Fixation Ability Research Articles

Suppression of CO2 induced lithium anode corrosion by fluorinated functional group in quasi-solid polymer electrolyte enabling long-cycle and high-safety Li-CO2 batteries

Given high theoretical energy density and environmental-friendly CO2 fixation ability, rechargeable Li-CO2 battery is explored as a promising energy storage device. However, its cycling stability and safety are challenged by the continuous pulverization of Li anode and the leakage of liquid electrolytes (LEs). Herein, a quasi-solid polymer electrolyte (QSPE) with -CF3 functional groups was designed and in-situ fabricated for Li-CO2 battery. The solidification of electrolyte avoids the leakage of LEs and effectively inhibits the diffusion of the acid CO2 and cathode by-products to etch Li anode. Besides, the introduction of -CF3 can construct a fish scale-like LiF-rich solid electrolyte interface on Li anode, which induces the uniform and dense deposition of Li to inhibit the deeper Li from being further etched. The QSPE also exhibits high ion conductivity (1.98×10−3 S cm−1 at 25°C), enhanced Li+ transport number (0.47), and superb stability (>5.27 V vs. Li/Li+). Consequently, the Li-CO2 battery with QSPE delivers effectively suppressed pulverization of Li anode, extraordinary cyclic stability over 295 cycles (1250 h) at 50 μA cm−2, and lower overpotential (1.05 V) compared to the cells with LE. Moreover, the as-prepared QSPE also demonstrates excellent application potential in other Li metal batteries and flexible electronic devices.

Alfalfa growth and nitrogen fixation constraints in salt-affected soils are in part offset by increased nitrogen supply.

In China, alfalfa (Medicago sativa L.) is often grown on marginal land with poor soil fertility and suboptimal climate conditions. Soil salt stress is one of the most limiting factors for alfalfa yield and quality, through its inhibition of nitrogen (N) uptake and N fixation. To understand if N supply could improve alfalfa yield and quality through increasing N uptake in salt-affected soils, a hydroponic experiment and a soil experiment were conducted. Alfalfa growth and N fixation were evaluated in response to different salt levels and N supply levels. The results showed that salt stress not only significantly decreased alfalfa biomass, by 43%-86%, and N content, by 58%-91%, but also reduced N fixation ability and N derived from the atmosphere (%Ndfa) through the inhibition of nodule formation and N fixation efficiency when the salt level was above 100mmolNa2SO4L-1. Salt stress also decreased alfalfa crude protein by 31%-37%. However, N supply significantly improved shoot dry weight by 40%-45%, root dry weight by 23%-29%, and shoot N content by 10%-28% for alfalfa grown in salt-affected soil. The N supply was also beneficial for the %Ndfa and N fixation for alfalfa with salt stress, and the increase reached 47% and 60%, respectively. Nitrogen supply offset the negative effects on alfalfa growth and N fixation caused by salt stress, in part through improving plant N nutrition status. Our results suggest that optimal N fertilizer application is essential to alleviate the loss of growth and N fixation in alfalfa in salt-affected soils.

Isolasi Bakteri Fiksasi Nitrogen dan Fosfat pada Limbah Cair Karet (Hevea brasiliensis)

This research was conducted with the aim of knowing the types of bacteria that are able to fix nitrogen and dissolve phosphate in liquid rubber waste in Perdamean Village, Labuhanbatu Regency. The research method used is the description method with bacterial isolation techniques, and then tests are carried out, namely testing the ability of nitrogen fixation and testing the ability of phosphate solubilizers. The results showed that bacterial isolates capable of fixing nitrogen were found to have high absorbance values, namely 1,340 ABS. In the phosphate solubilizing ability test, there were 2 isolates that were unable to dissolve phosphate. In conclusion, isolating nitrogen and phosphate fixation bacteria from liquid rubber waste is a way to prevent pollution and the destruction of existing ecosystems in the environment.
 
