Role Of Grains Research Articles

OsNAC121 regulates root development, tillering, panicle morphology, and grain filling in rice plant.

Transcription factors in coordination with phytohormones form an intricate regulatory network modulating vital cellular mechanisms like development, growth and senescence in plants. In this study, we have functionally characterized the transcription factor OsNAC121 by developing gene silencing and overexpressing transgenic rice plants, followed by detailed analyses of the plant architecture. Transgenic lines exhibited remodelling in crown root development, lateral root structure and density, tiller height and number, panicle and grain morphologies, underpinning the imbalanced auxin: cytokinin ratio due to perturbed auxin transportation. Application of cytokinin, auxin and abscisic acid increased OsNAC121 gene expression nearly 17-, 6- and 91-folds, respectively. qRT-PCR results showed differential expressions of auxin and cytokinin pathway genes, implying their altered levels. A 47-fold higher expression level of OsNAC121 during milky stage in untransformed rice, compared to 14-day old shoot tissue, suggests its crucial role in grain filling; as evidenced by a large number of undeveloped grains produced by the gene silenced lines. Crippled gravitropic response by the transgenic plants indicates their impaired auxin transport. Bioinformatics revealed that OsNAC121 interacts with co-repressor (TOPLESS) proteins and forms a part of the inhibitor complex OsIAA10, an essential core component of auxin signalling pathway. Therefore, OsNAC121 emerges as an important regulator of various aspects of plant architecture through modulation of crosstalk between auxin and cytokinin, altering their concentration gradient in the meristematic zones, and consequently modifying different plant organogenesis processes.

Gas chromatography-ion mobility spectrometry (GC-IMS) technique and its recent applications in grain research.

Grains are the primary source of food for most people worldwide and constitute a major source of carbohydrates. Many novel technologies are being employed to ensure the safety and reliability of grain supply and production. Gas chromatography-ion mobility spectrometry (GC-IMS) can effectively separate and sensitively detect volatile organic compounds. It possesses advantages such as speed, convenience, high sensitivity, no pretreatment, and wide applicability. In recent years, many studies have shown that the application of GC-IMS technology for grain flavor analysis can play a crucial role in grains. This article elucidates the working principle of GC-IMS technology, reviews the application of GC-IMS in grains in the past 5 years. GC-IMS technology is mainly applied in four aspects in grains. In grain classification, it distinguishes varieties, quality, origin, production year, and processing methods based on the trace differences in volatile organic compounds, thereby fulfilling various grain classification requirements such as origin tracing, geographical indication product recognition, variety identification, production year identification, and detection of counterfeit and inferior grain samples. In optimizing the processing technology of grains and their products, it can improve food flavor, reduce undesirable flavors, and identify better processing parameters. In grain storage, it can determine the storage time, detect spoilage phenomena such as mold and discoloration during storage, eliminate pests affecting storage, and predict the vitality of seeds after storage. In aroma evaluation of grains and their processed products, it can assess the impact of new raw materials, new technologies, fermentation processes, and even oral processing on the quality of grain products. This article also summarizes the characteristics of GC-IMS technology, compiles typical grain flavor compounds, and provides prospects for the future application of GC-IMS. © 2024 Society of Chemical Industry.

Strong magnetodielectric effect in Bi(La)Fe(Cr)O3 multiferroic nanomaterials

The Bi1-xLaxFe1-yCryO3 (x = 0.00, 0.06; y = 0.00, 0.03, 0.06, 0.09, 0.12) nanomaterials have been synthesized using the simple solvo-thermal technique. The Rietveld refinement of XRD analysis using FullProf Software confirms that all synthesized materials follow rhombohedral perovskite crystal structure of R3C space group. The dielectric and ac conductivity data are analyzed to understand the role of grain and grain boundary contributions. The enhancement of magnetic properties has been observed from SQUID measurement for the co-doped samples at room temperature. Also, a significant improvement in polarization has been observed for the doped nanocompounds from the ferroelectric hysteresis loop. The magneto-dielectric study reveals a large improvement in our co-doped BFO nanomaterials and the value is nearly three times of those reported earlier. The calculated energy storage efficiency for the co-doped samples are found to have as high as 51 %. The sample with x = 0.06 and y = 0.09 with a magneto dielectric coefficient of around 30 % and energy storage efficiency of 35 % is the most suitable for both spintronic and energy storage devices.

