Absence Of Arbuscular Mycorrhizal Fungi Research Articles

Arbuscular mycorrhizal fungi induce Zn uptake and antioxidant efficiency in broccoli (Brassica oleracea L.) exposed to Zn deficiency

Zinc (Zn) is an essential micronutrient for plant growth and development, and its deficiency in soil can be a significant problem for broccoli (Brassica oleracea L.) production. While the genetic efforts to breed Zn-efficient broccoli are complex, harnessing microbiomes is an emerging way to induce mineral efficiency in crops. In this study, broccoli, a non-host mycorrhizal species, was cultivated with or without zinc deficiency in the presence or absence of arbuscular mycorrhizal fungi (AMF), confirmed by the colonization efficiency in roots. Zn deficiency caused a significant decrease in morphological parameters and photosynthetic attributes being consistent with the decreased Zn levels in root and shoot relative to Zn-sufficient plants. However, the broccoli plants inoculated with AMF showed a substantial improvement in morphological and photosynthetic parameters in Zn-deficient conditions due to the significant increase in tissue Zn levels. In addition, AMF-inoculated plants under Zn deficiency showed a significant decrease in cell death (%), electrolyte leakage, and H2O2 levels compared to Zn-deficient plants, which further suggests the improvements in cellular status due to the AMF colonization. The real-time PCR experiments showed a significant induction in the expression of BoZIP1 and BoNRAMP1 genes in the roots of Zn-deficient broccoli inoculated with AMF, suggesting that AMF may be associated with the induction of these genes responsible for Zn-uptake and transport. We further observed the induction of POD (peroxidase), APX (ascorbate peroxidase) and SOD (superoxide dismutase), and S-metabolites (cysteine and glutathione) predominantly in the roots of Zn-starved broccoli inoculated with AMF which may confer tolerance to Zn-deficiency induced oxidative damage. This is the first report on the role of AMF in mitigating Zn-deficiency in broccoli which may promote the microbiome-aided improvement in plant health suffering from Zn-deficiency in broccoli and other vegetable crops.

A symbiotic footprint in the plant root microbiome

BackgroundA major aim in plant microbiome research is determining the drivers of plant-associated microbial communities. While soil characteristics and host plant identity present key drivers of root microbiome composition, it is still unresolved whether the presence or absence of important plant root symbionts also determines overall microbiome composition. Arbuscular mycorrhizal fungi (AMF) and N-fixing rhizobia bacteria are widespread, beneficial root symbionts that significantly enhance plant nutrition, plant health, and root structure. Thus, we hypothesized that symbiont types define the root microbiome structure.ResultsWe grew 17 plant species from five families differing in their symbiotic associations (no symbioses, AMF only, rhizobia only, or AMF and rhizobia) in a greenhouse and used bacterial and fungal amplicon sequencing to characterize their root microbiomes. Although plant phylogeny and species identity were the most important factors determining root microbiome composition, we discovered that the type of symbioses also presented a significant driver of diversity and community composition. We found consistent responses of bacterial phyla, including members of the Acidobacteria, Chlamydiae, Firmicutes, and Verrucomicrobia, to the presence or absence of AMF and rhizobia and identified communities of OTUs specifically enriched in the different symbiotic groups. A total of 80, 75 and 57 bacterial OTUs were specific for plant species without symbiosis, plant species forming associations with AMF or plant species associating with both AMF and rhizobia, respectively. Similarly, 9, 14 and 4 fungal OTUs were specific for these plant symbiont groups. Importantly, these generic symbiosis footprints in microbial community composition were also apparent in absence of the primary symbionts.ConclusionOur results reveal that symbiotic associations of the host plant leaves an imprint on the wider root microbiome – which we term the symbiotype. These findings suggest the existence of a fundamental assembly principle of root microbiomes, dependent on the symbiotic associations of the host plant.

