Portion Of Stem Research Articles

Ontogeny, structure and occurrence of interxylary cambia in Malpighiaceae

Deviations in the regular pattern of secondary growth have occurred multiple times over the history of woody plants and these have been treated under the term cambial variant. Here we present a type of cambial variant that has been studied in the 19th century, but that has never been named or had its ontogeny studied in detail. This cambial variant generates a vascular cylinder with a conspicuous crenate pattern and it is found in two lianescent lineages of Malpighiaceae; Stigmaphyllon and a clade informally called the Banisteriopsis nummifera group. Twenty species of Stigmaphyllon and two species of the Banisteriopsis nummifera group were sampled from naturally growing population to investigate ontogenic history starting from shoot apex to the thickest portion of stem by using traditional anatomical methods All species in these two clades have a regular cambium that produces bands of non-lignified axial parenchyma in the xylem by the onset of secondary growth. These xylem parenchyma cells, after a period of secondary growth, acquire meristematic activity and give rise to new, variant cambia referred here as ‘interxylary cambia’. These new cambia give rise to new vascular tissues within the secondary xylem. In Stigmaphyllon the variant cambia give rise to a large quantity of variant phloem, and not much variant xylem, while in the members of the Banisteriospsis nummifera group a large quantity of both secondary xylem and phloem is formed by every new interxylary cambia. Xylem and phloem originated from both cambial types have features similar to those of other Malpighiaceae lianas, except for the absence of septate fibers and perforated ray cells, the presence of stratified phloem and prismatic crystals in the phloem of the Banisteriopsis nummifera group and a concentric ring of cortical secretory cells characteristic of Stigmaphyllon. The cambial variant interxylary cambia is here named for the first time, and this new term is proposed to unmistakably denote its origin from within the secondary xylem, which is likely a synapomorphy for these two Malpighiaceae lineages.

A novel application of RNase H2-dependent quantitative PCR for detection and quantification of Grosmannia clavigera, a mountain pine beetle fungal symbiont, in environmental samples.

Mountain pine beetle (Dendroctonus ponderosae Hopkins; MPB) is an economically and ecologically important pest of pine species in western North America. Mountain pine beetles form complex multipartite relationships with microbial partners, including the ophiostomoid fungi Grosmannia clavigera (Robinson-Jeffrey and Davidson) Zipfel, de Beer and Wingfield, Ophiostoma montium (Rumbold) von Arx, Grosmannia aurea (Robinson-Jeffrey and Davidson) Zipfel, de Beer and Wingfield, Leptographium longiclavatum (Lee, Kim, and Breuil) and Leptographium terebrantis (Barras and Perry). These fungi are vectored by MPB to new pine hosts, where the fungi overcome host defenses to grow into the sapwood. A tree’s relative susceptibility to these fungi is conventionally assessed by measuring lesions that develop in response to fungal inoculation. However, these lesions represent a symptom of infection, representing both fungal growth and tree defense capacity. In order to more objectively assess fungal virulence and host tree susceptibility in studies of host–pathogen interactions, a reliable, consistent, sensitive method is required to accurately identify and quantify MPB-associated fungal symbionts in planta. We have adapted RNase H2-dependent PCR, a technique originally designed for rare allele discrimination, to develop a novel RNase H2-dependent quantitative PCR (rh-qPCR) assay that shows greater specificity and sensitivity than previously published PCR-based methods to quantify MPB fungal symbionts in pine xylem and MPB whole beetles. Two sets of assay probes were designed: one that amplifies a broad range of ophiostomoid species, and a second that amplifies G. clavigera but not other MPB-associated ophiostomoid species. Using these primers to quantify G. clavigera in pine stems, we provide evidence that lesion length does not accurately reflect the extent of fungal colonization along the stem nor the quantity of fungal growth within this colonized portion of stem. The sensitivity, specificity, reproducibility, cost effectiveness and high-throughput potential of the rh-qPCR assay makes the technology suitable for identification and quantification of a wide array of pathogenic and beneficial microbes that form associations with plants and other organisms, even when the microbial partner is present in low abundance.

