Abstract: Heavy metal-transporting P-type ATPase (HMA) has been implicated in the transport of heavy metals in plants. Here, we report the function and role of an uncharacterized member of HMA, OsHMA5 in rice (Oryza sativa). Knockout of OsHMA5 resulted in a decreased copper (Cu) concentration in the shoots but an increased Cu concentration in the roots at the vegetative stage. At the reproductive stage, the concentration of Cu in the brown rice was significantly lower in the mutants than in the wild-type rice; however, there was no difference in the concentrations of iron, manganese, and zinc between two independent mutants and the wild type. The Cu concentration of xylem sap was lower in the mutants than in the wild-type rice. OsHMA5 was mainly expressed in the roots at the vegetative stage but also in nodes, peduncle, rachis, and husk at the reproductive stage. The expression was up-regulated by excess Cu but not by the deficiency of Cu and other metals, including zinc, iron, and manganese, at the vegetative stage. Analysis of the transgenic rice carrying the OsHMA5 promoter fused with green fluorescent protein revealed that it was localized at the root pericycle cells and xylem region of diffuse vascular bundles in node I, vascular tissues of peduncle, rachis, and husk. Furthermore, immunostaining with an antibody against OsHMA5 revealed that it was localized to the plasma membrane. Expression of OsHMA5 in a Cu transport-defective mutant yeast (Saccharomyces cerevisiae) strain restored the growth. Taken together, OsHMA5 is involved in loading Cu to the xylem of the roots and other organs.

Abstract: The water status of plant leaves is dependent on both stomatal regulation and water supply from the vasculature to inner tissues. The present review addresses the multiple physiological and mechanistic facets of the latter process. Inner leaf tissues contribute to at least a third of the whole resistance to water flow within the plant. Physiological studies indicated that leaf hydraulic conductance (K leaf) is highly dependent on the anatomy, development and age of the leaf and can vary rapidly in response to physiological or environmental factors such as leaf hydration, light, temperature, or nutrient supply. Differences in venation pattern provide a basis for variations in K leaf during development and between species. On a short time (hour) scale, the hydraulic resistance of the vessels can be influenced by transpiration-induced cavitations, wall collapses, and changes in xylem sap composition. The extravascular compartment includes all living tissues (xylem parenchyma, bundle sheath, and mesophyll) that transport water from xylem vessels to substomatal chambers. Pharmacological inhibition and reverse genetics studies have shown that this compartment involves water channel proteins called aquaporins (AQPs) that facilitate water transport across cell membranes. In many plant species, AQPs are present in all leaf tissues with a preferential expression in the vascular bundles. The various mechanisms that allow adjustment of K leaf to specific environmental conditions include transcriptional regulation of AQPs and changes in their abundance, trafficking, and intrinsic activity. Finally, the hydraulics of inner leaf tissues can have a strong impact on the dynamic responses of leaf water potential and stomata, and as a consequence on plant carbon economy and leaf expansion growth. The manipulation of these functions could help optimize the entire plant performance and its adaptation to extreme conditions over short and long time scales.

Abstract: We use a novel dye-tracing technique to measure in vivo phloem transport velocity in cucumber (Cucumis sativus) plants during early seedling development. We focus on seedlings because of their importance in plant establishment and because they provide a simple source and sink model of phloem transport. The dye-tracing method uses a photodiode to track the movement of a bleach front of fluorescent dye traveling in the phloem from the cotyledons (source) to the roots (sink). During early seedling development, phloem transport velocity in this direction can change 2-fold depending on vascular connectivity and the number of actively growing sinks. Prior to leaf expansion, vascular bundles attached to the first developing leaf demonstrate a decline in basipetal phloem transport that can be alleviated by the leaf’s removal. At this stage, seedlings appear carbon limited and phloem transport velocity is correlated with cotyledon area, a pattern that is apparent both during cotyledon expansion and after source area manipulation. When the first leaf transitions to a carbon source, seedling growth rate increases and basipetal phloem transport velocity becomes more stable. Because bundles appear to operate autonomously, transport velocity can differ among vascular bundles. Together, these results demonstrate the dynamic and heterogeneous nature of phloem transport and underline the need for a better understanding of how changes in phloem physiology impact growth and allocation at this critical stage of development.