Mycorrhizal fungi mitigate nitrogen losses of an experimental grassland by facilitating plant uptake and soil microbial immobilization

Nitrogen (N) is one of the most limited nutrients of terrestrial ecosystems, whose losses are prevented in tightly coupled cycles in finely tuned systems. Global change-induced N enrichment through atmospheric deposition and application of vast amounts of fertilizer nowadays challenge the terrestrial N cycle. Arbuscular mycorrhizal fungi (AMF) are known drivers of plant-soil nutrient fluxes, yet a comprehensive assessment of AMF involvement in N cycling under global change is still lacking. Here we simulated N enrichment by fertilization in experimental grassland microcosms grown under greenhouse conditions in the presence or absence of AMF and steadily monitored different N pathways over nine months. We found that N enrichment by fertilization decreased the relative abundance of legumes, and the plant species dominating the plant community changed from grasses to forbs in the presence of AMF based on aboveground biomass. AMF always maintained plant N: phosphorus (P) ratio between 14 and 16, no matter changes in the soil N availability. Shifting plant N:P ratios due to the increased plant N and P uptake thus might be a primary pathway of AMF altering plant community composition. Furthermore, we constructed a comprehensive picture of AMFs' role in N cycling, highlighting that AMF reduced N losses primarily by mitigating N leaching, while N2O emissions played a marginal role. AMF reduced N2O emissions directly through the promotion of N2O-consuming denitrifiers. The underlying mechanism for reducing N leaching is mainly the AMF-mediated improved nutrient uptake and AMF-associated microbial immobilization. Our results indicate that synergies between AMF and other soil microorganisms cannot be ignored in N cycling, and the integral roles of AMF in N cycle terrestrial ecosystems can buffer the upcoming global changes.

Arbuscular mycorrhizal fungi reduce potassium, cadmium and ammonium losses but increases nitrate loss under high intensity leaching events

BackgroundNutrients and heavy metals can be lost from soils via leaching, and arbuscular mycorrhizal fungi (AMF) can influence these events. Soil column experiments were carried out to examine whether leaching intensity and AMF can alter nutrient and Cd uptake in white clover plants and the extent of their losses through leaching.ResultsThe presence of AMF significantly increased shoot and total biomass, as well as increased N, P, Cu and Zn uptake independent of water amount applied; while root P and Cu uptakes were promoted by AMF at any water amount treatments. Higher water amounts led to reductions in total N, K and Zn uptake for AMF-colonized plants in comparison to moderate water amount treatments. In the absence of AMF, white clover at low water amount treatment exhibited maximal root Cd uptake. At high water amount treatments, the presence of AMF significantly decreased leachate volumes and the amount of leached NH4+, K and Cd while AMF significantly increased the amounts of leached NO3−.ConclusionsOverall we found that AMF-colonized white clover plants reduced NH4+, K and Cd loss from soils but increased the risk of NO3− loss under high intensity leaching conditions.

Mycorrhization of strawberry plantlets potentiates the synthesis of phytochemicals during ex vitro acclimatization

Ex vitro strawberry plantlets from micropropagation and coinoculated with arbuscular mycorrhizal fungi (AMF) and biochar can provide beneficial health effects. In the present study, we evaluated the effects of different proportions of biochar in the presence and absence of AMF on the production of secondary metabolites in the leaves and roots of strawberry plantlets during ex vitro acclimatization. Additionally, the enzymatic activity of the substrate enriched with AMF and biochar was analyzed. The experiment consisted of the control (absence of the mycorrhizal community) and four biochar proportions (0, 3, 6, and 9% of the volume of the container) coinoculated with AMF. Plantlets produced on substrates enriched with AMF showed higher levels of polyphenols, flavonoids, phenolic acids, and tannins in the tissues analyzed than control plantlets. The combination of AMF and 9% biochar increased the content of total flavonoids in the leaves of strawberry plantlets and increased the activity of phosphatase. The substrate with up to 6% biochar and mycorrhizae showed increased β-glucosidase activity. In conclusion, mycorrhizae are excellent tools to improve the phytochemical quality of strawberry plantlets acclimatized ex vitro. The association between host plants, mycorrhizal symbionts, and bioactivators of these fungi potentiates properties beneficial to health, which can be exploited efficiently in sustainable agriculture.