Effects of Stem Length and Storage Duration on Sugar Losses in Sweet Sorghum

Abstract. Sweet sorghum ( (L.) Moench) is a multi-purpose crop, yielding fuel in the form of ethanol from its stem juice, food in the form of grain, and fodder from its leaves and bagasse. The sugars utilized for bioethanol production are contained in the stalks, in an amount varying between 12% and 25% of the fresh biomass, according to the genotypes and harvesting time. However, these carbohydrates can be easily lost during harvest and post-harvest, because of wrong machinery settings and prolonged periods of exposure of the cut material to the action of fermentative agents. For these reasons, the production of biofuel from sweet sorghum is very sensitive to harvest systems and storage methods, as they can influence remarkably the final energetic yield of the crop. The main objective of the present study was to monitor the time course of dry matter and sugar content in sweet sorghum stem over a long-time storage period. The analysis was carried out by dividing the stems into portions of different length in order to test different storage configuration by varying the stem portion stored to simulate the action of different harvest machines. This work has been designed to take into account a larger storage window respect previous experimentation. The research has provided evidence that sugar loss during the storage is highly influenced by the length of the stem portion, as well as by storage conditions. Total sugar content at harvest was on average 23.2%. The decreasing of sugar content continued during the storage period but at different rate for the different portions. At the end of storage, the sugar content of the whole stem was on average 6.6%, while the smallest portion (1/16 of the whole stem) had an average content of 1.0%. Indications on best storage conditions (storage form, storage location, storage ambient condition), as well as technical details regarding new potential harvesting solutions to decrease the speed rate of sugar loss have been provided. Keywords: Biofuel, Harvesting, Storage, Sugar losses, Sweet sorghum.

Effect of detopping and mepiquat chloride application in soybean (Glycine max)

Investigation was carried out in Punjab Agricultural University, Ludhiana, during kharif 2014 and 2015 to evaluate the effect of detopping and mepiquat chloride (MC) application on economics and seed quality of soybean (Glycine max L.) cv. SL 744. The experiment was laid-out in randomized complete block design having eight treatments as T1-control, T2-detopping (removal of 4–5 cm apical portion of main stem) at 50–55 days after sowing (DAS), T3-MC @ 200 ppm at 50–55 DAS, T4-MC @ 200 ppm at 50–55 and 65–70 DAS, T5-MC 250 ppm at 50–55 DAS, T6-MC @ 250 ppm at 50–55 and 65–70 DAS, T7-MC @ 300 ppm at 50–55 DAS and T8-MC @ 300 ppm at 50–55 and 65–70 DAS, with four replications. An increase in seed nitrogen and protein content with increase in level of MC was recorded but it could not reach the level of significance. Anon-significant effect of detopping and MC application on stover nitrogen and seed oil content was also recorded. A non-significant effect of growth regulation treatments on seed quality parameters viz., germination percentage, seedling length and dry weight, vigour index I & II and speed of germination index was recorded which indicates non-inhibitory effect of MC on seed quality of soybean. Detopping and application of MC @ 250 ppm at two growth stages resulted in highest gross and net returns and benefit to cost ratio (B: C) in comparison to control indicating economical viability of detopping and MC application.

Mechanical And Water Absorption Behavior Of Natural Fibers Reinforced Polypropylene Hybrid Composites

