Root Biomass Research Articles

Nitrogen reduction by 20 % with green manure retention reduces soil evaporation, promotes maize transpiration and improves water productivity in arid areas

ContextThe contradiction between high agricultural yields and water resource shortages is becoming increasingly serious. Reducing nitrogen appropriately with green manure retention can ensure high agricultural yields, but it remains unclear whether it can optimize crop water consumption characteristics and improve water productivity (WPc). ObjectiveThis study aims to investigate the effect of green manure retention combined with nitrogen reduction on water use characteristics of maize and its potential mechanisms. MethodsA field experiment was conducted at Wuwei Oasis Agricultural Experimental Station in China from 2020 to 2022, with five treatments: (i) traditional nitrogen application with green manure retention (N100), (ii) nitrogen reduction by 10 % with green manure retention (N90), (iii) nitrogen reduction by 20 % with green manure retention (N80), (iv) nitrogen reduction by 30 % with green manure retention (N70), and (v) nitrogen reduction by 40 % with green manure retention (N60). ResultsThe results showed that compared with the N100 treatment, 0−50 cm maize root biomass (RB), biomass accumulation (BA), and canopy cover (CC) were not significantly reduced in the N80 treatment. This model ensured a stable grain yield (GY) and improved 0−50 cm soil water storage (SWS) by 7.1−13.1 %. It effectively suppressed soil evaporation (E), promoted maize transpiration (T), reduced maize evapotranspiration (ET) by 4.8 %, and increased WPc by 1.8−26.6 %. Structural equation modeling (SEM) suggests that RB was the most important factor for improving WPc. In addition, this system ensures that economic benefits did not decrease. ConclusionIt can be seen that nitrogen reduction by 20 % with green manure retention is a reasonable nitrogen fertilizer management system to alleviate the contradiction between high maize yield and water resource shortages in the region. ImplicationsThe results of this study provide valuable insights into alleviating the contradiction between agricultural production and regional water resource scarcity.

Do Lignin Nanoparticles Pave the Way for a Sustainable Nanocircular Economy? Biostimulant Effect of Nanoscaled Lignin in Tomato Plants.

Agriculture has a significant environmental impact and is simultaneously called to major challenges, such as responding to the need to develop more sustainable cropping systems with higher productivity. In this context, the present study aimed to obtain lignin nanoparticles (LNs) from pomace, a waste product of the olive oil chain, to be used as a nanobiostimulant in tomato plants. The biostimulant effect of this biopolymer is known, but its reduction to nanometer size can emphasize this property. Tomato plants were subjected to different LN dosages (25, 50, and 100 mg L-1) by foliar application, and inductive effects on photosynthetic machinery, aerial and root biomass production, and root morphology were observed. The treated plants showed increased efficiency in catching and using light, while they reduced the fraction dissipated as heat or potentially toxic to cells for the possibility of creating reactive oxygen species (ROS). Finally, this benefit was matched by increased pigment content and a stimulatory action on the content of nitrogen (NBI) and antioxidant substances such as flavonoids. In conclusion, the present study broadens the horizon of substances with biostimulant action by demonstrating the validity and efficacy of nanobiostimulants obtained from biological residues from the olive oil production chain.

Effect of Buried Straw Bioreactor Technology on CO2 Efflux and Indian Cowpea Yields

This study evaluates the efficacy of buried straw bioreactor (SBR) technology in enhancing soil properties, CO2 efflux, and crop yield, specifically focusing on Indian cowpea cultivation within a greenhouse environment. Conducted at the Yuxi Demonstration Park in Fujian, China, the experiment utilized a randomized block design incorporating seven treatments with varying straw application rates (4.5, 6, and 7.5 kg m−2) and burial depths (20 and 30 cm) alongside a control group. The investigation revealed that SBR technology significantly increased soil temperature, CO2 efflux, soil total nitrogen (TN), and total organic carbon (TOC), contributing to a marked improvement in the biomass of Indian cowpea roots, stems, and leaves. Notably, the optimal results were observed with 7.5 kg m−2 straw applied at a 20 cm depth, enhancing soil temperature by 1.5–2.0 °C and multiplying cowpea biomass by 2.1–6.4 times relative to the control. This treatment also led to the highest increases in soil TOC and CO2 efflux, demonstrating the potential of SBR technology for carbon sequestration and suggesting its application as a sustainable agricultural practice in cold regions to ameliorate the soil’s physical and nutritional characteristics, thus supporting enhanced crop production. The study underscores SBR technology’s role in addressing the challenge of agricultural waste through the effective reuse of crop straw, promoting the circular development of agriculture while safeguarding the ecological environment.

