Laboratory investigation and core flood demonstration of enhanced biogenic methane generation from lignite.

Over the last several decades, coalbed methane (CBM) has emerged as an important energy source in developing nations like India as well as worldwide and is expected to play a significant role in the energy portfolio of the future. The current scenario of rapid exhaustion of fossil fuels is leading to the need to explore alternative and efficient fuel resources. The present study demonstrates enhanced methane production per gram of lignite (lowest-rank coal). Optimization of the bioconversion of lignite to methane revealed 55°C temperature and 1.5 g/L NaCl concentration as ambient conditions for the process. A scale-up study in the optimized condition showed 2,800 mM methane production per 25 g of lignite in anaerobic conditions. Further, Fourier transform Infrared (FTIR) and Gas Chromatography Mass Spectrometry (GCMS) analysis showed bioconversion of lignite into simpler intermediate substrates required for methane production. The results highlighted that the bacterial action first converts lignite into volatile fatty acids, which subsequently get converted into methane. Further, the exploration of indigenous microbial consortia in Tharad well (THAA) mainly comprises the order Methanosarcinales and Methanomicrobiales. The pathogenicity of the microbial consortium THAA was declared safe for use in mice via the oral route by The Energy and Resources Institute (TERI), India. The study demonstrated the development of indigenous consortia (TERI THAA), which can potentially enhance methane production from the lowest coal grade under extreme conditions in Indian coal beds.

Biosurfactant: an emerging tool for the petroleum industries.

The petroleum sector is essential to supplying the world's energy demand, but it also involves numerous environmental problems, such as soil pollution and oil spills. The review explores biosurfactants' potential as a new tool for the petroleum sector. Comparing biosurfactants to their chemical equivalents reveals several advantages. They are ecologically sustainable solutions since they are renewable, nontoxic, and biodegradable. Biosurfactants are used in a variety of ways in the petroleum sector. They can improve the mobilization and extraction of trapped hydrocarbons during oil recovery procedures. By encouraging the dispersion and solubilization of hydrocarbons, biosurfactants also assist in the cleanup of oil spills and polluted locations by accelerating their breakdown by local microorganisms. The review gives insights into alternative methods for the petroleum industry that are more viable and cost-effective.

Exhaust particle number and composition for diesel and gasoline passenger cars under transient driving conditions: Real-world emissions down to 1.5 nm.

Recent recommendations given by WHO include systematic measurements of ambient particle number concentration and black carbon (BC) concentrations. In India and several other highly polluted areas, the air quality problems are severe and the need for air quality related information is urgent. This study focuses on particle number emissions and BC emissions of passenger cars that are technologically relevant from an Indian perspective. Particle number and BC were investigated under real-world conditions for driving cycles typical for Indian urban environments. Two mobile laboratories and advanced aerosol and trace gas instrumentation were utilized. Our study shows that passenger cars without exhaust particle filtration can emit in real-world conditions large number of particles, and especially at deceleration a significant fraction of particle number can be even in 1.5-10 nm particle sizes. The mass concentration of exhaust plume particles was dominated by BC that was emitted especially at acceleration conditions. However, exhaust particles contained also organic compounds, indicating the roles of engine oil and fuel in exhaust particle formation. In general, our study was motivated by serious Indian air quality problems, by the recognized lack of emission information related to Indian traffic, and by the recent WHO air quality guidance; our results emphasize the importance of monitoring particle number concentrations and BC also in Indian urban areas and especially in traffic environments where people can be significantly exposed to fresh exhaust emissions.

Culture-independent assessment of the indigenous microbial diversity of Raniganj coal bed methane block, Durgapur.