From the past decades, abundant usage of natural fibers is observed in polymeric composites due to factors like natural availability, cost economy, low density compared to synthetic fibers, easy processing and biodegradability. Coastal regions of India including Andhra Pradesh and Tamil Nadu are well known for immense plantations of Banana fiber (BF) and coconut fiber (CF) trees.The stem portion of these plantations are usually discarded as waste. This study evaluated usage of this fibrous waste from banana and coconut plantations as reinforcement in thermoplastic polypropylene(PP) to form a hybrid composite structure. This study aims to reduce the cost of conventional plastics by utilizing the optimal quantity of natural fiber reinforcement. Issues such as water absorption and fiber/matrix delamination of natural fiber reinforcements are considered for obtaining better application characteristics. The samples of BF/CF reinforced polypropylene hybrid composite are manufactured using twin screw extruder and injection moulding machines at different fiber loadings(CF/BF/PP)of 15/5/80, 10/10/80 and 5/15/80 wt.%. The effect of fiber loading on hybrid composites is studied. The mechanical properties such as tensile strength, flexural strength and impact strength of the resultant hybrid composites are optimized based on fiber loading. The moisture absorption characteristics of the hybrid materials are also evaluated.

Effect of anti-browning solutions on quality of fresh-cut fennel during storage

Fresh-cut fennel (Foeniculum vulgare Mill. subsp. vulgare var. azoricum cv. Orion) is a very perishable crop due to the browning that affects the cut-surface, especially on the stem portion of the slices. The occurrence of browning is the main cause of quality loss and decrease of visual acceptance of this product. In the present work the effectiveness of different anti-browning solutions (0.5% ethanol, 1% L-ascorbic acid, 0.5% L-cysteine at pH 7, 1% citric acid and 0.5% 4-hexylresorcinol) on maintaining quality characteristics of fresh-cut fennel during 6days at 5°C in air conditions were investigated. Results showed that dipping in solutions of citric acid, ascorbic acid, cysteine and 4-hexylresorcinol, did not result in substantial improvement of the appearance of fresh-cut fennels cut-surfaces compared to water control. Among all applied anti-browning solutions, dipping in 1% citric acid and 0.5% 4-hexylresorcinol produced a more severe browning than control, in both stem and sheath cut-surfaces. Dipping for 2min in 0.5% ethanol was effective in preserving visual quality of fresh-cut fennel stored in air for six days at 5°C, significantly reducing the browning in both stem and sheath cut-surface. In addition ethanol is a ‘generally recognized as a safe’ (GRAS) product and did not negatively influence the aroma of fresh-cut fennel. Based on these considerations, dipping in 0.5% ethanol for 2min could be a useful pretreatment for extending the shelf-life of fresh-cut fennel.

In-vivo antiemetic and antinociceptive, cytotoxic and in-vitro thrombolytic potential of hydro-alcoholic stem and leaves extract of jatropha gossypiifolia.

This study describes the biological investigations of hydro-alcoholic leaves and stem extract of Jatropha gossypiifolia, a plant belonging to the family Euphorbiaceae, to reveal their possible contribution as an antiemetic, antinociceptives, cytotoxic and thrombolytic factor. The leaves and stems of Jatropha gossypiifolia were extracted with methanol. The leaves extracts were used for the observation of thrombolytic potential. Result reveals that the leaves at a concentration of 2.5mg/mL, showed maximum activity (27.255 ± 0.90%), whereas 20 mg/mL sample solution showed the lowest activity (7.722 ± 0.26%), when comparing positive control streptokinase. The extracts were used for the investigation of cytotoxic activity considering vincristine sulfate as a positive control. The leaves and the stems portion have considerable cytotoxic property (LC50 are 0.00532 µg/ml for stems and 0.000109 µg/ml for leaves, respectively) when comparing with positive control. The methanolic extract showed potent antiemetic activity at the highest concentration both at leaves and stem extracts as compared to positive control metoclopramide. Where metoclopramide shows 73% of inhibition, there leaves and the stem portion of the plant shows 90% and 91% of emesis inhibition respectively. By using a standard protocol, the crude methanolic stem and leaves extract of J. gossypiifolia was conducted to attempt for antinociceptives activities, where Diclofenac Na is used as a standard. The crude methanolic extract of leaves and stem exhibit 31.07% and 30.79% writhing inhibition in test animals respectively, which are statistically significant. The results of the study showed that the plant extract has potential thrombolytic, cytotoxic, antiemetic and antinociceptive activities.

