctolagus cuniculus) in Qena, Upper Egypt.

In Egypt, domestic rabbits are commercially used for meat production. Adversely, gastrointestinal helminthiasis largely delays such concern. Passalurus ambiguus is a common intestinal nematode that infects rabbits causing intestinal disorders and death in severe infection. Therefore, domestic rabbits collected from several locations (poultry slaughter shops, rabbits farms, markets and public owners) in Qena, Upper Egypt. Passalurus ambiguus worms were detected in 90 out of 200 rabbits (45%). Grossly, they appeared as small white nodules in the appendix of the rabbits examined. Adult worms were described morphologically using light and scanning electron microscopy. Adult male measured 4.622 mm (2.838-7.172 mm) in length and 0.278 mm (0.139-0.558 mm) in width. Adult female measured 5.622 mm (2.347-9.532 mm) in length and 0.314 mm (0.185-0.381 mm) in width. SEM showed a transverse cuticular striations on the body of both males and females, four papillae on the dorsal and ventral surface and the mouth was triangular and surrounded by three teeth. Phylogenetic data proved the occurrence of the intestinal nematode, Passalurus ambiguus. Microscopically, heavy worms infestated the appendiceal layers causing appendicitis manifested by granuloma with hyperplasia in the epithelial lining inducedobstruction in the lumen. It could be concluded that morphological features, molecular phylogenetic data, and histopathological findings clearly identified the present species as Passalurus ambiguus Rudolphi, 1819.

Micromorphology of endemic Centaurea glaberrima subsp. divergens (Asteraceae)

In this study, the micromorphology of the vegetative and reproductive structures of the endemic Centaurea glaberrima Tausch subsp. divergens (Vis.) Hayek (Asteraceae), using scanning electron microscope (SEM), is presented for the first time. Uniseriate whip-like non-glandular and biseriate glandular trichomes are found on the surface of all aboveground parts (stem, leaves, peduncles, involucral bract). On the adaxial leaf epidermis ribbed thickenings (striation pattern) of outer periclinal cell walls, slightly curved anticlinal cell walls and anomocytic stomata are noticed. Rugose abaxial surface with thorny protuberances of the involucral bract is documented. Corolla is glabrous with longitudinally parallel epidermal cells with distinct straight outline. Isopolar, radially symmetric and tricolporate microechinate pollen grains are seen. Short stylar hairs, without cuticular striations, are present along the outer sides of the style, while the inner sides (abaxial surface) constitute the papillate stigmatic surface. Microcharacters found in cypsela are as follows: slightly ribbed body; rotund base; lateral and concave insertion; short, unicellular curly acute trichomes; smooth epidermis; fine-sulcate ornamentation; rod shaped epidermal cells with short, obtuse end walls and straight anticlinal walls; poorly developed minutely dentate pericarp rim; and dimorphic pappus with bristles of different length and morphology, with pinnules restricted to the margins of the bristles. The results obtained contribute to knowledge about the micromorphology of the studied endemic species and provide features for its better identification. The taxonomic significance of the analyzed characters is discussed. Some well defined microcharacters of the studied species might have taxonomic value.

Mechanical buckling can pattern the light-diffracting cuticle of Hibiscus trionum.

Many species have cuticular striations that play a range of roles, from pollinator attraction to surface wettability. In Hibiscus trionum, the striations span multiple cells at the base of the petal to form a pattern that produces a type of iridescence. It is postulated, using theoretical models, that the pattern of striations could result from mechanical instabilities. By combining the application of mechanical stress with high-resolution imaging, we demonstrate that the cuticle buckles to create a striated pattern. Through mechanical modeling and cryo-SEM fractures, we show that the cuticle behaves like a bilayer system with a stiff film on a compliant substrate. The pattern of buckling aligns with the direction of the stress to create a larger-scale pattern. Our findings contribute to the understanding of the formation of tissue-wide patterns in living organisms.

Rudnicula goffi n. sp. (Acariformes: Trombiculidae) from the diadem leaf-nosed bat Hipposideros diadema (Geoffroy) (Chiroptera: Hipposideridae) on Bali, Indonesia.

