Plant Biomass Research Articles

Wood-Based Biochar Ratio Used for Partial Peat Replacement in Growing Media for Antirrhinum majus Pot Production

Biochar has been promoted mostly as a soil supplement that improves plant growth/yield and to a lesser extent as a growing medium component. The alarmed situation for peat substitution in growing medium renders biochar as a promising substitute for current research. In this study, biochar derived by wood-based materials was evaluated at different ratios (0, 5, 10, 15, and 20% v/v) for peat partial substitution for Antirrhinum majus pot production. Biochar had increased potassium content and pH, which affected the growing media properties (total pores space and water filled capacity) and decreased nitrogen and phosphorus content in the media. Adding ≥15% biochar increased plant height and decreased flowering, but no effect was observed on plant biomass produced. The presence of biochar increased the total phenols and flavanols content and antioxidant capacity, with greater effects at the higher biochar rates used. This resulted in lipid peroxidation and an increase in hydrogen peroxide content, causing oxidative stress. Potassium and magnesium accumulated more but nitrogen and phosphorus were accumulated less in snapdragon leaves. Biochar at 10% can be considered as a successful candidate to partially substitute peat, and efforts to improve growing media characteristics are required for A. majus pot production.

Influence of Enhanced Synthesis of Exopolysaccharides in Rhizobium ruizarguesonis and Overproduction of Plant Receptor to these Compounds on Colonizing Activity of Rhizobia in Legume and Non-Legume Plants and Plant Resistance to Phytopathogenic Fungi.

Rhizobial exopolysaccharides (EPS) may provide stabilization of membranes against external factors, as well as improved surface adhesion, but their role in interaction with legume and non-legume plants is still far from understanding. In this work, the transcriptional regulator RosR of Rhizobium ruizarguesonis, which regulates the synthesis of EPS, was overproduced in a pHC60 plasmid and expressed in the RCAM 1026 strain. This resulted in an improved production of EPS by this recombinant strain. Comparative analysis of the inoculation of pea Pisum sativum plants with R. ruizarguesonis pHC60-rosR and strain carrying the empty plasmid revealed an essential increase in the number of nodules, root length and biomass in plants inoculated with this EPS-overproducing strain. It demonstrates that the enhanced EPS synthesis by rhizobia may stimulate plant root colonization and subsequent nodule formation in pea plants. The influence of enhanced EPS synthesis in rhizobia on colonizing activity was also estimated in non-legume plant tomato Solanum lycopersicum. Our findings shown the increased colonization of the root surface and stimulation of the shoot biomass of inoculated plants. Inoculation of pea and tomato with EPS-overproducing rhizobial strain essentially increased plant resistance to phytopathogenic fungi Fusarium culmorum and F. oxysporum in both legume and non-legume plants, demonstrating a significant biocontrol effect of this recombinant strain. Furthermore, we have identified the PsLYK10 gene that encodes a putative EPS receptor in P. sativum, although no significant effect of PsLYK10 overexpression on nodulation in legume (pea P. sativum) and colonization of roots of non-legume plants by rhizobia was found compared to enhanced production of EPS by rhizobia.

Manipulating the light spectrum to increase the biomass production, physiological plasticity and nutritional quality of Eruca sativa L

The extensive development in light-emitting diodes (LEDs) in recent years provides an opportunity to positively influence plant growth and biomass accumulation and to optimize biochemical composition and nutritional quality. This study aimed to assess how different light spectra affect the growth, photosynthesis and biochemical properties of Eruca sativa. Therefore two LED lighting modes - red:blue (RB, 1:1) and red:green:blue (RGB, 2:1:2) were compared to the conventional white light fluorescent tubes (WL). Plant biomass, photosynthetic performance, several antioxidants, polyamines and nitrates contents were analyzed across different treatments. The plant growth was affected by the light quality - the presence of green light in the spectrum resulted in smaller plants and leaves, and correspondingly less biomass. RB spectral mode enhanced the total antioxidant and guaiacol peroxidase activity, pigments, flavonoids, polyphenols, ascorbate and polyamines contents. This effect under RB was combined with better leaf development compared to RGB and less nitrate in the leaves among all treatments. The RB light generated modifications in polyamines, which are interrelated with the nitrate content, further induce important metabolite and antioxidant changes. Both RB and RGB enhanced photosynthesis. The afterglow thermoluminescence band varied according to leaves development, being higher in RB and WL as a consequence of their faster growth. The RB light spectrum was found to be the most efficient for promoting the growth, biochemical composition, and overall quality of Eruca sativa compared to RGB and WL. These findings suggest that RB LEDs can be an effective tool for improving crop production in controlled environments.