ARBUSCULAR MYCORRHIZAS IN SUGARCANE UNDER PLANTING SYSTEMS AND SOURCES OF NITROGEN

The aim of this work was to evaluate the density of spores and mycorrhizal colonization in roots of varieties of sugarcane (RB86-7515, CTC-4 and CTC-15), under planting systems, being the planting of stem portions and pre-sprouted seedlings (PSS) along with 3 sources of nitrogen: granular fertilizer, leaf application and inoculation with diazotrophic bacteria ( Azospirillum brasilense ). The experiment was deployed on the experimental campus of the Evangelical School of Goianesia, and were collected soil samples for spore count after the first cut. The experimental design was arranged in factorial 3x2x3 in randomized blocks with subdivided plots using 4 repetitions per treatment, where factor 1 was represented by varieties, factor 2 by planting systems and factor 3 by nitrogen sources. The planting of PSS associated with foliar fertilization and A. brasiliense presented better colonization that in PSS with granular fertilizer and stem portions with leaf fertilizer and via inoculant. The granular fertilizer showed increased amounts of spores over the foliar fertilization and inoculation of Azospirillum brasilense, the planting system of stem portions presented greater quantity of spores over the planting of PSS, , it is worth mentioning that approximate results of spore density, mycorrhizal colonization and productivity without adding granular fertilizer are satisfactory for reducing the use of fertilizers.

Locally heated dormant cambium can re-initiate cell production independently of new shoot growth in deciduous conifers (Larix kaempferi)

The periodicity of cambial cell division accounts for the formation of growth rings in trees. Cambial reactivation controls earlywood width and annual ring width, thereby affecting wood quantity and quality. However, despite the fact that cambial reactivation has been one of the most commonly reported features in cambium studies, we have not yet elucidated what directly triggers it in spring in deciduous conifers.Here we recorded responses of winter dormant cambium of deciduous conifers (Larix kaempferi) to artificial heating once (between February and March 1999) in a cooler area and three times (between December 1995 and March 1996) in a warmer area. Stem surfaces were locally warmed (19°C–24°C) for 2–4 weeks at breast height in the cooler area and at breast height and the crown base in the warmer area. The localization of storage starch surrounding the cambium during the heating periods was observed to assess the growth potential of the dormant cambium under localized heating.To resume cell division, dormant cambium in the heated portions often required heating for 2 weeks in the warmer area, whereas that in the cooler area required 3 weeks of heating. In locally heated stem portions, phloem storage tissues surrounding the cambium were rich in starch; however, cell growth of the reactivated cambium was slow, and cambial derivatives differentiated into phloem rather than xylem during periods of winter cambial dormancy. By contrast, sustained cambial activity and xylem differentiation were observed in stem portions warmed even after natural cambial reactivation occurred in non-heated stem portions.The results suggest that in deciduous conifer trees, cambial dormancy is imposed by low air temperature during mid-late winter, and a rise in temperature directly triggers cambial reactivation independently of new shoot growth in spring. However, continued cell division in the reactivated cambium and xylem differentiation of cambial derivatives might require certain factors, which originate from elongating shoots, besides starch stored in phloem.

Genome-wide identification of novel microRNAs from genome sequences using computational approach in the mudskipper (Boleophthalmus pectinirostris)