 Keywords: Nitrogen Fixation, Rubber Liquid Waste, Phosphate Solvent

The Screening of Plant Growth-promoting Rhizobacteria based on the Ability to Promote the Growth and Nodulation of Soybean (Glycine max L.) Seedlings

Plant growth-promoting rhizobacteria (PGPR), which were isolated from the plant rhizosphere, decrease the addition of chemical fertilizer (N) and promote plant growth. Some PGPR isolates can fixate nitrogen, solubilize phosphate, produce phytohormones, and control soil pathogens. This study has focused on isolating rhizobacteria from root nodules of Edamame, Glycine max L, Dieng Peanut, Solanum sp. and Peanut root. Eleven isolates were assayed to examine their activities, including the ability of nitrogen fixation, produce Indol Acetic Acid hormone, siderophore, ammonia, and catalase activity. Furthermore, 11 isolates were tested to promote soybean growth in pot experiments using sterile sand media and the test of symbiotic capacity. The results showed that six isolates (RhizE2, RhizE3, RhizE4, RhizKdKbm1, Bio2DW, and Bio3DW) could form root nodules, and four isolates (RhizE2, RhizE3, RhizKdKbm1, and Bio2DW) showed a symbiotic capacity of more than 90%. RhizE2 significantly increased the number of nodules and dry weight of the entire plant (24.08 g) in comparison with plants without inoculation and added N fertilizer (11.59 g) and added N fertilizer (19.60 g). RhizE2 can be further developed as a biological fertilizer agent, especially for soybean plants. From all parameters observed, the plants inoculated with RhizE2 showed the best growth result.

Preliminary symbiotic performance of indigenous soybean (Glycine max)-nodulating rhizobia from agricultural soils of Tanzania

Globally, the increase in human population continues to threaten the sustainability of agricultural systems. Despite the fast-growing population in Sub-Saharan Africa (SSA) and the efforts in improving the productivity of crops, the increase in the yield of crops per unit area is still not promising. The productivity of crops is primarily constrained by inadequate levels of soil nutrients to support optimum crop growth and development. However, smallholder farmers occasionally use fertilizers, and the amount applied is usually small and does not meet plant requirements. This is due to the unaffordability of the cost of fertilizers, which is enough to suffice the crop requirement. Therefore, there is a need for alternative affordable and effective fertilization methods for sustainable intensification and improvement of the smallholder farming system's productivity. This study was designed to evaluate the symbiotic performance of indigenous soybean nodulating rhizobia in selected agricultural soils of Tanzania. In total, 217 rhizobia isolates were obtained from three agroecological zones, i.e., eastern, northern, and southern highlands. The isolates collected were screened for N2 fixing abilities under in vitro (nitrogen-free medium) and screen house conditions. The results showed varying capabilities of isolates in nitrogen-fixing both under in vitro and screen house conditions. Under in vitro experiment, 22% of soybean rhizobia isolates were identified to have a nitrogen-fixing capability on an N-free medium, with the highest N2-fixing diameter of 1.87 cm. In the screen house pot experiment, results showed that soybean rhizobia isolate significantly (P < 0.001) influenced different plant growth and yield components, where the average shoot dry weight ranged from 2.49 to 10.98 g, shoot length from 41 to 125.27 cm whilst the number of leaves per plant ranged from 20 to 66. Furthermore, rhizobia isolates significantly (P = 0.038) increased root dry weight from 0.574 to 2.17 g. In the case of symbiotic parameters per plant, the number of nodules was in the range of 0.33–22, nodules dry weight (0.001–0.137 g), shoot nitrogen (2.37–4.97%), total nitrogen (53.59–6.72 g), and fixed nitrogen (46.878–0.15 g) per plant. In addition, the results indicated that 51.39% of the tested bacterial isolates in this study were ranked as highly effective in symbiosis, suggesting that they are promising as potential alternative biofertilizers for soybean production in agricultural soils of Tanzania to increase productivity per unit area while reducing production cost.

Biological Nitrogen Fixation of Cowpea in a No-Till Intercrop under Contrasting Rainfed Agro-Ecological Environments