Edaphic factors mediate the responses of forest soil respiration and its components to nitrogen deposition along an urban-rural gradient

Exploring the influences of nitrogen deposition on soil carbon (C) flux is necessary for predicting C cycling processes; however, few studies have investigated the effects of nitrogen deposition on soil respiration (Rs), autotrophic respiration (Ra) and heterotrophic respiration (Rh) across urban-rural forests. In this study, a 4-year simulated nitrogen deposition experiment was conducted by treating the experimental plots with 0, 50, or 100 kg·ha−1·year−1 of nitrogen to check out the mechanisms of nitrogen deposition on Rs, Ra, and Rh in urban-rural forests. Our finding indicated a positive association between soil temperature and Rs. Soil temperature sensitivity was significantly suppressed in the experimental plots treated with 100 kg·ha−1·year−1 of nitrogen only in terms of the urban forest Rs and Ra and the rural forest Ra. Nitrogen treatment did not significantly increase Rs and had different influencing mechanisms. In urban forests, nitrogen addition contributed to Rh by increasing soil microbial biomass nitrogen and inhibited Ra by increasing soil ammonium‑nitrogen concentration. In suburban forests, the lack of response of Rh under nitrogen addition was due to the combined effects of soil ammonium‑nitrogen and microbial biomass nitrogen; the indirect effects from nitrate‑nitrogen also contributed to a divergent effect on Ra. In rural forests, the soil pH, dissolved organic C, fine root biomass, and microbial biomass C concentration were the main factors mediating Rs and its components. In summary, the current rate of nitrogen deposition is unlikely to result in significant increases in soil C release in urban-rural forests, high nitrogen deposition is beneficial for reducing the temperature sensitivity of Rs in urban forests. The findings grant a groundwork for predicting responses of forest soil C cycling to global change in the context of urban expansion.

Impact of abiotic stressors on nutrient removal and rhizomicrobiome composition in floating treatment wetland with Equisetum hyemale

Floating treatment wetlands (FTW) are receiving growing interest as a phyto-technology. However, there are significant research gaps regarding the actual role of plant species and plant-microbiome interactions. In this study, the nutrient uptake of Equisetum hyemale was examined in FTW microcosms under the influence of abiotic stressors: As (3 mg/L) and Pb (3 mg/L) as well as Cl− (300 and 800 mg/L) in reference to a control during a short screening experiment. High removal efficiency of nutrients in water solutions, up to 88 % for TN and 93 % for PO4-P, was observed. However, PO4-P removal was inhibited in the As reactor, with a maximum efficiency of only 11 %. Lead and As were removed with high efficiency, reaching 98 % and 79 % respectively. At the same time only Pb was effectively bound to root biomass, reaching up to 51 %. Limited As accumulation of 0.5 % in plant roots suggests that microbial processes play a major role in its reduction. The development and structure of microbiome in the microcosms was analysed by means of 16S rRNA gene amplicon sequencing, proving that Pb was the most influential factor in terms of selection pressure on specified bacterial groups. In the As treatment, the emergence of a Serratia subpopulation was observed, while the Cl− treatment preserved a rhizobiome composition most closely resembling the control. This study indicates that E. hyemale is a suitable species for use in FTWs treating Pb polluted water that at the same time is capable to withstand periodic increases in salinity. E. hyemale exhibits low As binding in biomass; however, extended exposure might amplify this effect because of the slow-acting, but beneficial, mechanism of As uptake by roots and shoots. Microbiome analysis complements insights into mechanisms of FTW performance and impact of stress factors on bacterial structure and functions.