A new species of chigger mite, Rudnicula goffi n. sp., is described from the diadem leaf-nosed bat Hipposideros diadema (Geoffroy) (Hipposideridae) caught in the Goa Peteng Cave on Bali (Indonesia). The new species differs from the closely related species by the presence of scutum with AL windows, lateral scutal margins with cuticular striations and fSt = 2 + 2 + 2. A list of all available records of Rudnicula species is provided. The genus is restricted to the tropics of Southeast Asia, Australia, Melanesia, and the subtropics of eastern Asia. A key to the known species of Rudnicula based on the morphology of the larvae is also provided.

A new species of the Cymbasoma longispinosum species-group (Copepoda: Monstrilloida) from Belize, western Caribbean

Cymbasoma belizense sp. n. is described from an adult female collected during a zooplankton survey of the Corozal Bay Wildlife Sanctuary (CBWS), adjacent to Chetumal Bay, a large binational embayment on the northwestern Caribbean Basin. The new species is a member of the Cymbasoma longispinosum species-group; it resembles C. chelemense Suárez-Morales & Escamilla, 1997 from the Gulf of Mexico and C. jinigudira Suárez-Morales & McKinnon, 2014 from Australia. This is the eighth nominal species known in this species-group, the second one recorded from the Caribbean Sea Basin, and the first one in the Belizean coast. The new species is distinguished by a combination of characters, including the body proportions, the structure and armature of the fifth legs, the cephalic ornamentation, with a fringe of faint cuticular striae, the relative length and bifurcation point of the ovigerous spines, and details of the antennule armature. Comparative comments and data including the distribution and taxonomical characters of members of this species-group are presented. Records of this nominal species from different geographic areas should be revised carefully because they could represent undescribed species. A key to the females of the currently known species of this group also provided.

Micromorphological alterations induced by simulated acid rain on the leaf surface of Joannesia princeps Vell. (Euphorbiaceae)

Acid rain has been detected in natural protected areas of the Atlantic Rainforest in Brazil. We evaluated the effects of simulated acid rain on the leaf blade surface of Joannesia princeps, aiming to assess the species potential as biosensor of acidic precipitation. Seedlings were subjected to simulated rain prepared with pH 4.5 H2SO4-acidulated water and, in the control treatment, pH 6.0 deionized water. Severe microstructural damage was detected in the youngest leaves, consisting in wilting of epidermal common cells, which resulted on alteration of the epidermal relief due to formation of grooves among these wilted cells. Stomatal guard cells were also structurally altered, no longer presenting the turgid aspect which was visible in the control treatment. Epidermal microrelief is characterized by the presence of cuticular striae, which might have been crucial to determine the species susceptibility due to increased roughness and decreased wettability. The implications of this hypothesis are further discussed in light of recent research addressing the responses of native tree species to acid rain. The micromorphological alterations found occurred prior to the onset of visible symptoms, and therefore suggest the use of J. princeps as a biosensor of the impact by acid precipitation.

Stigma, pollen tube transmitting tract, and epidermal micromorphology of the style of Sarracenia purpurea (Sarraceniaceae)

Entomophilous flowers of the genus Sarracenia have a unique umbrella-shaped style, which consists of a broadened and flattened umbrella canopy and a thin cylindrical umbrella stalk. Anatomical and micromorphological features of the style of Sarracenia purpurea L. were studied using light microscopy and scanning electron microscopy. This study found that the pollen tube transmitting tracts (PTTTs) start as a semi-solid canal filled with endotrophic conducting tissue, and run from the peripheral to the center of the canopy where the PTTT becomes a hollow canal supported by ectotrophic conducting tissue. The presence of stomata on the epidermis of the canopy and chloroplasts in its ground parenchyma indicate photosynthetic activities. Convex epidermal cells with intense cuticular striations on the canopy that are similar yet different from those on various regions of the sepals and petals indicate that it may provide contrasting visual cues for pollinators. Multicellular secretory glands and trichomes, which may provide olfactory cues and tactical cues respectively, are also found on the canopy. Thus, the stylar umbrella not only serves as a region for pollen grain capture, pollen germination, and pollen tube transmission but may also play an important role during pollinator–flower interactions.