Nitrogen (N) availability under no-till intercropping systems has not been widely investigated in diverse agro-ecological regions in Limpopo Province. Two seasons of rainfed experiments were conducted during 2018/19 and 2020/21 in a 2 × 4 × 2 factorial design to measure the biological nitrogen fixation (BNF) ability of cowpea in an intercropping system with four grain sorghum cultivars at two test locations, Ofcolaco and Syferkuil, of Limpopo Province using the natural abundance technique. The cowpea nitrogen isotope composition (δ 15N‰) ranged from 0.2 ‰ to 4‰ at Ofcolaco, whereas at Syferkuil, the range was 2 ‰ to 7 ‰. The N derived from air (Ndfa) was from 35% to 92% at Ofcolaco and 4% to 70% at Syferkuil during the two cropping seasons. The amount of N2 fixed across locations and seasons ranged from 1 kg ha−1 to 71 kg ha−1. In the intercropping system, cowpea fixed more N at higher densities compared with lower densities at the two experimental sites. Biomass was significantly correlated with N accumulated by cowpea (r2 > 0.9) at all locations and across seasons. N accumulated in sole cultures was 30% more at Ofcolaco and 36% more at Syferkuil compared with binary cultures. Furthermore, the treatment combination, cowpea density, as well as cropping system, significantly affected N fixation and accumulation. For high productivity, cowpea intercrop with grain sorghum cultivar Enforcer is recommended, as both crops complemented each other when intercropped. The research should investigate further the root distribution and biomass production of sorghum and cowpea, as well as their impact on N intake.

Adaptive Evolution of Rhizobial Symbiosis beyond Horizontal Gene Transfer: From Genome Innovation to Regulation Reconstruction.

There are ubiquitous variations in symbiotic performance of different rhizobial strains associated with the same legume host in agricultural practices. This is due to polymorphisms of symbiosis genes and/or largely unexplored variations in integration efficiency of symbiotic function. Here, we reviewed cumulative evidence on integration mechanisms of symbiosis genes. Experimental evolution, in concert with reverse genetic studies based on pangenomics, suggests that gain of the same circuit of key symbiosis genes through horizontal gene transfer is necessary but sometimes insufficient for bacteria to establish an effective symbiosis with legumes. An intact genomic background of the recipient may not support the proper expression or functioning of newly acquired key symbiosis genes. Further adaptive evolution, through genome innovation and reconstruction of regulation networks, may confer the recipient of nascent nodulation and nitrogen fixation ability. Other accessory genes, either co-transferred with key symbiosis genes or stochastically transferred, may provide the recipient with additional adaptability in ever-fluctuating host and soil niches. Successful integrations of these accessory genes with the rewired core network, regarding both symbiotic and edaphic fitness, can optimize symbiotic efficiency in various natural and agricultural ecosystems. This progress also sheds light on the development of elite rhizobial inoculants using synthetic biology procedures.

Halophytic Plant Halostachys belangeriana (Moq.) Botsch as a Source of Plant Growth-Promoting Endophytic Bacteria

Halostachys belangeriana (Moq.) Botsch also known as Halostachys caspica C. A. Mey belongs to the Chenopodiaceae family and is distributed in deserts of Asian countries. The plant grows in severe salinity and drought conditions and its survival and growth can be associated with the activity of endophytic bacteria. The objective of our research was to isolate and screen endophytic bacteria from Halostachys belangeriana for plant growth promotion and reveal their plant-beneficial traits. Methods. Halostachys belangeriana (Moq.) Botsch plants were collected from the saline soil of the Kyzylkum desert in Uzbekistan in spring. The endophytic bacteria were isolated from the tissues of plants by cutting the outer sterilized shoots and roots and putting them into the water to let bacteria come from the tissues into the water. The suspension was transferred onto Tryptic Soy Agar to let bacteria grow and form separate colonies. The colonies different in shape and color were used to get pure cultures of bacteria. The bacteria were screened using plant growth-promoting activity in Petri plates by inoculating wheat seeds with the suspension of isolated bacteria. The best plant growth promoters were identified by analyzing their 16S rRNA gene and comparing it with sequences registered in GenBank of NCBI. The strains were tested for wheat growth promotion in a pot experiment and then examined for their plant-benefi cial traits: N2-fixation, phosphates solubilization, production of indole-3-acetic acid (IAA), 1-aminocyclopropane-1-carboxylate deaminase (ACC-deaminase), and siderophores. Results. A total of 25 isolates of endophytic bacteria were obtained from the tissues of Halostachys belangeriana (Moq.) Botsch. Due to the high efficiency of isolates SSU-4, SSU-7, SSU-16, SSU-18, and SSU-21 in the stimulation of wheat shoot and root growth, they were chosen for identification and (OK559720), Bacillus endophyticus SSU-7 (OK559721), Bacillus subtilis SSU-16 (OK559722), Isoptericola halotolerans SSU-18 (OK559723) and Pseudomonas kilonensis SSU-21 (OK559724), respectively. The single inoculation of seeds with tested strains increased the root and shoot length and plant fresh weight. The coinoculation of seeds with a mixture of five strains resulted in an even more increase in plant growth parameters. It was revealed that the tested strains had at least two plant-beneficial properties. The strains B. pumilus SSU-4 and P. kilonensis SSU-21 had the ability for nitrogen fixation. All strains produced IAA; however, the most active IAA producer was P. kilonensis SSU-21. Three of five strains had phosphates solubilization ability and produced ACC-deaminase and siderophores. The strains B. pumilus SSU-4 and P. kilonensis SSU-21 possessed four of five tested plant-beneficial properties. The strains B. endophyticus SSU-7 and I. halotolerans SSU-18 had three of five tested plant-beneficial traits, and B. subtilis SSU-16 could just produce IAA and ACC-deaminase. Conclusions. This is the first report about the isolation of plant growth-promoting endophytic bacteria from the desert halophytic plant Halostachys belangeriana (Moq.) Botsch. The most efficient plant growth-promoting strains were: B. pumilus SSU-4, B. endophyticus SSU-7, B. subtilis SSU-16, I. halotolerans SSU-18, and P. kilonensis SSU-21. After field experiments, these strains can be suggested for use as bioinoculants improving plants growth.