Synchrotron tomography of magnetoprimed soybean plant root system architecture grown in arsenic-polluted soil.

The present study evaluated the repercussions of magnetopriming on the root system architecture of soybean plants subjected to arsenic toxicity using synchrotron radiation source based micro-computed tomography (SR-µCT). This will be used evey where as abbreviation for the technique for three-dimensional imaging. Seeds of soybean were exposed to the static magnetic field (SMF) of strength (200 mT) for 1h prior to sowing. Magnetoprimed and non-primed seeds were grown for 1 month in a soil-sand mixture containing four different levels of sodium arsenate (0, 5, 10, and 50 mg As kg-1 soil). The results showed that arsenic adversely affects the root growth in non-primed plants by reducing their root length, root biomass, root hair, size and number of root nodules, where the damaging effect of As was observed maximum at higher concentrations (10 and 50 mg As kg-1 soil). However, a significant improvement in root morphology was detected in magnetoprimed plants where SMF pretreatment enhanced the root length, root biomass, pore diameter of cortical cells, root hair formation, lateral roots branching, and size of root nodules and girth of primary roots. Qualitative analysis of x-ray micro-CT images showed that arsenic toxicity damaged the epidermal and cortical layers of the root as well as reduced the pore diameter of the cortical cells. However, the diameter of cortical cells pores in magnetoprimed plants was observed higher as compared to plants emerged from non-primed seeds at all level of As toxicity. Thus, the study suggested that magnetopriming has the potential to attenuate the toxic effect of As and could be employed as a pre-sowing treatment to reduce the phytotoxic effects of metal ions in plants by improving root architecture and root tolerance index. This study is the very first exploration of the potential benefits of magnetopriming in mitigating the toxicity of metals (As) in plant roots utilizing the micro-CT technique.

Study on Associations between Root and Aboveground Growth of Mixed-Planting Seedlings of Populus tomentosa and Pinus tabuliformis under Soil Nutrient Heterogeneity

Near-natural transformation can convert artificial monoculture forests into mixed forests with diverse ages, multi-layered structures, and enhanced ecological functions. This transformation optimizes stand structure, improves soil physical and chemical properties, and enhances stand productivity and species diversity. This study aimed to explore the relationship between the underground roots and aboveground growth of Pinus tabuliformis and Populus tomentosa under conditions of nutrient heterogeneity, with the goal of advancing plantation transformation. This research focused on 1-year-old Populus tomentosa and 5-year-old Pinus tabuliformis, employing two planting densities (25 cm and 50 cm) and three fertilization levels, low (50 g·m−2), medium (100 g·m−2), and high (200 g·m−2), using Stanley Potassium sulfate complex fertilizer (N:P:K = 15:15:15). Each treatment had three replicates, resulting in a total of nine experimental groups, all planted in circular plots with a radius of 1 m. Standard major axis (SMA) regression was used to analyze the allometric relationship between underground fine root biomass and aboveground organ biomass. This study further explored correlations between fine root length, root surface area, volume, biomass, and aboveground biomass, culminating in a mixed-effects model. The mixed-effects model quantified the relationships between underground roots and aboveground growth in varying soil nutrient environments. The results indicated optimal root growth in Populus tomentosa and Pinus tabuliformis, characterized by maximum root length, surface area, and volume, under conditions of 200 g·m−2 soil nutrient concentration and 50 cm planting distance; Populus tomentosa fine roots had a vertical center at a depth of 8.5 cm, whereas Pinus tabuliformis roots were centered at depths of 5–7.5 cm, indicating differing competitive strategies. Pinus tabuliformis exhibited competitive superiority in the soil’s surface layer, in contrast to Populus tomentosa, which thrived in deeper layers. The study of the allometric growth model revealed that under conditions where the nutrient gradient was 200 g·m−2 and the planting distance was 25 cm, Populus tomentosa demonstrated its highest allometric growth index (2.801), indicative of positive allometric growth. Furthermore, there was a notable inclination of resource allocation towards the aboveground, which enhances the accumulation of aboveground biomass. The mixed-effects model equation showed a clear linear relationship between underground roots and aboveground biomass. The final fitting coefficient of the model was high, providing a robust theoretical basis for future management practices. The mixed-effects model revealed the following hierarchy of fixed-effect coefficients for root system characteristics affecting aboveground biomass: fine root volume (132.11) > fine root biomass (6.462) > root surface area (−4.053) > fine root length (0.201). In subsequent plantation reconstruction and forest management, increasing soil fertility and planting distance can promote the growth of underground roots and biomass accumulation. Appropriately increasing soil fertility and reducing planting distance can effectively promote aboveground biomass accumulation, achieving sustainable forest development.

