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During a survey of marine biodiversity in the deep sea off northeastern Guam, two marine desmoscolecid nematodes belonging to the subgenus Tricoma were discovered. Tricoma (Tricoma) disparseta sp. nov. was described based on specimens collected from sponge and starfish habitats on a seamount at depths ranging from 1300 to 1500 m. Tricoma (Tricoma) disparseta sp. nov. is distinguished by having 59 to 62 main rings, 9 to 10 subdorsal setae, and 14 to 18 subventral setae on each side. Notable features include the differentiation in length and insertion between the subdorsal and subventral setae, as well as the amphid extending to the second or third main ring. Additionally, the spicules have a relatively small capitulum at the proximal end, while the gubernaculum is bent into a hooked shape. The specimen of T. (T.) longirostris observed in this study closely resembles previously reported specimens, characterized by 78 main rings, a long and narrow head shape, eight to nine subdorsal setae, 14 to 15 subventral setae, and a gubernaculum with a knobbed apophysis. Two Tricoma species from the Northwest Pacific Ocean are described in detail, and pictorial keys and comparative tables for species identification are provided for groups with 50 to 64 main rings.

Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) Mediterranean (Q biotype) is a major pest of tomato (Solanum lycopersicum L.; Solanaceae) globally. To our knowledge, no whitefly resistant cultivar has been released commercially, and breeding programs are hampered by the lack of resistance sources to this insect which are related closely to the cultivated tomato. Two non-free-choice experiments on B. tabaci with 22 landrace (S. lycopersicum) and wild tomato (S. lycopersicum var. ‘cerasiforme') populations from Mexico were performed to find sources of antibiosis resistance to this insect. Plants were infested with 20 insects per 1 leaflet of each plant using plastic micro-cages. In both assays, the number of adults and eggs were counted at 4 d post infestation, the number of nymphs (12 d post infestation), new adults, and non-glandular trichomes at 28 d post infestation. The highest B. tabaci resistance was detected in the UTC-SV13 population followed by UTC-SV12, UTC-SV1, and UTC-SV3 with a range of 15.0 to 20.0 dead adults, 0.0 to 16.5 eggs, 0.0 to 12.6 nymphs, 0.0 to 9.7 new adults per leaflet, and with a reproduction index of 0.0 to 21.7. Ten populations showed an intermediate level of resistance significantly lower in the number of dead adults, eggs, nymphs, new adults, and reproduction index compared to the commercial cultivar (‘Bonny Best') used as the standard. The remaining 8 genotypes and the commercial cultivar were fully susceptible to B. tabaci. The number of non-glandular trichomes correlated significantly with the number of eggs, nymphs, and new adults emerging from the infested plants, suggesting that the density of non-glandular trichomes is favorable for whitefly reproduction. Those genotypes with moderate to high levels of resistance to B. tabaci are potential candidates for developing commercial tomato cultivars with some resistance levels to this insect.

BackgroundGomphrena perennis (Gpe) and G. pulchella (Gpu) are perennial glyphosate-tolerant amaranthaceous weeds of central and northern Argentina where glyphosate-resistant soybeans are grown with no-till. The study of weeds leaves morphoanatomy is important to understand environmental adaptation and could be used to explain herbicide absorption. Leaf surfaces of Gomphrena species were previously described for phylogenetic studies, and morphoanatomy of two Gomphrena perennis populations was characterized for glyphosate tolerance. There are no reports on comparative studies of Gpe and Gpu. We hypothesize that these two species differ in their morpho anatomical characteristics.ObjectiveThe aim of this research was to characterize and compare their leaf morphoanatomy throughout their life cycle.MethodsFully developed leaves of the upper middle third were extracted from plants grown in pots in a greenhouse at three phenological stages: eight true leaves (S1), beginning of branching (S2), and full flowering (S3). In both leaf sides, densities of epidermal cells, stomata and trichomes, and ostiole lengths were quantified. In main and secondary bundle anatomic parameters were measured: thickness of total blade, upper and lower epidermis, and mesophyll, and sheath length.ResultsBoth species are amphiestomatic. Gpu had higher stomata densities in lower epidermis than Gpe at S1. Gpu had higher trichome densities than Gpe, whereas the latter presented higher values in anatomic variables mainly in secondary bundle (total blade and total mesophyll) at all stages.ConclusionsThere were no marked differences in the morphoanatomy between the two species throughout their life cycle.