Phytoremediation of Soil Contaminated with Heavy Metals via Arbuscular Mycorrhiza (Funneliformismosseae) Inoculation Ameliorates the Growth Responses and Essential Oil Content in Lavender (Lavandula angustifolia L.)

Phytoremediation of heavy metals (HMs) is an efficient methodology to remove toxic metals from the soil. On the other hand, arbuscular mycorrhizal fungi (AMF) are utilized as biological fertilizers as they improve root expansion, nutrient uptake, shoot growth, and plant biological performance. In this study, the effect of AMF inoculation on the morphological traits, macro- and micronutrient contents, essential oil content (EOC), and essential oil yield (EOY) of lavender (Lavandula angustifolia L.) was investigated, under HM (Pb and Ni) stress in greenhouse conditions. The performed treatments were as follows: AMF (Funneliformis mosseae) inoculation (5 g kg−1 soil), and HM stress, including Pb (150 and 225 mg kg−1 soil from Pb(NO3)2) and Ni (220 and 330 mg kg−1 soil from Ni(NO3)2). The controls were the absence of AMF and HM treatments. The results showed that the contamination with Pb and Ni decreased plant height, branch number, fresh and dry weights of shoots and roots, and P, K, Mg, Fe, Zn, and Mn contents. At the same time, AMF inoculation modulated the adverse effects of Pb and Ni treatments. AMF inoculation and lower concentrations of Pb and Ni increased the EOC and EOY of lavender plants, whereas the higher levels of HMs reduced the morphobiometric traits. AMF inoculation increased the Pb and Ni contents in roots. The treatment with Pb at 220 mg kg−1 led to a higher stress effect than that of Ni treatment. In conclusion, the results recommend AMF inoculation as a helpful procedure to improve the growth responses and EOY of lavender in environments polluted with the tested HMs and suggest that AMF inoculation is potentially efficient in mitigating HM stress effects.

Mycorrhizal symbiosis alleviates plant water deficit within and across generations via phenotypic plasticity

Abstract Phenotypic plasticity is essential for organisms to adapt to local ecological conditions. It is expected that mutualistic interactions, such as arbuscular mycorrhizal (AM) symbiosis, mediate plant phenotypic plasticity, although it is not clear to what extent this plasticity may be heritable (i.e. transgenerational plasticity). We tested for plant plasticity within‐ and across‐generations in response to AM symbiosis and varying water availability in a full factorial experiment over two generations, using a genetically uniform line of a perennial apomictic herb, Taraxacum brevicorniculatum. We examined changes in phenotype, performance and AM fungal colonization of the offspring throughout plant development. AM symbiosis and water availability triggered phenotypic changes during the life cycle of plants. Additionally, both factors triggered adaptive transgenerational effects especially detectable during the juvenile stage of the offspring. Water deficit and absence of AM fungi caused concordant plant phenotypic modifications towards a ‘stress‐coping phenotype’, both within and across generations. Parental environment also affected AM fungal colonization of the offspring. Juvenile offspring of amply watered parents and adut offspring of mycorrhizal parents had increasing length of root colonized by AM fungi when they were under water stress. Synthesis. We show that, in addition to providing beneficial transgenerational effects in offspring traits proxies of fitness (such as increased biomass, survival or nutritional status), AM symbiosis can trigger transgenerational plasticity in anatomical and physiological traits related to resource‐use acquisition, and further influence offspring AM fungal colonization. Our results show that AM symbiosis could improve plants' ability to cope with environmental stress, not only within, but also across generations.

Mycorrhizal associations change root functionality: a 3D modelling study on competitive interactions between plants for light and nutrients.

