Mature Zone Research Articles

Comparing Essentiality of SOS1-Mediated Na+ Exclusion in Salinity Tolerance between Cultivated and Wild Rice Species.

Soil salinity is a major constraint that affects plant growth and development. Rice is a staple food for more than half of the human population but is extremely sensitive to salinity. Among the several known mechanisms, the ability of the plant to exclude cytosolic Na+ is strongly correlated with salinity stress tolerance in different plant species. This exclusion is mediated by the plasma membrane (PM) Na+/H+ antiporter encoded by Salt Overly Sensitive (SOS1) gene and driven by a PM H+-ATPase generated proton gradient. However, it is not clear to what extent this mechanism is operational in wild and cultivated rice species, given the unique rice root anatomy and the existence of the bypass flow for Na+. As wild rice species provide a rich source of genetic diversity for possible introgression of abiotic stress tolerance, we investigated physiological and molecular basis of salinity stress tolerance in Oryza species by using two contrasting pairs of cultivated (Oryza sativa) and wild rice species (Oryza alta and Oryza punctata). Accordingly, dose- and age-dependent Na+ and H+ fluxes were measured using a non-invasive ion selective vibrating microelectrode (the MIFE technique) to measure potential activity of SOS1-encoded Na+/H+ antiporter genes. Consistent with GUS staining data reported in the literature, rice accessions had (~4–6-fold) greater net Na+ efflux in the root elongation zone (EZ) compared to the mature root zone (MZ). Pharmacological experiments showed that Na+ efflux in root EZ is suppressed by more than 90% by amiloride, indicating the possible involvement of Na+/H+ exchanger activity in root EZ. Within each group (cultivated vs. wild) the magnitude of amiloride-sensitive Na+ efflux was higher in tolerant genotypes; however, the activity of Na+/H+ exchanger was 2–3-fold higher in the cultivated rice compared with their wild counterparts. Gene expression levels of SOS1, SOS2 and SOS3 were upregulated under 24 h salinity treatment in all the tested genotypes, with the highest level of SOS1 transcript detected in salt-tolerant wild rice genotype O. alta (~5–6-fold increased transcript level) followed by another wild rice, O. punctata. There was no significant difference in SOS1 expression observed for cultivated rice (IR1-tolerant and IR29-sensitive) under both 0 and 24 h salinity exposure. Our findings suggest that salt-tolerant cultivated rice relies on the cytosolic Na+ exclusion mechanism to deal with salt stress to a greater extent than wild rice, but its operation seems to be regulated at a post-translational rather than transcriptional level.

Introns in the Naa50 gene act as strong enhancers of tissue-specific expression in Arabidopsis

Naa50 is the catalytic subunit of N-terminal acetyltransferase complex E, which plays an important role in regulating plant development, endoplasmic reticulum stress and immune responses in Arabidopsis. In this study, the complete genomic sequence (but not the coding sequence) of Naa50 rescued the phenotype of Naa50 deletion mutants. Naa50 expression was noted in whole roots except for central root cap cells. The deletion of intron 1 resulted in a loss of Naa50 expression in the root meristem zone and in the epidermis, cortex and endodermis of the elongation zone and mature zone, while the deletion of intron 2 decreased Naa50 expression in the epidermis, cortex and endodermis of the root elongation zone and mature zone. The native Naa50 promoter together with introns 1 and 2 promotes the expression of Naa50 in sepal vascular bundles, filaments, pollen and stigmas; however, neither intron has positive effect on Naa50 expression in mature rosette leaves. The results of this study show that introns 1 and 2 in the Naa50 gene function as enhancers to promote the tissue-specific expression of Naa50.