Study on the Growth Dynamics of Tartary Buckwheat Flowers and Grains, as Well as Material Basis and Physiological Changes of Their Seed-Setting Differences

Tartary buckwheat is a cereal crop that has both medicinal and food origins. However, the underlying factors that contribute to Tartary buckwheat’s flowering and seed-setting characteristics, effective grain formation, and physiological changes are still not well understood. This study aimed to investigate the flowering and seed-setting characteristics of different parts of Tartary buckwheat, as well as the grain-filling characteristics after flowering. To achieve this, Tartary buckwheat cultivars with high (QK3) and low (XQ2) seed-setting rates were selected for pot and field experiments. The study found that Tartary buckwheat undergoes flowering and seed setting simultaneously. Many wilted flowers and grains were observed 45 and 51 d after flowering. Compared to XQ2, QK3 exhibited a higher grain formation rate and seed-setting rate by 7.42% and 26.16%, respectively. Additionally, QK3 had a significantly lower grain abortion rate by 12.03%. The 1000-grain weight and average grain-filling rate of QK3 were 11.10% and 14.81% higher than those of XQ2, respectively. QK3 exhibited a faster maximum grain-filling rate (Rmax), reaching 18.38% faster than XQ2. Additionally, the dry matter average distribution rate in the main stem and branched grains of QK3 was 13.26% and 23.07% higher than that of XQ2, respectively. The sucrose concentration, SS, and SSS enzyme activities of QK3 were all higher than those of XQ2, by 0.29–25.99%, 5.22–11.62%, and 6.64–12.47%, respectively. Correlation analysis revealed a significant positive correlation between sucrose, soluble sugar, and starch concentration during the grain formation process and SS and SSS activities. This suggests that the levels of SS, SSS, soluble sugar, and sucrose in the grain play a crucial role in grain filling.

Tunable electrical and impedance characteristics of Co–Zn doped M-type Sr Hexaferrites: Role of grain, grain boundaries, electrical transport mechanisms and software/circuit modeling

M-type hexaferrites SrCoxZnxFe12-2xO19 (x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0) have been synthesized using the sol-gel method. The structural, dielectric, and electrical properties of Zn2+ and Co2+ substituted strontium ferrite have been carried out. The dielectric and electric properties of prepared hexaferrites have been examined over the frequency range of 100 Hz to 2 MHz. The formation of the hexagonal phase has been confirmed by the X-ray diffraction (XRD) analysis. The substitution of Co2+ and Zn2+ causes a reduction in crystallite size from 39.50 to 26.42 nm being the smallest in the case of x = 1.0. Scanning electron microscopy (SEM) indicates the formation of honeycomb-like grain structures in composition x = 1.0. The dielectric spectrum shows that the dielectric constant and loss tangent vary non-monotonically with the doping of Co–Zn content. A non-Debye type relaxation is shown by the electric modulus of the prepared compositions. There is a reduction in relaxation time with the increase in doping of Co–Zn. The impedance spectra indicate the effects of both grain and grain boundaries on the electrical properties. The impedance analysis has been presented with the modeling of electrical processes in the samples using an equivalent circuit model comprising of parallel RC circuit for grains and grain boundaries. The obtained simulated results are in agreement with the measured results.

A study of the effect of the Cu and Cr co-doping on structural, magnetic and dielectric properties of barium hexaferrites synthesized in presence of mentha leaves extract

In the reported research work, we investigated the structural, thermal, magnetic, surface morphology, Raman spectroscopic and dielectric properties of Cu-Cr co-substituted M-type barium hexaferrites for lossless low-frequency applications. By using the green synthesis approach with mentha leaves extract, we synthesized a series of M-type BaCuxCrxFe12‐2xO19 (0.0 ≤x≤0.5) hexaferrite with varying Cu-Cr content. A simple heat treatment method was used to prepare hexaferrite samples. The samples were heated to 1100 °C and thoroughly characterized for their structural, thermal, magnetic, Raman spectroscopic and low frequency dielectric study. The results of XRD finding revealed the formation of M-phase along with secondary phase of BaFe2O4. The Raman spectroscopic analysis shows the successful replacement of Cu and Cr ions in place of Fe ions, and the substituted samples hold the hexagonal shape as visible from FESEM images. All samples show a hard magnetic nature with multi-domain structures, and x = 0.2 composition has a maximum Ms of 68.99 Am2/kg and lowest Hc of 0.1 T. Cole-Cole graphs show shifting of peaks position with Cu-Cr substitutions and increasing frequency, which gives the insight of the role of grain and grain boundaries. These findings open up exciting possibilities for using these hexaferrites in loss-less, and low-frequency applications.