Exploring the variability of root system architecture under drought stress in heat-tolerant spring-wheat lines

Background and aimsGlobal wheat production is under threat due to climate change, specifically heat and drought and their combination. This study aims to address the root trait responses of heat-tolerant wheat genotypes to drought.MethodsThe variability in root traits of CIMMYT wheat lines, which were previously developed for heat stress tolerance (HTWL), was evaluated alongside 10 Pakistani-approved varieties under three cultivation conditions and soil moisture levels.ResultsOur findings revealed that the plasticity of the wheat root system is highly pronounced, with rhizosphere conditions exerting a more substantial influence (5–49%) than the genotypic response (1–14%). Furthermore, in the hydroponic and pot system, we noted higher maximum-root length (1.5–1.8 fold) and root-to-shoot ratio (3.4–10.6 fold) as compared to field condition, while the root biomass was substantially higher in the field trial (3-57 fold). Nonetheless, persistent drought conditions exerted contrasting impact with reduction in most of the traits except specific root length and harvest index which were increased under drought.ConclusionsThe variation in root traits against drought indicates the potential for the development of improved genotypes that can withstand multiple stresses. Furthermore, it is crucial to consider rhizosphere conditions when selecting genotypes, as the plasticity of wheat roots may lead to misinterpretations if rhizosphere conditions are disregarded. Root dry weight and root-to-shoot ratio are more stable traits as compared to maximum root length and specific root length. It is recommended to evaluate a broader range of rhizosphere conditions to select tolerant genotypes.

Genetic and functional traits limit the success of colonisation by arbuscular mycorrhizal fungi in a tomato wild relative.

To understand whether domestication had an impact on susceptibility and responsiveness to arbuscular mycorrhizal fungi (AMF) in tomato (Solanum lycopersicum), we investigated two tomato cultivars ("M82" and "Moneymaker") and a panel of wild relatives including S. neorickii, S. habrochaites and S. pennellii encompassing the whole Lycopersicon clade. Most genotypes revealed good AM colonisation levels when inoculated with the AMF Funneliformis mosseae. By contrast, both S. pennellii accessions analysed showed a very low colonisation, but with normal arbuscule morphology, and a negative response in terms of root and shoot biomass. This behaviour was independent of fungal identity and environmental conditions. Genomic and transcriptomic analyses revealed in S. pennellii the lack of genes identified within QTLs for AM colonisation, a limited transcriptional reprogramming upon mycorrhization and a differential regulation of strigolactones and AM-related genes compared to tomato. Donor plants experiments indicated that the AMF could represent a cost for S. pennellii: F. mosseae could extensively colonise the root only when it was part of a mycorrhizal network, but a higher mycorrhization led to a higher inhibition of plant growth. These results suggest that genetics and functional traits of S. pennellii are responsible for the limited extent of AMF colonisation.

Tropical root responses to global changes: A synthesis.