Herbert screws fixation of high-energy navicular body fractures

Background: The purpose of this study was to assess the ability of Herbert screw fixation in navicular fractures to restore medial column stability, maintain reduction and determine the impact this approach may have on the development of avascular collapse of the navicular. We hypothesized that Herbert screw fixation of comminuted fractures of the navicular can be safely reduced and maintained to union with a low incidence of avascular collapse. Materials and Methods: A retrospective chart review was performed on 7 patients with navicular body fractures treated with open reduction and internal fixation with Herbert screw fixation at Sri Lakshmi Narayana Institute of Medical Sciences, Puducherry over a period of 2 years. Results: All fractures united. No patient developed a deep infection. There was no loss of reduction, implant failure with excellent functional and radiological outcome Conclusion: Herbert screw fixation provides excellent functional and radiological outcome for isolated navicular body fracture.

Combining abilities of soybean progenies and bradyrhizobium strains for biological nitrogen fixation

AbstractWe aim to study the biological nitrogen fixation (BNF) ability of soybean (Glycine max) progenies and their ability for symbioses using different Bradyrhizobium strains, as well as select progenies and strains that are more efficient in BNF to guide strategies in soybean breeding. An experiment was conducted in a greenhouse, evaluating 24 soybean progenies and five Bradyrhizobium strains. Mean values from analysis of variance were compared by the Scott–Knot test, and partial diallel analysis was performed to estimate general and specific combining ability. Following analysis of the greenhouse experiment, 10 soybean progenies and two Bradyrhizobium strains (SEMIA 587 and INPA 03–11B) were selected to carry out a field trial experiment. Biological nitrogen fixation was affected by genotype, strain, and genotype × strain interactions. Additive effects were predominant on the traits related to BNF, indicating that recurrent selection could be an effective breeding strategy. The progenies showed higher values for the traits related to field nodulation but did not improve seed yield. The EA‐8 progeny stood out for high yield and had good results in traits related to BNF and early maturity. The INPA 03–11B strain had the best result for seed yield, indicating high potential for use as an inoculant in soybean crops.

Tailoring defects in SrTiO3 by one step nanoarchitectonics for realizing photocatalytic nitrogen fixation in pure water.

Surface contamination of materials by nitrogenous impurities is a major problem that can bias the quantification of ammonia in photocatalytic N2 fixation reactions. In this work, SrTiO3 nanocubes were prepared by using a nitrogenous precursor and engineered with Ti3+ sites and oxygen vacancy defects in a one-step solvothermal approach. It was observed that the synthesized materials were containing surface nitrogenous impurities and therefore a rigorous cleaning procedure was adopted to eliminate them to the best extent. The contribution of unavoidable surface impurities was deduced in the form of adventitious NH3 by employing control experiments and a realistic photocatalytic NH3 generation was achieved. It was found that pristine SrTiO3 showed no photocatalytic activity, whereas one of the defected SrTiO3 materials showed the highest NH3 formation under natural sunlight in pure water, which was ascribed to the tuned defect sites, enhanced surface area and efficient separation of photogenerated charges. Based on the experimental results, a stringent protocol has been suggested for materials synthesis while working with nitrogenous precursors and for subsequent photocatalytic N2 fixation experiments. Thus, the present study provides a simple and affordable procedure for catalyst synthesis for the studied application and expands the scope of perovskite oxide materials to fabricate efficient photocatalysts for sustainable NH3 production.

