Spongy Cells Research Articles

Biosystematic studies of genus Withania Pauquy in Egypt

Withania (Solanaceae, Solanoideae) is a widespread genus. Comparative macro-, micro-morphological, anatomical, and molecular features of this genus in Egypt were examined using light and scanning electron microscopy to reassess the conflicted taxonomic relationships between the two studied species. The most significant morphological differences that have been found were: the shape of the lamina, apex, anther, and stigma, and the ratio of calyx tube/lobe; anatomical examination of taxonomic interest are as follows: number of vascular bundles, presence of ears and distribution of accessory vascular bundles in petiole and shape of spongy cells, and number of lower parenchyma in the midrib region of the leaf; trichomes of both species showed no significant differences; pollen, and seed characters are of taxonomic significance in differentiation and characterization between them. Protein profiling revealed that W. somnifera has only conserved proteins, while W. obtusifolia possessed both conserved and additional proteins in their SDS-PAGE banding patterns. Eleven starts codon-targeted (ScoT) primers were applied and produced 96 amplicons with an average of 70.83% polymorphism/primer. W. obtusifolia generated more polymorphic bands and maintained monomorphic ones. SDS-PAGE disclosed that both Withania species were 50% related. While Scot-Dendrogram revealed that both Withania species were poorly related. So, protein and molecular analyses showed considerable genetic variations between these two species.

STUDY ON ANATOMICAL CHARACTERIZATIONOF RHINACANTHUS NASUTUS (L.) KURZ

Rhinacanthus nasutus (L.) Kurz, belonging to the family Acanthaceae, is an herbaceous shrub. This plant holds significant value in traditional medicine. The leaves of R. nasutus are commercially available as tea bags, marketed as a natural remedy for various ailments. However, the conservation status of R. nasutus necessitates appropriate protective measures to ensure its sustainability. Anatomical studies provide various histological layers, including the epidermis, cortex, vascular bundles, and pith. The leaves feature numerous diacytic stomata and hypostomatic nature. The leaf midrib exhibits a narrow epidermis with numerous glandular hairs. The medulla contains arc-shaped vascular bundles and lateral accessory bundles, with the stele comprising linear xylem elements towards the inner side and phloem elements on the outer region. Transfusion tracheids are present between the palisade and spongy cells, with tissues containing large quantities of oil droplets. The petiole shows a narrow epidermis with numerous glandular hairs. The vascular region features a V-shaped stele. The stem reveals the stelar region is extensive and the inner region is rich in developed xylem elements with linear multiple vessels. The medullary ray cells are narrow, and the pith region displays intruded primary xylem with thick-walled parenchyma cells. Wood anatomical analysis shows xylem parenchyma cells that are paratracheal. The vessel elements possessing perforation plates and transverse walls with bordered pits. Tracheids have a narrow lumen, and the lateral walls contain simple pits. The wood demonstrates multiseriate ray parenchyma and the bark consists of phloem rays and narrow fibers. In conclusion, R. nasutus exhibits a variety of histological and anatomical characteristics that support its traditional medicinal uses. The detailed anatomical studies contribute to understanding the plants structural adaptations and potential environmental interactions, thereby facilitating its identification and utilization in herbal medicine. The conservation of this species is critical to preserving its medicinal value and ensuring its availability for future research and therapeutic applications.

Assessment of the changes in growth, photosynthetic traits and gene expression in Cynodon dactylon against drought stress