Investigation on various properties of Dy0.7Ca0.3MnO3:TiO2 based nano-micro composites

In the present research work, manganite metal oxide nano-micro composites have been synthesized successfully wherein, chemically grown Dy0.7Ca0.3MnO3 was combined in different weight ratio composition of micron sized TiO2 (i.e., 0 %, 10 %, 20 %, 30 %, 40 % and 100 %). Prepared nano-micro DCMO:TiO2 has been characterized further wherein, structural aspects have been carried out using X-ray diffraction and W-H plot measurements which provides information regarding crystalline size, lattice strain and crystallinity. FESEM and HRTEM has been characterized for the assessment of the crystallinity and granular morphology. The elemental composition with desired stoichiometric quantities has been verified using EDAX. SAED patterns gives detailed information about intereticular distance and angles between crystallographic planes. Different frequency dependent electrical properties (i.e., dielectric constant (ε’), a.c. conductivity (σac) and impedance (Z)) carried out in the frequency range of 20 Hz to 2 MHz. The observed modified electrical properties have been understood using different theoretical models, mechanisms and different aspects (role of grain and crystalline size). Temperature dependent magnetization (M-T) measurements have been carried out to evaluate the magnetic phase shifting of the sample which has been understood using ZFC and FCC protocols. These phase shifting has been verified using M-H loop at different temperatures of 5 K and 300 K. The adaptation in magnetic properties have been discussed using different magnetic aspects.

Investigating the microplastic behavior of hierarchical polycrystalline [formula omitted]-TiAl microstructures

Hierarchical, nano-twinned microstructures are a promising route to optimize the strength and deformability of metals and alloys. The present paper investigates the role of grain and twin boundaries and the effect of twin spacing on the evolution of plasticity in a twinned, polycrystalline γ-TiAl microstructure. Via atomistic simulations of uniaxial compression tests it is possible to disentangle these influencing factors, and the results show that the onset of plasticity is governed by the sub-grain structure of the samples, while the Schmid factor does not play a prominent role. At high strains in uniform or only slightly twinned models, grain boundary sliding is one of the major deformation mechanisms, whereas twin-boundary-mediated plastic deformation dominates the highly twinned structures. Moreover, based on analyzing the degree of localization parameter, it is inferred that upon decreasing the lamellae size, higher uniformity of shear strain in the samples can be achieved. These results can be used to inform mesoscale numerical modeling of hierarchical TiAl microstructures.

Transcriptome profiling disclosed the effect of single and combined drought and heat stress on reprogramming of genes expression in barley flag leaf.

Despite numerous studies aimed at unraveling the genetic background of barley's response to abiotic stress, the modulation of the transcriptome induced by combinatorial drought and increased temperature remains largely unrecognized. Very limited studies were done, especially on the flag leaf, which plays an important role in grain filling in cereals. In the present study, transcriptome profiles, along with chlorophyll fluorescence parameters and yield components, were compared between barley genotypes with different flag leaf sizes under single and combined drought and heat stress. High-throughput mRNA sequencing revealed 2,457 differentially expressed genes, which were functionally interpreted using Gene Ontology term enrichment analysis. The transcriptomic signature under double stress was more similar to effects caused by drought than by elevated temperature; it was also manifested at phenotypic and chlorophyll fluorescence levels. Both common and stress-specific changes in transcript abundance were identified. Genes regulated commonly across stress treatments, determining universal stress responses, were associated, among others, with responses to drought, heat, and oxidative stress. In addition, changes specific to the size of the flag leaf blade were found. Our study allowed us to identify sets of genes assigned to various processes underlying the response to drought and heat, including photosynthesis, the abscisic acid pathway, and lipid transport. Genes encoding LEA proteins, including dehydrins and heat shock proteins, were especially induced by stress treatments. Some association between genetic composition and flag leaf size was confirmed. However, there was no general coincidence between SNP polymorphism of genotypes and differential expression of genes induced by stress factors. This research provided novel insight into the molecular mechanisms of barley flag leaf that determine drought and heat response, as well as their co-occurrence.