Subsurface geology and geochemical evaluation of the Middle Jurassic-Lower Cretaceous organic-rich intervals, West Kalabsha area, Western Desert, Egypt

The West Kalabsha (WKAL) area is a western extreme exploratory area of the Faghur Basin in the Western Desert of Egypt. The study of four wells (WKAL; A-1 X, K-1 X, P-1X, and C-1 X), interpreted with twenty seismic lines, shows that the area is dissected by a series of normal faults with an irregular, E–W strike direction. The general trend of the throw is toward the south–southeast. The most prospective area for hydrocarbon (HC) migration is toward the north (upthrown side) of an E-W striking normal fault north of the WKAl-K-1 X and A-1 X wells. The WKAL-P-1 X and WKAL-K-1 X wells in the Faghur Basin were selected for both geochemical evaluation of possible source rock intervals and burial history modelling within the basin. Integration of the wire-line logs with geochemical analysis identified six organic matter-rich intervals (OMRIs) within the Middle Jurassic-Lower Cretaceous sequence. Four intervals are in the Alam El-Bueib-3C (AEB-3C) member with a cumulative vertical thickness of 530ft. The other OMRIs are 110ft in thickness recorded within the AEB-6 (10ft) and Upper Safa (100ft) members. The studied organic matter (OM) reveals type III, IIIC, and IV kerogens (mainly gas-prone) with a terrestrial origin. They have reached a maturity level consistent with the late oil window. The expulsion threshold depth detected in the WKAL-P-1 X well is 12000ft in the AEB-3C member, whereas the active source depth limit (ASDL) is 15000ft in the Safa Member. The present study suggests a paleo-geothermal gradient range between 1.13oF/100ft and 1.39oF/100ft with an estimated regional erosion of 5500 to 7000ft of strata mainly between the Paleozoic-Jurassic and Cretaceous-Tertiary boundaries. The present-day geothermal gradient based on bottom-hole temperatures shows a geothermal gradient of 1.4oF/100ft (WKAL-P-1 X), that increases to the north to 1.65oF/100ft (WKAL-K-1 X). Burial history modelling reveals that sedimentary strata entered the mature oil zone in the Early Cretaceous (110–115Ma) at depths of 7500–8000ft in the deepest part of WKAL-P-1 X and WKAL-K-1 X wells (Paleozoic strata). Maturation continued to present, resulting in Jurassic and Lower Cretaceous strata currently falling into the late oil window.

Glycosaminoglycan, Antimicrobial Defence Molecule and Cytokine Appearance in Tracheal Hyaline Cartilage of Healthy Humans.

Hyaline cartilage is an important tracheal structure, yet little is known about its molecular composition, complicating investigation of pathologies and replacement options. Our aim was to research tracheal hyaline cartilage structure, protective tissue factors and variations in healthy humans. The tissue material was obtained from 10 cadavers obtained from the Riga Stradins University Institute of Anatomy and Anthropology archive. Tissues were stained with Bismarck brown and PAS for glycosaminoglycans, and immunohistochemistry was performed for HBD-2, HBD-3, HBD-4, IL-10 and LL-37. The slides were inspected by light microscopy and Spearman’s rank correlation coefficient was calculated. The extracellular matrix was positive across hyaline cartilage for PAS, yet Bismarck brown marked positive proliferation and growth zones. Numerous positive cells for both factors were found in all zones. All of the antimicrobial defence molecules and cytokines were found in a moderate number of cells, except in the mature cell zone with few positive cells. Spearman’s rank correlation coefficient revealed strong and moderate correlations between studied factors. Hyaline cartilage is a tracheal defence structure with a moderate number of antimicrobial defence protein and cytokine immunoreactive cells as well as numerous glycosaminoglycan positive cells. The extracellular matrix glycosaminoglycans provide structural scaffolding and intercellular signalling. The correlations between the studied factors confirm the synergistic activity of them.

Brassinosteroid signaling restricts root lignification by antagonizing SHORT-ROOT function in Arabidopsis.

Cell wall lignification is a key step in forming functional endodermis and protoxylem (PX) in plant roots. Lignified casparian strips (CS) in endodermis and tracheary elements of PX are essential for selective absorption and transport of water and nutrients. Although multiple key regulators of CS and PX have been identified, the spatial information that drives the developmental shift to root lignification remains unknown. Here, we found that brassinosteroid (BR) signaling plays a key role in inhibiting root lignification in the root elongation zone. The inhibitory activity of BR signaling occurs partially through the direct binding of BRASSINAZOLE-RESISTANT 1 (BZR1) to SHORT-ROOT (SHR), repressing the SHR-mediated activation of downstream genes that are involved in root lignification. Upon entering the mature root zone, BR signaling declines rapidly, which releases SHR activity and initiates root lignification. Our results provide a mechanistic view of the developmental transition to cell wall lignification in Arabidopsis thaliana roots.

