Garden Soil Research Articles

Role of extracted nanosilica from rice husk on the structure, property and biodegradability of low density polyethylene/starch biodegradable film

AbstractStarch blended low‐density polyethylene (LDPE) has been extensively used to produce packaging film, but it has very low mechanical properties. This work emphasises the extraction of nanosilica from rice husk as a property‐enhancing filler for producing high‐quality packaging material. Nanosilica (200 nm) was obtained by chemical treatment followed by further size reduction through cryomill. The obtained nanomaterial was found to have a high surface area (189.64 m2/g) and pore volume (.462 cc/g) with high compatibility with the other materials in the matrix. The SEM and TEM analysis indicates the uniformity in particle size of the nanomaterial with an agglomerating tendency. The X‐ray diffractometer (XRD) and fourier transform infrared spectroscopy (FTIR) analysis reveals that the obtained material is amorphous in nature. The nanomaterial is dispersed in various proportions in LDPE/starch matrix, and it is observed that the highest tensile strength (9.62 MPa) can be obtained at 1.5% nanosilica content in the matrix. A continuous increase in Young's modulus and stiffness from 372.3 to 440.12 MPa and 20 243.2 to 28 559.42 N/m, respectively, when 1.5% of nanosilica is dispersed in the biodegradable matrix. Garden soil was a better degrading medium for the sample containing 20% of starch with weight loss of 10.32% and reduction of tensile strength and tear strength values to 5.987 MPa and 99.165 N/mm respectively, in 1 year.

Is it healthy urban agriculture? Human exposure to potentially toxic elements in urban gardens from Andalusia, Spain

Different vegetable species and topsoils were collected from different urban gardens of Seville, Cordoba, and Huelva (South Spain) and from two small towns in a mining area (Riotinto), together with topsoil close to the plants. The concentration of potentially toxic elements (PTEs) (As, B, Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, and Zn) was evaluated in edible plant parts and in the soils. The same species were also purchased from Seville local markets and from a peri-urban area (domestic garden in a rural area) and also analyzed. Plant/soil pollution relation was studied and human health risk was assessed by different parameters. Soils of urban gardens from the mining area were more contaminated with As, Cr, Cu, Pb, and Zn in comparison with other locations, and generally, soils from cities showed higher values of As, Pb, and Zn than the peri-urban ones. The mean concentration of almost all potentially toxic elements was higher in leafy than in fruiting and bulbous species. Arsenic, Cd, and Pb concentrations were below health-based guidance values in all vegetables except Cd in one sample in the peri-urban area. In general, PTEs concentration in vegetables from city urban gardens did not exceed the one found in market vegetables for almost all studied elements, except in lettuce for almost elements. The hazard quotient (HQ) values were lower than the unit for all PTEs in plant species from the studied gardens, as well as the hazard index (HI), indicating that consumption of these vegetables can be considered safe and without risk to human health. Also, cancer risk values for As were below the established limits in all vegetables from the studied urban gardens, including those from the As-contaminated soils in the mining area.

Evaluation of antibacterial activity of selected plant extracts against Serratia marcescens

Abstract BACKGROUND: Serratia marcescens is a well-known Gram-negative, rod-shaped bacterium commonly found in soil, animal skin, hospital environment, and plant-based raw materials. It is an opportunistic pathogen that causes serious infections, including pneumonia, bloodstream infection, wound infection, meningitis, and respiratory and urinary tract infections. Due to multiple resistant strains of S. marcescens being identified, new and effective plant-based antimicrobial compounds/drugs against S. marcescens must be searched. The present study is focused to explore the Stem of Neem (Azadirachta indica), Seed of Nirgundi (Vitex negundo) and Clove buds (Syzygium aromaticum) for their antibacterial activity against the isolated S. marcescens. METHODS: The S. marcescens was isolated from the garden soil of CARI Jhansi and identified based on various morphological and biochemical tests. We also checked the antibiotic profile of isolated S. marcescens. The ethanolic and methanolic extracts of the selected plant parts were prepared and explored for their antibacterial activity against S. marcescens using the disc diffusion method. RESULTS: The antibiotic profile of S. marcescens showed resistance to multiple broad-spectrum antibiotics, including erythromycin, rifampicin, chloramphenicol, and narrow-spectrum antibiotic vancomycin. At the same time, it was sensitive to kanamycin, streptomycin, ciprofloxacin, and ofloxacin. We observed that both methanolic and ethanolic extracts of clove buds were effective, while only the ethanolic extract of Nirgundi seed and Neem stem were found to be effective against S. marcescens. CONCLUSION: From this study, we conclude that both methanolic and ethanolic extracts of Clove buds, while only the ethanolic extract of Nirgundi seed and Neem stem, were found effective and showed significant inhibition of growth of S. marcescens.