Tropical ecosystems face escalating global change. These shifts can disrupt tropical forests' carbon (C) balance and impact root dynamics. Since roots perform essential functions such as resource acquisition and tissue protection, root responses can inform about the strategies and vulnerabilities of ecosystems facing present and future global changes. However, root trait dynamics are poorly understood, especially in tropical ecosystems. We analyzed existing research on tropical root responses to key global change drivers: warming, drought, flooding, cyclones, nitrogen (N) deposition, elevated (e) CO2, and fires. Based on tree species- and community-level literature, we obtained 266 root trait observations from 93 studies across 24 tropical countries. We found differences in the proportion of root responsiveness to global change among different global change drivers but not among root categories. In particular, we observed that tropical root systems responded to warming and eCO2 by increasing root biomass in species-scale studies. Drought increased the root: shoot ratio with no change in root biomass, indicating a decline in aboveground biomass. Despite N deposition being the most studied global change driver, it had some of the most variable effects on root characteristics, with few predictable responses. Episodic disturbances such as cyclones, fires, and flooding consistently resulted in a change in root trait expressions, with cyclones and fires increasing root production, potentially due to shifts in plant community and nutrient inputs, while flooding changed plant regulatory metabolisms due to low oxygen conditions. The data available to date clearly show that tropical forest root characteristics and dynamics are responding to global change, although in ways that are not always predictable. This synthesis indicates the need for replicated studies across root characteristics at species and community scales under different global change factors.

Role of cover crop roots in soil organic carbon accrual—A review

AbstractAppropriate cover crop (CC) management is an important tool for the improvement of soil carbon stock; however, the relationships between carbon accumulation and CC root traits remain unclear. A literature review was performed to identify the extent and focus of recent research and to answer questions about the role of root traits of CCs in soil C accumulation with regard to species selection, mixture composition and agronomic management. The findings based on the analysis of 69 publications show that a range of root traits such as root biomass, architecture, depth of rooting, root chemical composition, as well as quantity and quality of rhizodeposition, can contribute to soil structure formation and C accumulation. These traits are usually species specific, and it seems that appropriate species combinations in the mixtures can offer the highest potential for optimization of C stock across various environments. However, there has been twice as much recent research on roots of CC monocultures than on mixtures, with little attention paid to agronomic aspects such as plant spatial arrangement or soil tillage in relation to CC root development. Considerations of real management under field conditions could be beneficial in providing greater accuracy of estimation of the contribution of CCs in increasing the SOC stock in croplands.

Estimating the global root exudate carbon flux

Root exudation, the export of low-molecular weight organic carbon (C) from living plant roots to soil, influences microbial activity, nutrient availability, and ecosystem feedbacks to climate change, but the magnitude of this C flux at ecosystem and global scales is largely unknown. Here, we synthesize in situ measurements of root exudation rates and couple those to estimates of fine root biomass to estimate global and biome-level root exudate C fluxes. We estimate a global root exudate flux of 13.4 (10.1–20.2) Pg C y−1, or about 9% (7–14%) of global annual gross primary productivity. We did not find differences in root mass-specific exudation rates among biomes, though total exudate fluxes are estimated to be greatest in grasslands owing to their high density of absorptive root biomass. Our synthesis highlights the global importance of root exudates in the terrestrial C cycle and identifies regions where more in situ measurements are needed to improve future estimates of root exudate C fluxes.

Wheat dwarfing reshapes plant and fungal development in arbuscular mycorrhizal symbiosis.

The introduction of Reduced height (Rht) dwarfing genes into elite wheat varieties has contributed to enhanced yield gain in high input agrosystems by preventing lodging. Yet, how modern selection for dwarfing has affected symbiosis remains poorly documented. In this study, we evaluated the response of both the plant and the arbuscular mycorrhizal fungus to plant genetic variation at a major Quantitative Trait Locus called QTL 4B2, known to harbor a Rht dwarfing gene, when forming the symbiosis. We used twelve inbred genotypes derived from a diversity base broadened durum wheat Evolutionary Pre-breeding Population and genotyped with a high-throughput Single Nucleotide Polymorphism (SNP) genotyping array. In a microcosm setup segregating roots and the extra-radical mycelium, each wheat genotype was grown with or without the presence of Rhizophagus irregularis. To characterize arbuscular mycorrhizal symbiosis, we assessed hyphal density, root colonization, spore production, and plant biomass. Additionally, we split the variation of these variables due either to genotypes or to the Rht dwarfing genes alone. The fungus exhibited greater development in the roots of Dwarf plants compared to non-Dwarf plants, showing increases of 27%, 37% and 51% in root colonization, arbuscules, and vesicles, respectively. In addition, the biomass of the extra-radical fungal structures increased by around 31% in Dwarf plants. The biomass of plant roots decreased by about 43% in mycorrhizal Dwarf plants. Interestingly, extraradical hyphal production was found to be partly genetically determined with no significant effect of Rht, as for plant biomasses. In contrast, variations in root colonization, arbuscules and extraradical spore production were explained by Rht dwarfing genes. Finally, when mycorrhizal, Dwarf plants had significantly lower total P content, pointing towards a less beneficial symbiosis for the plant and increased profit for the fungus. These results highlight the effect of Rht dwarfing genes on both root and fungal development. This calls for further research into the molecular mechanisms governing these effects, as well as changes in plant physiology, and their implications for fostering arbuscular mycorrhizal symbiosis in sustainable agrosystems.