Carbon Stock Estimation of Poplar Plantations Based on Additive Biomass Models

Accurate estimation of biomass and carbon stocks in forest ecosystems is critical for understanding their roles in carbon sequestration and climate change mitigation. Currently, the development of stand biomass models and carbon stock estimation at the regional scale has emerged as a prominent research priority. In this study, 225 Populus spp. (poplar) trees in Shandong Province, China, were destructively sampled to obtain the biomass of their components. Two models (MS1 and MS2) were developed using allometric equations and the seemingly unrelated regression (SUR) method to ensure additive properties across tree components. The model evaluation employed the leave-one-out jackknife (LOO) method, considering statistics such as adjusted R-squared (Ra2), root mean square error (RMSE), mean absolute percent error (MAPE), and mean absolute error (MAE). The results from our models demonstrated high accuracy, with MS2 slightly outperforming MS1 after incorporating tree height as an independent variable. The models reliably estimated component-specific biomass and carbon stocks, with distinct variations observed in the carbon content among foliage (47.14 ± 2.07%), branches (47.26 ± 2.48%), stems (47.67 ± 2.21%), and roots (46.37 ± 2.78%). Carbon stocks in poplar plantations increased with the diameter class, ranging from 5 to 35 cm and correspondingly from 3.670 to 172.491 Mg C ha−1. As the diameter class increases, the carbon allocation strategy of poplars aligns with the CSR strategy, transitioning from prioritizing growth competition to emphasizing self-stabilization. Our research proposes a robust framework for assessing biomass and carbon stocks in poplar plantations, which is essential for evidence-based forest management strategies.

Ameliorating arsenic and PVC microplastic stress in barley (Hordeum vulgare L.) using copper oxide nanoparticles: an environmental bioremediation approach

The present study investigates the impact of varying concentrations of PVC microplastics (PVC–MPs) – specifically 0 (no PVC–MPs), 2, and 4 mg L− 1 –alongside different arsenic (As) levels of 0 (no As), 150, and 300 mg kg− 1 in the soil, with the concurrent application of copper oxide–nanoparticles (CuO–NPs) at 0 (no CuO –NPs), 25 and 50 µg mL− 1 to barley (Hordeum vulgare L.) plants. This research primarily aims to assess plant growth and biomass, photosynthetic pigments and gas exchange characteristics, oxidative stress indicators, as well as the response of various antioxidants (both enzymatic and non-enzymatic) and their relevant genes expression, proline metabolism, the AsA–GSH cycle, and cellular fractionation within the plants. The findings showed that increased levels of PVC–MPs and As stress in the soil significantly reduced plant growth and biomass, photosynthetic pigments, and gas exchange characteristics. Additionally, PVC–MPs and As stress increased oxidative stress in the roots and shoots, as evidenced by elevated levels of malondialdehyde (MDA), hydrogen peroxide (H2O2), and electrolyte leakage (EL), which in turn stimulated the production of various enzymatic and non-enzymatic antioxidants, gene expression, and sugar content. Furthermore, a notable increase in proline metabolism, the AsA–GSH cycle, and cellular pigmentation was observed. Conversely, the application of CuO–NPs resulted in a substantial improvement in plant growth and biomass, gas exchange characteristics, and the activity of enzymatic and non-enzymatic antioxidants, along with a reduction in oxidative stress. Additionally, CuO–NPs enhanced cellular fractionation while decreasing proline metabolism and the AsA-GSH cycle in H. vulgare plants. These outcomes provide new insights into sustainable agricultural practices and offer significant potential in addressing the critical challenges of heavy metal contamination in agricultural soils.