Relation between solid phase speciation and oral/lung bioaccessibility of metal(loid)s polluted soils in inhabited area: Contribution of synchrotron-based experiment

The presence of contaminated sites/soils in or near cities can pose significant risks to public health. The city of Viviez (France) was taken in reference site bears significant industrial responsibility, particularly in zinc metallurgy, with the presence of a now rehabilitated smelter. This has led to soil contamination by zinc (Zn), lead (Pb), arsenic (As), and cadmium (Cd), with concentrations reaching up to 4856 mg kg−1, 1739 mg kg−1, 195 mg kg−1, and 110 mg kg−1, respectively. The aim of this study is to comprehend the contamination patterns of the site post-rehabilitation, the geochemical behavior of each element, and their speciation (analyzed through BCR, XRD, and XANES) in relation to associated health risks due to metals accessibility for oral ingestion and inhalation by the local population. The findings revealed that elements inducing health risks were not necessarily those with the highest metal contents. All results are discussed in terms of the relationship between element speciation, stability of bearing phases, and their behavior in different media. XANES is an important tool to determine and estimate the Pb-bearing phases in garden soils, as well as the As speciation, which consist of Pb-goethite, anglesite, and Pb-humate, with variations in proportions (the main phases being 66 %, 12 % and 22 % for Pb-goethite, anglesite, and Pb-humate, respectively) whereas As-bearing phase are As(V)-rich ferrihydrite-like. A new aspect lies in the detailed characterization of solid phases before and after bioaccessibility tests, to qualify and quantify the bearing phases involved in the mobility of metallic elements to understand the bioaccessibility behavior. Ultimately, the health risk associated with exposure to inhabitants, in terms of particle ingestion and inhalation, was assessed. Only ingestion-related risk was deemed unacceptable due to the levels of As and Pb.

Tea plantation shade tree leaf influences the susceptibility of rhizosphere microbial consortium: A comprehensive study on their leaf extract cross tolerance

Leguminous shade trees are ubiquitous parts of tea plantations of the Terai region. However, their shed leaves might have an effect on the soil microflora under those shade trees, so it is important to find out how leaf litter affect the soil microflora. Isolation of soil microbial consortia followed by downstream experiments were conducted to observe the tolerance/susceptible pattern of those soil microflora against the fallen leaves. Sample from under Albizia odoratissima has higher organic carbon, organic matter and nitrogen content but the same property was found to be low in the sample collected under Melia azedarach. Isolation of consortia was done on nutrient agar. In vitro tolerance assay was conducted to find out the tolerance pattern against leaf extracts, heavy metal salts, pesticides, antibiotics and antifungals. Heavy metals salts like Arsenic trioxide (AS2O3) and Cupric chloride (CuCl2); and pesticides like Thiamethoxam; Spiromesifen; Phorate etc. showed no inhibition against all the isolated consortia. Co-Trimoxazole and Augmentin have not showed any inhibition except consortia under Derris robusta, whereas no antifungals but Itraconazole had an impact over all the consortia. Shade trees, being a crucial member of the tea plantations, cannot be removed but replacement of these with other species could be a probable option, besides this limited use of chemical pesticides and fertilizers should be taken into consideration strictly to restrain the microbial population in tea garden soil. So, this study has disclosed the acceptability of each and every shade tree used in this region.