Fatigue crack growth behavior of 42CrMo high-strength steel with tempered sorbite/bainite microstructures: Roles of grain and constituent in microstructures

Microstructural differences through the thickness have always been an attention focus for large-scale steel structures, since they could significantly influence fatigue crack propagation (FCP) characteristics. Here, the effects of microstructure in FCP behaviors of 42CrMo steel were analyzed with emphasis on two different tempered sorbite/bainite (TS/B) microstructures: (i) fine TS/B structures (M42); (ii) coarse TS/B structures (M52). The results show that the FCP rate is relatively slower for M52 than for M42 in the regime through the later stage of near-threshold (I-L) to the early stage of Paris-regime (Ⅱ-E) with low ΔK, but is fairly similar for the two cases in the other ΔK regimes. Under relatively low ΔK, the FCP path of M52 is more tortuous with numerous micro-cracks in B and larger-sized crack deflections at the carbides and boundaries compared to M42, especially in the I-L where fatigue micro-cracks can deflect at the single coarse carbide, thereby resulting in roughness-induced crack closure and crack retardation behavior. Theoretical analysis shows that FCP behaviors are closely related to the cyclic plastic region size (Δrp) at the crack-tip. In the early stage of near-threshold region, Δrp is restricted within a grain-size scale for both steels, thus leading to a similar FCP rate. However, from the I-L to the Ⅱ-E, coarse B/ferrite-grains in M52 are always larger than the Δrp of fatigue crack-tip, and thereby lead to numerous micro-cracks formation and crack deflections at the carbides and B boundaries, inducing crack closure. In the later stage of Paris region, B/ferrite-grains in the two cases are much smaller than Δrp, so that FCP behaviors depend on the microstructure group effects, or overall strength and fracture toughness of materials, which cause the close FCP rate.

High Ionic Conduction and Polarity-Induced Piezoresponse in Layered Bimetallic Rb4Ag2BiBr9 Single Crystals

The emergence of lead-free metal-halide perovskites in modern-day energy research is primarily due to their competent semiconducting and optoelectronic properties, as well as their nontoxicity and improved stability in ambient operating conditions. However, a detailed understanding of ion transport dynamics and the relaxation behavior of these materials is still elusive. In this article, we report on the single-crystal (SC) growth of a bimetallic two-dimensional layered Rb4Ag2BiBr9 and explore its dielectric, piezoelectric, and ferroelectric properties. The dielectric attributes are investigated by studying the temperature-dependent complex impedance, complex electric modulus, and AC conductivity over an extensive frequency range from 4 Hz to 8 MHz. The role of grain and grain boundaries in the effective impedance is established using the Maxwell–Wagner equivalent circuit model from the Nyquist plots. The observed electric modulus spectra are studied using the Havriliak–Nigami and the Kohlrausch–Williams–Watts formalisms to understand the ionic transport and relaxation mechanisms in Rb4Ag2BiBr9. The DC conductivity and relaxation time show Arrhenius-like behavior with the inverse temperature validating the hopping motion of ions. The values of the activation energy required for ion hopping are calculated independently from the relaxation time, hopping frequency, and DC conductivity Arrhenius plots and are in good agreement with a value of 0.47 eV. The scaling of the temperature-dependent conductivity and electric modulus spectra into a single master curve demonstrates the congruence of the ionic conduction and the relaxation phenomena at different temperatures for Rb4Ag2BiBr9. This SC demonstrates decent thermal and ambient stability up to 500 °C and 12 months, respectively. The pristine orthorhombic Rb4Ag2BiBr9 SC shows a piezoelectric amplitude value of ∼564 pm at the maximum applied bias (±10 V), and a saturation polarization of ∼0.14 nC/cm2 estimated from the piezoelectric force microscopy and polarization hysteresis loop measurement, respectively. The ferroelectric and semiconducting attributes of this material can be harnessed for prospective applications as a thin film in designing mechanical energy harvesters as well as functional photoferroelectrics, such as optical switches and ferroelectric photovoltaics.