Fracturing and pore-fluid distribution in the Marlborough region, New Zealand from body-wave tomography: Implications for regional understanding of the Kaikōura area

Relative to more mature fault zones, immature fault zones that have accumulated smaller total displacement are characterized by less efficient strain localization and more complicated earthquake ruptures. How differences in maturation are reflected in regional-scale upper-crustal fracturing is not well known. Recently, complicated earthquake ruptures associated with immature fault zones, such as the 2016 Kaikōura earthquake in New Zealand, have occurred in areas that are in regional proximity (<100 km away) to more mature faults. Here we examine whether inefficient strain localization in less mature fault zones is associated with a broader distribution and anomalously elevated concentration of fractures over distances of tens of kilometers. We use regional seismic arrival-time tomography in a broad area around the Kaikōura earthquake to investigate lateral variations in Vp and Vp/Vs. Focusing on the extensively faulted but compositionally uniform Torlesse-Pahau terrane in the Marlborough region where the earthquake occurred, we attribute lateral variations in Vp and Vp/Vs to differences in concentration of fluid-filled fractures. Using numerical models relating seismic velocities and fracturing, we solve for the lateral variation in concentration of ∼0.01 aspect ratio fluid-filled fractures. We find that areas near the Kaikōura rupture have >3% elevated fracture porosity compared to the adjacent area to the north. The elevated regional fracturing in the Kaikōura area is interpreted to result from more distributed deformation, and broader distribution of earthquakes, due to inefficient localization of strain from a regionally uniform strain rate field, highlighting the relationship between relative maturity of upper-crustal fault zones and lateral variability of regional upper-crustal properties.Plain language summary:When earthquakes occur in immature fault zones (areas that have accumulated small total displacement), they tend to rupture multiple poorly developed faults of diverse orientations. In contrast, more mature fault zones are associated with more developed, smoother faults and more localized earthquake activity. How these differences in maturation are reflected in the regional distribution of fractures is not well known. Here we use the arrival times of P and S waves from earthquakes to constrain seismic velocities (Vp and Vp/Vs) and use numerical models to relate seismic velocities to fracture concentration. We focus on the Marlborough region of the South Island, New Zealand, where immature fault zones recently ruptured during the 2016 Kaikōura earthquake but which also has more mature fault zones <100 km away. We find elevated fracture concentrations (3% higher fracture porosity), indicative of more distributed deformation along immature fault zones relative to more mature fault zones. In immature settings, fracturing is not as effectively localized along individual fault traces, leading to a broadly distributed fracture network.

Sugarcane Root Transcriptome Analysis Revealed the Role of Plant Hormones in the Colonization of an Endophytic Diazotroph.

Some sugarcane germplasms can absorb higher amounts of nitrogen via atmospheric nitrogen fixation through the bacterial diazotrophs. Most endophytic diazotrophs usually penetrate through the root, colonize inside the plant, and fix the nitrogen. To assess the plant’s bacterial association during root colonization, strain GXS16 was tagged with a plasmid-bear green fluorescent protein (GFP) gene. The results demonstrated that the strain can colonize roots all the way to the maturation zone. The strain GXS16 showed maximum nitrogenase enzyme activity at pH 8 and 30°C, and nitrogenase activity is less affected by different carbon sources. Further, strain GXS16 colonization response was investigated through plant hormones analysis and RNAseq. The results showed that the bacterial colonization gradually increased with time, and the H2O2 and malondialdehyde (MDA) content significantly increased at 1 day after inoculation. There were no substantial changes noticed in proline content, and the ethylene content was detected initially, but it decreased with time. The abscisic acid (ABA) content showed significant increases of 91.9, 43.9, and 18.7%, but conversely, the gibberellin (GA3) content decreased by 12.9, 28.5, and 45.2% at 1, 3, and 5 days after inoculation, respectively. The GXS16 inoculation significantly increased the activities of catalase (CAT), superoxide dismutase (SOD), polyphenol oxidase (PPO), ascorbate peroxidase (APX), and glutathione reductase (GR) at different timepoint. In contrast, the peroxisome (POD) activity had no changes detected during the treatment. In the case of RNAseq analysis, 2437, 6678, and 4568 differentially expressed genes (DEGs) were identified from 1, 3, and 5 days inoculated root samples, and 601 DEGs were shared in all samples. The number or the expression diversity of DEGs related to ethylene was much higher than that of ABA or GA, which indicated the critical role of ethylene in regulating the sugarcane roots response to GXS16 inoculation.