Microplastic contamination in soils of urban allotment gardens (Toruń, Poland)

Microplastic contamination in soils of urban allotment gardens (Toruń, Poland)

Understanding and exploring the diversity of soil microorganisms in tea (Camellia sinensis) gardens: toward sustainable tea production.

Leaves of Camellia sinensis plants are used to produce tea, one of the most consumed beverages worldwide, containing a wide variety of bioactive compounds that help to promote human health. Tea cultivation is economically important, and its sustainable production can have significant consequences in providing agricultural opportunities and lowering extreme poverty. Soil parameters are well known to affect the quality of the resultant leaves and consequently, the understanding of the diversity and functions of soil microorganisms in tea gardens will provide insight to harnessing soil microbial communities to improve tea yield and quality. Current analyses indicate that tea garden soils possess a rich composition of diverse microorganisms (bacteria and fungi) of which the bacterial Proteobacteria, Actinobacteria, Acidobacteria, Firmicutes and Chloroflexi and fungal Ascomycota, Basidiomycota, Glomeromycota are the prominent groups. When optimized, these microbes' function in keeping garden soil ecosystems balanced by acting on nutrient cycling processes, biofertilizers, biocontrol of pests and pathogens, and bioremediation of persistent organic chemicals. Here, we summarize research on the activities of (tea garden) soil microorganisms as biofertilizers, biological control agents and as bioremediators to improve soil health and consequently, tea yield and quality, focusing mainly on bacterial and fungal members. Recent advances in molecular techniques that characterize the diverse microorganisms in tea gardens are examined. In terms of viruses there is a paucity of information regarding any beneficial functions of soil viruses in tea gardens, although in some instances insect pathogenic viruses have been used to control tea pests. The potential of soil microorganisms is reported here, as well as recent techniques used to study microbial diversity and their genetic manipulation, aimed at improving the yield and quality of tea plants for sustainable production.

Effect of Bacillus pumilus Strains on Heavy Metal Accumulation in Lettuce Grown on Contaminated Soil

Increasing number of heavy metal on land needs to be addressed through sustainable ways and various species of Bacillus can be used to mitigate heavy metals. The research work entitled “Effect of Bacillus pumilus strains on heavy metal accumulation in lettuce grown on contaminated soil” focuses on functional role of Bacillus pumilus strains inoculated with lettuce seed in mitigating heavy metal present in chromite mining soil. This experiment was conducted at ornamental horticulture nursery, the University of Agriculture Peshawar. In this experiment, factor A was three Bacillus pumilus strains (sequence C-2PMW-8, C-1 SSK-8 and C-1 PWK-7) while soil used for this experiment was collected from Prang Ghar mining site and lettuce seeds were grown in three levels of chromite mining soil (2.27, 4.65 and 7.14 %).The experimental design used during this research was randomized complete block design with two factors and was replicated thrice. The collected data related to effect of chromite mining soil and Bacillus pumilus strains indicated that these both factors have significant influence on growth parameters. For mining soil minimum days to germinate (14 days) was noted in lettuce grown on garden soil inoculated with sequence. Maximum germination percentage noted was (100%) for C-1 SSK-8 grown on garden soil, dry weight of lettuce leaf (5.0 g) for lettuce inoculated with C-1 SSK-8 and C-1 PWK-7 strains, survival percentage (77.9%) for C-1 SSK-8 treated lettuce for sequence C-2 PMW-8. Maximum germination percentage noted was (88%) for garden soil, fresh leaf weight (17.3g), dry leaf weight (6.5g), number of leaf per plant (16), leaf area (49.0 cm2) were noted in garden soil with no chromite mining soil. Results related to heavy metals accumulation showed that minimum chromium was (2.3 mg kg-1) in lettuce and (1.9 mg kg-1) in soil for all three sequences. It can be concluded that chromite mining soil significantly reduced the growth and survival of lettuce, but when lettuce was inoculated with Bacillus.pumilus strains it enhances the growth and survival. Similarly, minimum heavy metal accumulation in plant and soil, regardless of type of B. pumilus used, all three sequences has same mitigating effect on heavy metal in both soil and lettuce. All the three Bacillus pumilus strains ensured reduction in heavy metals content (Cr) in lettuce, below the maximum permissible limits of WHO/FAO 2011.