Influence of La3+ substitutions on structural, dielectric and electrical properties of spinel cobalt ferrite

La3+ doped cobalt ferrites with composition CoLaxFe2−xO4 (0.00 ≤ x ≤ 0.20) were synthesized by a co-precipitation method. X-ray diffraction (XRD) analysis confirm the formation of single-phased spinel structure for all synthesized samples. The result of La3+ doping on dielectric and electrical properties of cobalt ferrites was investigated. Dielectric constant and dielectric loss decrease with increasing frequency whereas alternating current (AC) electrical conductivity increases with increasing frequency. The AC electrical conductivities were effectively modeled by employing the Jonscher’s power law. Role of grain and grain boundary on impedance has been explored from nyquist plots and equivalent electrical circuits were proposed to clarify the impedance spectroscopy results. The Direct Current (DC) electrical resistivities were estimated by two probe method within the temperature range of 303K–700K. DC electrical resistivity decreases with increasing temperature and explained by hopping mechanism. DC electrical resistivity and drift mobility decreases with La3+ doping. Activation energies were calculated by employing the Arrhenius plot. Activation energy found to increases with La3+ substitutions. Maximum value of DC electrical resistivity achieved was 9.26 x 10+8 (Ω-cm) with crystallite size 17 nm. Current-Voltage (I–V) measurements were carried out within 0→6V→0V→ –6V→0V voltage range. It is worth mentioning that all doped sample exhibited remarkable and improved nonlinear hysteresis loop-type behavior than pour sample. Variation in resistance, in current-voltage loops, is clarified by considering space charge limited conduction (SCLC) model and oxygen vacancies migration across the metal-semiconductor interface. Out study suggest that La3+ doped cobalt ferrites may be tested as an active material for possible applications in non-volatile memory devices and neuromorphic applications.

Structural and Impedance Analysis of 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 Ceramic

Background: Since (1-x)[Pb(Mg1/3Nb2/3)O3]-(x)PbTiO3 (PMN-PT) ceramic has a high dielectric constant and piezoelectric coefficient, it has been widely investigated for profound applications in electro-optical devices, sensors, multilayer capacitors and actuators. Objectives: The objective of this paper is to study the structural and electrical properties of 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (0.7PMN-0.3PT) ceramic to understand the biphasic structural nature using Rietveld Refinement. Also, it characterises the type of conduction process as well as the role of grain and grain boundary resistance in the material on the basis of electrical properties such as impedance and modulus to understand the relaxation process. Methods: 0.7PMN-0.3PT is synthesised by mixed oxide method using PbO, MgO, Nb2O5 and TiO2 as precursor materials. Results: The XRD data reveals the biphasic structure of the tetragonal phase with the space group of P4mm and the monoclinic phase with the space group of Pm. The complex impedance analysis clearly represents the effect of grain on the overall resistance and departs from normal Debye-type behaviour. Also, the resistance is found to decrease with temperature, thereby confirming the semiconducting nature of the sample. The presence of long as well as short-range mobility of charge carriers is confirmed from the modulus and impedance analysis. The influence of long-range motion is observed at high temperatures and of short-range motion at low temperatures. Conclusion: XRD analysis confirmed the biphasic structure of the M+T phase. The frequencydependent modulus and impedance spectroscopy show the presence of a relaxation effect in the ceramic which is found to increase with temperature. The Nyquist plot shows that the resistance is decreased with temperature, thereby confirming the NTCR behaviour in the studied sample.

Microstructure and mechanical properties of unalloyed molybdenum fabricated via wire arc additive manufacturing

Molybdenum is an important high-temperature structural material but has poor processability. Additive manufactured unalloyed Mo is generally very small and the mechanical properties is seldomly studied. In this work, wire arc additive manufacturing was adopted, and crack-free molybdenum parts with high-density (99.0%) and characteristic size of 20 mm×20 mm×120 mm were successfully fabricated by short-track scanning. The microstructure and mechanical properties of samples in both the as-deposited and heat-treated states were studied and compared. Large columnar grains were observed, which were basically along the 〈001〉 direction. Heat treatment leads to grain coarsening, and the elimination of some sub-grain boundaries. Due to the weakened effect of grain and sub-grain boundary hardening, the mechanical properties of heat-treated specimens were worse than that of as-deposited specimens at room temperature. Both of them exhibit brittle fracture features. Under high temperature, the ductile fracture is observed, and the as-deposited specimen has similar strength and ductility, compared with the heat-treated specimens, suggesting a weak role of grain and sub-grain boundary at high temperature. A large number of fragments were observed at the fracture surface after high-temperature tests, which was MoO3 by energy dispersive spectroscopy test.