Effect of Al2O3 on migration and distribution of chromium and chromium fixation effect in stainless-steel slag glass-ceramics

Stainless-steel slag was used to prepare glass-ceramics, which could solidify chromium (Cr) in the slag. The migration and distribution state of chromium in the slag during the preparation of the glass-ceramics have a great influence on the chromium fixation ability of the glass-ceramics. In this paper, the effects of Al2O3 content in the glass-ceramics on the migration and distribution of chromium during the nucleation and crystallization steps, and on the chromium fixation effect of the glass-ceramics were systematically studied. The results show that in the nucleation stage, with the increase of Al2O3 content, the number of chromium spinel (Cr-spinel) nanocrystals formed in the glass first increases and then decreases, and Cr in the glass phase gradually migrates to Cr-spinel nanocrystals. TEM and XPS analyses show that during crystallization, part of Cr in Cr-spinel diffuses into diopside lattice, and the other part of Cr still exists in Cr-spinel wrapped by diopside. Cr in the glass phase also diffuses and migrates into the diopside lattice with the formation of diopside crystals. The optimal Al2O3 content is 11.8wt.%, which results in 97.94wt.% of the total Cr being fixed in the diopside crystalline phase. The ability of chromium fixation is very high giving a very low Cr leaching concentration of 0.004mg/l. The research results provide theoretical and technical support for increased chromium fixation and realizing harmless and high-value utilization of stainless-steel slag.

Effect of goethite-loaded montmorillonite on immobilization of metal(loid)s and the micro-ecological soil response in non-ferrous metal smelting areas

In this work, the immobilization stabilization and mechanism of heavy metal(loid)s by goethite loaded montmorillonite (GMt) were investigated, and the soil microbial response was explored. The simulated acid rain leaching experiment showed that GMt had a higher acid tolerance and the more stable heavy metal(loid)s fixation ability. The soil incubation demonstrated that GMt significantly decreased the available Cd, Zn, Pb and As concentration. Interestingly, higher immobilization of heavy metals was observed by GMt in highly acid leached and acidic soils. The richness and diversity of bacterial communities improved after the addition of GMt. GMt induced the enrichment of the excellent functional bacteria of the phylum Proteobacteria as well as the genus Massilia and Sphingomonas. The main immobilization mechanisms of heavy metal(loid)s by GMt include electrostatic interaction, complexation, precipitation and oxidation. The addition of the GMt also optimizes the soil bacterial community structure, which further facilitates the immobilization of heavy metal(loid)s. Our results confirm that the novel GMt has a promising application in the immobilization and stabilization of heavy metal(loid)s contaminated soils in non-ferrous metal smelting areas.

Sample preparative procedure for Pseudomonas aeruginosa observation under scanning electron microscope

Scanning electron microscope (SEM) is a popular tool used for observing bacteria surface and morphology. Using Pseudomonas aeruginosa as a model, this work aimed to show a SEM preparative procedure that is simple and economical but does not result in considerable data loss. This was accomplished via testing fixing ability of 10% formalin versus 2.5% glutaraldehyde, efficiency of air drying versus t-butyl alcohol drying method. Following that, polypropylene, dialysis tubing and agar were also assessed for their ability to serve as a supporting material for cell adhesion in preparing sample for SEM. Consequently, obtained data showed that the procedure using 24-hour 10% formalin fixation and t-butyl alcohol drying preserved well bacterial morphology. With this procedure, little cell or membrane damage was seen while extracellular structures were clearly observed. Furthermore, when this procedure was applied with different types of substrates including polypropylene, dialysis tubing, and agar, it showed that sample fixed on polypropylene maintained well extracellular structures meanwhile sample fixed on agar presented well bacterial morphology. In conclusion, our data suggested that coating samples on polypropylene, followed by 24-hour 10% formalin fixation and t-butyl alcohol drying was appropriate for observing bacteria under SEM.