It is widely acknowledged that conventional mining and extraction techniques have left many parts of the world with depleting coal reserves. A sustainable method for improving the recovery of natural gas from coalbeds involves enhancing the production of biogenic methane in coal mines. By taking a culture-independent approach, the diversity of the microbial community present in the formation water of an Indian reservoir was examined using 16S rRNA gene amplification in order to study the potential of microbial-enhanced coal bed methane (CBM) production from the deep thermogenic wells at a depth of 800-1200 m. Physicochemical characterization of formation water and coal samples was performed with the aim of understanding the in situ reservoir conditions that are most favorable for microbial CBM production. Microbial community analysis of formation water showed that bacteria were more abundant than archaea. Proteobacteria, Firmicutes, and Bacteroidetes were found as the most prevalent phyla in all the samples. These phyla play a crucial role in providing substrate for the process of methanogenesis by performing fermentative, hydrolytic, and syntrophic functions. Considerable variation in the abundance of microbial genera was observed amongst the selected CBM wells, potentially due to variable local geochemical conditions within the reservoir. The results of our study provide insights into the impact of geochemical factors on microbial distribution within the reservoir. Further, the study demonstrates lab-scale enhancement in methane production through nutrient amendment. It also focuses on understanding the microbial diversity of the Raniganj coalbed methane block using amplicon sequencing and further recognizing the potential of biogenic methane enhancement through microbial stimulation. The findings of the study will help as a reference for better strategization and implementation of on-site microbial stimulation for enhanced biogenic methane production in the future.

Enhanced Oil Recovery Using Indigenous Microbiome of High Temperature Oil Reservoirs.

Crude oil is a primary energy source used for economic expansion across the world. Secondary recovery processes employed by industries to recover oil from oil wells leave behind 70% of the oil trapped in marginal and deleted zones of reservoirs. To recover the oil from depleted zones, microbial enhanced oil recovery (MEOR) tertiary processes were introduced, which involve the production of metabolites from the indigenous microbiome. In this study, the indigenous microbiota was identified as Marinobacterium sp., Silvanigrella sp., Petrothermobacter sp., Pseudomonas sp., Bacillus sp., Nitrincola sp., Halomonas sp., Uncultured Roseovarius sp., and Phaeobacter. Further, the secondary metabolites such as volatile fatty acids (ethanol, acetone, and acetate), biomass, gases (CO2, CH4), and biosurfactants were estimated through gas chromatography and FTIR spectroscopy. Once stable microbial growth was attained in the baltch media, it was optimized through response surface methodology (RSM) to minimize the process cost. The optimized media with 9 g/L of molasses, 1.75 g/L of sodium bicarbonate, and 1.25 g/L of ammonium chloride showed a significant impact on metabolite production. Additionally, core flood studies to simulate field studies were performed that represented that TeriK-1 brought a significant increment of 18.9%, which makes it suitable for MEOR field implementation. This study is one of its kind where the indigenous thermophilic sp. was successfully established and is capable of producing the secondary metabolites that aid in the MEOR process.

Nutrient optimization for indigenous microbial consortia of a Bhagyam oil field: MEOR studies.

The microbial enhanced oil recovery (MEOR) method is an eco-friendly and economical alternative technology. The technology involves a variety of uncertainties, and its success depends on controlling microbial growth and metabolism. This study is one of a kind that showed successful tertiary recovery of crude oil through indigenous microbial consortia. In this study, a medium was optimized to allow ideal microbial growth under reservoir conditions through RSM. Once the nutrient recipe was optimized, the microbial metabolites were estimated through gas chromatography. The maximum amount of methane gas (0.468 mM) was produced in the TERIW174 sample. The sequencing data set showed the presence of Methanothermobacter sp. and Petrotoga sp. In addition, these established consortia were analyzed for their toxicity, and they appeared to be safe for the environment. Furthermore, a core flood study showed efficient recovery that was ~25 and 34% in TERIW70 and TERIW174 samples, respectively. Thus, both the isolated consortia appeared to be suitable for the field trials.

A metagenomic assessment of gut microbiota in Indian colon cancer patients.

Background: Gut microbiota plays an important role in the development of different diseases including colorectal cancer. The geography, lifestyle, and dietary habits of Indians are different from Western world, thus microbiome studies of Western population could not be extrapolated to their Indian counterparts. Method: Therefore, we have conducted a study on gut microbiota in Indian healthy subjects and patients of colon cancer using 16S ribosomal RNA Amplicon sequencing. Operational taxonomic units were calculated for different bacterial taxon including phylum, class, order, family, and genus level. Results: Observed results indicated a considerable difference in the bacterial diversity in both the groups. Phylum Firmicutes was significantly dominated in both the groups followed by Bacteroidetes, Actinobacteria, and Proteobacteria which clearly indicates the dominance of phylum Firmicutes in Indian population. Phylum Firmicutes and Actinobacteria were significantly abundant in the healthy group while phylum Bacteroidetes in the colon cancer group. Bacterial genera Megamonas, Megasphaera, Mitsuokella, and Streptococcus were significantly abundant in the healthy group and Veillonella, Prevotella, and Eubacterium in the colon cancer group. Bacterial genus Bradyrhizobium was present in the healthy group and Alistipes, Coprococcus, Dorea, and Rhodococcus were present in the colon cancer group but absent in the healthy group. Conclusion: There was a considerable difference in bacterial diversity in both the study groups indicating dysbiosis in the colon cancer group.