Cell-type-specific H+-ATPase activity and antioxidant enzymes improve the Echinacea purpurea L. Moench tolerance to salinity stress at different NO3-/NH4+ ratios

While the importance of biochemical processes in plant adaptive responses is widely accepted, only a limited number of studies have addressed cell-type specific and enzymatic activities in E. purpurea under salt stress conditions. So, various antioxidant enzymatic activities, H+ transport activity, and non-invasive ion flux mechanisms in the root apex and mature zones of E. purpurea grown at different NO3-/NH4+ ratios (90:10, 80:20, and 70:30) were studied in salinity stress condition (0, 15, 30, and 60 mM NaCl). Various parameters, photosynthetic and transpiration rates, gas exchange, ion accumulation, electrolyte leakage (EL) in addition to antioxidant enzyme activities and cell-specific mechanisms were measured according to the standard methods. Based on the results, 60 mM NaCl salinity stress significantly decomposed the cell membrane, causing to increase in the electrolyte leakage and malondialdehyde (MDA) content (89.4% compared with control) and a decrease in the photosynthetic rate (84% compared with control). The activity of antioxidant enzymes such as superoxide dismutase (SOD) and ascorbate peroxidase (APX), catalase (CAT), and glutathione peroxidase (GP) significantly increased up to 30 mM NaCl to diminish the free radicals content by increasing the hydrogen peroxide (H2O2) concentration (89.4% compared with control). High Na+ and Cl- content and their accumulation in the leaves caused to inhibit the antioxidants enzymes activities at 60 mM NaCl salinity stress. Based on the nitrogen (N) supply form, more antioxidant activities and physiological properties were found at the 90:10 NO3-/NH4+ ratio. Salinity stress is caused to limit the root apex growth in a high tissue- and treatment-specific manner. The differential sensitivity between the two zones originates from a 10-fold difference in K+ efflux and H+-ATPase activity between the mature zone and the apical region.

Arabidopsis ROOT ELONGATION RECEPTOR KINASES negatively regulate root growth putatively via altering cell wall remodeling gene expression.

Receptor-like kinases (RLKs) play key roles in regulating various physiological aspects in plant growth and development. In Arabidopsis thaliana, there are at least 223 leucine-rich repeat (LRR) RLKs. The functions of the majority of RLKs in the LRR XI subfamily were previously revealed. Only three RLKs were not characterized. Here we report that two independent triple mutants of these RLKs, named ROOT ELONGATION RECEPTOR KINASES (REKs), exhibit increased cell numbers in the root apical meristem and enhanced cell size in the elongation and maturation zones. The promoter activities of a number of Quiescent Center marker genes are significantly up-regulated in the triple mutant. However, the promoter activities of several marker genes known to control root stem cell niche activities are not altered. RNA-seq analysis revealed that a number of cell wall remodeling genes are significantly up-regulated in the triple mutant. Our results suggest that these REKs play key roles in regulating root development likely via negatively regulating the expression of a number of key cell wall remodeling genes.

Comparative Transcriptome Analysis Reveals Common and Developmental Stage-Specific Genes That Respond to Low Nitrogen in Maize Leaves.