Sourgrass(Digitaria insularis, L. Mez ex Ekman)is a weed that requires high rates of glyphosate ((N-[phosphonomethyl]-glycine) forcontrol, verylittle of the herbicide applied isabsorbed by theleaves. Morphological and histological differences in leaves of glyphosate-resistant and glyphosate-susceptible plantsshould explain the contrast of variance between herbicide susceptibility. Leaves of different growth andphenological stages were collected and submitted to histological andelectron microscopy scanning analysis. Those plants were also submitted to a glyphosate dose-response curve analysis. The results suggest thatbiotypes exhibits differences infoliar structures that can influence the uptake and translocation of glyphosate. A thinparenchyma, lesser distance amongvascular bundles, and higher phloem sizewere found in resistant biotypes (differences close to 10%). Minor stomata number and higher epicuticular waxy deposition in stomata and leaf surface were found in resistant plants when leaves came from regrowth, leading to a possiblelesser herbicide absorption. Resistant plants showed absence of trichomes in late stages of development (64% less trichomes than susceptible plants). The higher concentration of trichomes in susceptible plants can be an absorption pathfor glyphosate getthrough the cuticle.

This paper reports two newly discovered species of Tricoma (Tricoma)—T. (T.) discrepans sp. nov. and T. (T.) parasetosa sp. nov.—obtained from the subtidal sediments at a depth of 13 m around Jindo Island, Korea. Tricoma (T.) discrepans sp. nov. differs from its congeners in possessing 40–41 main rings, an uncovered first main ring, large vesicular amphidial fovea, and a distinctly thickened tail cuticle that is densely covered with secretions and adhering particles. Somatic setae in males exhibit pronounced sexual dimorphism, with the subventral setae more than twice as thick as the subdorsal setae, a morphological feature documented here for the first time within the subgenus Tricoma (Tricoma). Tricoma (T.) parasetosa sp. nov. can be recognized by 31 (rarely 32) main rings, two pairs of long, thick posterior somatic setae inserted on massive peduncles, a vesicular amphidial fovea extending to the second main ring, and a gubernaculum proximal end gently curved ventrally. Although the labial region is indistinct, the species bears two conspicuous lateral labial projections and a prominent cephalic concretion. Together, these results broaden the current understanding of Tricoma diversity in the northwestern Pacific and emphasize additional morphological variation within Desmoscolecida based on detailed Differential Interference Contrast (DIC) and Scanning Electron Microscope (SEM) analyses.

This study provides a taxonomic analysis of three newly discovered species of free-living marine nematodes in the subgenus Tricoma from the East Sea, Korea. Tricoma (Tricoma) polyringulata sp. nov. is characterized by its relatively small body size, with lengths of 280–370 µm in males and 320–390 µm in females, and 75–89 main rings. Diagnostic features include an uncovered first ring, triangular head shape, amphidial fovea with slight constriction, and a unique pattern of somatic setae, comprising 7–9 subdorsal and 8–12 subventral setae. Tricoma (Tricoma) fortiseta sp. nov. is distinguished by 65–69 main rings, 10–12 subdorsal setae, and 17–20 subventral setae, along with a hexagonal head, a well-defined labial region with six lips, and bifid-tipped cephalic setae located medially on the head. Tricoma (Tricoma) uljinensis sp. nov. exhibits 67–70 main rings, with a thick, sclerotized head that is 1.5 times as wide as its length, gently triangular in shape. Its diagnostic features include a gubernaculum bent downward near its midpoint and a conical terminal ring, with 25–39% of the desmos covered. Detailed morphological descriptions of each species are provided, along with a comparative table of morphological traits for species with 61–75 main rings and an illustrated key for identification.