Heritability, signal perception and autoregulation of root nodulation in chickpea

Chickpea (Cicer arietinum L.) establishes symbiotic interactions with Mesorhizobium to develop root nodules where nitrogen fixation occurs. This symbiotic relationship can fix atmospheric nitrogen (N2) up to 140 kg N/ha that contribute nearly 80% nitrogen requirement of the crop. Global researchers had revealed the existence of natural variations in chickpea germplasm for nodulation traits with high heritability. Surprisingly, the contribution of environmental variation is too low for Biological Nitrogen Fixation (BNF) traits and high broad-sense heritability (>60) was observed for early nodulation, late nodule senescence and high nodule number traits. Correlation studies indicated a strong positive correlation between nodule number at flowering stage with total nodule weight and plant biomass and seed protein content. Nod Factor receptors in chickpea (CaNFR1 and CaNFR5) are characterized recently that forms phylogenetically distinct group along with M. truncatula, P. sativum, and L. japonicus. Critical role of cytokinin signalling through members of two component system (TCS) in nodulation was investigated in chickpea. The chickpea ortholog CaHK19 was the master spigot of cytokinin perception in chickpea. The co-expression pattern of CaHKs and CaNIN clearly indicated a link between cytokinin perception and downstream expression of CaNIN in chickpea as earlier established in Medicago. Genes involved in AON pathway are partially revealed in chickpea. CaRND1, CaRDN2, and CaRDN3 (C. arietinum Root-Determined Nodulation) function as receptors for signals produced from the roots. Revealing the molecular basis of root nodule organogenesis and their regulatory mechanisms along with identification of potential genetic stock will help on breeding or engineering chickpea genotypes with high symbiotic efficiency, extended nitrogen fixation and high symbiotic efficiency make grain legumes as nitrogen fixing factories to fertilize the soil in a sustainable way.

Beyond low lignin: Identifying the primary barrier to plant biomass conversion by fermentative bacteria.

Renewable alternatives for nonelectrifiable fossil-derived chemicals are needed and plant matter, the most abundant biomass on Earth, provide an ideal feedstock. However, the heterogeneous polymeric composition of lignocellulose makes conversion difficult. Lignin presents a formidable barrier to fermentation of nonpretreated biomass. Extensive chemical and enzymatic treatments can liberate fermentable carbohydrates from plant biomass, but microbial routes offer many advantages, including concomitant conversion to industrial chemicals. Here, testing of lignin content of nonpretreated biomass using the cellulolytic thermophilic bacterium, Anaerocellum bescii, revealed that the primary microbial degradation barrier relates to methoxy substitutions in lignin. This contrasts with optimal lignin composition for chemical pretreatment that favors high S/G ratio and low H lignin. Genetically modified poplar trees with diverse lignin compositions confirm these findings. In addition, poplar trees with low methoxy content achieve industrially relevant levels of microbial solubilization without any pretreatments and with no impact on tree fitness in greenhouse.

The roles of nanoparticle-enriched biochars in improving soil enzyme activities and nutrient uptake by basil plants under arsenic toxicity

Enriched biochar with improved properties and functionality can play a significant role in providing sustainable solutions for mitigating heavy metal contamination in soil. In this experiment, the effects of solid and enriched biochars (potassium-enriched biochar (BC-K), magnesium-enriched biochar (BC-Mg), both individually and combined) were examined on soil microbial and enzyme activities, as well as nutrient uptake by basil plants cultivated in a soil with three levels of arsenic (nontoxic, 50 mg As kg−1 soil, and 100 mg As kg−1 soil). Biochar-related treatments, increased soil organic matter (65–76%), while decreased availability of arsenic (6–55%) in the soil. The microbial biomass carbon (by about 123%) and soil basal respiration (by about 256%), and soil enzymatic activities (β-glucosidase, urease, alkaline phosphatase, and dehydrogenase) were enhanced by enriched biochars under arsenic toxicity. The solid and particularly enriched biochars decreased arsenic content and improved nitrogen and phosphorus contents of roots and shoots, root length, root activity, and root and shoot biomass in basil plants. Therefore, it is conceivable to suggest that enriched biochars are superior treatments for improving nutrient absorption rates and basil growth under arsenic toxicity through decreasing arsenic mobility and increasing soil microbial activities.