Drought stress considered a key restrictive factor for a warm-season bermudagrass growth during summers in China. Genotypic variation against drought stress exists among bermudagrass (Cynodon sp.), but the selection of highly drought-tolerant germplasm is important for its growth in limited water regions and for future breeding. Our study aimed to investigate the most tolerant bermudagrass germplasm among thirteen, along latitude and longitudinal gradient under a well-watered and drought stress condition. Current study included high drought-resistant germplasm, “Tianshui” and “Linxiang”, and drought-sensitive cultivars; “Zhengzhou” and “Cixian” under drought treatments along longitude and latitudinal gradients, respectively. Under water deficit conditions, the tolerant genotypes showed over-expression of a dehydrin gene cdDHN4, antioxidant genes Cu/ZnSOD and APX which leads to higher antioxidant activities to scavenge the excessive reactive oxygen species and minimizing the membrane damage. It helps in maintenance of cell membrane permeability and osmotic adjustment by producing organic osmolytes. Proline an osmolyte has the ability to keep osmotic water potential and water use efficiency high via stomatal conductance and maintain transpiration rate. It leads to optimum CO2 assimilation rate, high chlorophyll contents for photosynthesis and elongation of leaf mesophyll, palisade and thick spongy cells. Consequently, it results in elongation of leaf length, stolon and internode length; plant height and deep rooting system. The CdDHN4 gene highly expressed in “Tianshui” and “Youxian”, Cu/ZnSOD gene in “Tianshui” and “Linxiang” and APX gene in “Shanxian” and “Linxiang”. The genotypes “Zhongshan” and “Xiaochang” showed no gene expression under water deficit conditions. Our results indicate that turfgrass show morphological modifications firstly when subjected to drought stress; however the gene expression is directly associated and crucial for drought tolerance in bermudagrass. Hence, current research has provided excellent germplasm of drought tolerant bermudagrass for physiological and molecular study and future breeding.

Pharmacognostic study and sedative activity of Bryophyllum pinnatum stem methanol extract and fractions

Insomnia is known as sleep insufficiency and is considered a capital public health concern. Bryophyllum pinnatum which belongs to the family Grassulaceae is used in folkloric medicine to treat various kind of ailment. The aim of the study was to undertake a pharmacognostic study of the stem and determine the sedative/hypnotic ability of the methanol extract and fraction of the stem. The physicochemical analysis indicated moisture content (12.68%), total ash (3.75%), acid insoluble ash (2.60%), water soluble ash (2.00%), water soluble extractive (6.02%) and alcohol soluble extractive (10.80%). The organoleptic evaluation of the powdered leaves revealed an odorless, green plant with bitter taste. The microscopic analysis of the leaf revealed palisade cell, spongy cell, stoma, collenchyma, xylem tissue, phloem tissue. The transverse section of the stem revealed epidermis, endodermis, xylem and cortex. The acute toxicity result revealed that Picralima nitida had no adverse effect in Wistar mice. The result showed that ethyl acetate fraction had sedative/hypnotic ability, affected the level of liver enzymes (ALT, AST, ALP), improved kidney function, and insignificantly increased body weight of mice. This study demonstrated that B. pinnatum could be an alternative medicine in pharmacological treatment of insomnia.

Cross-sectioning to the core of conifers: pith anatomy of living Araucariaceae and Podocarpaceae, with comparisons to fossil pith

Summary Pith in woody species fulfills essential roles, from functioning as the first vascular tissue in shoots, to serving as starch storage and facilitating heartwood formation. While the spongy cells of pith may die and be reabsorbed at maturity by some species, the pith persists throughout the lifespan of conifer trees. Pith features and functions of extant conifers have been documented in contemporary studies, and pith anatomy has been described for extinct progymnosperms and coniferous ancestors through fossils. However, up to now, few studies have described the wood anatomy of pith in living conifers and covered only 24 species in four families. Here we describe the pith of 7 genera and 16 species from the previously unstudied conifer families of Araucariaceae and Podocarpaceae, based on stained and unstained cross-sections. Comparisons between pith sections of the same tree in successive years yielded insights into maturation of the conifer pith. Conservative pith characteristics were identified among genera and families. Araucariaceae pith is dissimilar on a familial level, but the genus Araucaria is unified by pith shape and heterocellularity. In contrast, all Podocarpaceae piths develop secondary cracks, and most species have irregularly shaped piths. Beyond our study of similarities and differences of pith in Araucariaceae and Podocarpaceae, a look at pith patterns in the paleobotanical record and further examples in living conifers could increase the understanding of conserved characteristics and pith evolution.