Biodegradability and Water Absorption of Macadamia Nutshell Powder-Reinforced Poly(lactic Acid) Biocomposites

This study investigates the biodegradability and water absorption properties of Macadamia nutshell powder and poly(lactic acid) (PLA) biocomposites using a Design of Experiments (DOE) approach. The influences of processing methods, the Macadamia nutshell powder’s weight content, and the powder’s condition are studied. A biodegradability test is performed in accordance with the American Society for Testing and Materials (ASTM) D5338-11 by burying the test specimens in wet garden soil at a controlled temperature of 50 °C and 100% humidity. The specimens obtained by counter-rotating processing exhibit varying weight loss patterns with an increasing powder weight content, while the specimens obtained by co-rotating processing demonstrate consistent behaviour. This study highlights the complex nature of PLA biodegradation, which is affected by diverse factors such as test conditions and environments, thereby contributing to a deeper understanding of the sustainability implications. A water absorption test is carried out in accordance with ASTM D570-98. It is shown that the water absorption characteristics are predominantly determined by the hydrophilic nature of Macadamia nutshells, with an increased powder weight content leading to higher absorption. Pure PLA, due to its hydrophobic nature, exhibits minimal water absorption. By unravelling the complexities of PLA biodegradation and water absorption in Macadamia nutshell and PLA biocomposites, this study not only advances the understanding of materials’ behaviour but also underscores the potential sustainability implications of utilizing natural resources in composite materials. This research contributes valuable insights to the broader discourse on environmentally friendly materials and their role in promoting sustainable practices.

Comparative investigation of powder and extract of biochar from Broussonetia papyrifera on the growth and eco-physiological attributes of Vigna radiata

This study compared the impact of biochar (in powder and extract forms) derived from the invasive tree Broussonetia papyrifera on the growth and eco-physiological responses of Vigna radiata (mung bean) under laboratory and experimental dome environments. The primary objective was to investigate the sustainable utilization potential of biochar derived from invasive plants. Powdered biochar was mixed into garden soil at amendment rates of 0.5%, 1%, 2%, and 4%, while for extract treatments, the seedlings were irrigated with extracts of these concentrations. The responses of plants were found to be dependent on the concentration and type of treatment (i.e., powder or extract) used. The highest levels of growth and eco-physiological responses were observed at a concentration of 1% for biochar extract and 2% for powdered biochar. In addition, the impacts were more pronounced in the roots than in the shoots. The biochar amendment resulted in a 7‒73% increase in root length and a 12‒148% increase in plant dry biomass when compared to the control. Crop growth, water use efficiency, and leaf area were greater in powdered biochar, but net photosynthesis (Pn), transpiration rate, and stomatal conductance were higher in plants treated with biochar extract. Adding powdered biochar to soil increases its pH, electrical conductivity (EC), moisture content, soil organic C, and amounts of available N, P, and K; however, the effects of applying biochar extracts were less pronounced. Crop growth and eco-physiological responses were found to be positively correlated, regardless of the biochar form used. Following biochar extract treatment, EC was found to be negatively correlated with Pn. The study revealed that powdered biochar had superior growth responses and soil improvement compared to biochar extract at higher concentrations. However, biochar extract also had comparable effects and can be beneficial in short-term cropping systems such as urban farming (e.g., in kitchen gardens and vegetable production) at lower concentrations (up to 2%). The findings of the study provide a baseline for future evaluations regarding the sustainable application of biochar liquor (water extract) as a source of nutrients and the powdered residual biochar as a potential material for adsorbing environmental contaminants or improving soil quality.