Abstract: The concentration of ions in plant cells and tissues is an essential factor in determining physiological function. In the present study, we established that concentration gradients of mobile ions exist in both xylem exudates and tissues within a barley (Hordeum vulgare) primary leaf. For K(+) and NO3 (-) , ion concentrations generally decreased from the leaf base to the tip in both xylem exudates and tissues. Ion gradients were also found for Pi and Cl(-) in the xylem. The hydathode strongly absorbed Pi and re-translocated it to the rest of the plant, whereas Cl(-) was extruded. The ion concentration gradients developed early during leaf growth, increased as the tissue aged and remained under both high and low transpiration conditions. Measurement of the expression profiles of Pi, K(+) and NO3 (-) transporters along the longitudinal axis of the leaf revealed that some transporters are more expressed at the hydathode, but for most transporters, there was no significant variation along the leaf. The mechanisms by which longitudinal ion gradients develop in leaves and their physiological functions are discussed.

Abstract: Three cultivars of Alternanthera bettzickiana (Regel) G.Nicholson have been evaluated for their tolerance and adaptability potential to salt stress. During the experiment, 5 salt regimes were maintained: 18 (control), 50, 100, 150, and 200 mM NaCl. Salinity adversely affected all growth shoot length and leaves per plant. Root fresh and dry weight decreased with an increase in salinity levels in all 3 cultivars. A. bettzickiana 'Green' was the most tolerant among the cultivars under study, with relatively lower ion leakage through roots, larger vascular region area, and wide metaxylem vessel in roots and stems recorded. Also observed were greater phloem and pith cell area in stems that increased midrib thickness, cortical cell area, vascular bundle area, and metaxylem area in leaves with increase in salinity level. Moreover, the vascular region area in roots, cortical cell area, vascular region thickness, metaxylem area, phloem cell area and pith cell area in stems, leaf thickness, epidermal thickness, cortical cell area, vascular bundle area, and metaxylem area in leaves were recorded in this cultivar with an increase in salinity levels. All cultivars showed increased Na+ and Cl- content and decreased K+ and Ca2+ with an increase in the salt level of the medium.

Abstract: The presence of thin-walled parenchymatous cells in the inner bundle sheath of species of the liliaceous genera Aloe, Chamaealoe, Astroloba, Lomatophyllum, Gasteria, Haworthia, Asphodeline, Asphodelus, Bulbine, Eremurus and Trachyandra was observed and described. Some species, however, have lignified sclerenchymatous cells in this position and this is general in Kniphofia. Cells in this region produce a secretion in the form of a copious exudate in many species of Aloe, or much sparser contents in the case of related genera. The leaves of most species contain small amounts of anthraquinones, while the related anthrone-C-glycosides accumulate in others. A wide range of other phenolic substances occurs, recognized as distinct zones on thin layer chromatograms, but mainly consisting of unidentified compounds. It is not certain if synthesis occurs in the thin-walled bundle sheath cells or if these have only a storage function. Another layer of rather smaller parenchymatous cells in the outer bundle s...

Abstract: Background Plants that utilize the highly efficient C4 pathway of photosynthesis typically possess kranz-type leaf anatomy that consists of two morphologically and functionally distinct photosynthetic cell types, the bundle sheath (BS) and mesophyll (M) cells. These two cell types differentially express many genes that are required for C4 capability and function. In mature C4 leaves, the plastidic rbcL gene, encoding the large subunit of the primary CO2 fixation enzyme Rubisco, is expressed specifically within BS cells. Numerous studies have demonstrated that BS-specific rbcL gene expression is regulated predominantly at post-transcriptional levels, through the control of translation and mRNA stability. The identification of regulatory factors associated with C4 patterns of rbcL gene expression has been an elusive goal for many years.