Belowground plant competition: uncoupling root response strategies of peas.

Belowground plant competition has been shown to induce varying responses, from increases to decreases in root biomass allocation or in directional root placement. Such inconsistencies could result from the fact that root allocation and directional growth were seldom studied together, even though they might represent different strategies. Moreover, variations in belowground responses might be due to different size hierarchies between plants, but this hypothesis has not been studied previously. In a greenhouse rhizobox experiment, we examined the way both root allocation and directional root placement of Pisum sativum are affected by the size and density of Festuca glauca neighbours, and by nutrient distribution. We found that root allocation of P. sativum increased with the density and size of F. glauca. By contrast, directional root placement was unaffected by neighbour size and increased either towards or away from neighbours when nutrients were patchily or uniformly distributed, respectively. These results demonstrate that directional root placement under competition is contingent on the distribution of soil resources. Interestingly, our results suggest that root allocation and directional placement might be uncoupled strategies that simultaneously provide stress tolerance and spatial responsiveness to neighbours, thus highlighting the importance of measuring both when studying belowground plant competition.

Biosynthesized Selenium Nanoparticles as an Effective Tool to Combat Soil Metal Stresses in Rice (Oryza sativa L.).

Nanotechnology has demonstrated significant potential to improve agricultural production and increase crop tolerance to abiotic stress including exposure to heavy metals. The present study investigated the mechanisms by which aloe vera extract gel-biosynthesized (AVGE) selenium nanoparticles (Se NPs) alleviated cadmium (Cd)-induced toxicity to rice (Oryza sativa L.). AVGE Se NPs, chemically synthesized bare Se NPs, and NaSeO3 as an ionic control were applied to Cd-stressed rice seedlings via root exposure in both hydroponic and soil systems. Upon exposure to AVGE Se NPs at 15 mg Se/L, the fresh root biomass was significantly increased by 100.7% and 19.5% as compared to Cd control and conventional bare Se NPs. Transcriptional analyses highlighted that AVGE Se NPs activated stress signaling and defense related pathways, including glutathione metabolism, phenylpropanoid biosynthesis and plant hormone signal transduction. Specifically, exposure to AVGE Se NPs upregulated the expression of genes associated with the gibberellic acid (GA) biosynthesis by and 4.79- and 3.29-fold as compared to the Cd-alone treatment and the untreated control, respectively. Importantly, AVGE Se NPs restored the composition of the endophyte community and recruit of beneficial species under Cd exposure; the relative abundance of Azospirillum was significantly increased in roots, shoots, and the rhizosphere soil by 0.73-, 4.58- and 0.37-fold, respectively, relative to the Cd-alone treatment. Collectively, these findings highlight the significant potential of AVGE Se NPs to enhance plant growth and to minimize the Cd-induced toxicity in rice and provide a promising nanoenabled strategy to enhance food safety upon crop cultivation in contaminated agricultural soils.