Anatomical profiles validate gall morphospecies under similar morphotypes.

Plant galls are generated by the stimuli of gall-inducing organisms on their hosts, creating gall morphotypes that vary in color, shape, size, and tissue organization. Herein, we propose to compare the structural features of gall morphotypes on the superhost Croton floribundus (Euphorbiaceae) in order to recognize gall morphospecies, i.e., galls with similar shapes but different internal structures. Non-galled leaves and galls were analyzed macroscopically, histologically, and histochemically for the detection of primary metabolites, and the results obtained were used for statistical analyses of similarity. Among the eight gall morphospecies, four are globoid, two are lenticular, one is fusiform and one is marginal leaf rolling. Stomatal differentiation and the occurrence of different types of trichomes were impaired in some gall morphospecies. Three patterns of organization of the ground system are recognized, ranging from the maintenance of mesophyll cells that differentiate into palisade and spongy cells dorsiventrally to the formation of a complex cortex with three morphofunctional layers. The marginal leaf rolling galls have the simplest anatomical structures, quite similar to those of the non-galled host leaf, while lenticular, globoid (types I to IV), and fusiform galls are anatomically more complex. Herein, we report on eight gall morphospecies occurring on C. floribundus, which are distinguished by morpho-anatomical attributes and show the disruption of the morphogenetic patterns of the host leaf toward the morphogenesis of unique gall features.

Study Of Some Anatomical Features Of Stevia Rebaudiana (Bertoni) Bertoni Grown In Iraq

The leaves of Stevia rebaudiana, from Asteraceae family, are a source of steviol glycosides, which are utilized as a sweeter, more favorite addition. Among the most important anatomical results that were reached through the research and which distinguish the plant from an anatomical point of view are uniseriate-multicellular of non-glandular trichomes that are covered the epidermis of stem and leaves. Also, the vertical walls of the ordinary epidermis cells in the upper and lower epidermis that are heavily sinuous and the stomata scattered in both of it, the type of the stomata anomocytic. In addition, the mesophyll which differentiated into 2-3 layers of palisade cells under the upper epidermis and the spongy cells after it and the cross-section of midrib region of the leaf as crescent shape and the vascular bundle central, crescent shape.

Leaf Anatomical Traits of Lianas and Trees at the Canopy of Two Contrasting Lowland Tropical Forests in the Context of Leaf Economic Spectrum

The leaf economic spectrum describes a comprehensive framework of how the surrounding environment modulates leaf functional traits (LFT) and how these are associated between them. This framework has traditionally focused on physiological, chemical, and biomass assignation traits, but rarely in leaf anatomical traits. Here we compare leaf anatomical metrics and traits of 40 liana and tree species from two lowland tropical forests in Panama with contrasting rainfall regimes: Parque Natural Metropolitano (dry-forest) and Parque Nacional San Lorenzo (wet-forest). Then we evaluate how anatomical traits are associated with well-established LFTs. Anatomical metrics were collected from leaf cross-section images estimating the area, thickness, cell count, and size of the upper and lower epidermis and palisade and spongy mesophyll. Ratios between metrics were performed as potential anatomical traits to reduce the leaf size effect between species. Our results suggest that anatomical changes between life forms are associated with increases in the palisade area and thickness of trees in comparison with lianas, while anatomical changes between forest type species are related to increases in the spongy area and thickness of wet-forest species than dry-forest. These differences could be associated with the high photosynthetic rates of trees or the need to enhance the gas exchange in humid environments. Our results also suggest that anatomical traits are related to well-established LFT; however, the degree of association between them may depend on the life forms and forest type. For example, our results suggest that reductions in the palisade and spongy cell density are associated with increases in leaf mass area and maximum photosynthetic capacity, but this association was not observed when we compared life forms or forest types. The use of leaf anatomical information may facilitate to describe the mechanism that drives the leaf economy, improving our understanding of the resource allocation strategies embedded in functional groups.