Assessment of phytotoxicity bioassay and metal accumulation potential of Ricinus communis L. genotypes during cultivation in iron mine soil of Jharkhand, India

ABSTRACTS Seed germination and early seedling growth are crucial characteristics for determining a plant species ability to survive in stressed soil including mine soil (MS). In the present study, four genotypes of castor bean (Ricinus communis L.) an industrially important bioenergy crop, were grown in iron MS with different treatments of garden soil (GS) (0%, 25%, 50%, 75%, and 100%) to examine germination, growth indices (tolerance index (TI), seedling vigor index (SVI)) and metal accumulation potential. The study recorded significantly high germination, growth and biomass in 75% GS treatments and for the cultivar MSC-55. The TI was highest in 75% GS treatments for all genotypes, with no significant difference. The metal accumulation potential of castor was evaluated for Fe, Pb, Cu and Ni, all of which were detected in high concentration in iron MS. The translocation factors (TF) for Fe and Ni were recorded <1 for all genotypes which imply metals are stabilized in the castor roots, although for Cu and Pb it was found >1. The bioaccumulation factor was recorded highest for Fe (1.224–7.433) and Pb (0.846–9.056) for all genotypes. Furthermore, the root accumulation of Fe, Pb and Ni was observed highest with 8039.20, 177.70 and 88.10 mg kg−1, respectively. The metal extraction ratio (MER) for Fe and Pb showed the highest. Overall, the highest MER was recorded in order of MSC-55 > Leetos > Swati-1515 > Sai-33. The finding of the study indicates that the genotypes MSC-55 followed by Leetos can grow in MS and accumulate multiple metals in their root and shoots and can be employed as phytostabilizers and phytoextractors.

Enhancing Herbage Growth, Yield and Quality of Stevia (Stevia rebaudiana Bertoni) using Bio-Organic Nutrients in Varied Soil Media

The present method of stevia propagation is still insufficient to meet its increasing demand. Moreover, the use of organic inputs as substitutes for inorganic fertilizers to improve soil quality and productivity is also desired. In this study, the effects of bio-organic nutrients and different growing media compositions on Stevia’s herbage growth, yield and quality were determined. A completely randomized design was used with 20 rooted stem cuttings per replication at one cutting per potting bag, laid in a 4 × 4 factorial arrangement. Growing Media (garden soil alone [GS]; GS + rice hull [RH]; GS + vermicompost [VC]; and GS+RH+VC) served as factor A while bio-organic nutrients (fermented fruit juice [FFJ]; vermi tea [VT]; seaweed tea [ST] and control) as factor B. There were 16 treatment combinations replicated four times. Results showed that GS+RH+VC consistently improved the survival rate, plant height, leaf and shoot count per plant, weight (fresh and dry), and herbage yield of Stevia. Furthermore, VT boosted the herbage yield and visual quality. In terms of interaction effects, plants grown in garden soil mixed with vermicompost (GS+VC) with VT application developed more leaves than other treatment combinations. Hence, these bio-nutrients and growing media composition significantly enhanced the production of Stevia.

Effect of charcoal and spent engine oil on some growth indices of &lt;i&gt;Rhizophora racemosa&lt;/i&gt; g. Mayer grown in garden soil

This study investigated the effect of charcoal and spent engine oil on some growth indices of mangrove seedlings Rhizophora racemose G. Mayer grown in garden soil. The aim was to discover means of improving mangrove nursery growth and survival in the Niger Delta area of Nigeria. Rhizophora racemose was planted in garden soil amended with four different treatments: C (Garden soil only), PC (Garden soil + Charcoal), PCSEO (Garden soil + Charcoal + 6% Spent engine oil), and SSEO (Garden soil + 6% Spent engine oil), with three replicates each and randomized complete block design was adopted for the study. The effect of these treatments was monitored biweekly on some growth indices – plant height, leaf area, leaf length, number of leaves and stem girth, except for root length, number of roots, fresh weight, dry weight and chlorophyll content of R. racemosa which were obtained at 18th week after planting. The study revealed that PC treatment had the highest values for plant height, number of leaves, fresh weight, plant girth, root length when compared to other treatments (C, PCSEO and SSEO) while SSEO recorded the least values. Among the treatments, there were significant differences in the plant height, fresh weight and root length of R. racemosa at P = 0.05. The garden soil amended with charcoal improved the performance of R. racemosa than in spent engine oil alone (PC &gt; PCSEO &gt; SSEO). This could be attributed to the presence of heavy metals in spent engine oil. Again, the charcoal amended soil had higher values for growth indices when compared with the control (C) treatment. This suggest that charcoal has the potency of improving garden soil fertility, plant survival and productivity. Therefore, charcoal could be beneficial in environmental conservation, restoration of endangered forest especially the mangroves in the Niger Delta polluted with crude oil. The study recommends that, charcoal should be incorporated in reforestation and afforestation approaches of mangrove forests.