FTIR spectroscopic features of the pteridosperm Ruflorinia orlandoi and host rock (Springhill Formation, Lower Cretaceous, Argentina)

Ruflorinia orlandoi (Pteridospermophyta) fronds are chemically analyzed for the first time by semi-quantitative Fourier transform infrared (FTIR) spectroscopy. This analysis allows the chemical characterization of the mesophyll and cuticle revealing the functional groups preserved in different frond parts (pinnae and rachis). The specimens collected in the Springhill Formation at the Río Correntoso locality (Lower Cretaceous, Santa Cruz province, Argentina) are compressions with very well-preserved cuticular features. The R. orlandoi remains (pinnae and rachis) are spectroscopically analyzed into two samples: compressions (Cp) and cuticles (Ct). Additionally, a third sample form from the host rock and named associated coal (V) is spectroscopically analyzed. Semi-quantitative data derived from Cp, Ct, and V spectra are evaluated by principal component analysis. The results indicate that Cp samples have a similar chemical composition whereas Ct samples show a greater variability. The latter could be related to intraspecific variability of foliar characters (e.g., trichomes and cuticular striations). Furthermore, Ct samples exhibit high contents of aromatic carbon groups suggesting a distinctive composition, likely including cutin/cutan biomacropolymers and/or phenolic compounds. Considering each specimen, the rachis shows a higher aromatic carbon content than pinnae as a consequence of the presence of more lignified tissues in the former. The V samples have the lowest relative intensity of aliphatic groups. On the other hand, the functional-group composition of R. orlandoi remains and V samples are compared with kerogen types and coal macerals showing a general chemical composition similar to type II kerogen. The latter is related to cuticles, spores, pollen grains, and resins.

Redescription of Tanqua tiara (von Linstow, 1879) Blanchard, 1904 (Nematoda: Gnathostomatidae) from Varanus flavescens (Hardwicke and Gray, 1827) (Reptilia: Varanidae) from Birbhum district, West Bengal, India.

Tanqua tiara (von Linstow, 1879) Blanchard, 1904, recovered from the stomach of water monitor lizard, Varanus flavescens (Hardwicke and Gray, 1827), collected from the Dubrajpur town, Birbhum district of West Bengal, India, is redescribed with light as well as scanning electron microscopy. This species is characterised by presence of two large lateral pseudolabia followed by massive cephalic bulb. The inner surface of each pseudolabium is folded into five rounded tooth-like formations which fit into corresponding folds on adjacent pseudolabium. Spicules are equal and similar. Gubernaculum is absent. Caudal papillae are sessile and five pairs in number. Present nematode differs from earlier descriptions of T. tiara in having five pairs of caudal papillae and an unpaired median precloacal papilla. Position of phasmids has also been reported in present study. Actual structure of cervical papillae and cuticular striations have been shown in present SEM studies which are also different from earlier descriptions. Dubrajpur is recorded as new geographical area for this parasite.

First Report of Meloidogyne graminicola (Nematoda: Meloidogynidae) on Barley (Hordeum vulgare) in Brazil