Single-cell RNA-seq describes the transcriptome landscape and identifies critical transcription factors in the leaf blade of the allotetraploid peanut (Arachis hypogaea L.).

SummarySingle‐cell RNA‐seq (scRNA‐seq) has been highlighted as a powerful tool for the description of human cell transcriptome, but the technology has not been broadly applied in plant cells. Herein, we describe the successful development of a robust protoplast cell isolation system in the peanut leaf. A total of 6,815 single cells were divided into eight cell clusters based on reported marker genes by applying scRNA‐seq. Further, a pseudo‐time analysis was used to describe the developmental trajectory and interaction network of transcription factors (TFs) of distinct cell types during leaf growth. The trajectory enabled re‐investigation of the primordium‐driven development processes of the mesophyll and epidermis. These results suggest that palisade cells likely differentiate into spongy cells, while the epidermal cells originated earlier than the primordium. Subsequently, the developed method integrated multiple technologies to efficiently validate the scRNA‐seq result in a homogenous cell population. The expression levels of several TFs were strongly correlated with epidermal ontogeny in accordance with obtained scRNA‐seq values. Additionally, peanut AHL23 (AT‐HOOK MOTIF NUCLEAR LOCALIZED PROTEIN 23), which is localized in nucleus, promoted leaf growth when ectopically expressed in Arabidopsis by modulating the phytohormone pathway. Together, our study displays that application of scRNA‐seq can provide new hypotheses regarding cell differentiation in the leaf blade of Arachis hypogaea. We believe that this approach will enable significant advances in the functional study of leaf blade cells in the allotetraploid peanut and other plant species.

Partial disintegration of vegetable cell wall during cooking improves vitamin K1 (phylloquinone) bioaccessibility in in vitro digestion.

Vegetables rich in vitamin K consumption could prevent bleeding and maintain bone status. The aims of the present work were to investigate i) the effect of household cooking (i.e., boiling for 5minat 100°C in distilled water and stir-frying for 3minat 180°C in hot canola oil) on phylloquinone bioaccessibility of five rich phylloquinone leafy vegetables, namely Water spinach (Ipomoea aquatic Forssk), Amaranth (Amaranthus blitum subsp. oleraceus L.), Chinese broccoli (Brassica alboglabra), Pak choi (Brassica rapa L.) and Drumstick (Moringa oleifera Lam.), and ii) the structural changes of these leaves before and after in vitro gastro-intestinal digestion. All the experiments were realized in triplicate for each vegetable. The amounts of phylloquinone in leafy vegetables were noticeable in almost all species and ranged from 94 to 182μg/100g DM. Their cell wall polysaccharide contents greatly varied from 4.3 to 8.4g for 100g. The content in bioaccessible phylloquinone was low in raw leaves (<25μg/100g DM) as well as its bioaccessibility (<15%). Leaf pectin content impaired phylloquinone bioaccessibility using principal component analysis. Boiling and stir-frying significantly improved the bioaccessibility of phylloquinone in leaves by a factor of three to twelve and two to seven respectively (p<0.05). These variations were associated with changes in leaf structure. Palisade and spongy cells appeared ruptured and disorganized after stir-frying. Given the estimated bioaccessibility of phylloquinones, the consumption of 500g of cooked wet leaves per day would cover phylloquinone needs of an individual adult average body weight.

Design and analysis of four-jaws microgripper with integrated thermal actuator and force sensor for biomedical applications.