MicroRNAs (miRNAs), approximately 22 nucleotides (nt) long, are small, non-coding RNA molecules with important regulatory functions in gene expression. They are mostly conserved among the organisms and this conservation makes them a good source for the identification of novel miRNAs by computational genomic homology. The miRNA repertoire of a major aquaculture species, Boleophthalmus pectinirostris, has been unknown until recently. Currently, the B. pectinirostris whole-genome sequences have been completed, making it more convenient for us to focus on computational prediction for novel miRNA homologs. Following a range of strict filtering criteria, a total of 62 potential miRNAs were identified for the first time; they belong to 39 different miRNA families. All these miRNAs were observed in the stem portion of the stable stem–loop structures. The minimum free energy (MFE) of the predicted miRNAs ranged from −21.6 to −62.7 kcal/mol with an average of −39.2 kcal/mol. The A + U ranged from 32.5 to 69.1% with an average value of 52.2%. The phylogenetic analysis of predicted miRNAs revealed that miR-23a-3p, miR-184-3p, miR-214-5p, and miR-338-3p from B. pectinirostris are evolutionary highly conserved showing more similarity with other fish species. To verify the predicted miRNAs, selected miRNAs representing 16 of the 39 families were confirmed by stem–loop RT-PCR, indicating that the computational approach that we used to identify the miRNAs is a highly efficient and affordable alternative method. Taken together, these findings provide a reference point for further research on miRNAs identification in fish species, meanwhile, our study also will be useful for further insight into biological functions of miRNAs and improved understanding of genome in B. pectinirostris.

Culturable fungal endophytes in shoots of Dendrobium aqueum Lindley – An imperiled orchid

Three non–mycorrhizal endophytic fungi were isolated and identified in a threatened epiphytic orchid Dendrobium aqueum Lindley. Stem, leaf and pseudobulb segments obtained from wild plants collected from Kolli hills, Tamil Nadu, India were used to isolate the fungi. Both morphology and molecular sequencing of internal transcribed spacer (ITS) regions of endophytic fungi revealed that all three isolates belonged to the genus Colletotrichum. Endophytes colonization rate was higher on basal stem segments (27.78%) compared to other stem portions, leaves (16.67%) and pseudobulbs (16.67%). All three endophytes showed organ specificity with higher assemblage in stem segments, whereas leaf and pseudobulb segments contained only one endophyte. The wild plants showed no major disease symptoms to affect leaf or plant growth, except few minor dark or grey spots on the mature senescing leaves. Hence, the Colletotrichum isolates were found to be the dominant endophytes of D. aqueum, perceived to have a symbiotic relationship with it, as there were no other fungal isolates found in this study.

Stepping Library-Based Post-SELEX Strategy Approaching to the Minimized Aptamer in SPR.

When evolved from SELEX (systematic evolution of ligands by exponential enrichment), aptamers are generally about 70-130 nucleotides in length and needed to be effectively truncated for further diagnosis or therapeutic uses. Post-SELEX optimization is then aroused to simplify the aptamer sequence and improve the affinity property. In this work, we report a new post-SELEX strategy based on a stepping library for the first time. With a hypothesis that one nucleobase can influence the whole binding affinity through its adjacent base stacking and potential steric hydrogen bonding interaction, we designed a stepping library composed of all probable nucleotide truncation directions. We employed an aptamer 807-39nt toward EPO-α as a model, and surface plasmon resonance (SPR) as an efficient screening and evaluation method to optimize all label-free sequences in the library. We have successfully picked out In27 as the minimized aptamer from a mini library of only 35 sequences. Aptamer In27 has a sole loop, without the original stem portion of the initial aptamer, but retains the whole binding affinity. We have also defined the key nucleotide contribution by site mutagenesis with natural bases, and finally produced a degenerated sequence with higher or the same good affinities. Furthermore, we explored different binding behaviors between aptamer In27 and other recognition molecule such as agglutinin, monoclonal antibody, or receptor by competition or binding assays. Our work provides a new and efficient post-SELEX optimization strategy, as well as a minimized aptamer In27 with an explicit degenerated sequence and a defined binding behavior. That would enhance their great potential in future diagnosis and therapy.