A Lipopolysaccharide Synthesis Gene rfaD from Mesorhizobium huakuii Is Involved in Nodule Development and Symbiotic Nitrogen Fixation.

Rhizobium lipopolysaccharide (LPS) is an important component of the cell wall of gram-negative bacteria and serves as a signal molecule on the surface of rhizobia, participating in the symbiosis during rhizobia-legume interaction. In this study, we constructed a deletion mutant of ADP-L-glycerol-D-mannoheptosyl-6-exoisomerase (rfaD) of Mesorhizobium huakuii 7653R and a functional complementary strain. The results showed that the deletion of rfaD did not affect the free-living growth rate of 7653R, but that it did affect the LPS synthesis and that it increased sensitivity to abiotic stresses. The rfaD promoter-GUS reporter assay showed that the gene was mainly expressed in the infection zone of the mature nodules. The root nodules formation of the rfaD mutant was delayed during symbiosis with the host plant of Astragalus sinicus. The symbiotic phenotype analyses showed that the nodules of A. sinicus lost symbiotic nitrogen fixation ability, when inoculated with the rfaD mutant strain. In conclusion, our results reveal that the 7653R rfaD gene plays a crucial role in the LPS synthesis involved in the symbiotic interaction between rhizobia and A. sinicus. This study also provides new insights into the molecular mechanisms by which the rhizobia regulate their own gene expression and cell wall components enabling nodulation in legumes.

Salicylic acid induced signaling against nickel-induced toxicity: Responses of growth, exopolysaccharides, phostosystem II photochemistry, nitrogen metabolism status and antioxidant system of Anabaena sp. PCC 7120

The Anabaena sp. PCC 7120 is a filamentous cyanobacterium which is well known for its nitrogen fixing ability but nickel (Ni2+) contamination (in water bodies) has a negative impact on its growth. The negative impact of Ni2+ can be ameliorated by calcium (Ca2+)-mediated nitric oxide (NO) signaling induced by salicylic acid (SA) treatment. The present study was performed to investigate the relation between SA and NO mediated by Ca2+ and to understand this interaction several inhibitors and scavengers were used in different combinations. Results showed that Ni2+- toxicity declined growth (measured in terms of dry weight; DW), contents of exopolysaccharide and photosynthetic pigments, and also negatively affected the PSII photochemistry (OJIP transient parameters: Fm, Fv, Fm/Fo, Fv/Fo, Ψo, ФPo, ФEo, Area, N, and PIABS were suppressed; while Fo, Fo/Fm, Fo/Fv, Sm, ФDo, ABS/RC, TRo/RC, ETo/RC and DIo/RC were raised) and nitrogen metabolism. However, supplementation of SA, Ca2+ (CaCl2) and sodium nitroprusside (SNP; donor of nitric oxide (NO) to the culture medium counteracted the negative impact of Ni2+ thereby improving the growth. Further, to investigate the relation between Ca2+and NO, when c-PTIO (2–4-carboxyphenyl- 4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide; scavenger of NO) was supplemented to Ni+SA+Ca2+ and EGTA (ethyleneglycol-bis (β- aminoethyl)- N,N,N,N- tetraacetic acid; Ca2+chelator) to Ni+SA+NO treated culture medium, the recovery on above studied traits caused due to Ca2+ and NO was arrested even in presence of SA suggesting the signaling behavior of Ca2+ and NO in SA induced pathway. Moreover, the impact was worsened under c-PTIO supplemented Ni+SA+Ca2+than EGTA supplemented Ni+SA+NO treatment suggesting key role of Ca2+ in mediating NO signaling induced by SA. Conclusively, this is the first study that demonstrates the relation between SA and NO mediated by Ca2+in Ni2+-stressed Anabaena sp. PCC 7120.