Summary Recent studies show that the variation in root functional traits can be explained by a two‐dimensional trait framework, containing a ‘collaboration’ axis in addition to the classical fast–slow ‘conservation’ axis. This collaboration axis spans from thin and highly branched roots that employ a ‘do‐it‐yourself’ strategy to thick and sparsely branched roots that ‘outsource’ nutrient uptake to symbiotic arbuscular mycorrhizal fungi (AMF).Here, we explore the functionality of this collaboration axis by quantifying how interactions with AMF change the impact of root traits on plant performance. To this end, we developed a novel functional–structural plant (FSP) modelling approach that simulates plants competing for light and nutrients in the presence or absence of AMF.Our simulation results support the notion that in the absence of AMF, plants rely on thin, highly branched roots for their nutrient uptake. The presence of AMF, however, promotes thick, unbranched roots as an alternative strategy for uptake of immobile phosphorus, but not for mobile nitrogen.This provides further support for a root trait framework that accommodates for the interactive effect of roots and AMF. Our modelling study offers unique opportunities to incorporate soil microbial interactions into root functionality as it integrates consequences of belowground trait expression.

Effects of arbuscular mycorrhizal fungi on the growth and toxic element uptake of Phragmites australis (Cav.) Trin. ex Steud under zinc/cadmium stress

Arbuscular mycorrhizal fungi (AMF) play an important role in improving plant tolerance and accumulation of zinc (Zn) and cadmium (Cd). The growth, physiology and absorption of elements and transport in Phragmites australis (P. australis) were investigated under Zn and Cd stress to identify the transport mechanisms of toxic trace elements (TE) under the influence of AMF. Thus, AMF were observed to alleviate the toxic effects of Zn and Cd on P. australis by increasing plant biomass and through different regulatory patterns under different TE concentrations. The activities of superoxide dismutase (SOD) and ascorbate peroxidase (APX) increased under Zn stress, and the activities of SOD, catalase (CAT), peroxidase (POD), and APX significantly increased under high concentrations of Cd. AMF differ in their strategies of regulating the transport of different metals under TE stress. Under Zn stress, the concentration of Zn in P. australis decreased by 10–57%, and the effect on Zn translocation factor (TFZn) was concentration-dependent. AMF increased the TFZn under low concentration stress, but decreased under high concentration stress. Under Cd stress, the concentration of Cd increased by as much as 17–40%, and the TFCd decreased. AMF were also found to change the interaction of Zn×Cd. In the absence of AMF, Cd exposure decreased the Zn concentrations in P. australis at Zn100 mg/L and Zn300 mg/L, while it increased the contents of Zn at Zn700 mg/L. The opposite trend was observed following treatment with AMF. However, regardless of the concentration of Cd, the addition of Zn decreased the concentration of Cd in both treatments in both the presence and absence of AMF. Under different TE stress conditions, the regulation of metal elements by AMF in host plants does not follow a single strategy but a trade-off between different trends of transportations. The findings of our study are important for applying AMF-P. australis systems in the phytoremediation of Zn-Cd co-contaminated ecosystems.

Arbuscular mycorrhizal fungi alleviate the negative effects of increases in phosphorus (P) resource diversity on plant community structure by improving P resource utilization

Nutrient resource utilization is essential for plant community composition and productivity. Previous studies found that an increase in resource diversity causes species losses and reduces plant diversity. Arbuscular mycorrhizal (AM) fungi can increase plant productivity and nutrient uptake, however, whether AM fungi can reduce the negative influence of nutrient resource diversity on plant composition is still not well understood. A microcosm experiment was conducted with four phosphorus (P) sources (at five levels of P resource diversity) and two AM fungal species, and the plant community composition, aboveground biomass, and P content were measured and calculated. Plant species diversity and richness decreased with increasing soil P resource diversity in the absence of AM fungi, while the decrease was less when AM fungi were present. The biomass and P content of the aboveground plants increased with increasing AM fungal diversity and soil P resource diversity. The results of a structural equation model suggest that AM fungi could reduce the negative effects of increasing P resource diversity on plant community composition by improving plant density and P uptake. Our results indicate that AM fungi can maintain higher plant species diversity and increase plant productivity by increasing P resource utilization efficiency.