Submerged macrophyte root oxygen release reduces sediment oxygen demand: A positive feedback loop in shallow lakes

Shallow lakes have two stable ecological states, macrophyte dominated or algal dominated. The macrophyte dominated state is the more desired state as it generally has clearer water that is safe for contact recreation. Whereas the algal dominated state is considered degraded, resulting from high anthropogenic nutrient inputs, with turbid water that is often unsafe for contact recreation. These ecological states are somewhat resilient due to in-lake feedback loops that maintain or enhance conditions for the dominate primary producer. For the macrophyte dominated state, many of these feedback loops are theoretically plant density dependent, but rarely has the plant density required to initiate these feedback loops been identified. Here we illustrate the plant density dependence of a previously unstudied feedback loop present in the macrophyte dominated state. Increased densities of Isoëtes kirkii were able to reduce sediment oxygen demand through their root oxygen releases. This reduction in sediment oxygen demand occurred at 32 plants m−2 in a garden soil and 63 plants m−2 in the sediment of a hypo-eutrophic lake, a disparity likely due to the higher initial sediment oxygen demand present in the lake sediments. In a shallow lake, plants present in the hypolimnion will reduce sediment oxygen demand, increasing the amount of time required before anoxic conditions are created and the resulting release of dissolved reactive phosphorus. This will likely decrease the potential for subsequent algal blooms and the associated shading of submerged macrophytes, thus maintaining in-lake conditions that favour macrophytes.

УСОВЕРШЕНСТВОВАНИЕ ПРИЕМОВ ПЕРЕВОДА ОЗДОРОВЛЕННЫХ IN VITRO ВИНОГРАДНЫХ РАСТЕНИЙ В УСЛОВИЯ ПОЧВЕННОЙ КУЛЬТУРЫ

The article discusses techniques for improving the properties of a nutrient substrate used for planting healthy in vitro grape plants. The research was carried out on the basis of the laboratory of biotechnology ARRIV&amp;W – branch of FSBSI FRARC on an interspecific hybrid Krasnostop Carpi. The purpuse of the study is to improve the ways of adapting healthy in vitro plants to non–sterile conditions. With microclonal reproduction of grapes, death most often occurs when transferring test tube plants to non-sterile conditions. The selection of the composition of the soil substrate and the improvement of its water-physical and biological properties helps to reduce the risk of plant death. In our studies, peat, garden soil and river sand (1:1:1) were used as part of the substrate, to which “Aquasin hydrogel” and “Trichoderma Veride” endomycorrhizal preparation containing mycelium and spores of Trichoderma viride fungi, strain 471, were added. The plants were planted in a 500 ml container, had been adapted to non-sterile conditions and had been grown for 90 days on racks of accelerated plant cultivation (RAPC). In the process, the indicators of the preservation of initial plants, their growth, development and spread of the root system were noted. As a result, it can be concluded that the combined use of hydrogel and mycorrhiza ensures the best survival and preservation of plants of the Krasnostop Carpi variety. The mycorrhizal preparation promotes better development of the leaf surface, and the addition of hydrogel ensures better development of the root system, which will provide plants with better survival in open ground conditions of the basic mother plantation. Key words: HEALTHY IN VITRO GRAPES, HYDROGEL, MYCORRHIZA, SUBSTRATE, ADAPTATION TO NON-STERILE CONDITIONS

Populasi dan Keanekaragaman Fungi Mikoriza Arbuskular pada Rizosfer Tanaman Lada (Piper nigrum L.) Monokultur dan Polikultur

