Anatomy of the sporophyte of Anemia phyllitidis var. phyllitidis (Anemiaceae) from a riparian forest (Tucumán, Argentina)

Background and Aims: In Argentina seven species of the genus Anemia are recognized; one of them, A. phyllitidis, has two varieties. The anatomical records for A. phyllitidis var. phyllitidis are scarce and refer to the ontogeny of stomata, epidermis structure and type of petiole stele. This variety, which occurs in riparian forests, is affected by the increase of seasonal ecological pressures. There is scarce information about its sporophyte anatomy; hence, the aim of this work was to characterize it.Methods: Five specimens were collected from the margin of the El Parque stream (Tucumán-Argentina). A part was herborized and the other part was fixed in FAA. Subsequently, conventional histological techniques were used and stoma density and size of stomata and trichomes were determined. Histochemical tests were performed to detect starch (lugol) and phenolic compounds (10% ferric chloride).Key results: Anemia phyllitidis var. phyllitidis shows diarch roots and dictyostelic rhizome covered with glandular trichomes. The petiole is covered by glandular trichomes, epidermis and subepidermis composed of lignified fibers, vascular bundle with phloem surrounding xylem, two-layered pericycle surrounded by endodermis and cortical tissue with starch and phenolic compounds. Sterile pinnae have pericytic, anomocytic, and desmocytic stomata (mean size 49.8 µm × 38.7 µm); glandular trichomes; dorsoventral hypostomatic lamina, vascular bundles with pericycle and endodermis. Fertile pinnae are anatomically similar to the rachis. Silica is present in some epidermal cells of the different organs.Conclusions: The sporophyte of A. phyllitidis var. phyllitidis showed anatomical, morphological and physiological traits that reveal its adaptation to the riparian habitat where it grows. At the same time, the description of this variety is deepened and unpublished data for the genus are provided, such as the presence of stegmata in the fertile pinnae.

Tomato Protein Phosphatase 2C (SlPP2C3) influences fruit ripening onset and fruit glossiness

Abscisic acid (ABA) plays a vital role in coordinating physiological processes during fresh fruit ripening. Binding of ABA to receptors facilitates the interaction and inhibition of type 2C phosphatase (PP2C) co-receptors. However, the exact mechanism of PP2C during fruit ripening is unclear. In this study, we determined the role of tomato ABA co-receptor type 2C phosphatase SlPP2C3, a negative regulator of ABA signalling and fruit ripening. SlPP2C3 selectively interacted with monomeric ABA receptors and SlSnRK2.8 kinase in both yeast and tobacco epidermal cells. Expression of SlPP2C3 was ABA-inducible, which was negatively correlated with fruit ripening. Tomato plants with suppressed SlPP2C3 expression exhibited enhanced sensitivity to ABA, while plants over-expressing SlPP2C3 were less sensitive to ABA. Importantly, lack of SlPP2C3 expression accelerated fruit ripening onset and affected fruit glossiness by altering the outer epidermis structure. There was a significant difference in expression of cuticle-related genes in pericarp between wild-type and SlPP2C3 suppressed lines based on RNA sequencing (RNA-seq) analysis. Taken together, our findings demonstrate that SlPP2C3 plays an important role in the regulation of fruit ripening and fruit glossiness in tomato.

Study on Leaf Epidermis Structure and Dust-Retention Ability of Five Machilus Species

Taking the leaves of five Machilus species as a research object, they are Machilus oreophila, Machilus chinensis, Machilus microcarpa, Machilus lichuanensis and Machilus suaveolens. By measuring leaf surface area, cell length and width , the total dust retention, pH value of retention fluid and the content of Pb, Cr, Fe, Cu and Cd of metallic elements were measured, and compare the dust retention of five plant seedling leaves ability. The results showed that: the leaves of different kinds of Machilus have different dust abilities. Comprehensive analysis can be obtained from five kinds of Machilus dust ability in descending order of M. suaveolens > M. lichuanensis > M. chinensis > M. microcarpa > M. oreophila. ********* In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 4, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue. *********