Synthesis, characterization, method development, and validation of nor-ethylmorphine hydrochloride reference material using established analytical techniques for dope control analysis.

Ethylmorphine is permitted internationally for therapeutic purposes where morphine is not indicated across the globe. Nor-ethylmorphine a major metabolite of ethylmorphine. To differentiate the intake of morphine from ethylmorphine, nor-ethylmorphine stable reference material is desirable. There is no available commercial source and no data for reference material context for this substance. Therefore, nor-ethylmorphine HCl was synthesized and characterized, and purity and potency were assessed using nuclear magnetic resonance (NMR), high-resolution mass spectrometry (HRMS), Fourier transform infrared spectroscopy (FT-IR), thermogravimetry (TGA), and high-performance liquid chromatography (HPLC). Purity and potency were found to be 98.29% and 96.40%, respectively, providing a fit for purpose reference material for doping control analysis in sports.

Identification and probiotic potential of lactic acid bacteria from camel milk.

In the present study, a total of 80 presumed lactic acid bacteria (LAB) were isolated from camel milk. Selected LAB were identified as Lactococcus lactis (cam 12), Enterococcus lactis (cam 14) and Lactobacillus plantarum (cam 15) and their potential were tested by tolerance & de-conjugation of bile salts, antimicrobial activity, surface hydrophobicity and adhesion potential) along with this of probiotics were evaluated for curd formation and assessed for sensory properties and syneresis. Selected LABs showed antimicrobial activity against wide range of pathogenic bacteria (Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus cereus and Escherchiaia. coli). LAB (cam 12, cam 14 and cam15) were highly sceptible to chloramphenicol, vancomycin, and tetracyclin. In vitro adhesion studies with Caco-2 cells demonstrated strong adhesion activity with hydrophobicity (99%) was observed. Acute oral toxicity of E. lactis and L. plantarum showed non-toxic, non-virulent and safe for industrial application. The study provides potential LAB which may act as a substitute of functional food, synthetic feed and industrial curd formulation with in the shortest span (240 min at 28-32 °C).

Biosurfactant: A Next-Generation Tool for Sustainable Remediation of Organic Pollutants.

Petroleum hydrocarbons are energy resources that majorly contribute pollutants to the environment. These pollutants may cause serious health issues, and hence, for the regulation of these contaminants, the development of sustainable alternative technologies has been considered, without causing further harm to the environment. One such alternative is biosurfactants (having low toxicity and being biodegradable) produced by numerous microbial species that have a tendency to remediate organic pollutants. Biosurfactants are amphiphilic compounds that are categorized into two types based on their molecular mass. Biosurfactants can be generated extracellularly or as a part of the cell membrane of microorganisms (bacteria, fungi, and algae). This review provides a detailed view of the types of biosurfactants, their properties, and the mechanism involved in the degradation of oil spills.

Instigation of indigenous thermophilic bacterial consortia for enhanced oil recovery from high temperature oil reservoirs.

The purpose of the study involves the development of an anaerobic, thermophilic microbial consortium TERIK from the high temperature reservoir of Gujarat for enhance oil recovery. To isolate indigenous microbial consortia, anaerobic baltch media were prepared and inoculated with the formation water; incubated at 65°C for 10 days. Further, the microbial metabolites were analyzed by gas chromatography, FTIR and surface tension. The efficiency of isolated consortia towards enhancing oil recovery was analyzed through core flood assay. The novelty of studied consortia was that, it produces biomass (600 mg/l), bio-surfactant (325 mg/l), and volatile fatty acids (250 mg/l) at 65°C in the span of 10 days, that are adequate to alter the surface tension (70 to 34 mNm -1) and sweep efficiency of zones facilitating the displacement of oil. TERIK was identified as Clostridium sp. The FTIR spectra of biosurfactant indicate the presence of N-H stretch, amides and polysaccharide. A core flooding assay was designed to explore the potential of TERIK towards enhancing oil recovery. The results showed an effective reduction in permeability at residual oil saturation from 2.14 ± 0.1 to 1.39 ± 0.05 mD and 19% incremental oil recovery.