Abstract: In maize, the structure of bundle sheath cell (BSC) chloroplasts is less subject to salinity stress than that of mesophyll cell (MC) chloroplasts. To elucidate the difference in sensitivity to salinity, antioxidant capacities and localization of reactive oxygen species were investigated in both chloroplasts. Transmission electron microscopic observation showed that O2 (-) localization was found in both chloroplasts under salinity, but the accumulation was much greater in MC chloroplasts. H2 O2 localization was observed only in MC chloroplasts of salt-treated plants. In isolated chloroplasts, the activities of superoxide dismutase (SOD, EC 1.15.1.1), ascorbate peroxidase (APX, EC 1.11.1.11) and dehydroascorbate reductase (DHAR, EC 1.8.5.1) were increased by salinity. While the enhancement of SOD activity was similar in both chloroplasts, the increase of APX and DHAR activities were more pronounced in BSC chloroplasts than in MC chloroplasts. Monodehydroascorbate reductase (MDHAR, EC 1.6.5.4) and glutathione reductase (GR, EC 1.6.4.2) were undetectable in BSC chloroplasts, while they increased in MC chloroplasts under salinity. Although ascorbate content increased by salinity only in BSC chloroplasts, glutathione content increased significantly in both chloroplasts, and was higher in MC chloroplasts than in BSC chloroplasts. The content of thiobarbituric acid-reactive substances, which is an indicator of lipid peroxidation, was significantly increased by salinity in both chloroplasts. These results suggested O2 (-) -scavenging capacity was comparable between both chloroplasts, whereas H2 O2 -scavenging capacity was lower in MC chloroplasts than in BSC chloroplasts. Moreover, the increased lipid peroxidation under salinity was associated with the structural alteration in MC chloroplasts, while it had less impact on the structure of BSC chloroplasts.

Abstract: As the world population grows, our need for food increases drastically. Limited amounts of arable land lead to a competition between food and fuel crops, while changes in the global climate may impact future crop yields. Thus, a second “green revolution” will need a better understanding of the processes essential for plant growth and development. One approach toward the solution of this problem is to better understand regulatory and transport processes in C4 plants. C4 plants display an up to 10-fold higher apparent CO2 assimilation and higher yields while maintaining high water use efficiency. This requires differential regulation of mesophyll (M) and bundle sheath (BS) chloroplast development as well as higher metabolic fluxes of photosynthetic intermediates between cells and across chloroplast envelopes. While previous analyses of overall chloroplast membranes have yielded significant insight, our comparative proteomics approach using enriched BS and M chloroplast envelopes of Zea mays allowed us to identify 37 proteins of unknown function that have not been seen in these earlier studies. We identified 280 proteins, 84% of which are known/predicted to be present in chloroplasts (cp). 74% have a known or predicted membrane association. 21 membrane proteins were 2-15 times more abundant in BS cells, while 36 proteins were more abundant in M cp envelopes. These proteins could represent additional candidates of proteins essential for development or metabolite transport processes in C4 plants. RT-PCR confirmed differential expression of thirteen candidate genes. Cp association was confirmed using GFP labeling. Genes for a PIC-like protein and an ER-AP-like protein show an early transient increase in gene expression during the transition to light. In addition, PIC gene expression is increased in the immature part of the leaf and was lower in the fully developed parts of the leaf, suggesting a need for/incorporation of the protein during chloroplast development.