Recovering energy biomass from sustainable forestry using local labor resources

Logging residues from sustainable forest operations can be recovered as biomass feedstock for renewable energy generation. Under the conditions of developing economies, residue recovery is best performed with manual techniques, because labour cost is still low, whereas capital availability is limited. Furthermore, manual recovery minimizes fossil inputs and creates employment opportunity for self-employed forest villagers in disadvantaged rural areas, and it may help contrasting landscape neglect and rampant urbanization. This study offers the example of residue recovery from the regeneration cut of mature Turkish pine (Pinus brutia Ten.). Even after all stem and branch portions are recovered to a minimum small-end diameter of 4 cm for the production of conventional firewood logs, residues amount to 15–30 fresh t ha−1 and require windrowing before replanting. Approximately 50% of the residue can be recovered as energy biomass, after separating the fibre rich portion from twigs and leaves. This operation allows additional recovery, while minimizing nutrient removal. Productivity was estimated between 0.3 and 0.7 fresh t h−1, for a three-men crew. Manual extraction of processed residues to the roadside proceeded at a pace between 0.8 and 1.7 fresh t h−1 for the same crew. Best results were obtained when processing was performed after removing all conventional product, and before windrowing the residues. The most effective extraction method was throwing the biomass sticks downhill to the roadside. Processing and extraction cost amounted to 27 € fresh t−1, or 8.3 € MWh−1. After accounting for delay time, for chipping, transportation and all other indirect cost, total delivered cost amounted to 14.3 € MWh−1. That was over the 10 € MWh−1 target, indicating the need for increased efficiency, possibly obtained through better mechanization. The results of this study might be generalized and extended to many other developing economies, where the rational recovery of logging residues may offer significant economic, environmental and social benefits.

Sugars levels of four sugarcane genotypes in different stem portions during the maturation phase.

Maturation is a characteristic of sugarcane plant (Saccharum spp.) and even when grown under the same soil and climate conditions the varieties differ on the maturation curve. Thus, studies that allow establishing maturation curves of different sugarcane genotypes in the local soil and climate may indicate the proper harvesting period to ensure better quality of the raw material. This study aimed to analyze the levels of soluble sugars during the maturation phase and assess the technological and productivity indexes of four irrigated sugarcane genotypes in the region of Rio Largo, Alagoas. The experiment was conducted in randomized blocks in a 4 x 2 x 5 factorial: four genotypes (RB92579, RB98710, RB99395 and RB961003), two stem portions (internodes 1-4 and internodes 5-8) and five seasons (82, 49, 25, 13 and 3 days before harvesting), each treatment with three replications. Internodes 1-4 showed the highest levels of reducing sugars, while the largest accumulation of sucrose and total soluble solids occurred in internodes 5-8. RB99395 genotype showed more stability in the sugar levels during sugarcane maturation, which can indicate early maturation and high agricultural yield.

Functionally interchangeable cis-acting RNA elements in both genome segments of a picorna-like plant virus

Cis-acting RNA structures in the genomes of RNA viruses play critical roles in viral infection, yet their importance in the bipartite genomes of the picorna-like, plant-infecting comoviruses has not been carefully investigated. We previously characterized SLC, a stem-loop structure in the 5′ untranslated region (UTR) of the bean pod mottle comovirus (BPMV) RNA2, and found it to be essential for RNA2 accumulation in infected cells. Here we report the identification of SL1, a similar cis-acting element in the other BPMV genome segment - RNA1. SL1 encompasses a portion of RNA1 5′ UTR but extends into the coding sequence for nine nucleotides, thus was missed in the previous study. While the stems of SL1 and SLC share little sequence similarity, their end loops are of the same size and identical for 11 of 15 nucleotides. Importantly, SL1 and SLC are functionally interchangeable, and separate exchanges of the stem and loop portions were likewise well tolerated. By contrast, the conserved loop sequence tolerated minimal perturbations. Finally, stem-loop structures with similar configurations were identified in two other comoviruses. Therefore, SL1 and SLC are likely essential comoviral RNA structures that play a conserved function in viral infection cycles.

Interferon-inducible ribonuclease ISG20 inhibits hepatitis B virus replication through directly binding to the epsilon stem-loop structure of viral RNA.