A growing leaf can be divided into three sections: division zone, elongation zone, and maturation zone. In previous studies, low nitrogen (LN) inhibited maize growth and development, especially leaf growth; however, the gene expression in response to LN in different regions in leaf were not clear. Here, using hydroponics and a transcriptome approach, we systematically analyzed the molecular responses of those zones and differentially expressed genes (DEG) in response to LN supply. Developmental stage-specific genes (SGs) were highly stage-specific and involved in distinct biological processes. SGs from division (SGs–DZ) and elongation zones (SGs–EZ) were more related to developmentally dependent processes, whereas SGs of the maturation zone (SGs–MZ) were more related to metabolic processes. The common genes (CGs) were overrepresented in carbon and N metabolism, suggesting that rebalancing carbon and N metabolism in maize leaves under LN condition was independent of developmental stage. Coexpression modules (CMs) were also constructed in our experiment and a total of eight CMs were detected. Most of SGs–DZ and SGs–EZ were classified into a set termed CM turquoise, which was mainly enriched in ribosome and DNA replication, whereas several genes from SGs–MZ and CGs were clustered into CM blue, which mainly focused on photosynthesis and carbon metabolism. Finally, a comprehensive coexpression network was extracted from CM blue, and several maize CONSTANS-LIKE(ZmCOL) genes seemed to participate in regulating photosynthesis in maize leaves under LN condition in a developmental stage-specific manner. With this study, we uncovered the LN-responsive CGs and SGs that are important for promoting plant growth and development under insufficient nitrogen supply.

Developmental Characteristics of the Glomerular and Tubular Portion of the Nephron in the Human Foetal Kidney Cortex: Morphometrical and Immunohistochemical Analysis

This study aimed to morphometrically examine the development of glomeruli and tubules in the kidney cortex of human foetuses at different gestational ages (GAs). We also investigated the expression of the proliferation marker Ki-67 and apoptosis-related markers Bcl-2 and Bax during nephrogenesis using immunohistochemistry. Kidney samples from 38 human foetuses of both sexes with GA ranging from 13 to 40 weeks were analysed. The samples were divided into 7 groups based on GA, each corresponding to 1 lunar month. Foetal kidneys showed a spatiotemporal gradient of nephron differentiation with the transient stages of nephron anlage located in the nephrogenic zone and immature nephrons located in the subjacent maturation zone. In the inner cortex, nephrons establish the morphological characteristics of definitive nephrons. The average area, perimeter, and Feret’s diameter of the glomeruli formed within the kidney cortex gradually decreased up to a period of 29–32 weeks of gestation and subsequently increased until a period of 37–40 weeks. There was a weak negative correlation with GA. In contrast, the areal density of glomeruli increased up to a period of 21–24 weeks and then gradually decreased until a period of 37–40 weeks, showing a moderate negative correlation with GA. The average area of renal tubules slightly decreased until a period of 21–24 weeks of gestation and then gradually increased until a period of 36–40 weeks, showing a moderate positive correlation with GA. The average areal density of renal tubules increased significantly until a period of 21–24 weeks of gestation, remained relatively constant until a period of 33–36 weeks, and then increased significantly at 36–40 weeks. There was a strong positive correlation with GA. Our results showed that Ki-67 was expressed in numerous cells of the metanephric mesenchyme, pretubular aggregates, renal vesicles, comma-shaped bodies, and early S-shaped bodies. During subsequent development and the spatial expansion of nephrons towards the mature zone, the expression of Ki-67 was markedly reduced. Similarly, Bcl-2 was strongly expressed in induced nephrogenic progenitor cells, pretubular aggregates, renal vesicles, and comma-shaped bodies. As vascularisation and maturation of the nephron proceeded, Bcl-2 staining became less intense and limited to the parietal layer of the Bowman’s capsule and renal tubules. Weak Bax expression was observed in individual scattered cells within segments of the nephrons at all developmental stages. In the mature zone, more intense Bax staining was observed in the renal tubules.