Improving the sustainability of arable cropping systems by modifying root traits: A modelling study for winter wheat

AbstractModifying root systems by crop breeding has been attracting increasing attention as a potentially effective strategy to enhance the sustainability of agriculture by increasing soil organic matter (SOM) stocks and soil quality, whilst maintaining or even improving yields. We used the new soil‐crop model USSF (Uppsala model of Soil Structure and Function) to investigate the potential of this management strategy using winter wheat as a model crop. USSF combines a simple (generic) crop growth model with physics‐based descriptions of soil water flow, water uptake and transpiration by plants. It also includes a model of the interactions between soil structure dynamics and organic matter turnover that considers the effects of physical protection and microbial priming on the decomposition of SOM. The model was first calibrated against field data on soil water contents and both above‐ground and root biomass of winter wheat measured during one growing season in a clay soil in Uppsala, Sweden using the GLUE method to identify five ‘acceptable’ parameter sets. We created four model crops (ideotypes) by modifying root‐related parameters to mimic winter wheat phenotypes with improved root traits. Long‐term (30‐year) simulations of a conventionally tilled monoculture of winter wheat were then performed to evaluate the potential effects of cultivating these ideotypes on the soil water balance, soil organic matter stocks and grain yields. Our results showed that ideotypes with deeper root systems or root systems that are more effective for water uptake increased grain yields by 3% and SOM stocks in the soil profile by ca. 0.4%–0.5% in a 30‐year perspective (as an average of the five parameter sets). An ideotype in which below‐ground allocation of dry matter was increased at the expense of stem growth gave even larger increases in SOM stocks (ca. 1.4%). An ideotype combining all three modifications (deeper and more effective root systems and greater root production) showed even more promising results: compared with the baseline scenario, surface runoff decreased while yields were predicted to increase by ca. 7% and SOM stocks in the soil profile by ca. 2%, which is roughly equivalent to ca. 20% of the 4‐per‐mille target (https://4p1000.org/).

Strategies to enhanced production of biomass and natural antioxidants of <i>Cichorium intybus</i> L. hairy roots by using nanoparticle elicitors

This study describes the influence of silver nanoparticles (AgNPs) and selenium nanoparticles (SeNPs) on the biomass and phytochemical production in the hairy root (HR) cultures of Cichorium intybus L. The HRs were grown in ½ Murashige and Skoog (MS) medium supplemented with sucrose (30 g/L) and AgNPs or SeNPs at two selected concentrations for 25 days on the shaker at 110 rpm in the dark. The results showed that SeNPs stimulated HR growth whereas AgNPs inhibited it at both concentrations used. Peroxidase activity was higher than catalase activity. In most cases, the antioxidant enzyme activities were significantly higher in the HRs elicited by elicitors than in control HRs. The activities of catalase and peroxidase reached their highest levels at approximately 16.7 and 486.4 u/mg protein, respectively. DPPH radical scavenging activity was highest in the HRs elicited by AgNPs. AgNPs (3.25 and 1.5625 mg/L) elicited HR extracts had significantly enhanced the production of total phenolic, and total flavonoid contents compared to the control HR extracts. The maximum total phenolic content was 87.04 ± 6.23 mg/g gallic equivalent, and it was 139.03 ± 3.56 mg/g ascorbic acid equivalent in total flavonoid content in the HRs elicited by AgNPs. The HRs elicited by SeNPs produce an average amount of total phenolic, flavonoid, and DPPH radical scavenging activity which were also significantly higher than those produced by control HRs. The results from our study suggested the effectiveness of the elicitation process in enhancing the root biomass, total phenolic, and flavonoid content. NPs-elicited Chicory HRs offered an effective and favorable in vitro method to improve the production of bioactive compounds for potential uses in pharmaceutical industries.

Variation in soil quality in tropical dryland agroecosystem: Impact of different crop sequences