Hepatitis B virus (HBV) replicates its DNA genome through reverse transcription of a viral RNA pregenome. We report herein that the interferon (IFN) stimulated exoribonuclease gene of 20 KD (ISG20) inhibits HBV replication through degradation of HBV RNA. ISG20 expression was observed at basal level and was highly upregulated upon IFN treatment in hepatocytes, and knock down of ISG20 resulted in elevation of HBV replication and attenuation of IFN-mediated antiviral effect. The sequence element conferring the susceptibility of HBV RNA to ISG20-mediated RNA degradation was mapped at the HBV RNA terminal redundant region containing epsilon (ε) stem-loop. Furthermore, ISG20-induced HBV RNA degradation relies on its ribonuclease activity, as the enzymatic inactive form ISG20D94G was unable to promote HBV RNA decay. Interestingly, ISG20D94G retained antiviral activity against HBV DNA replication by preventing pgRNA encapsidation, resulting from a consequence of ISG20-ε interaction. This interaction was further characterized by in vitro electrophoretic mobility shift assay (EMSA) and ISG20 was able to bind HBV ε directly in absence of any other cellular proteins, indicating a direct ε RNA binding capability of ISG20; however, cofactor(s) may be required for ISG20 to efficiently degrade ε. In addition, the lower stem portion of ε is the major ISG20 binding site, and the removal of 4 base pairs from the bottom portion of ε abrogated the sensitivity of HBV RNA to ISG20, suggesting that the specificity of ISG20-ε interaction relies on both RNA structure and sequence. Furthermore, the C-terminal Exonuclease III (ExoIII) domain of ISG20 was determined to be responsible for interacting with ε, as the deletion of ExoIII abolished in vitro ISG20-ε binding and intracellular HBV RNA degradation. Taken together, our study sheds light on the underlying mechanisms of IFN-mediated HBV inhibition and the antiviral mechanism of ISG20 in general.

Distinctive wood anatomy of the root-parasitic family Lennoaceae (Boraginales)

The four species of Lennoaceae have strands of primary plus secondary xylem in a background of starch-rich parenchyma. These strands constitute a cylinder with large primary rays. The wood within these strands is markedly different from that of other families in the crown group of Boraginales such as Cordiaceae and Ehretiaceae, most of which are woody. Lennoaceae differ because they lack fibrous cells (libriform fibers), lack rays within the vascular strands, and have markedly elliptical vessel-to-vessel pits without vestures. Lennoaceae have secondary xylem with short, wide vessel elements with thick walls, horizontally elongate elliptical pits, simple perforation plates much narrower than the vessel lumen; variously uneven vessel wall thickenings; and axial parenchyma. The wood of Lennoaceae shows resemblances to unrelated succulents such as Kalanchoe (Crassulaceae) and Lithops (Aizoaceae). The vessel features also suggest adaptation to high water tensions as root parasites in desert areas, whereas the lack of imperforate tracheary elements may relate to support of the underground stem portions by sand or rock detritus. Habit and ecology are more important in the architecture of lennoaceous xylem than systematic affinities. The four species of Lennoaceae differ from each other in minor xylary features.

Biological Investigation of Jatropha gossypiifolia: A Stiff Medicinal Plant in Bangladesh

This study describes a biological investigations of methanolic extract of Jatropha gossypiifolia, a plant belonging to the family Euphorbiaceae. The aim of this investigation was to expose the viable phytochemical constituents properly as their contribution towards the antioxidant, anthelmintic and membrane stabilizing activities. The anthelmintic test was conducted on earthworm Pheritima phosthuma using five unique concentrations of the extract and albendazole as standard drug. The extracts were used for the investigation of antioxidant activity followed by DPPH assay and using BHT as a standard. The crude methanolic stem and leaves extract of J. gossypiifolia was conducted to attempt for membrane stabilizing activities using standard protocols. The leaves and the stems portion considerably have the antioxidant property of 3.186 µg/ml and 10.56 µg/ml respectively. According to the absorbance values of the various extract solutions, results of the colorimetric analysis of total phenolic are that the leaves cover the highest Phenolic content (65.66mg/g in GAE) rather than the stem portion (33.332mg/g in GAE). The leaves and stem methanolic extract was found both at hypotonic solution and heat induced conditions, inhibit 39.19±0.26%, 38.17±0.14 and 27.39±0.15%, 26.97±0.47% hemolysis of erythrocyte membrane respectively, when comparing standard acetyl salicylic acid. The preliminary phytochemical evaluation of methanolic extract of J. gossypiifolia confirmed the presence of glycosides, tannins, phytosterols, triterpenoids, diterpenes, saponins and phenols both at its leaves and stem portions. The results of the study showed that the plant extract has potential membrane stabilizing, anthelmintic, antioxidant activities with significant phytochemicals.