Plant types shape soil microbial composition, diversity, function, and co‐occurrence patterns in cultivated land of a karst area

AbstractPlants can alter microbial communities through root exudates, and change the characteristics of the soil. However, the relationship between soil microbial communities and environmental factors is not well understood. Here, we studied bacterial and fungal communities and their relationships with environmental factors. We integrated data of environmental factors, microbial composition, diversity, functional prediction, and co‐occurrence network from uncultivated, maize, cabbage, and cocozelle soils in a karst area of Southwest China. Soil bacterial and fungal community composition differed with plant types. Maize soil had more taxa and greater alpha diversity of bacteria and fungi than other soils. In maize soil, the relative abundance of Actinobacteria and Ascomycota was significantly lower than that in uncultivated soil, while its contents of soil organic matter (OM), alkali‐hydrolyzable nitrogen, and total nitrogen (TN) showed the opposite trend. These indicators were not significantly different between cabbage and cocozelle soils. The results of the Mantel test and the RDA analysis indicated that TN and OM were important drivers of bacterial and fungal communities. Functional prediction and network analysis showed that maize soil had a high nitrogen fixation capacity and a complex and stable network. To summarize, maize soil not had a low relative abundance of Ascomycota and high content of TN and OM, nitrogen fixation ability, and a rich microbial community. Therefore, cultivating maize is suitable for improving soil microbial community. These findings might help in formulating a reasonable cultivation management program to prevent land degradation in the karst areas.

Evaluation of bioactive compounds from robust consortium microalgae species under actual flue gas exposure

The application of phototrophic microalgae for biological CO2 fixation has been regarded as a sustainable means to curb emissions, treat wastewater, and provide essential and valuable bioactive compounds that can serve multitudes industries, e.g., aquaculture, nutraceutical, and biofuel. This article highlights the utilization of microalgae consortium to enhance carbon fixation ability. Marine microalgae species were isolated and identified from their native condition of seawater discharge canals at the TNB Janamanjung Sdn. Bhd.’s coal-fired power station. The experimental runs were performed with exposure of actual flue gas as a CO2 source from a live operating coal-fired power plant. The bioassays of protein and amino acids were conducted to the consortium to explore potential bio-products. The proximate analysis illustrated that the consortium content of protein (45%), lipid (21%), and carbohydrate (17%) is comparable and more balanced from other types of mono species. Also, the essential amino acid content of 42% is encouragingly good and exceeds some other species and other sources. Premises and observations from various microalgae research works are collated and presented in a manner sufficient to highlight the essential roles of this tiny creature to become our mentor in providing some solutions to our worldly problems.

Morpho-Physiological Responses of Soybean Varieties to Salinity Stress

Soybean (Glycine max L. Merr) has a tremendous value in agriculture as a good source of high-quality plant protein and vegetable oils in one hand and nitrogen fixing ability on the other, now a day largely growing in coastal salt marshes areas of Bangladesh. The aim of this study was to evaluate morphological and physiological responses of soybean varieties (Shohag, BARI Soybean-6, BARI Soybean-5 and Binasoybean-4) to pot grown plants in different concentrations of salinity level i.e., control (0.3), 4, 8 and 12 dS m−1 during 2020-21. Irrespective of the variety, with the increase of salinity levels physiological parameters as well as seed yield were greatly affected. Salinity stress decreased total chlorophyll (Chl a+b) and total dry matter (TDM) was reduced due to salinity stress, which ultimately reduced seed yield irrespective of the variety. Sodium (Na+), calcium (Ca2+), potassium (K+) ion content and the potassium sodium ratios (K+: Na+) in leaf tissue were significantly affected by salinity levels. Under salinity stress, BARI Soybean- 6 showed a higher K+: Na+ ratio in leaf, which indicates higher tolerance to salinity compared to others. However, H2O2 and MDA contents was comparatively lower in the respective variety. This variety also showed higher TDM production, filled pods plant-1 and seed yield plant-1 in all salinity levels compared to other varieties. Results revealed that, soybean var. BARI Soybean-6showedmore tolerance against salinity stress compared to other varieties.
 Bangladesh Agron. J. 2022, 25(1): 15-22

Pristine and ruthenium-doped TiO[formula omitted] nanoclusters for nitrogen reduction reaction: Ab initio study of structure and adsorption

The Haber-Bosch process has been the workhorse of ammonia synthesis for more than a century, but its environmental cost has instigated the search for greener methods of nitrogen activation. Photocatalysis using doped titanium dioxide (TiO2) stands out as a promising method. In this work, we explore the electronic properties of pristine and Ru-loaded TiO2 clusters and the activation of nitrogen, hydrogen and ammonia on these clusters. We study the effect of the cluster size and the role of Ru on the electronic properties of the clusters and their activation capabilities. We show that loading with Ru enhanced the nitrogen fixation ability, yet it does not influence the adsorption of hydrogen and ammonia, avoiding catalyst poisoning.