Abstract: Development of a pre-vascularized tissue-engineered construct with intrinsic vascular system for cell growth and tissue formation still faces many difficulties due to the complexity of the vascular network of natural bone tissue. The present study was to design and form a new vascularized tissue-engineered construct using pre-differentiated rADSCs, arteriovenous vascular bundle and porous nHA-PA 66 scaffold. rADSCs were pre-differentiated to endothelial cells (rADSCs-Endo) and then incorporated in nHA-PA 66 scaffolds in vitro. Subsequently, in vivo experiments were carried out according to the following groups: Group A (rADSCs-Endo/nHA-PA 66 scaffold with arteriovenous vascular bundle), Group B (rADSCs/nHA-PA 66 scaffold with arteriovenous vascular bundle); Group C (nHA-PA66 scaffold with arteriovenous vascular bundle), Group D (nHA-PA 66 scaffold only). The vessel density and vessel diameter were measured based on histological and immunohistochemical evaluation, furthermore, the VEGF-C, FGF-2 and BMP-2 protein expressions were also evaluated by western blot analysis. The results of in vivo experiments showed that the vessel density and vessel diameter in group A were significantly higher than the other three groups. Between Group B and C, no statistical difference was observed at each time point. In accordance with the results, there were dramatically higher expressions of VEGF-C and FGF-2 protein in Group A than that of Group B, C and D at 2 or 4 weeks. Statistical differences were not observed in VEGF-C and FGF-2 expression between Group B and C. BMP-2 was not expressed in any group at each time point. Compared with muscular wrapping method, arteriovenous vascular bundle implantation could promote vascularization of the scaffold; and the angiogenesis of the scaffold was significantly accelerated when pre-differentiated rADSCs (endothelial differentiation) were added. These positive results implicate the combination of pre-differentiated rADSCs (endothelial differentiation) and arteriovenous vascular bundle may achieve rapidly angiogenesis of biomaterial scaffold.

Abstract: The discovery of abundant plasmodesmata at the bundle sheath/phloem interface in Oleaceae (Gamalei, 1974) and Cucurbitaceae (Turgeon et al, 1975) opened the questions whether these plasmodesmata are functional in phloem loading and how widespread is symplasmic loading Analysis of over 800 dicot species allowed the definition of ‘open’ and ‘closed’ types of the minor vein phloem depending on the abundance of plasmodesmata between companion cells and bundle sheath (Gamalei, 1989; 1990) These types corresponded to potential symplasmic and apoplasmic phloem loaders, respectively; however, this definition covered a spectrum of diverse structures of phloem endings Here, a review of detailed cytological analyses of minor veins in 320 species from the subclass Asteridae is presented, including data on several cell types and their combinations which have not been reported previously The percentage of Asteridae species with ‘open’ minor vein cytology which also contain sieve-element-companion cell complexes with ‘closed’ cytology, ie that show specialization for both symplasmic and apoplasmic phloem loading, was determined Along with recent data confirming the dissimilar functional specialization of structurally different parts of minor vein phloem in the stachyose-translocating species Alonsoa meridionalis (Voitsekhovskaja et al, 2009), these findings suggest that apoplasmic loading is indispensable in a large group of species previously classified as putative symplasmic loaders Altogether, this study provides formal classifications of companion cells and of minor veins, respectively, in 24 families of the Asteridae based on their structural features, opening the way to a close investigation of the relationship between structure and function in phloem loading

Abstract: Peanut ( Arachis hypogaea L. TVM-2) was grown in field under drought stress in comination with paclobutrazol (PBZ) and abscisic acid (ABA) in order to study their individual and combined effects on leaf anatomical characteristics. The thickness of the leaf, upper and lower epidermis and the number of cells per unit area in the palisade and spongy regions were very much reduced under drought stress. The palisade and spongy layers of mesophylls were well differentiated and the cells are wider and longer as compared to shorter palisade and spongy parenchyma of control. The number of palisade and spongy cells increased per unit area with all treatments as compared with drought stressed and unstressed plants. The vascular bundles of the paclobutrazol treated plants were narrow and dense when compared to control. The xylem vessels of PBZ and ABA treated leaves were much narrow when compared to control plants. Among the treatments the present findings revealed that the growth regulator treatments to the drought stressed plants have great impact on the anatomy of Arachis hypogaea plants.