Oxygen Diffusion in Ceramic Mixed Conducting La0.6Sr0.4Co0.2Fe0.8O3−δ : The Role of Grain and Twin Boundaries

Measurements of the oxygen diffusivity of ceramic samples of the mixed ionic electronic conductor La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF6428) have shown the appearance of grain boundary tails in diffusion profiles at temperatures below 600 °C. Analysis of the tails yields values of the grain boundary diffusion products (). The activation enthalpies for the grain boundary and lattice diffusion are very close at 1.69 eV and 1.61 eV respectively, suggesting a common diffusion mechanism. Comparison with literature values on both lattice and grain boundary diffusion products have shown that values of obtained for LSCF6428 are the highest yet recorded for any oxide material. The reasons for this high value are discussed, including the degree of nonstoichiometry of the parent lattice and the possible involvement of the twin boundaries found in these ceramic samples.

Nitrogen application affects maize grain filling by regulating grain water relations

Grain water relations play an important role in grain filling in maize. The study aimed to gain a clear understanding of the changes in grain dry weight and water relations in maize grains by using hybrids with contrasting nitrogen efficiencies under differing nitrogen levels. The objectives were: 1) to understand the changes in dry matter and percent moisture content (MC) during grain development in response to different nitrogen application rates and 2) to determine whether nitrogen application affects grain filling by regulating grain water relations. Two maize hybrids, high N-efficient Zhenghong 311 (ZH311) and low N-efficient Xianyu 508 (XY508), were grown in the field under four levels of N fertilizer: 0, 150, 300, and 450 kg N ha–1 during three growing seasons. Dry weight, percent MC and water content (WC) of basal–middle and apical grains were investigated. The difference in the maximum WC and filling duration of basal–middle and apical grains in maize ears resulted in a significant difference in final grain weight. Grain position markedly influenced grain drying down; specifically, the drying down rate of apical grains was faster than that of basal–middle grains. Genotype and grain position both influenced the impact of nitrogen application rate on grain filling and drying down. Nitrogen rate determined the maximum grain WC and percent MC loss rate in the middle and the late grain-filling stages, thus affecting final grain weight. The use of high N-efficient hybrids, combined with the reduction of nitrogen application rate, can coordinate basal–middle and apical grain drying down to ensure yield. This management strategy could lead to a win–win situation in which the maximum maize yield, efficient mechanical harvest and environmental safety are all achieved.

Impact of Drought Stress on Grains Filling in Rice and its Management: A Review

Rice (Oryza sativa L.) is the world’s single most important staple food source for over half of the world’s population, whose demand is expected to increase as human population increases almost exponentially every year. There are different kinds of abiotic and biotic stresses that a rice plant endures. Among the different forms of environmental stresses, drought hampers the production of rice grains notably. The reality of climate change is so stark that more and more droughts are expected to be evident in the distant future. Water, being a requisite for rice cultivation, is gradually becoming a highly limited resource across the earth. In comparison to other cereal crops, rice is more sensitive to the soil water content. Decrease of soil water content or the unavailability of water triggers drought stress in rice. Therefore, the management of drought stress for the growth of rice plants is essential as even moderate stress during reproductive growth may result in a drastic reduction of grain yield. The distinct changes brought about by drought stress not only range from morphological to physiological changes but also from biochemical to molecular changes as well. A number of starch synthesis related enzymes like granule bound starch synthase I (GBSSI), soluble starch synthase IIa (SSIIa) play important role in grain filling, which are also affected by limited water under drought environment. Due to water scarcity, the rate of photosynthesis decreases, as a result of which dry matter accumulation decreases, which ultimately affects grain filling in rice. Drought causes delayed flowering as well as spikelet sterility, followed by low grain yield during harvesting. The prevalence of drought over longer periods causes reactive oxygen species to form within the rice plants which subsequently denatures proteins and nucleic acids. In many places where drought continues for longer periods, rice plants die resulting in huge loss of grain yields. The effective strategies that have been adopted involves-the development of stable drought tolerant rice varieties through plant breeding programs, the development of short duration rice cultivars which have short growing cycle and harvesting periods that may help the plant to escape drought, the development of rice plants having deep root system such that it can penetrate the soil to find the available moisture and water required for growth, as well as the development of transgenic drought tolerant rice plants which over express specific genes to withstand drought, are few of the effective management strategies that need special attention. Thus, it can be said that drought management for rice production is a crucial step towards food security and food production in the world. The present discussions will emphasize on the negative impact of drought in rice plants and also discuss possible key management practices that can address the existing and imminent drought related problems on rice plants.