This research paper presents design and analysis of the multi-jaw microgripper that can manipulate microbiological organisms and species, cell probing and measurement, biomedical sample sorting, and preparation. Four jaws, actuated with a single thermal chevron actuator, can grip microbiological species ranging from 300 to 700 μm, 1 to 340 μm, 100 μm pool, and 1 to 120 μm spongy cells, respectively. Jaws are designed in such a way that they can grip regular, irregular, and spongy shaped biological species and their organelles. Parametric analysis of the microgripper exhibited that at 10V, the efficiency of the thermal actuator is at maximum with respect to displacement, force, and temperature. To enhance displacement to voltage ratio and increase the energy efficiency, a class 3 lever mechanism has been incorporated. The amplification factors at four jaws are 17.21, 13.82, 4.02, and 4.93, respectively. For controlled application of the force to microspecies, two electrostatic force sensors have been amalgamated with jaws having capacitive sensitivities of 1.59 nf/μm, 1.91 nf/μm, 17 nf/μm, and 14.5 nf/μm, respectively. Electrothermal, static, and electrostatic analyses have been carried out with the finite element methods based software IntelliSuite®. Stress magnitudes are within the limits of structural integrity of silicon having a factor of safety 2.5. Thermal analysis revealed that at a differential voltage of 10V, the maximum temperature goes up to 425 °C. Buckling analysis results depicted that the critical load for the thermal actuator is 241 μN with the buckling load factor greater than unity. This paper focuses on microbiological applications only; however, the designed microgripper can be used to manipulate micro-objects, microstructures, microelectronics parts, and micro assembly.

Comparison of petiole anatomy in Flemingia and its potential for delimitation of species

Socio-economically, different species of Flemingia are used worldwide for various purposes like food, folk medicine to cure various ailments, as a source of non-timber products (e.g., resin, dye, host for lac insect, toothbrush, etc.). Therefore, species level identification is important even in the absence of reproductive structures as it will help to avoid adulteration. In this context, petiole anatomy may be effectively employed since it is considered to be one of the diagnostic characters for the discrimination of taxa at species level. Thus, in the present study, petiole anatomy of 16 species of Flemingia is investigated to find additional diagnostic features for species level identification. Amongst these 16 species, 13 had trifoliolate leaves whereas three, F. strobilifera, F. chappar and F. paniculata possessed unifoliolate leaves. The petiole was winged except for F. chappar and F. vestita. The wings were much larger in F. nana, F. paraecox and F. sootepensis while in F. paniculata, F. strobilifera and F. wightiana they were just a small outgrowth/projection. The number of vascular bundles in wings varied from 1 to 5. The cortex was composed of palisade and spongy cells which were restricted to the wing region of F. praecox and F. sootepensis. Cortical fibres formed a cap like structure external to the vascular bundle in F. angustifolia, F. nana, F. procumbens, F. sootepensis, F. strobilifera and F. vestita whereas a complete ring was formed in the remaining species. Besides these features, outline of the stem and presence or absence of wing on the dorsal side of the petiole is another important character of taxonomic value. Histological structure and the composition of the petiole of all the species is described in detail and discussed in relation to its diagnostic significance.

Anatomical variation of mesophyll conductance due to salt stress in Populus cathayana females and males growing under different inorganic nitrogen sources.

Synergistic regulation in leaf architecture and photosynthesis is essential for salt tolerance. However, how plant sex and inorganic nitrogen sources alter salt stress-dependent photosynthesis remains unknown. Leaf anatomical characteristics and photosynthesis of Populus cathayana Rehder females and males were investigated under salt stress conditions combined with nitrate NO3- and ammonium NH4+ supplies to clarify the underlying mechanisms. In salt-stressed females, we observed an increased mesophyll spongy cell density, a reduced chloroplast density, a decreased surface area of chloroplasts adjacent to the intercellular air space (Sc/S) and an increased mesophyll cell area per transverse section width (S/W), consequently causing mesophyll conductance (gm) and photosynthesis inhibition, especially under NH4+ supply. Conversely, males with a greater mesophyll palisade tissue thickness and chloroplast density, but a lower spongy cell density had lower S/W and higher Sc/S, and higher gm and photosynthesis. NH4+-fed females had a lower CO2 conductance through cell wall and stromal conductance perpendicular to the cell wall, but a higher chloroplast conductance from the cell wall (gcyt1) than females supplied with NO3-, whereas males had a higher chloroplast conductance and lower CO2 conductance through cell wall when supplied with NO3- instead of NH4+ under salt stress. These findings indicate sex-specific strategies in coping with salt stress related to leaf anatomy and gm under both types of nitrogen supplies, which may contribute to sex-specific CO2 capture and niche segregation.