Abstract: Gochnatia polymorpha (Less.) Cabrera, Asteraceae, is popularly known as cambara and cambara-de-folha-grande in Brazil. It is used in traditional medicine to treat respiratory and gastrointestinal disorders. Pharmacological studies revealed antiinflammatory, antispasmodic, antibacterial and antiviral activities. The goal of this paper was to carry out morphological and anatomical studies in order to describe the aerial parts of G. polymorpha. The botanical material was collected, fixed, and prepared according to usual light and scanning electron microtechniques. The leaves are simple, oblong-lanceolate to elliptical-lanceolate in form with mucronate acute apex, rounded base, entire or slightly toothed margin, and short petiole. In transection, the epidermis is uniseriate along the leaf blade. A subepidermal layer next to the adaxial side is present. Anomocytic stomata are seen only on the abaxial surface. Capitate glandular trichomes and T-shaped non-glandular trichomes occur on the leaves. The mesophyll is dorsiventral and minor collateral vascular bundles are enclosed by a sheath of thickwalled parenchymatic cells. The midrib is biconvex and the petiole has a circular shape. The epidermis of the stem consists of a single layer of cells with glandular and nonglandular trichomes. The vascular cylinder shows typical structure and perivascular fiber caps are next to the phloem.

Abstract: Paepalanthus sect. Diphyomene comprises 18 species with a convoluted taxonomic history. Aiming to correlate anatomical structures with the systematics of this group and its relatives, we studied the anatomy of scapes, reproductive axis bracts, and leaves of 20 Paepalanthus species. Bracts and leaves show differences in epidermal cell thickening; mesophyll width; vascular bundle arrangement; presence or absence of a hypodermis; types of cells in the vascular bundle sheath extensions; margin shape and composition; and presence or absence of aquiferous parenchyma. Scapes differ in contour, rib number, and pith size. Some diagnostic characters found are presence of aquiferous parenchyma and absence of vascular bundle sheath extensions in leaves of P. urbanianus; vascular bundles decreasing in size towards the margin of leaves and bracts, and scapes with a triangular contour in P. flaccidus; scapes with nine ribs in P. acanthophyllus and ten in P. macer. All anatomical features are summarized in tables. These results aid in the identification and characterization of the species of P. sect. Diphyomene. They also support the current section circumscription, reinforcing the relevance of the anatomical characters in order to define natural groups.

Abstract: In the recent years, human activities such industry and agriculture promote heavy metal release into the environment. Lead is the most contaminant metals in environment which adversely affects both plant and human life. The present study was undertaken to determine the effects of Pb on structural characteristics in Medicago sativa L. 30 days plants treated with Pb in 5 treatments (0,120, 240, 500, 1000µM Pb) with 3 repeat in per treatment for 10 days. Histochemical method of lead detection revealed significant accumulation of this metal in cortex and xylem tissues in roots and in stems lead deposits on cell wall of collenchymas tissues. The analysis of scanning electron micrographs of the leaf surface of M. sativa grown on hydroponic culture treated with Pb showed an increase in the size of guard cells in adaxial surface and decrease in abaxial surface, decrease in size of stomata aperture and closure of stomata in 1000 µM Pb in medium. Alternation of epicuticular waxes is one of the most important of pollution symptoms, in our study, alteration in structure and deposition of epicuticular waxes were observed. Also anatomical characteristics of stem and root affected by Pb contamination. Under Pb toxicity, anatomical symptoms including increase the diameter of stems and root as well as amplified vascular bundles and pith area were obsreved.

Abstract: SummaryBoron (B)-deficiency is a nutritional problem in the citrus industry worldwide. Under B-deficient conditions, symptoms such as corky split veins, small fruit, low tree vigour, and low fruit yield appear. In this study, we investigated the anatomical responses of mature leaves and the albedo of mature fruit of HB pummelo [Citrus grandis (L.) Osbeck] to B-deficiency. Under B-deficient conditions, the numbers of parenchyma cells in the vascular bundles of the leaf and fruit mesocarp increased significantly. The ratio of the area of the phloem to the area of the vascular bundle also increased, while the ratio of the area of the xylem to the area of the vascular bundle decreased in both tissues. Moreover, we observed alterations in the xylem elements under B-deficient conditions. The average lengths of xylem vessels were 216.7 µm and 175.4 µm in leaf main veins and in fruit mesocarp, respectively, both significantly lower than the corresponding values in B-sufficient control plants. However, B-deficienc...