Determination of NPS Fertilizer Rate on Bread Wheat (Triticum Aestivum L.) in Yaya Gullele District of North Shewa Zone, Oromia, Ethiopia

Inappropriate crop management practices are among the key elements that contributed to the low production of wheat. Moreover, the application of balanced fertilizers and nutrient requirements of the crop is the basis to produce more crop yield from the land under cultivation. Hence, a field experiment was conducted in the 2020 & 2021 main cropping season to determine the NPS fertilizer rate in relative to determined the P-critical and P-requirement factor for wheat and to estimate the economically feasible NPS fertilizer rate for higher yield of wheat in Yaya gulale District. Accordingly the result indicated that, plant height was not significantly (P > 0.05 ) influenced by the NPS fertilizer rate but spike length, biomass, and grain yield were highly significantly (P < 0.05) affected by the NPS fertilizer rate. The highest plant height (86.72cm), spike length (6.57cm), biomass yield (12163kg ha-1) and grain yield (3327 kg ha-1) of wheat were recorded by the application of 75% P-critical from NPS fertilizer rate supplemented with recommended Nitrogen whereas, the lowest value was recorded from the field without fertilizer which was significantly inferior to all other treatments. Furthermore, the economic analysis indicates that, application of NPS fertilizer at the rate of 75% P-critical in NPS fertilizer with recommended Nitrogen fertilizer (92 kg N ha-1) for the production of wheat was more economically beneficial for the district. In conclusion, farmers and other end users could be advised to use 75% PC from NPS fertilizer rate with recommended nitrogen for wheat production in the district and other areas having similar soil types and agro- ecology.

Divergent contributions of microbes and plants to soil organic carbon in the drawdown area of a large reservoir: Impacts of periodic flooding and drying

The distribution patterns and accumulation mechanisms of plant and microbial residues, along with their potential contributions to soil organic carbon (SOC), remain subjects of considerable debate, particularly within drawdown areas affected by reservoir operation. In this study, surface soil samples (0–10 cm) were collected from three different elevations within the drawdown area of the Three Gorges Reservoir. Amino sugars and lignin phenols served as biomarkers for microbial residues and plant-derived materials, respectively. The results revealed that with increasing duration of flooding, the content of amino sugars increased from 0.26 mg g−1 to 0.64 mg g−1, whereas the content of lignin phenols decreased from 204.09 mg kg−1 to 37.93 mg kg−1. Moreover, as the duration of flooding increased, the contribution of microbial necromass carbon (MNC) to SOC rose from 29% to 47%, while the contribution of plant-derived carbon to SOC gradually declined. Plants biomass and iron minerals influenced the accumulation of lignin phenols, whereas amino sugars were affected by plants biomass, microbial biomass carbon and nitrogen, and clay minerals. The periodic flooding and drying events induced alterations in carbon inputs and environmental characteristics within the drawdown area, resulting in fluctuations in the contributions of plants and MNC to SOC in this region. The findings of this study highlight the critical role played by both plant- and microbial-derived carbon in the retention and turnover of SOC within the terrestrial-aquatic transition zone.

High CO2 dampens then amplifies N-induced diversity loss over 24 years.

Rising levels of atmospheric carbon dioxide (CO2) and nitrogen (N) deposition affect plant communities in numerous ways1-11. Nitrogen deposition causes local biodiversity loss globally12-14, but whether, and if so how, rising CO2 concentrations amplify or dampen those losses remains unclear and is almost entirely unstudied. We addressed this knowledge gap with an open-air experiment in which 108 grassland plots were grown for 24 years under different CO2 and N regimes. We initially found that adding N reduced plant species richness less at elevated than at ambient CO2. Over time, however, this interaction reversed, and elevated CO2 amplified losses in diversity from enriched N, tripling reductions in species richness from N addition over the last eight years of the study. These interactions resulted from temporal changes in the drivers of diversity, especially light availability, that were in turn driven by CO2 and N inputs and associated changes in plant biomass. This mechanism is likely to be similar in many grasslands, because additions of the plant resources CO2 and N are likely to increase the abundance of the dominant species. If rising CO2 generally exacerbates the widespread negative impacts of N deposition on plant diversity, this bodes poorly for the conservation of grassland biodiversity worldwide.