Macroscopic-microscopic characteristics and AFLP fingerprint for identification of Erythroxylum novogranatense, E. cambodianum and E. cuneatum endemic to Thailand

Erythroxylum novogranatense (Morris) Hieron, E. cambodianum Pierre and E. cuneatum (Miq.) Kurz in family Erythroxylaceae was traditionally used as an antipyretic, general stimulant and gastrointestinal diseases. Due to their morphological similarity, the correct identification was necessary for the quality control in herbal medicine. E. novogranatense (Morris) Hieron, E. cambodianum Pierre and E. cuneatum (Miq.) Macroscopic and microscopic characteristics evaluated Kurz endemic to Thailand according to WHO standard guideline and amplified fragment length polymorphism (AFLP) fingerprint. Morphological characters of E. novogranatense, E. cambodianum and E. cuneatum were similar in their flower, fruit and seed but different in stem and leaf. Microscopic characteristics from these three species, including constant leaf numbers, showed individual values. The stomata were classified as paracytic type. The midrib transverse section showed distinct characters of the epidermis, palisade cell, stomata, spongy cell, parenchyma, xylem vessel, phloem tissue and collenchyma. AFLP fingerprint showed highly polymorphisms 97.42% with the number of bands (349 bands) ranging between 50-750 bands. Primer E+ACG/M+CTT had the highest number of AFLP band (91 bands). The dendrogram generated from UPGMA could separate these three species. In summary, the combination of morphological characteristics, microscopic investigation and AFLP fingerprinting can be used to identify plant species and determine the genetic relationship among three Erythroxylum species.

Energy dissipation and photosynthetic electron flow during the transition from juvenile red to mature green leaves in mango (Mangifera indica L.)

Leaf colouration during development from juvenile red to mature green leaves is a genetically controlled process in mango (Mangifera indica L.). This study aimed to determine the pigmentation pattern and electron transport flow in both red and green leaves under varied light intensity. In this study, 5- and 10-day old juvenile red and mature green leaves, respectively, were used. Three different photosynthetic active radiation levels (600 ± 5, 1000 ± 5 and 1200 ± 5 µmol m−2 s−1) were chosen to examine chlorophyll a fluorescence (O-J-I-P) transients. The vacuole of spongy cells in mesophyll contained anthocyanin in the juvenile leaf and rapidly degraded during the colour transition from red to green. A significant difference in chlorophyll, carotenoid and anthocyanin pigments was observed in both leaf types. The O-J-I-P parameters revealed that light intensity has a greater influence on the PSII electron transport chain than on PSI. Furthermore, the PSI of both leaves appeared to be more tolerant than that in PSII. The red leaf performed more energy dissipation than the green leaf after elevated light intensity exposure. O-J-I-P transients can be used as a sensitive, non-destructive method for measuring energy dissipation induced by intense radiation in plants.

Diagnostic signs of morphological and anatomical structure of Medicago falcata L. raw materials