Has the Construction of National High-Tech Zones Promoted Regional Economic Growth?—Empirical Research from Prefecture-Level Cities in China

As a “special economic zone” and “policy test field” in the region, the national high-tech zone is an important strategy for the country to promote the development of high-tech industries and regional economy, but its effect needs to be verified. This paper uses panel data of 281 prefecture-level cities in China from 1994 to 2019, and uses the differences-in-differences method to study the impact of high-tech zones on regional economic development. On this basis, the heterogeneity effects of different types of high-tech zones on regional economic growth are explored. The empirical research results show that the national high-tech zone promotes regional economic growth, and this conclusion still holds after conducting multiple robustness tests. Further research found that the promotion of national high-tech zones to economic development showed the law of “diminishing marginal effect”: Compared with higher-level cities, lower-level cities gained faster development from the construction of national high-tech zones. Compared with the developed regions in the east, the underdeveloped regions in the west have achieved faster development from the construction of the national high-tech zone. In addition, this paper finds that growth-type high-tech zones have a greater marginal contribution to regional economic growth than mature high-tech zones; multi-zone high-tech zones have a greater marginal contribution to regional economic growth than single-zone high-tech zones. The research of this paper shows that the national high-tech zones as “policy test fields” and “special economic zones” can not only drive economic development, but also help narrow the economic development gap between regions through their rational distribution. This provides important inspiration for the future layout of the national high-tech zone and the establishment of other related policies.

Auxin-Cytokinin Balance Shapes Maize Root Architecture by Controlling Primary Root Elongation and Lateral Root Development.

The root system is responsible for water and nutrients uptake from the soil, and therefore, its extension is basic for an efficient acquisition. The maize root system is formed by different types of roots, and the lateral root branching substantially increases the surface for nutrient uptake. Therefore, the regulation of lateral root formation is fundamental in the development of root functions. Root architecture is basically controlled by auxin and cytokinins, which antagonize in the formation of lateral roots (LR) along the primary root axis, with auxin, a stimulator, and cytokinins inhibitors of LR development. This interaction has been analyzed in several zones along the primary root where LRs in different developmental stages were located. The root has been divided into several zones, such as meristem, elongation zone, and mature zone, according to the developmental processes occurring in each one. As Arabidopsis root elongated more slowly than maize root, these zones are shorter, and its delimitation is more difficult. However, these zones have previously been delimitated clearly in maize, and therefore, they analyze the effect of exogenous hormones in several LR developmental stages. The inhibitory effect of cytokinin on lateral root formation was observed in already elongated primary root zones in which initial events to form new lateral roots are taking place. Contrarily, auxin increased LR formation in the primary root segments elongated in the presence of the hormone. The inhibitory effect of cytokinin was reversed by auxin in a concentration-dependent manner when both hormones were combined. However, auxin is unable to recover LR development in primary root zones that have been previously elongated only in the presence of cytokinin. This antagonistic auxin-cytokinin effect on LR development depended on the balance between both hormones, which controls the root system architecture and determines the formation of LR during the process of initiation.

ANALYSIS OF QUANTITY, QUALITY AND LEVEL MATURITY OF THE KLASAFET FORMATION BEDROCK USING TOTAL ORGANIC CARBON (TOC) AND ROCK-EVAL PYROLYSIS (REP) CASE STUDY OF KYANITE-1 WELL

The Salawati Basin is one of the basins located in the western part of the Bird's Head of Papua Island and is estimated to be of Tertiary. This basin was formed as a result of the activity of the Sorong Fault which began to be active since the Early Pleistocene. One of the rock formations that has the potential to become source rock in the Salawati Basin is the Klasafet Formation. The age of Klasafet Formation is between Middle Miocene and Late Miocene, which consists of claystone and limestone. Geochemical analysis is one of the techniques in interpreting the source rock potential. This analysis consists of three parts, namely the analysis of quantity, quality and maturity level of the source rock. From the results of the quantity analysis of source rock for the Klasafet Formation, the Total Organic Carbon (TOC) value ranges from fair to good. The quality analysis shows that the source rock of the Klasafet Formation tends to produce type III kerogen, while the maturity level analysis of the Klasafet Formation is in the immature-early mature zone.