Abstract: Based on maize stem anatomical structure in different deep loosening modes and nitrogen application rates,the lodging mechanism and control measures were discussed in microcosmic angle.The result showed that stem epidermis thickness,vascular bundle number and area,xylem and phloem area was strongly inversely associated with lodging.Through deep loosening and appropriate rate of nitrogen all can adjust vascular bundle structure and epidermis thickness.The influence of lodging rate,big vascular bundle was bigger than the small vascular bundle in the vascular bundle area,and phloem than xylem in vascular bundle internal structure.Stem epidermis thickness and lodging rate are significantly negative correlation.Deep loosening and nitrogen can improve transmission efficiency of vascular bundle.Nitrogen content of stem had significantly negative correlated to lodging rate of maize.But phosphorus content and potassium content of stem had no significantly negative correlated to lodging rate of maize.The flexural strength of stem had negative correlated to lodging rate of maize.Nitrogen application rates in 225 kg/ha and combine with interleave row deep loosening treatment,the vascular bundle internal structure was developed,the transmission efficiency was highest,the flexural strength was largest,and the rate of lodging was lowest.

Abstract: The response of the stem of a resistant host (Impatiens baslamina) to infection by the parasitic flowering plant Cuscuta japonica was studied with light and electron microscopy. The intra- and interfascicular cambial cells in the host stem first reacted to the penetrating upper haustorium by dividing, and the differentiation of the host xylem (vascular) tissues proceeded toward interfascicular areas from vascular bundles. When the host vascular tissue was invaded by the endophyte (haustorial portion in the host stem), the host xylem was displaced, and host vessels became occluded with parenchyma cells, resulting in tyloses. As the parasitism progressed, areas of the host stem penetrated by the endophyte became swollen via secondary growth and cell division in the parenchymatous cortex, pith, and interfascicular areas. During this intrusion by the endophyte, darkly stained necrotic reactions were detected at the interface between the host tissue and the invading endophyte. The results suggested that in the host tissues penetrated by the parasite, the formation of secondary tissue and swellings caused by active cell division of ground tissue and host vessel occlusion by tyloses constitute the host structural defense against the parasite.

Abstract: The lamina, main vein and peduncle anatomical properties of Centaurea sadleriana Janka plants from two populations, were examined using light and scanning electron microscopy. The indumentum was comprised of glandular and non-glandular trichomes of two types. The leaves were amphistomatic, isolateral, with strongly developed palisade tissue. Secretory ducts were observed along the phloem or sclerenchyma of large vascular bundles. Collenchyma alternated with chlorenchyma in the main vein and peduncle. Large groups of strongly lignified sclerenchyma were present along the phloem of peduncle vascular bundles. These features, together with thickened walls of epidermal cells and cuticle, numerous trichomes and thick-walled parenchyma in the perimedullar zone, were perceived as a xeromorphic peduncle structural adaptation. Non-enzymatic antioxidant compounds of phenolic origin were detected in small amounts and their respective content was higher in leaves compared to inflorescences. Compounds of phenolic orgin showed positive correlation with total potenial of antioxidant activity indicated by the DPPH assay. Greater total quantity of polyphenols and tannins was detected in leaves of plants from Zobnatica locality, while leaves of plants from Rimski Sanac were characterized by higher content of total flavonoids and proantocyanidins. Phytochemical analysis showed that dominant secondary biomolecules in inflorescences were phenolic pigments including anthocyanins and leucoanthocyanins, and free quinones in leaves.