Arbuscular mycorrhizal fungi against the false root-knot nematode activity in Capsicum annuum: physiological responses in plants

ABSTRACT Nacobbus aberrans affects plants growth and development, and decreases the production of numerous horticultural crops. Several investigations have shown that symbiosis with arbuscular mycorrhizae can confer tolerance to pathogens through different action mechanisms, such as nutrient space competition and plant resistance induction. The aim of this study was to analyse the potential of three arbuscular mycorrhizal fungi (AMF): Rhizophagus intraradices B1, Rhizophagus intraradices A2 and Funneliformis mosseae in the control of N. aberrans, and to evaluate the physiological and biochemical responses to inoculation in pepper plants. The experiment was conducted under controlled conditions. Mycorrhization percentages, chlorophyll, carotenes, soluble proteins, proline, phenolic compounds, total and reducing sugar content, relative conductivity of root cell membranes and final nematode population were determined. The mycorrhization percentages were higher in plants parasitised by N. aberrans than in those not parasitised. The final population of nematodes was reduced in the presence of mycorrhizae. In the absence of AMF, parasitism by N. aberrans caused a decrease in the soluble proteins and chlorophyll content. The loss of functionality of infected roots in the plants induced water stress, reflected by the accumulation of proline, sugar and increased the relative conductivity of cell membranes. At the same time, as a product of pathogenesis, phenolic compounds accumulated. Inoculation with AMF decreased the proline, sugars, phenolic compounds content and relative conductivity. These results show the potential for the use of AMF in pepper production to reduce the population of N. aberrans, being the strain R. intraradices B1 as the most promising candidate.

Suitability of Mycorrhiza-Defective Rice and Its Progenitor for Studies on the Control of Nitrogen Loss in Paddy Fields via Arbuscular Mycorrhiza.

Employing mycorrhiza-defective mutants and their progenitors does not require inoculation or elimination of the resident microbial community in the experimental study of mycorrhizal soil ecology. We aimed to examine the suitability of mycorrhiza-defective rice (non-mycorrhizal, Oryza sativa L., cv. Nipponbare) and its progenitor (mycorrhizal) to evaluate nitrogen (N) loss control from paddy fields via arbuscular mycorrhizal (AM) fungi. We grew the two rice lines in soils with the full community of AM fungi and investigated root AM colonization. In the absence of AM fungi, we estimated rice N content, soil N concentration and microbial community on the basis of phospholipid fatty acids; we also quantified N loss via NH3 volatilization, N2O emission, runoff and leaching. In the presence of AM fungi, we did not find any evidence of AM colonization for non-mycorrhizal rice while mycorrhizal rice was colonized and percentage of root colonization was 17–24%. In the absence of AM fungi, the two rice lines had similar N content, soil N concentration and microbial community. Importantly, there was no significant difference in N loss via all the four pathways between mycorrhizal and non-mycorrhizal systems. This mycorrhizal/non-mycorrhizal rice pair is suitable for further research on the role of AM fungi in the control of soil N loss in paddy fields.

Arbuscular mycorrhizal fungi and organic manure have synergistic effects on Trifolium repens in Cd-contaminated sterilized soil but not in natural soil

The objective of this study was to examine the effects of arbuscular mycorrhizal fungi (AMF) and organic manure on the growth and element uptake of Trifolium repens and the soil chemical and biological characteristics in sterilized and natural soils. An increase in organic manure input reduced mycorrhizal colonization in the sterilized soil treatment. In comparison to the treatments in which AMF inoculation did not occur, AMF inoculation significantly promoted the biomass of shoots and roots in the sterilized soil at the 2.5 and 5% organic manure incorporation levels, whereas AMF had no effect on biomass in the natural soil. Regardless of soil type and whether AMF inoculation occurred, the N, P, K and Mg concentrations of the shoots and roots and the Cd concentration of the roots were increased by organic manure amendment. In comparison to the 2.5% organic manure amendment treatment, the addition of 5% organic manure to the sterilized soil decreased the N, P, K, Ca and Cd contents in the absence of AMF but had no negative effect on the N, P, K, Mg and Cd contents in the presence of AMF. The soil available P, pH, microbial biomass carbon, microbial biomass nitrogen, dissolved organic carbon, diethylenetriamine pentaacetic acid (DTPA)-extractable Cd and root Cd concentrations increased with increasing organic manure input. These results indicate that additive effects of AMF inoculation and organic manure on the growth and nutrient contents of Trifolium repens occurred in the Cd-contaminated sterilized soil but not in the natural soil, implying the limited function of nonnative AMF introduced into natural soils.