Assessing implications of nanoplastics exposure to plants with advanced nanometrology techniques

Despite the increasing attention given to the impacts of nanoplastics in terrestrial environments, there is limited data about the effects on plants, and the quantitative information on uptake. In the present study, wheat plants grown in hydroponics were exposed to Pd-doped nanoplastics. This allowed us to quantify nanoplastics uptake and translocation to the shoots. Visualization of nanoplastics in roots was performed with synchrotron micro X-ray fluorescence (µXRF). Nanoplastics accumulated on the root epidermis, especially at the root tip and in root maturation zones. A close relationship between plant roots, rhizodeposits and nanoplastics behaviour was shown. Reinforcement of the cell wall in roots was evidenced using Fourier transform infrared spectroscopy (FTIR) and synchrotron-computed microtomography (µCT). Synchrotron-computed nanotomography (nanoCT) evidenced the presence of globular structures but they could not be identified as nanoplastics since they were observed both in the control and treated roots. By utilizing the inorganic tracer in the doped-nanoplastics, this study paves the road for elucidating interactions in more complex systems by using an integrative approach combining classical phytotoxicity markers with advanced nanometrology techniques.

LATERAL GROWTH AFFECTS XYLEM MATURATION PROPERTIES OF 8-YEAR-OLD BIG-LEAF MAHOGANY (SWIETENIA MACROPHYLLA)

The area of juvenile wood zone of an 8-year-old planted big-leaf mahogany (Swietenia macrophylla) was uniform regardless of diameter. Hence, it was assumed that xylem maturation is dependent on diameter. Radial distribution patterns with reference from the pith exhibited short fibre and vessel lengths, narrow vessel width and low xylem density, and exhibited gradual increase outward and became more or less stable near the bark. However, the radial distribution patterns of fibre width and modulus of elasticity were scattered regardless of tree diameter sizes. Fibre length, vessel length, vessel width and xylem density of the juvenile wood zones showed significant differences compared with the transition and mature wood zones. However, no significant difference was observed between transition wood zone and mature wood zone except for fibre length. A negative correlation was observed in fibre length, vessel length, vessel width and xylem density in terms of their relationship with diameter at breast height and the radial distribution of fibre (i.e. b-value), and the diameter boundaries of the three wood zones. At diameters 18.08, 17.36, 16.23 and 17.87 cm respectively, fibre length, vessel length, vessel width and xylem density can be used to identify xylem maturation boundary.

The role of NADPH oxidases in regulating leaf gas exchange and ion homeostasis in Arabidopsis plants under cadmium stress

NADPH oxidase, an enzyme associated with the plasma membrane, constitutes one of the main sources of reactive oxygen species (ROS) which regulate different developmental and adaptive responses in plants. In this work, the involvement of NADPH oxidases in the regulation of photosynthesis and cell ionic homeostasis in response to short cadmium exposure was compared between wild type (WT) and three RBOHs (Respiratory Burst Oxidase Homologues) Arabidopsis mutants (AtrbohC, AtrbohD, and AtrbohF). Plants were grown under hydroponic conditions and supplemented with 50 µM CdCl2 for 24 h. Cadmium treatment differentially affected photosynthesis, stomatal conductance, transpiration, and antioxidative responses in WT and Atrbohs mutants. The loss of function of RBOH isoforms resulted in higher Cd2+ influx, mainly in the elongation zone of roots, which was more evident in AtrbohD and AtrbohF mutants. In the mature zone, the highest Cd2+ influx was observed in rbohC mutant. The lack of functional RBOH isoforms also resulted in altered patterns of net K+ transport across cellular membranes, both in the root epidermis and leaf mesophyll. The analysis of expression of metal transporters by qPCR demonstrated that a loss of functional RBOH isoforms has altered transcript levels for metal NRAMP3, NRAMP6 and IRT1 and the K+ transporters outward-rectifying K+ efflux GORK channel, while RBOHD specifically regulated transcripts for high-affinity K+ transporters KUP8 and HAK5, and IRT1 and RBOHD and F regulated the transcription factors TGA3 and TGA10. It is concluded that RBOH-dependent H2O2 regulation of ion homeostasis and Cd is a highly complex process involving multilevel regulation from transpirational water flow to transcriptional and posttranslational modifications of K/metals transporters.

Radijalna varijabilnost gustine drveta i dužine vlakana u drvetu crvenog hrasta (Quercus rubra L.)