Stronger increase of methane emissions from coastal wetlands by non‐native Spartina alterniflora than non‐native Phragmites australis

Societal Impact StatementThe invasive species S. alterniflora and P. australis are fast growing coastal wetland plants sequestering large amounts of carbon in the soil and protect coastlines against erosion and storm surges. In this global analysis, we found that Spartina and Phragmites increase methane but not nitrous oxide emissions, with Phragmites having a lesser effect. The impact of the invasive species on emissions differed greatly among different types of native plant groups, providing valuable information to managers and policymakers during coastal wetland planning and restoration efforts. Further, our estimated net emissions per wetland plant group facilitate regional and national blue carbon estimates.Summary Globally, Spartina alterniflora and Phragmites australis are among the most pervasive invasive plants in coastal wetland ecosystems. Both species sequester large amounts of atmospheric carbon dioxide (CO2) and biogenic carbon in soils but also support production and emission of methane (CH4). In this study, we investigated the magnitude of their net greenhouse gas (GHG) release from invaded and non‐invaded habitats. We conducted a meta‐analysis of GHG fluxes associated with these two species and related soil carbon content and plant biomass in invaded coastal wetlands. Our results show that both invasive species increase CH4 fluxes compared to uninvaded coastal wetlands, but they do not significantly affect CO2 and N2O fluxes. The magnitude of emissions from Spartina and Phragmites differs among native habitats. GHG fluxes, soil carbon and plant biomass of Spartina‐invaded habitats were highest compared to uninvaded mudflats and succulent forb‐dominated wetlands, while being lower compared to uninvaded mangroves (except for CH4). This meta‐analysis highlights the important role of individual plant traits as drivers of change by invasive species on plant‐mediated carbon cycles.

Root traits of soybeans exposed to polyethylene films, polypropylene fragments, and biosolids

Biosolid use imports microplastics into the rhizosphere where they may interfere with root-soil-microbial interactions and cause morphological adaptations in crop root systems. Few studies have examined the response of crop roots to microplastics at documented soil concentrations, and many studies collect root traits using destructive techniques. Hence, there is little information on when and how microplastics effect the physical structure of root systems. Using the rhizobox method, soybeans (Glycine max) were grown in soil amended with biosolid microplastic mimics (polyethylene film or polypropylene fragments at 2,000 and 15,000 particles/kg dry soil) or biosolids and imaged weekly until maturity (11 weeks) using a custom scanner system. Plant biomass increased in the polyethylene treatments and decreased in the high concentration polypropylene treatment. Relative to the Control, polyethylene treatments had larger root length, reduced root diameters, reached maturity faster, had deeper root systems, and had a greater number of lateral roots. In contrast, polypropylene treatments had a mixed response, with high concentrations eliciting a lower root length, fewer laterals, and a more vertical root orientation. Segmented linear regression revealed that root growth in the Control and Biosolid treatments continued through the course of the experiment, while the microplastic treatments reached maturity up to two weeks earlier. Imagery revealed that microplastics elicited deeper rooting depth within the first week and differences in all root traits were evident by the development of the first trifoliate leaflets. Microplastic effects on root traits at early life stages suggest soil physiological drivers, while increased branching frequency and lower lateral elongation are suggestive of changes in soil nitrogen availability. The minimal difference in root traits in the biosolid treatment may be attributable to differences in microplastic properties or counteractive effects by other biosolid constituents.