Aquatic Plants, Landoltia punctata, and Azolla filiculoides as Bio-Converters of Wastewater to Biofuel.

The aquatic plants, Azolla filiculoides, and Landoltia punctate, were used as complementing phytoremediators of wastewater containing high levels of phosphate, which simulates the effluents from textile, dyeing, and laundry detergent industries. Their complementarities are based on differences in capacities to uptake nitrogen and phosphate components from wastewater. Sequential treatment by L. punctata followed by A. filiculoides led to complete removal of NH4, NO3, and up to 93% reduction of PO4. In experiments where L. punctata treatment was followed by fresh L. punctata, PO4 concentration was reduced by 65%. The toxicity of wastewater assessed by shrimps, Paratya australiensis, showed a four-fold reduction of their mortality (LC50 value) after treatment. Collected dry biomass was used as an alternative carbon source for heterotrophic marine protists, thraustochytrids, which produced up to 35% dry weight of lipids rich in palmitic acid (50% of total fatty acids), the key fatty acid for biodiesel production. The fermentation of treated L. punctata biomass by Enterobacter cloacae yielded up to 2.14 mol H2/mole of reduced sugar, which is comparable with leading terrestrial feedstocks. A. filiculoides and L. punctata can be used as a new generation of feedstock, which can treat different types of wastewater and represent renewable and sustainable feedstock for bioenergy production.

Exploration of Performance Kinetics and Mechanism of Action of a Potential Novel Bioflocculant BF-VB2 on Clay and Dye Wastewater Flocculation.

This study explores production of an efficient bioflocculant; BF-VB2, by strain Bacillus sp. TERI VB2 and proposes its potential application in wastewater treatment. One milligram of BF-VB2 can effectively flocculate 1980.0 mg ± 5.0 mg of kaolin particles leading to 99.0% ± 0.5% enhancement in flocculation activity and 99.6% ± 1.0% reduction in turbidity; in less time. BF-VB2 when applied for treatment of textile dyeing industrial wastewater revealed reduction in dye color (82.78% ± 3.03%), COD (92.54% ± 0.24%), TSS (73.59% ± 0.71%), and chloride ions (81.90% ± 0.716%). The best-fit kinetic model (for both COD removal, and dye decolorization) was pseudo-first order with regression coefficient of 0.98 and 0.95, and rate constant of 4.33 × 10-2 and 1.83 × 102, respectively. Bridging due to presence of surface charges have been proposed as flocculation mechanism. From results obtained during test-tube studies, flocculation in larger volumes (0.01-5.0 L) was also performed to intend taking up BF-VB2 for in situ industrial wastewater treatment. This eco-friendly polysaccharide bioflocculant had longer shelf-life, stability to pH and temperature, cation-independence, and emerged to be more efficient than other flocculants assessed. This study proposed BF-VB2 as a potential natural flocculant candidate for industrial application.

Analytical Investigation of Cymbopogon citratus and Exploiting the Potential of Developed Silver Nanoparticle Against the Dominating Species of Pathogenic Bacteria.