Transcriptome portrait of cellulose-enriched flax fibres at advanced stage of specialization.

Functional specialization of cells is among the most fundamental processes of higher organism ontogenesis. The major obstacle to studying this phenomenon in plants is the difficulty of isolating certain types of cells at defined stages of in planta development for in-depth analysis. A rare opportunity is given by the developed model system of flax (Linum usitatissimum L.) phloem fibres that can be purified from the surrounding tissues at the stage of the tertiary cell wall deposition. The performed comparison of the whole transcriptome profile in isolated fibres and other portions of the flax stem, together with fibre metabolism characterization, helped to elucidate the general picture of the advanced stage of plant cell specialization and to reveal novel participants potentially involved in fibre metabolism regulation and cell wall formation. Down-regulation of all genes encoding proteins involved in xylan and lignin synthesis and up-regulation of genes for the specific set of transcription factors transcribed during tertiary cell wall formation were revealed. The increased abundance of transcripts for several glycosyltransferases indicated the enzymes that may be involved in synthesis of fibre-specific version of rhamnogalacturonan I.

Biological and functional evaluation of a novel pyrolytic carbon implant for the treatment of focal osteochondral defects in the medial femoral condyle: assessment in a canine model.

BackgroundOsteochondral defects continue to be a clinical treatment challenge, and when left untreated, may cause pain and functional impairment. Pyrolytic carbon is a unique isotropic biomaterial used in heart valve and small joint replacements due to its excellent wear properties and biocompatibility with bone and articular cartilage. Therefore, a proposed solution is to utilize a focal pyrolytic carbon hemiarthroplasty implant as an alternative resurfacing treatment strategy for isolated cartilage lesions.MethodsA canine model (n = 9) was used to evaluate the in vivo histologic response and function of a pyrolytic carbon implant replacing a full-thickness osteochondral defect in the medial femoral condyle (MFC) of the knee. The gross appearance and histologic results were compared to an identical cobalt-chromium (Co-Cr) alloy implant placed in a defect in the contralateral MFC and evaluated up to 52 weeks.ResultsExtensive bone incorporation to the stem portion was observed for both implant types. The total mean histologic score for the cartilage of the MFC surrounding the pyrolytic carbon implants was significantly improved compared to that of the Co-Cr alloy implants at all evaluation periods (p < 0.05). Histologic grading and gross observations at 52 weeks for pyrolytic carbon implants were similar to those of Co-Cr alloy implants at 24 weeks. At 24 weeks, the mean total histologic score for Co-Cr alloy implants was 11.6 ± 0.7 (0–16 range point; 16 = normal appearance), while at 52 weeks, the mean total score for the pyrolytic carbon implants was 11.7 ± 1.3. Mean total histologic score of opposing medial tibia cartilage for the pyrolytic carbon implants was superior to that of the Co-Cr alloy group at all evaluation periods and significantly improved over the Co-Cr alloy implant group at 24 weeks (p = 0.001) and 52 weeks (p < 0.001).ConclusionsUse of a pyrolytic carbon implant for reconstruction of a focal cartilage defect demonstrated effective implant fixation and superior in vivo response compared to an identical Co-Cr alloy implant.