Topiciality. Flora of Azerbaijan has a diverse vegetation cover and is rich in choice. However, today these sources of raw materials are not fully used to meet the needs of medicine and national economy. We conducted a resource reconnaissance survey of species of the genus Medicago in Azerbaijan and identified regions of mass growth. New natural habitats are located in different environmental conditions and it is possible to change the diagnostic features of the morphological and anatomical structure of plant materials, as well as the chemical composition. The combination of additional morphological and anatomical features allows a more accurate determination of the authenticity of the raw material. Aim. To study the diagnostic signs of morphological and anatomical structure of Medicago falcata L. raw materials from the flora of Azerbaijan. Materials and methods. Plant samples were fixed in a solution made in 0.1 M phosphate buffer (pH = 7.4), containing 2.5 % glutar-aldehyde, 2 % paraformal-aldehyde, 4 % sucrose, and 0.1 % picric acid. The fixed materials have been submitted to the Electron Microscopy Laboratory of the Azerbaijan Medical University for study by electron microscopy. Samples have been postfixed in 1 %-osmium tetraoxide solution prepared in phosphate buffer (pH 7.4) within two hours after being left in the same fixer for one day. Araldite-Epon blocks made from materials using general methods adopted in electron microscopy. The semi-thin (1-2 µm) sections from the blocks taken on a EM UC7 (Leica, Germany) ultramicrotome, stained with methylene blue, azure II, and basic fuchsin were observed under microscope Primo Star (Zeiss, Germany) and images of required parts were shot with EOS D650 (Canon, Chine) digital camera. Results and discussion. Multicellular trichome covered on both leaf sides. Adaxial epidermis a sheet plate have sinuous cells, and abaxial epidermis have differed slightly sinuous cells with clear-shaped walls. In leaflet anatomy of plant vascular bundles are of the collateral type. Stomatas are located from both sides of a leaf. Stomata belong to anisocytic structure. The epidermis of the stem consists of elongated thick-walled cells with anisocytic stomata. The calyx is densely covered by trichomes. The outer epidermis of cross-section of the keel petals cells is the wing horns cells form. And inner epidermis consists of oval cells. Mesophyll cells inside the leaf consist of loose spongy cells on the underside with several conducting bundles (dorsoventral). Conclusions . Morphological and anatomical studying of raw material Medicago falcata L. has shown, that there are prominent features of a structure:four large conductive bundles are located on the cross section of the stem at the corners of the ribs on two sides. Between angular conductive bundles, there are three conductive bundles, and the other two sides are located along one conductive bundle. Therefore, M. Falcata L. differs from M. Sativa L. The epidermis of the stem consists of elongated thickened-walls cells with anisocytic stomata. The indicated diagnostic morphological and anatomical characters could be used in the compilation of a monograph and in identifying plant materials on the raw material of Medicago falcata L.

Leaf structure and chlorophyll content in Torreya grandis 'Merrillii' with Nalepella abiesis infestation

Objective The aim is to provide a theoretical basis for the prevention and control of Nalepella abiesis and to study the damage mechanism and chlorophyll content from N. abiesis on leaves of Torreya grandis 'Merrillii'. Method Dynamic changes in leaf tissue structure, stomatal structure, chloroplast ultrastructure, and chlorophyll content were studied using the fluorescence microscope, transmission electron microscope (TEM), scanning electron microscope (SEM), and spectrophotometer. Result The palisade cells changed in shape and decreased in number for an increase in days after inoculation (DAI) with mites. By the 40th day, thickness of the palisade tissue decreased considerably; spongy cells shrank; spongy tissue became looser; around stomata the cuticular peg was destroyed; guard cells shrank; and stomata shrank revealing obvious injury. Mesophyll cells gradually swelled and became deformed with the gap between cells becoming larger and larger. Also, the number of chloroplasts gradually decreased with the appearance of starch grains. By the 12th day, the number of osmiophilic granules within the chloroplast had increased with grana lamellae becoming more and more irregular in structure, especially on the 25th day, and finally disintegrating and disappearing on the 40th day. There was no significant difference in chlorophyll content between ck and the treatment with mite infection from 0 to 12 d, but a significant difference occurred from 25 to 40 d(P Conclusion N. abiesis infestation could destroy the structure of the mesophyll cells and leaf stomata of T. grandis 'Merrillii' leading to a decreased chlorophyll content that could affect photosynthesis.

Elevated temperature and ozone modify structural characteristics of silver birch (Betula pendula) leaves.