Wood density and fibre length are two wood properties that are important in determining the quality of wood for commercial use. The fibre length of red oak has not been studied to the same extent as in other oak species. The aim of this paper is to explore the anatomical variation and wood density of red oak wood, as valuable information for researchers in other fields. Samples were taken in a 60-year-old red oak stand in the south part of Belgrade on the site of Stepin Lug. Along the south radius, the disc samples of 20 x 20 mm were cut from the sapwood, mature and juvenile wood. Ovendry density and fibre length were measured from the pith to the bark. According to the obtained data, the average oven-dry density of wood per radius is 0.694 g/cm3 . The lowest is in the juvenile wood and ranges from 0.628 to 0.681 g/cm3 , then in the part of sapwood - 0.662 g/cm3 , and the highest is in the mature wood where the density ranges from 0.707 to 0.740 g/cm3 . The presented values show certain differences, but also conform to literature data on the density of some industrial species from the genus Quercus L. The obtained results of the wood fibre length show that it varies from 0.99 to 1.33 mm which was measured in mature wood. The average length in a mature zone is 1.26 (1.16-1.33) mm, while in a juvenile area the average length is 1.02 (0.85-1.23) mm. Based on the known wood fibre length, it is possible to determine the density of red oak wood. In this research, a positive influence was determined in both parts of the tree, juvenile and mature, but a better mathematical dependence was obtained in the mature zone.

Discovery of the Lower-Middle Jurassic high potential source rocks based on the geochemical investigation from the Indus Basin, Pakistan

The Lower to Middle Jurassic sedimentary succession of the Indus Basin, Pakistan represents thick strata of shale, siliciclastic and carbonate rocks. The shale is subjected to the experimental methods of total organic carbon contents (TOC), rock-eval™, vitrinite reflectance, and x-ray diffraction with clay mineralogy for identification of high potential source rock. This set of black shale having well-defined kerogen types I and II, an abundance of organic matter ≥2%, HI ≥ 150 or 200 mg HC/g TOC, Tmax ≤ 465 °C, good maturity such as 1.3–2.0 Ro%, thermal alteration index ≥2, and spore color index ≥5, and illite-smectite clay is strong enough (60–80%) to produce hydrocarbon. Furthermore, the stratigraphic thickness is ≤ 100 m in studied strata in a depth of 3500–4500 m in the Indus Basin feasible for future exploration. The chemical composition of black shale is siliceous mudstone, calcareous mudstone, argillaceous mudstone, and siliceous marlstone. The cross plot of OI versus HI and Tmax versus HI shows mature types II and I kerogen while the cross plots of TOC versus S1 + S2 with TOC versus generative potentials (GP) showing good to high potentials of indigenous hydrocarbons. The plotting of the Tmax versus productive index (PI) exhibits that the kerogen mostly lies in the mature zone, having the capacity of oil generation. Besides the geochemical properties, the studied rock is thick and widely disturbed across the Indus Basin deposited under the dysoxic-anoxic setting. Moreover, the Lower to Middle Jurassic strata are correlated with the equivalent stratigraphic formations in India and China for their importance in the regional context.

Evaluation of Petroleum Source Rock Using Well Logs in the Niger Delta Region of Nigeria

Petroleum source rock potential evaluation was carried out on eight wells of the Niger Delta’s Agbada Formation by assessing some source parameters from well logs and through well logs analysis based on organic matter effect and relationship on and with well logs. Source rock determinant parameters such as volume of shale (Vsh), total organic content (TOC), and amount of generated hydrocarbon (S2) was derived from well logs following established organic matter effects on well logs using Schlumberger's Techlog 2015 software, while hydrogen index (HI) was calculated using known values of TOC and S2 respectively. Well log data used for the analysis includes GR log, resistivity, sonic and Density logs. Apart from deriving source rock parameters, the well logs were also used to identify, quantify and somewhat determine mature zones of source rock intervals by correlation with TOC, S2, and HI source parameters respectively, Therefore, a source interval criterion composing of high GR log, high resistivity, high sonic and low-Density was developed alongside source rock parameters. Results of the analysis in the area show poor to fair source rock quality rating in terms of TOC, and insufficient source rock thickness fit for sustaining a world-class petroleum province like the ND petroleum province and further depicting that the Agbada FM may not be the principal source rock of the area. It is, therefore, recommended that more elaborate studies covering greater depths of the Agbada FM be carried out in other to properly represent the true source quality of the area.