Engineered reduction of S-adenosylmethionine alters lignin in sorghum

BackgroundLignin is an aromatic polymer deposited in secondary cell walls of higher plants to provide strength, rigidity, and hydrophobicity to vascular tissues. Due to its interconnections with cell wall polysaccharides, lignin plays important roles during plant growth and defense, but also has a negative impact on industrial processes aimed at obtaining monosaccharides from plant biomass. Engineering lignin offers a solution to this issue. For example, previous work showed that heterologous expression of a coliphage S-adenosylmethionine hydrolase (AdoMetase) was an effective approach to reduce lignin in the model plant Arabidopsis. The efficacy of this engineering strategy remains to be evaluated in bioenergy crops.ResultsWe studied the impact of expressing AdoMetase on lignin synthesis in sorghum (Sorghum bicolor L. Moench). Lignin content, monomer composition, and size, as well as biomass saccharification efficiency were determined in transgenic sorghum lines. The transcriptome and metabolome were analyzed in stems at three developmental stages. Plant growth and biomass composition was further evaluated under field conditions. Results evidenced that lignin was reduced by 18% in the best transgenic line, presumably due to reduced activity of the S-adenosylmethionine-dependent O-methyltransferases involved in lignin synthesis. The modified sorghum features altered lignin monomer composition and increased lignin molecular weights. The degree of methylation of glucuronic acid on xylan was reduced. These changes enabled a ~20% increase in glucose yield after biomass pretreatment and saccharification compared to wild type. RNA-seq and untargeted metabolomic analyses evidenced some pleiotropic effects associated with AdoMetase expression. The transgenic sorghum showed developmental delay and reduced biomass yields at harvest, especially under field growing conditions.ConclusionsThe expression of AdoMetase represents an effective lignin engineering approach in sorghum. However, considering that this strategy potentially impacts multiple S-adenosylmethionine-dependent methyltransferases, adequate promoters for fine-tuning AdoMetase expression will be needed to mitigate yield penalty.

Impacts of plastic pollution on soil–plant properties and greenhouse gas emissions in wetlands: A meta-analysis

Plastic pollution in wetlands has recently emerged as an urgent environmental problem. However, the impacts of plastic contamination on soil-plant properties and greenhouse gas (GHG) emissions in wetlands remain unclear. Thus, this study conducted a meta-analysis based on 44 study sites to explore the influence of plastic pollution on soil physicochemical variables, soil microorganisms, enzyme activity, functional genes, plant characteristics, and GHG emissions (CO2, CH4, and N2O) in different wetland types. Based on the collected dataset, the plastic pollution significantly increased soil organic matter and organic carbon by on average 28.9 % and 34.2 %, respectively, while decreased inorganic nutrient elements, bacteria alpha diversity and enzyme activities by an average of 5.9 −14.2 %. The response of bacterial abundance to plastic pollution varied depending on phylum classes. Plant biomass and photosynthetic efficiency were decreased by an average of 12.8 % and 18.4 % due to plastic pollution. The concentration and exposure time of plastics play a key role in influencing the soil and plant properties in wetlands. Furthermore, plastic exposure notably increased the abundance of the functional genes related to C degradation and the ammonia oxidizing microorganisms, and the consequent CO2 and N2O emissions (with effect sizes of 2.10 and 1.94, respectively). We also found that plastic concentrations and exposure duration affected the wetland soil–plant system. Our results might be helpful to design further investigations on plastic effects and develop appropriate measures for mitigating plastic pollution in wetlands.

Phytostabilisation of arsenic contaminated gold mine waste using the native species Juncus usitatus, Poa labillardieri and Themeda triandra