To study the effects of slightly elevated temperature and ozone (O3) on leaf structural characteristics of silver birch (Betula pendula Roth), saplings of four clonal genotypes of this species were exposed to elevated temperature (ambient air temperature+0.8-1.0 °C) and elevated O3 (1.3-1.4× ambient O3), alone and in combination, in an open-air exposure field over two growing seasons (2007 and 2008). So far, the impacts of moderate elevation of temperature or the combination of elevated temperature and O3 on leaf structure of silver birch have not been intensively studied, thus showing the urgent need for this type of studies. Elevated temperature significantly increased leaf size, reduced non-glandular trichome density, decreased epidermis thickness and increased plastoglobuli size in birch leaves during one or both growing seasons. During the second growing season, O3 elevation reduced leaf size, increased palisade layer thickness and decreased the number of plastoglobuli in spongy cells. Certain leaf structural changes observed under a single treatment of elevated temperature or O3, such as increase in the amount of chloroplasts or vacuole, were no longer detected at the combined treatment. Leaf structural responses to O3 and rising temperature may also depend on timing of the exposure during the plant and leaf development as indicated by the distinct changes in leaf structure along the experiment. Genotype-dependent cellular responses to the treatments were detected particularly in the palisade cells. Overall, this study showed that even a slight but realistic elevation in ambient temperature can notably modify leaf structure of silver birch saplings. Leaf structure, in turn, influences leaf function, thus potentially affecting acclimation capacity under changing climate.

MORPHOLOGICAL, ANATOMICAL AND GEOGRAPHICAL DISTRIBUTION STUDIES OF SPECIES Horwoodia dicksoniae (Turrill) IN IRAQ

This research aims to study the morphological anatomical characteristics and geographical distribution of the species Horwoodia dicksoniae (Turrill) belong to Brassicaceae family in Iraq. The results were revealed the morphological characteristics of the root, stem, leaves, fruits and seeds, abaxial surface of the leaf characterized by covered with simple hairs. The fruits were circular in shape with wide wing and have one seed. The seeds were conical shape and pustular surface configuration. The anatomical characteristics of the root, stem, and leaf were studied and the cross-section of the root was characterized by thick periderm layer and cortex layer consisting primarily of parenchyma cells, stem cross section was characterized by thick layer of cuticle, as well as epidermis layer that followed the cuticle layer was double epidermis, but the layer of phloem is composed of rectangular cells and arranged in a continuous ring. Cross section of leaf was bifacial , leaf contains palisade cells in the form of a rectangle at the top surface of the leaf and irregular spongy cells at the low surface and distinguish the middle vein of the leaf as a circular shape. The epidermis was characterized by an Anisocytic type. The study of geographical distribution has been shown that the species is widespread in the desert region of Iraq.

English

To investigate the effects of quarries emissions on the leaf morpho-anatomy of Romi, Nabali and K18 olive cultivars in Taffouh village (Palestine), one set of olive cultivars of two-years old was cultivated close to quarries while the control set was cultivated almost 4 km from quarries. The morphology of six month-old leaves was examined. Leaf segments were fixed in compound fixative of formaldehyde, acetic acid and 70% ethanol (FAA). The segments were then embedded in Paraplast plus and 5 m thick sections were stained with safranin and fast green. A reduction in trichome density was evident for the three cultivars in response to exposure to quarries emission, with high density in the abaxial epidermis. Moreover, the abaxial epidermis of the three cultivars possessed elaborated and well-developed trichomes. The leaves of Romi cultivar exhibit increase in all leaf components except the adaxial epidermis while Nabali cultivar exhibited a reduction in all leaf components. Nevertheless, K18 cultivar exhibited a reduction only in palisade and spongy layers due to exposure to quarries pollutions. In conclusion, quarries emissions led to condensed palisade and spongy cells in all cultivars. In addition, Romi cultivar showed a variegated increase in all morpho-anatomical parameters concomitant with increased sclerophylly of leaves following their exposure to quarries emissions. This cultivar proved to be the most resistant to quarries stress which implies it is well suited for olive production. Key words: Adaptation, leaf anatomy, Olea europea, olive, quarries stress, trichome.