Winter barley (Hordeum vulgare L.) has become a growing addition to cereal crops in Brazil and, until recently, the root-knot nematode (Meloidogyne sp.) has not been reported to infect barley in this country. Meloidogyne graminicola is a major pathogen of rice (Oryza sativa L.) and causes significant yield losses in both upland and flooded fields in Rio Grande do Sul, Brazil (Negretti et al. 2017). In September 2017, many nematode galls were observed on the roots of barley plants (cv. BRS Brau), and samples were taken from areas in Santa Maria county (29°45′S; 53°38′W), Rio Grande do Sul State, Brazil. Meloidogyne sp. was identified using esterase phenotypes (n = 40), perineal patterns (n = 40), morphological measurements of second-stage juveniles (J2) (n = 50), and amplification and sequencing of the ITS1-5.8S-ITS2 rRNA region and the D2–D3 fragment of the 28S ribosomal RNA gene. The barley root systems were also processed to determine the number of J2s and eggs of Meloidogyne sp. The nematode population density observed in the samples was 2,585 eggs plus J2s per gram of barley root. The J2s had the following morphometric characteristics: length (L) = 458.2 ± 38.0 (390.0 to 476.0) µm, a = 26.6 ± 1.5 (24.9 to 29.4), c = 6.15 ± 0.4 (5.1 to 7.6), stylet = 14.2 ± 0.5 (13.4 to 15.0) µm, dorsal esophageal gland orifice (DGO) = 3.9 ± 0.4 (3.4 to 4.6) µm, tail length = 70.5 ± 4.7 (63.1 to 75.3) µm, and hyaline tail terminus = 19.5 ± 1.8 (14.5 to 25.5) µm. The female’s perineal patterns were oval with a low dorsal arch without a lateral line. The cuticular striations were smooth and thick in the dorsal region of the vulva, and the phasmids were close together (13.1 to 17.9 μm). These morphological characteristics matched the original description of M. graminicola (Golden and Birchfield 1968). The polymorphisms of esterase bands seen using electrophoresis revealed the phenotype VS-1 (Rm = 0.71) typical of M. graminicola. The sequence homologies were determined by comparing them with those from GenBank. PCR amplicons of D2–D3 of the 28S and ITS1-5.8S-ITS2 rRNA regions were 531 bp (GenBank MH707259) and 440 bp (MH703577), respectively. The sequences of both markers exhibited 99 and 100% identity, respectively, with sequences corresponding to M. graminicola isolates (D2–D3: MH843665 and KY660544; ITS: MH842692 and KY346887) from Brazil and China. Identification of the nematode species was confirmed by PCR using the species-specific sequence-characterized amplified region (SCAR) with primer sets GRAJ17-1F and GRAJ17-1R. PCR amplification using SCAR produced a specific fragment of the expected size (∼230 bp) in M. graminicola (Mattos et al. 2019). In greenhouse tests, barley plantlets from cv. BRS Brau that were maintained in pots with sterilized soil were inoculated with 5,000 eggs plus J2s of the original population of M. graminicola using 10 replicates; a noninoculated control was included in the test. After 60 days, the growth of all the inoculated plants was reduced compared with that of the control. Galling symptoms on the roots were similar to those in the field, with a nematode reproduction factor (final population/initial population) of 28.5. There were no galls on the roots of noninoculated plants, and plant development was not affected. The morphological and molecular characteristics of the reisolated root-knot nematode were identical to those of M. graminicola. M. graminicola has been reported on barley in India (Vaish et al. 2012). To our knowledge, this is the first report on M. graminicola parasitizing barley in Brazil. This finding is of great importance for Brazilian barley production because this nematode can severely damage barley plants and become a major problem for the cultivation of this crop.

Leaf micromorphology of the Persicaria sect. Cephalophilon (Polygonaceae) and its systematic re-evaluation

A comparative study of the leaf microstructures of 19 taxa belonging to the Persicaria sect. Cephalophilon and related four Koenigia taxa was performed by LM and SEM to evaluate their systematic significance. Both amphistomatic and hypostomatic leaves were observed in the taxa studied. The stomatal size ranged from 17.04–41.96 × 13.41–37.30 μm, and stomata on the adaxial side were larger than those on the abaxial side in general. Anomocytic stomata occurred most commonly, but more than one type of stomata was observed on the same surface. Paracytic stomata was found in both Persicaria palmata and P. criopolitana. The epidermal cells usually have straight to sinuate anticlinal cell walls (ACW), and the ACW on the abaxial side of most taxa is much more undulated than that on the adaxial side. Cuticular striation was observed in most of the studied taxa, which was restricted to only the adaxial side. Two types of crystals were observed: druse and prismatic, and seven types of trichome were recognized: five types of non-glandular trichomes (stellate with smooth surface, multiseriate with either smooth or striated surface, and uniseriate with either smooth or papillose surface), and two types of glandular trichomes (peltate and long-stalked pilate). The leaf micromorphology in this study was categorized into five types based on the stomata, epidermis, crystal and trichome, as further systematic significance of the leaf epidermal characters within the P. sect. Cephalophilon are discussed. In addition, we propose a new taxonomic combination in the P. sect. Cephalophilon.