La gran mayoría de las especies de Bacopa (Gratioleae-Plantaginaceae) son plantas macrófitas que presentan una serie de adaptaciones morfológicas, anatómicas y ecofisiológicas en sus órganos vegetativos. Se estudió la anatomía vegetativa de cinco especies de Bacopa presentes en el Iberá y una de humedales del Paraguay. Para el estudio de la anatomía foliar y caulinar se realizaron cortes paradermales y transversales a mano alzada y con micrótomo rotativo a partir de material previamente fijado. Se encontraron diferencias entre las 6 especies de Bacopa analizadas, en la hoja relacionadas a: tipos de tricomas; tipos, distribución y densidad de estomas; y en el tipo de mesofilo. Para el tallo, se caracterizaron dos patrones de aerénquima cortical que se relacionan con los ambientes que habitan las especies y sus adaptaciones al mismo. A modo de conclusión se elaboró una clave dicotómica con caracteres anatómicos vegetativos de las especies de Bacopa que crecen en los humedales. Most Bacopa species (Gratioleae-Plantaginaceae) are macrophyte plants with a series of morphological, anatomical, and eco-physiological adaptations in their vegetative organs. We studied the vegetative anatomy of five Bacopa species present in the Iberá Macrosystem, and one species of Paraguay wetland. To study leaf and cauline anatomy, paradermal and transverse sections were made with freehand and rotating microtome from previously fixed material. The anatomical studies showed differences between the Bacopa species analyzed concerning the leaf: types of trichomes; types, distribution, and the density of stomata; and mesophyll type. In terms of the stem, two patterns of cortical aerenchyma were characterized, which are related to the environments inhabited by the species and their adaptations. As a conclusion, a dichotomous key was elaborated with vegetative anatomical characters of the Bacopa species that grow in wetlands.

El macrosistema Iberá presenta diversos tipos de vegetación, donde además de las acuáticas y palustres hay bosques hidrófilos, sabanas con predominio de gramíneas y praderas con especies arbustivas intercaladas entre las herbáceas. Estudios previos de anatomía foliar solo fueron realizados en plantas acuáticas y palustres. En este trabajo se estudió la anatomía foliar en especies predominantes o frecuentes que crecen en pastizales y bosques del macrosistema Iberá, con el objetivo de detectar caracteres estructurales de las hojas que puedan representar valor adaptativo a estos ambientes. Se analizaron hojas de 42 especies correspondientes a 26 familias, con microscopía óptica y electrónica de barrido. Se realizó un análisis estadístico en base a una matriz de datos, compuesta por los caracteres anatómicos y el ambiente en que crecen las especies estudiadas. Los caracteres analizados de la epidermis fueron: diseño de la cutícula, estomas, tricomas, diseño de células epidérmicas de ambas epidermis, donde se observa un predominio de idéntica morfología en ambas caras. En el mesofilo se evaluó su tipo, presencia y forma de cristales de calcio e inulina, y distribución de estructuras glandulares como laticíferos, cavidades y células secretoras. Los datos reportados son discutidos en relación a la bibliografía disponible. El análisis de agrupamiento (UPGMA) muestra que las especies que habitan en los mismos ambientes no presentan características anatómicas similares.

Morphological features of flowers and inflorescences from 13 of 14 species of subtribe Leiboldiinae are analyzed, with the goal of identifying characters with taxonomic value for the delimitation of genera and species. The principal characters to recognize genera in the subtribe are: presence of palaea on the receptacle (Bolanosa), number of series in the involucre and pappus (Stramentopappus), shape of the apices of the phyllaries (Lepidonia), and colour and duration of the pappus. At the specific level, the more important characters are diversity and distribution of trichomes, colour of florets and differences in the sculpturing of the surfaces of the petals. Se analizaron las principales características morfológicas de las flores e inflorescencias de 13 de las 14 especies de la subtribu Leiboldiinae, con el objetivo de identificar caracteres con valor taxonómico en la delimitación genérica y específica. Entre los caracteres que permiten reconocer géneros en la subtribu destacan la presencia de páleas en el receptáculo (Bolanosa), número de series del involucro y el vilano (Stramentopappus), forma del ápice de los filarios (Lepidonia), color y duración del vilano. A nivel específico los caracteres más importantes son la diversidad y disposición de tricomas, color de las flores y las diferencias en la escultura de la superficie de los pétalos.