Arsenic (As) contaminated gold mine waste represents a significant issue for ecosystem and human health, as it is a known carcinogen and environmental toxin. Bendigo in Victoria, Australia, has reported As concentrations up to 22,000 mg/kg, exceeding the national soil guidance values (100 mg/kg) by 220-fold. To reduce exposure and potential human health risk, remediation or risk management strategies are required. Traditional remediation, such as excavation and landfill, often fail to improve soil conditions and are expensive. Biological remediation using plants (phytoremediation) represents a cost-effective strategy that results in the restoration of soil function and ecosystem services. There is a need to identify native plants for phytoremediation as current research focuses on fern species, which are not suitable for Bendigo. This study aimed to identify a native phytostabilising plant by conducting a mesocosm experiment involving Juncus usitatus, Poa labillardieri, and Themeda triandra. Plants grew in mine waste for 100 days; all survived and bioaccumulated As in the roots (phytostabilisation). Poa labillardieri grew significantly more biomass (roots 0.24 ± 0.01 g; shoots 0.22 ± 0.03 g (d/w)) and bioaccumulated the most As (~ 100 mg/kg plant biomass). The bacterial community was investigated to assess soil health and As association. The rhizosphere microbiota stabilised after root colonisation for Poa labillardieri and Themeda triandra, as indicated by richness and evenness changes. The two dominant phyla were Actinobacteriota and Proteobacteria, which displayed As tolerance. A keystone taxon, Latescibacterota, exhibited a positive relative association with As remediation. Poa labillardieri is a good candidate for future phytostabilisation trials.

Neural network cognitive analysis of accumulation metals by marigold

The article presents the results of studies to assess the effect of humic acids, taken at a concentration of 250 ppm, on the process of induced phytoextraction of heavy metals from soils selected near Norilsk. Phytoxtraction was carried out by different types of marigold plants: Tagetes patula and Tagetes erecta. The studies were carried out in greenhouse conditions under controlled spectral illumination (light culture). The duration of the experiment was 21 days. A short vegetation period was chosen based on the conditions of a short summer period typical for this region, where it is more rational to keep records of the systemic removal of toxicants from contaminated soils by several cycles of their sowing/cutting per season, already at the juvenile phase of ontogenesis. For elemental analysis, the method of atomic emission spectrometry with inductively coupled plasma was used. To assess the level of efficiency of metal accumulation, the authors developed and used the original computing neural network CompNN, which allows calculating the cognitive significance index (CSI) based on empirical data on the accumulation of toxicants, both in shoots and roots of plants. The results of the study showed that the introduction of an organic additive in the form of humic acids into the soil led to inhibition of the growth of the above-ground part of T. patula. As for T. erecta, the rate of accumulation of green plant biomass did not change when humic acids were added. The decrease in the biomass of shoots of T. patula plants is explained by an increase in the accumulation of metals in them by an average of 91.6% for the variants. The content of metals in the shoots of T. erecta under the influence of humic acids, on the contrary, decreased by 17.3% on average. A similar result was observed in relation to the root zone: the trend of change in the fixation of metals for both plant species here was 40.8 and 10.8%, respectively. Calculation of CSI indices also showed that the addition of humic acids in T. patula increases the intensity of metal accumulation from the soil in its biomass in all variants, while in T. erecta, on the contrary, it decreases. The performed cluster analysis demonstrated the fixation of metals in the main buffer zone of plants, and also made it possible to isolate nickel into a separate homogeneous series. With regard to the distribution of this element in the shoots by variants, experience has shown that it has demonstrated here the proximity of convergence with copper. The correlation coefficients of their accumulation with the CSI index in the shoots of both plants were r = 0.82; 0.87 for Cu and r = 0.87; 0.83 for Ni. The proximity of these values indicates the priority nature of the accumulation of these metals in the plant biomass of marigolds, and also characterizes the manifestation of certain interactions between them in contaminated soil by the type of antagonism or synergism.

Mitigation of microplastic toxicity in soybean by synthetic bacterial community and arbuscular mycorrhizal fungi interaction: Altering carbohydrate metabolism, hormonal transduction, and genes associated with lipid and protein metabolism