AbstractRole of crop diversification on productivity has been studied widely but its impact on soil carbon dynamics is least studied. The present study was designed to compare the effects of crop diversification in terms of rice‐based mixed crops viz. wheat (RW), chickpea (RC), and flaxseed (RF) and mono‐crops viz. pigeonpea (PP) and mustard (MU) on major soil quality including physical, chemical and biological parameters, total crop biomass, and carbon input (CI) in a tropical rainfed dryland agroecosystem. Trend of total crop biomass observed was: pigeonpea > rice > wheat > mustard > flaxseed > chickpea. Across all the crop sequences, CI into the soil through crop residues including stubbles and root biomass varied considerably and followed the trend: PP > RW > RF > RC > MU. Levels of soil organic carbon (SOC), humic acid, fulvic acid, water holding capacity (WHC), macro‐aggregate fraction, microbial biomass carbon and phosphorus, enzyme activities of alkaline phosphatase, and β‐glucosidase were higher whereas bulk density, meso‐, and micro‐aggregate fractions were lower in the mixed crops than mono‐crops. SOC was positively correlated to all the attributes except bulk density, meso‐, and micro‐aggregate fractions. Lower values of the various soil quality attributes in PP despite the highest CI into the soil as compared to all the mixed crops might be due to the soil carbon priming effect. This study indicated that the quantity of CI through mixed crops had less impact in sustaining soil fertility and productivity of agroecosystems and suggests that the quality of CI play vital role. Mixed cropping sequence especially rice‐wheat was found to be the better option for the dry tropics.

Attenuation of the effect of salinity on redwood (Caesalpinia platyloba) by saline compost

The objective of this research is to evaluate the effect of saline compost on the attenuation of salinity stress in palo colorado (Caesalpinia platyloba). A representative sample of saline soil was taken at Ciudad Universitaria Intercultural, sieved (mesh < 5mm) and composted with cattle manure and Cynodon dactylon garden grass pruning, in a 3:1:1 ratio (stubble: manure: saline soil), for 120 days, the characterization consisted of measuring the bulk density (DA), saturation point, pH and EC of the saturated paste extract. The effect of different concentrations of NaCl on the in vitro germination of palo colorado seeds was evaluated in a randomized complete block design with two substrates (blocks), B1) sand-perlite; B2) sand-perlite-salt compost, five treatments 0 M, 0.3 M, 0.4 M, 0.5 M and 0.6 M of NaCl, eight replicates per treatment. The control irrigation was with distilled water. The plants transference to polyethylene cups was fifteen days after sowing; the cups had the same substrate mixture. The variables measured were survival, leaf biomass and dry root biomass. The EC decreased during composting, from 9.45 dS/m low to 2.4 dS/m; the pH of the samples did not show a significant difference. It is concluded that neither the substrate nor the NaCl concentration significantly influenced the germination of palo colorado seeds, and that the saline compost had no effect on the mitigation of salt stress in palo colorado plants.

Evaluation of the Effectiveness of Innovative Sorbents in Restoring Enzymatic Activity of Soil Contaminated with Bisphenol A (BPA).

As part of the multifaceted strategies developed to shape the common environmental policy, considerable attention is now being paid to assessing the degree of environmental degradation in soil under xenobiotic pressure. Bisphenol A (BPA) has only been marginally investigated in this ecosystem context. Therefore, research was carried out to determine the biochemical properties of soils contaminated with BPA at two levels of contamination: 500 mg and 1000 mg BPA kg-1 d.m. of soil. Reliable biochemical indicators of soil changes, whose activity was determined in the pot experiment conducted, were used: dehydrogenases, catalase, urease, acid phosphatase, alkaline phosphatase, arylsulfatase, and β-glucosidase. Using the definition of soil health as the ability to promote plant growth, the influence of BPA on the growth and development of Zea mays, a plant used for energy production, was also tested. As well as the biomass of aerial parts and roots, the leaf greenness index (SPAD) of Zea mays was also assessed. A key aspect of the research was to identify those of the six remediating substances-molecular sieve, zeolite, sepiolite, starch, grass compost, and fermented bark-whose use could become common practice in both environmental protection and agriculture. Exposure to BPA revealed the highest sensitivity of dehydrogenases, urease, and acid phosphatase and the lowest sensitivity of alkaline phosphatase and catalase to this phenolic compound. The enzyme response generated a reduction in the biochemical fertility index (BA21) of 64% (500 mg BPA) and 70% (1000 mg BPA kg-1 d.m. of soil). The toxicity of BPA led to a drastic reduction in root biomass and consequently in the aerial parts of Zea mays. Compost and molecular sieve proved to be the most effective in mitigating the negative effect of the xenobiotic on the parameters discussed. The results obtained are the first research step in the search for further substances with bioremediation potential against both soil and plants under BPA pressure.