Indian biodiversity is a hub for medicinal plants. Extensive research has been carried out to select plants with numerous properties which can be used for human welfare. Present research is about Cymbopogon citratus, an economically valuable medicinal plant. In this study Cymbopogon citratus was elected as a subject plant over the five selected plants (Azadirachta indica, Plumeria obtuse, Sapindus mukorossi, Capsicum annuum and Phyllanthus emblica) on the basis of antibacterial effect against dominating pathogenic species of gram positive (Bacillus cereus, Bacillus licheniformis) and gram negative (Pseudomonas aeruginosa, Escherichia coli) bacteria. Further, bioactive agents behind antibacterial potential of Cymbopogon citratus was analyzed using analytical method (Phyto-chemical, FTIR, NMR and GC-MS). Due to the broad antimicrobial spectrum, silver nanoparticles have turned into a noteworthy decision for the improvement of new medication. Therefore, this investigation further elaborated in the development of Cymbopogon citratus silver nano-particles (CNPs). Antibacterial potential of CNPs examine in a range of C25-C150 (µg/ml) through minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) where, C25 (µg/ml) concentration of CNPs were recorded as the MIC for all bacterial species and C25 (µg/ml) and C50 (µg/ml) noted as the MBC for Pseudomonas aeruginosa, Escherichia coli and Bacillus cereus, Bacillus licheniformis, respectively. In agar disk diffusion assay of CNPs, maximum diameter of zone of inhibition was observed for C150 (µg/ml) concentration Bacillus cereus (20.12 ± 0.42), Bacillus licheniformis (22.34 ± 0.4), Pseudomonas aeruginosa (35.23 ± 0.46) and Escherichia coli (31.87 ± 0.24). Involvement of bioactive component as a reducing and capping agent can be confirmed through FTIR spectrum of CNPs. Moreover XRD, EDXRF and SEM showed crystalline and cuboidal nature of CNPs with ∼35 nm sizes. Prominently, cytotoxic analysis was conducted to understand the toxic effect of CNPs. This research highlights the potential of CNPs due to the bioactive components present in Cymbopogon citratus extract: Polyphenols (phenol; 1584.56 ± 16.32 mg/L, Flavanoids) and mixture of terpenoids (Citral, Myrcene, Farnesol, ß-myrcene and ß -Pinene).

Potential of dynamic bacterial communities in the bio-corrosion process: a proof study with surface morphology of metal coupons.

Bio-corrosion is a well-known phenomenon of corrosion caused by bacterial communities. It is considered as a worldwide problem as it causes billion-dollar damages to the pipeline industries (mainly oil and gas) each year. Therefore, this investigation was undertaken to understand the significance of bacterial communities in the bio-corrosion system by studying the physical alteration in the metal surface of coupons through different techniques (EIS, XRD, FT-IR and SEM) and the community identification of consortia responsible for the corrosion. Furthermore, supporting data were obtained from APS reductase assays and DAPI microscopy. The EIS plots suggested that the metal coupons in a biotic system were more prone to corrosion than the coupons in an abiotic system. FT-IR analysis of the biotic system validated the presence of magnetite (Fe3O4), goethite (α-FeOOH) and lepidocrocite (γ-FeOOH); the XRD spectrum confirmed the presence of oxide and sulphide of iron (Fe3O4 and FeS), which are considered as notable compounds for corroding substances. The community profile indicated the presence of mixed anaerobic consortia containing Firmicutes and Proteobacteria (beta and delta) in the cultured sample. The presence of Desulfovibro sp. and Clostridium sp. in the consortium revealed a synergistic effect, where the by-product of one species acted as a carbon source for the other species, which further established the bio-corrosion process by depositing oxides of iron and sulphur on the metal coupon surface. This study signifies that a mixed culture has a greater impact on the bio-corrosion process than the pure and single culture of Desulfovibro sp. Furthermore, this study also provides a bio-monitoring strategy for the pipeline industries.

Laboratory Investigation of Indigenous Consortia TERIJ-188 for Incremental Oil Recovery.

Bacterial Profile modification is an efficient process which brings the alteration in permeability of the porous media of the reservoir by selective plugging which eventually recover the residual oil. It is an advantageous and feasible method for residual oil recovery from high permeability zones of the reservoir. In this study, indigenous bacterial consortia, TERIJ-188 was developed from Gujarat oil fields. TERIJ-188 was identified as Thermoanaerobacter sp., Thermoanaerobacter brockii, Thermoanaerobacter italicus, Thermoanaerobacter mathranii, Thermoanaerobacter thermocopriae. The novelty of consortia was that it produces biomass (850 mg l-1), bio-surfactant (500 mg l-1), and volatile fatty acids (495 mg l-1) at 70°C in the span of 10 days, which are adequate to alter the permeability and sweep efficiency of high permeability zones facilitating the displacement of oil. The biosurfactant was analyzed for its functional group by FTIR and NMR techniques which indicate the presence of C-N bond, aldehydes, triacylglycerols. TERIJ-188 showed an effective reduction in permeability at residual oil saturation from 28.3 to 11.3 mD and 19.2% incremental oil recovery in a core flood assay. Pathogenicity test suggested that TERIJ-188 is non-toxic, non-virulent and safe for field implementation.