Abstract: Studies concerning the structure of plant embryos are very important in different areas of study such as plant systematics and evolution or the handling of native species. This work aims at evaluating the anatomy of the embryo and vegetative organs of Garcinia brasiliensis in order contribute to taxonomical, ecological, handling studies of this species. Some seeds were stored for anatomical analysis of the embryo and some were germinated to obtain young plants for anatomical analysis of the vegetative organs. Plants were cultivated in growth chamber for 120 d. Seeds and young plants were both fixed in a solution of formaldehyde, acetic acid, and 70% ethanol and usual plant microtechnique methods were employed. Slides were photomicrographed and a quantitative analysis of tissues was performed using UTHSCSA-Imagetool software. Histochemical analysis was performed for the detection of starch, lipids, alkaloids, and phenolic compounds. The G. brasiliensis embryo has rudimentary cotyledons and the reserves are stored in the hypocotyl-radicle axis. Most of the reserves are starch grains, stored in ground meristem cells, which contain a few oleossomes and alkaloids in the cell walls. The young plant leaves show dorsiventral and hypostomatous properties, including a one-seriated epidermis and a thick cuticle. In the midrib vascular bundle, the phloem is organized around the xylem vessels. The primary stem has a one-seriated epidermis and angular collenchyma. Adventitious roots are polyarch and show a one-seriated epidermis and endodermis. The anatomy of embryos and young plants of G. brasiliensis is similar to that of other Clusiaceae species.

Abstract: Sucrose concentrations in mature culm tissues of sugarcane, Saccharum spp. hybrids, approach one molar. Significant concentrations appear in both the symplastic and apoplastic compartments of the culm tissue. Apoplastic storage of sucrose in sugarcane apparently evolved to allow storage of extraordinarily high concentrations of sucrose without generating correspondingly high solute and turgor potentials. In addition, the relative apoplastic volume in mature culm tissue may be considerable and, if filled, may account for as much as 20% of the stored sucrose. The sucrose in the culm apoplast could potentially enter the xylem stream but is blocked by barriers in the cell walls of the bundle sheath, which prevents apoplastic movement of sucrose outside of the storage parenchyma. In addition to functioning as a storage reservoir, apoplastic sucrose apparently sustains symbiotic bacterial endophytes that may provide the plant with hormones, antifungal compounds, and nitrogen.

Abstract: The C4 grass Arundinella hirta exhibits a unique C4 anatomy, with isolated Kranz cells (distinctive cells) and C4-type expression of photosynthetic enzymes in the leaf sheath and stem as well as in the leaf blade. The border zones between these organs are pale green. Those between the leaf blade and sheath and between the sheath and stem are called the lamina joint and sheath pulvinus, respectively, and are involved in gravity sensing. We investigated the structure and localization of C3 and C4 photosynthetic enzymes in these tissues. In both zones the epidermis lacked stomata. The inner tissue was composed of parenchyma cells and vascular bundles. The parenchyma cells were densely packed with small intercellular spaces and contained granal chloroplasts with large starch grains. No C4-type cellular differentiation was recognized. Western blot analysis showed that the lamina joint and pulvinus accumulated substantial amounts of phosphoenolpyruvate carboxylase (PEPC), pyruvate,Pi dikinase (PPDK), and ribulose 1,5-bisphosphate carboxylase/oxygenase (rubisco). Immunogold electron microscopy revealed PEPC in the cytosol and both PPDK and rubisco in the chloroplasts of parenchyma cells, suggesting the occurrence of C3 and C4 enzymes within a single type of chlorenchyma cell. These data indicate that the lamina joint and pulvinus have unique expression patterns of C3 and C4 enzymes, unlike those in C4-type anatomy.

Abstract: The study of medicinal plants involves several areas of science. Anatomy contributes to species identification and consequently, with quality control of plant product. This paper describes the leaf and stem anatomy of Pimenta pseudocaryophyllus (Gomes) L.R. Landrum (Myrtaceae), collected in Seasonal Semideciduous Forest. The studied organs presented uniseriate epidermis covered by a thick cuticle and secretory cavities. The stem showed a continuous ring of vascular tissues around the pith, with phloem on both sides of the xylem. The leaf was hypostomatic, with trichomes on the abaxial face, with bifacial mesophyll and amphicrival vascular bundle, surrounded by a sclerenchymatous pericycle in the petiole and in the midrib. Among the histochemical tests, positive results were obtained for lipids, phenolic compounds, starch and calcium oxalate (druses). The species had anatomical features typical of the family and the secretory cavities present in leaves and stems were related to the secondary metabolites detected.