MICROMORPHOLOGICAL ANALYSIS OF THE AERIAN ORGANES OF MARRUBIUM ALYSSON L. FROM FLORA OF TUNISIA

The micromorphological investigations ofMarrubium alysson L.growing on the territory of the Tunisian Republic have been conducted.The aimof the study was to conduct comparative ecological and morphological researches ofMarrubium alyssonaerian parts, to study an anatomical structure of caulifoliary system elements including stems, petioles, leaf margins a structure of the epidermis.Materials and methods.As an object of the research, dried-up herb and herbarium specimens ofMarrubium alysson L., growing on the territory of the Tunisian Republic, were used. The micromorphological investigations were conducted by morphological and histochemical methods.Results and discussion.Comparative ecological and morphological researches have been conducted. The anatomic structure of the elements of the caulifoliary system including stems, petioles, leaf margins has been studied. The anatomic structure of the epidermis has been studied, too. The diacytic type of the stomatal apparatus, numerous branched trichomes with multicellular basis, located both on top and lower leaf parts have been found out. The conducted researches are a fragment of complex researches of perspective raw plants of Tunisian flora.Conclusion. Comparative eсological and micromorphological researches have been conducted, the anatomic structure of the stems, petioles, leaf margins, and also the epidermis structure of top and lower leaf parts has been also carried out. The diacytic type of the stomatal apparatus, trichomes with multicellular basis located both on top and lower leaf parts have been found out. The collenchyme is located in the subepidermal zone of a stem, petioles and in the zone of the central vein of a limb. The revealed signs can be included into product specification files on herbal raw materials

Epidermis structure in the brook trout (Salvelinus fontinalis) and its Arctic char (Salvelinus alpinus) hybrid

Brook trout (Salvelinus fontinalis) is a species of fish native to North-East America. Brook trout are also commercially raised in large numbers for food production. Skin infection and/or parasite outbreaks can have a serious economics effect on aquaculture businesses. For this reason, it has been hybridized with the more resistant Arctic char (Salvelinus alpinus). The aim of this study was an examination of the epidermal structure and dynamic in brook trout and its Arctic char hybrid which is less sensitive to skin infection. The samples of fish (72 brook trout, 72 brook trout × Arctic char hybrid) from fish farm in Pravíkov (49°19’10”N, 15°5’40”E) were collected five times during the year 2011. Absolute and relative epidermal thickness (in relation to body size) and relative proportion of secretory cells in a given volume of epidermis were measured. The epidermis structure of brook trout and brook trout × Arctic char hybrid both display similar seasonal dynamics, with a decrease in absolute and relative epidermal thickness and a reduction in the relative percentage of mucous secretory cells over the summer. On the other hand, the lower absolute (mean 103 µm (range 84–146 µm) in brook trout; 88 µm (range 68–115 µm) in hybrids) and relative epidermal thickness (mean 4.8 (range 3.6–6.8) in brook trout; 4.4 (range 2.9–6.4) in hybrids) and lower volume of secretory cells was observed to the hybrid (mean 28% (range 19–33%) in brook trout; 23% (range 10–30%) in hybrids). It can interrelate with their higher resistance to infection and/or parasite outbreaks.

Epidermis architecture and material properties of the skin of four snake species

On the basis of structural and experimental data, it was previously demonstrated that the snake integument consists of a hard, robust, inflexible outer surface ( Oberhäutchen and β-layer) and softer, flexible inner layers (α-layers). It is not clear whether this phenomenon is a general adaptation of snakes to limbless locomotion or only to specific conditions, such as habitat and locomotion. The aim of the present study was to compare the structure and material properties of the outer scale layers (OSLs) and inner scale layers (ISLs) of the exuvium epidermis in four snake species specialized to live in different habitats: Lampropeltis getula californiae (terrestrial), Epicrates cenchria cenchria (generalist), Morelia viridis (arboreal) and Gongylophis colubrinus (sand-burrowing). Scanning electron microscopy (SEM) of skin cross sections revealed a strong variation in the epidermis structure between species. The nanoindentation experiments clearly demonstrated a gradient of material properties along the epidermis in the integument of all the species studied. The presence of such a gradient is a possible adaptation to locomotion and wear minimization on natural substrates. In general, the difference in both the effective elastic modulus and hardness of the OSL and ISL between species was not large compared with the difference in epidermis thickness and architecture.