Microplastics (MPs) have become ubiquitous environmental pollutants, eliciting concerns about their negative impacts on terrestrial and agroecosystems. However, employing sustainable remediation approaches holds the potential to mitigate these negative impacts and bolster MPs tolerance in both the seeds and vegetative structures of plants. The current investigation explores the impact of arbuscular mycorrhizal fungi (AMF) and synthetic bacterial community (SynCom) as potential alleviators of MP-induced stress. Results exhibited that co-applied SynCom and AMF, resulted in the highest plant biomass, leaf area, pod per plant, and 100-seed weight under control (no MPs) and MPs stress. The combined application of SynCom and AMF enhanced colonization, association, and arbuscule abundance in the non-stressed plants (no MPs) as compared to stressed plants. The sole or co-application of SynCom and AMF enhanced the primary metabolites content and mitigated the MPs-induced reduction in soluble sugars, lipids, protein, and oil contents. Soybean inoculation stimulated the genes expression involved in lipid and protein biosynthesis, while a contradictory drift was noted for genes associated with lipid and protein degradation, underpinning the observed increment in protein and lipid content. Soybean inoculated with AMF exhibited the utmost α-amylase and β-amylase activities, demonstrating enhanced osmolyte (soluble sugar) production, mainly under MPs stress. Remarkably, sole or co-application further reinforces the positive effect of MPs stress on the osmoprotectants and antioxidant levels, for instance, phenol, flavonoid, glycine betaine contents, and glutathione-S-transferase (GST) activities. Subsequent to the stress release, a stress hormones known as abscisic acid (ABA) reduced in the seeds of inoculated soybean while gibberellin (GA), trans-zeatin riboside (ZR), and indole acetic acid (IAA) were increased. Therefore, it is concluded that the combined application of SynCom and AMF protected the soybean plants from MPs-induced oxidative damage by upregulating osmoprotectants and antioxidant levels. This study provides insights into the potential of sustainable remediation approaches in alleviating the complex impact of MPs on soybean, contributing to future strategies for environmental sustainability. Future studies could explore the optimization of SynCom and AMF formulations for different crops and environmental conditions, potentially leading to practical applications in sustainable agriculture and pollution management.

Inoculation with arbuscular mycorrhizal fungi improves plant biomass and nitrogen and phosphorus nutrients: a meta-analysis

Arbuscular mycorrhizal fungi (AMF) have profound effects on plant growth and nitrogen (N) and phosphorus (P) nutrition. However, a comprehensive evaluation of how plant N and P respond to AMF inoculation is still unavailable. Here, we complied data from 187 original researches and carried out a meta-analysis to assess the effects of AMF inoculation on plant growth and N and P nutrition. We observe overall positive effects of AMF inoculation on plant performance. The mean increases of plant biomass, N concentration, P concentration, N and P uptake of whole plant are 47%, 16%, 27%, 67%, and 105%, respectively. AMF inoculation induces more increases in plant concentrations and storage of P than N. Plant responses to AMF inoculation are substantially higher with single AMF species than with mixed AMF species, in laboratory experiments than in field experiments, and in legumes than in non-legumes. The response ratios of plant N and P nutrition are positively correlated with AMF colonization rate, N addition, P addition, and water condition, while unvaried with experiment duration. The biggest and smallest effect sizes of AMF inoculation on plant performance are observed in the application of nitrate and ammonium, respectively. Accordingly, this meta-analysis study clearly suggests that AMF inoculation improves both plant N and P nutrients and systematically clarifies the variation patterns in AMF effects with various biotic and abiotic factors. These findings highlight the important role of AMF inoculation in enhancing plant N and P resource acquisitions and provide useful references for evaluating the AMF functions under the future global changes.

Impact of plant-based soil amendments on improvement of mortgaged Farmland

A field experiment was conducted in Maoming, Guangdong, China to evaluate the effects of different plant-based soil amendments on soil quality, nutrient availability, plant growth, and land value. The application of plant-based soil amendments significantly increased the plant height, stem diameter, and biomass yield of corn, soybean, and rice crops. The greatest improvement was observed in corn crops, with a 12.6% increase in plant height, a 15% increase in stem diameter, and a 25.6% increase in biomass yield. Plant based soil amendments significantly improve soil quality, increase nutrient availability, and promote plant growth and productivity. Economic analysis shows that the use of plant-based soil amendments significantly increases the value of land, providing potential benefits for mortgage lenders and borrowers. This study emphasizes the importance of sustainable land use practices and the potential of plant-based soil improvement as an effective means of increasing land value. Bangladesh J. Bot. 53(3): 823-833, 2024 (September) Special