Evaluating the potential of indigenous methanogenic consortium for enhanced oil and gas recovery from high temperature depleted oil reservoir.

In past years, lots of research has been focused on the indigenous bacteria and their mechanisms, which help in enhanced oil recovery. Most of the oil wells in Indian subcontinent have temperature higher than 60 °C. Also, the role of methanogenic consortia from high temperature petroleum reservoir for enhanced oil recovery (EOR) has not been explored much. Hence, in the present study methanogens isolated from thermophilic oil wells (70 °C) were evaluated for enhanced oil recovery. Methane gas is produced by methanogens, which helps in oil recovery from depleted oil wells through reservoir re-pressurization and also can be recovered from reservoir along with crude oil as alternative energy source. Therefore, in this study indigenous methanogenic consortium (TERIL146) was enriched from high temperature oil reservoir showing (12 mmol/l) gas production along with other metabolites. Sequencing analysis revealed the presence of Methanothermobacter sp., Thermoanaerobacter sp., Gelria sp. and Thermotoga sp. in the consortium. Furthermore, the developed indigenous consortium TERIL146 showed 8.3% incremental oil recovery in sandpack assay. The present study demonstrates successful recovery of both oil and energy (gas) by the developed indigenous methanogenic consortium TERIL146 for potential application in thermophilic depleted oil wells of Indian subcontinent.

Polarized electrode enhances biological direct interspecies electron transfer for methane production in upflow anaerobic bioelectrochemical reactor.

The influence of polarized electrodes on the methane production, which depends on the sludge concentration, was investigated in upflow anaerobic bioelectrochemical (UABE) reactor. When the polarized electrode was placed in the bottom zone with a high sludge concentration, the methane production was 5.34 L/L.d, which was 53% higher than upflow anaerobic sludge blanket (UASB) reactor. However, the methane production was reduced to 4.34 L/L.d by placing the electrode in the upper zone of the UABE reactor with lower sludge concentration. In the UABE reactor, the methane production was mainly improved by the enhanced biological direct interspecies electron transfer (bDIET) pathway, and the methane production via the electrode was a minor fraction of less than 4% of total methane production. The polarized electrodes that placed in the bottom zone with a high sludge concentration enhance the bDIET for methane production in the UABE reactor and greatly improve the methane production.

Boron application improves yield of rice cultivars under high temperature stress during vegetative and reproductive stages.

It is reported that high temperatures (HT) would cause a marked decrease in world rice production. In tropical regions, high temperatures are a constraint to rice production and the most damaging effect is on spikelet sterility. Boron (B) plays a very important role in the cell wall formation, sugar translocation, and reproduction of the rice crop and could play an important role in alleviating high temperature stress. A pot culture experiment was conducted to study the effect of B application on high temperature tolerance of rice cultivars in B-deficient soil. The treatments comprised of four boron application treatments viz. control (B0), soil application of 1 kg B ha-1 (B1), soil application of 2 kg B ha-1 (B2), and foliar spray of 0.2% B (Bfs); three rice cultivars viz. Annapurna (HT stress tolerant), Naveen, and Shatabdi (both HT stress susceptible); and three temperature regimes viz. ambient (AT), HT at vegetative stage (HTV), and HT at reproductive stage (HTR). The results revealed that high temperature stress during vegetative or flowering stage reduced grain yield of rice cultivars mainly because of low pollen viability and spikelet fertility. The effects of high temperature on the spikelet fertility and grain filling varied among cultivars and the growth stages of plant when exposed to the high temperature stress. Under high temperature stress, the tolerant cultivar displays higher cell membrane stability, less accumulation of osmolytes, more antioxidant enzyme activities, and higher pollen viability and spikelet fertility than the susceptible cultivars. In the present work, soil application of boron was effective in reducing the negative effects of high temperature both at vegetative and reproductive stages. Application of B results into higher grain yield under both ambient and high temperature condition over control for all the three cultivars; however, more increase was observed for the susceptible cultivar over the tolerant one. The results suggest that the exogenous application of boron had a substantial effect on cell membrane stability, sugar mobilization, pollen viability, and spikelet fertility, hence the yield. The cultivars due to their variation in the tolerance level for high temperature stress behaved differently, and at high temperature stress, more response of the application of boron was seen in susceptible cultivars.