Investigation of impedance and leakage feature in BFO-BTO perovskite system

The present investigation focused on the analysis of structural, electrical impedance, and leakage features of the standard multifunctional-multiferroic perovskite BiFeO3-BaTiO3. We incorporated the standard Rietveld XRD refinement method for the study of the structure and other related parameters. The refinement result illustrates the tetragonal phase with space group P4mm is the most preferable structure for BiFeO3-BaTiO3 at room temperature. The SEM image reveals the polycrystalline nature of BiFeO3-BaTiO3. The electrical impedance feature of BiFeO3-BaTiO3 is investigated through the Nyquist plot over the temperature range (200 °C–325 °C) and frequency range (0.1–5000 kHz). The role of grain and grain boundary on the electrical impedance was found quite prominent within the specified temperature and frequency range. The temperature-dependent I-V characteristic feature of BiFeO3-BaTiO3 illustrates the semiconducting nature.

Effect of frequency and temperature on dielectric and impedance characteristics of cerium modified BaMnO3 ceramics

In this paper, we have mainly discussed the electric field (frequency) and thermal (temperature) effect on dielectric, and electrical (impedance, electrical, and conduction) properties of a solid-state reaction technique prepared cerium modified barium manganite (BaMn0.85Ce0.15O3). The dielectric study exhibits high dielectric constant, low tangent loss, dielectric dispersion, and negative temperature coefficient of resistance characteristics which makes the material useful for energy storage devices. Preliminary analysis of the impedance and electric modulus suggests the presence of a non-Debye type of relaxation process and the role of grain and grain boundaries in the resistive and capacitive properties of the material. Both Nyquist and Cole-Cole plots confirm the semiconductor nature of the sample at high temperatures. The fitted Nyquist data with ZSIMPWIN software showed the decrease of bulk resistance from 8.841 × 107Ω (at 25 °C) to 4.085 × 103 Ω (at 500 °C) which also confirms semiconducting properties and may be found suitable applications for sensors. The analysis of ac conductivity suggests the presence of the thermally activated relaxation process in the sample.

Site-specific, genotypic and temporal variation in photosynthesis and its related biochemistry in wheat (Triticum aestivum).

Photosynthesis in wheat (Triticum aestivum L.) pericarps may contribute appreciably to wheat grain yield. Consequently, we investigated the temporal variation of traits related to photosynthesis and sucrose metabolism in the pericarps and flag leaves of three wheat genotypes, Huandoy, Amurskaja 75 and Greece 25, which are reported to differ in expression of genes related to the C4 pathway in wheat grain. Significant site-specific, genotypic and temporal variation in the maximum carboxylation rate (Vc max ) and maximum rates of electron transport (J max ) (biological capacity of carbon assimilation) were observed early in ontogeny that dissipated by late grain filling. Although the transcript abundance of rbcS and rbcL in flag leaves was significantly higher than in the pericarps, in line with their photosynthetic prominence, both organ types displayed similar expression patterns among growth stages. The higher N concentrations in the pericarps during grain enlargement suggest increased Rubisco; however, expression of rbcS and rbcL indicated the contrary. From heading to 14days post-anthesis, wheat pericarps exhibited a strong, positive correlation between biological capacity for carbon assimilation and expression of key genes related to sucrose metabolism (SPS1 , SUS1 and SPP1 ). The strong correlation between spike dry weight and the biological capacity for carbon assimilation along with other findings of this study suggest that metabolic processes in wheat spikes may play a major role in grain filling, total yield and quality.