Arbuscular mycorrhizal fungi (AMF) is a type of fungus that comes from the endomycorrhizal group, these fungi have the ability to form symbiosis with almost 90% of higher plant species. Population and diversity of AMF are influenced by biotic factors and abiotic factors. This research aims to determine the differences in population, diversity and dominant types of AMF in the rhizosphere of pepper planted in monoculture and pepper in polyculture. The soil samples were taking from monoculture and polyculture pepper plantations in Air Naningan District, Tanggamus Regency. The AMF population was tested using the One way Annova test. Culture trapping was done using a factorial treatment with the first factor being the origin of the soil sample (K) and the second actor being the type of host plant (T). Treatments design used was randomize design (CRD). The results showed that the AMF population in polyculture pepper plantation soil samples was higher than monoculture pepper, based on the Shannon-Wiener Diversity Index, AMF diversity in monoculture pepper and coffee intercropping pepper plantations was higher than in cocoa intercropping pepper plantations, and the type of AMF was dominant. from the results of trapping culture with monoculture pepper garden soil samples, namely spores of the species code S7, in samples of coffee intercropping pepper plantations the code S7 is dominant, while in cocoa intercropping pepper plantations it is dominated by code S6. Keywords: Arbuscular mycorrhizal fungi, diversity, population.

Species of Laboulbeniales fungi parasitic on some common Indian insects: Isolation, visualization and characterization by Scanning Electron Micrographs (SEM)

The Laboulbeniales are a group of lesser-known fungi. They occur as ectoparasites on the exoskeleton of various arthropod species, mainly beetles, cockroaches, ants, dipterans and a few millipede genera appearing as hairs/bristles coming out of their cuticle. They are small, non-mycelial fungi forming compact multicellular thalli, starting from a two-celled sheathed ascospore which continues to envelop the mature thallus. The fungi, being obligate, spend their entire life cycle on their insect hosts. The present study attempted to locate the Laboulbeniales fungi in the common insects of India, isolate them and identify them based on morphology. Different species of insects; Carabid beetles - Stenolophus sp., Bembidion sp., Black ants - Camponotus sp., and Earwigs - Labidura riparia; were collected from different habitats of damp garden soil, river banks, light sources and entomological collection museum situated as different sites New Delhi. The insects were scrutinized for the presence of fungi through light and scanning electron microscopy. The morphological features of each fungus were recorded, and the species were characterized. The studies showed the presence of Laboulbenia anaplogenii and L. stenolophi on the legs of Stenolophus sp.; L. egens on Bembidion sp. legs; L. camponoti on the wings of black ants and Dimeromyces anisolabis on the legs of earwigs. The identification was made primarily based on the size, shape and structure of basal foot, receptacles, antheridia and foot of the thallus or it’s remnant scar found on the insect cuticle. This is the first Indian report of conducting scanning imaging of the Laboulbeniales fungi.

Optimizing callus induction and indirect organogenesis in non-dormant corm explants of Gloriosa superba (L.) via media priming

IntroductionGloriosa superba L. is an endangered ornamental plant of significant medicinal, commercial, and cultural value. This study establishes an efficient protocol for rapid in vitro propagation of this plant species through callus-mediated organogenesis using non-dormant corm explants.MethodsPlant tissue culture techniques were employed to facilitate the in vitro regeneration process of Gloriosa superba L. This encompassed various stages, including the acquisition of plant material, surface sterilization, formulation of growth media, and the execution of callogenesis, shooting, rooting, and acclimatization experiments.Results and DiscussionInvestigation into the impact of plant growth regulators on callogenesis unveiled diverse callus morphologies, dependent on regulator type and concentration, with the NAA and KN combination emerging as the most effective for callus induction. Specifically, the callus induction medium supplemented with 1.5 mg L−1 NAA, 0.5 mg L−1 KN, and 10 mg L−1 casein hydrolysate (CH) achieved remarkable results, boasting an 81.25% callus induction rate and a substantial callus biomass fresh weight of 333 mg. Furthermore, the combination of BAP and NAA facilitated optimal shoot primordia induction and shooting in callus derived from non-dormant corm explants. The shoot induction medium, enriched with 2.0 mg L−1 BAP, 0.5 mg L−1 NAA, 5 mg L−1 CH, and 20% (v/v) coconut water (CW), resulted in an impressive 83.33% shoot primordia formation rate and an average of 6.86 shoot primordia per callus. For root induction, the medium supplemented with 1.0 mg L−1 IBA displayed a high root induction rate of 81.25% and robust rooting (+++). Successful acclimatization of in vitro plantlets in controlled environments and shade net houses culminated in thriving growth, and upon transplantation into a garden soil blend (garden soil : sand : vermiculite, 2:1:1, v/v), with direct sunlight exposure, the plantlets demonstrated commendable development and form, boasting a 69% survival rate at the seven-week mark. These findings offer a robust foundation for scalable and sustainable propagation strategies, ensuring the conservation and utilization of this valuable species.

A Perspective on Plastics and Microplastics Contamination in Garden Soil in British Columbia, Canada

Plastic contamination is commonly reported in urban and rural soils, as well as in fresh and ocean waters. Canada’s government has attempted to limit the contamination of single-use plastic by banning the manufacturing and selling of specific types of plastic. In British Columbia, current regulations governing commercial composting state that when compost has less than 1% of its dry weight representing foreign materials (including plastic), it can be sold and used in soils. However, due to the low density of plastic and its potential to break down into microparticles, this amount may be enough to become toxic when used in agricultural soils. This paper studies contamination of plastic in garden soils and summarizes how this can affect the environment with a preliminary examination of a garden soil sample. The examination showed that the garden soil sample contained mainly low-density polyethylene, polyethylene and polypropylene plastics (identified through ATR-FTIR) in oxidized and unoxidized forms that can come from commercial composting and hypothesizes that this plastic could break down into microplastic particles. In order to limit the amount of plastic contamination in agricultural soils, it is necessary to modify current compost regulations in order to treat plastic differently than other foreign materials (glass, metal, wood).

Pyrolysis temperature affects biochar suitability as an alternative rhizobial carrier

Biochars produced from different feedstocks and at different pyrolysis temperatures may have various chemical and physical properties, affecting their potential use as alternative microbial carrier materials. In this study, biochars were produced from pine wood and oak feedstocks at various temperatures (400°C, 500°C, 600°C, 700°C and 800°C), characterized, and assessed for their potential as carriers for Bradyrhizobium japonicum (CB1809) strain. The biochars were then stored at two different storage temperatures (28°C and 38°C) for up to 90 days. Furthermore, the study also explored the role of potentially ideal carriers as inoculants in the growth of Glycine max L. (soybean) under different moisture levels i.e., 55% water holding capacity (WHC) (D0), 30% WHC (D1) and, 15% WHC (D2) using a mixture of 50% garden soil and 50% sand. The results were compared to a control group (without inoculants) and a peat inoculant. Among all the materials derived from pine wood and oak, pine wood biochar pyrolyzed at 400℃ (P-BC400) exhibited the highest CFU count, with values of 10.34 and 9.74 Log 10 CFU g− 1 after 90 days of storage at 28℃ and 38℃, respectively. This was notably higher compared to other biochars and peat carriers. Significant (p < 0.05) increases in plant properties: shoot and root dry biomass (174% and 367%), shoot and root length (89% and 85%), number of leaves (71%), membrane stability index (27%), relative water content (26%), and total chlorophyll (140%) were observed in plants treated with P-BC400 carrier inoculant compared to the control at D2; however, lower enrichment of δ13C (37%) and δ15N (108%) with highest number of root nodules (8.3 ± 1.26) and nitrogenase activity (0.869 ± 0.04) were observed under D2, as evident through PCA analysis, showing more nitrogen (N) fixation and photosynthetic activity. Overall, this experiment concluded that biochar pyrolyzed at lower temperatures, especially P-BC400, was the most suitable candidate for rhizobial inoculum and promoted soybean growth.