Arbuscular mycorrhiza contributes to the control of phosphorus loss in paddy fields

Phosphorus (P) loss from paddy fields is a significant issue in sustainable rice production by threatening water environments. We aimed to examine the suitability of mycorrhiza-defective rice (non-mycorrhizal) and its mycorrhizal progenitor to evaluate P loss control via arbuscular mycorrhizal (AM) fungi. We also aimed to investigate the AM effect on P loss via runoff and leaching. We grew the two rice lines in microcosms with and without AM fungi, measured P loss via runoff and leaching before and after nitrogen–phosphorus–potassium fertilization, and quantified plant P content and soil P concentration after the final harvest. Mycorrhizal and non-mycorrhizal rice pair systems in the absence of AM fungi had similar plant, soil, runoff, and leachate P contents (except PO43−). In the presence of AM fungi, the concentrations of all P forms in runoff water and leachate in mycorrhizal rice were lower than those in nonmycorrhizal rice regardless of their solubility in water and availability to plants. The cumulative P loss from mycorrhizal systems was 10% less than that from their nonmycorrhizal counterparts. This mycorrhizal/non-mycorrhizal rice pair is an efficient experimental tool for research on the control of P loss from paddy fields with AM fungi. AM colonization contributes to the sustainability of rice production by decreasing P loss from paddy fields.

Effects of mycorrhizal association and phosphate fertilization on the initial growth of coffee plants

ABSTRACT In the establishment of coffee crops, phosphate fertilization is one of the most important soil fertility managements. Aiming to minimize losses, among the options in use are fertilizers with a slow release of nutrients, combined with the inoculation of arbuscular mycorrhizal fungi (AMF). This study aimed to evaluate the initial growth of coffee plants inoculated with AMF and submitted to different types of phosphate fertilizers. The experiment was conducted in a greenhouse, using a complete randomized block design, in a 2 x 4 factorial scheme, with four replications. The first factor referred to the presence or absence of AMF (Rhizophagus clarus) and the second one to phosphate [monoammonium phosphate (MAP)], pelletized organomineral and grainy organomineral fertilizers, as well as a control (without fertilization). The plant height, leaf chlorophyll content, number of plagiotropic branches, leaf area, shoot and root dry matter mass, percentage of root colonization and leaf phosphorus were evaluated. The inoculation with AMF, associated with the pelletized organomineral fertilizer, provided a higher growth for the shoot and root system and higher phosphorus contents, in relation to the other treatments, and it can be an alternative to the implantation or renewal of coffee crops.

The Current Survey of Indigenous Arbuscular Mycorrhizal Fungi of Wheat (Triticum aestivum) in Benghazi’s Coastal Plain

Rhizospheres of crop plants are complexes of chemical and microbial interactions. Of importance, arbuscular mycorrhizal fungi (AMF) are beneficial microorgansims associated with roughly eighty-percent of terrestrial land plants. In this mutualistic symbiosis, the fungus receives the photosynthetic product (sugar) fixed from its host by photosynthesis. In return, the host plant gains a plethora of benefits from the fungus such as enhanced nutrient uptakes, protection against both biotic (soil-borne root pathogens, insect attack) and abiotic (drought, heavy metal pollution, and soil salinity) stresses. Taxonomically, AMF belong to a new erected phylum called Glomeromycota. The field study was conducted in a farm owned and supervised by The Great Man-Made Project in February 2019. The present study was performed to determine the presence or the absence of AMF in a field cultivated with wheat crops (Triticum aestivum, L.) during the vegetative stage, and also to investigate soil physiochemical properties effect on AMF colonization. Results showed that colonization of wheat plant roots were significantly low. The result clearly implies that high-input fertilizers viz., phosphorus fertilization, and agricultural practices such as intensive tillage drastically reduced AMF colonization.

Experimental evidence that phosphorus fertilization and arbuscular mycorrhizal symbiosis can reduce the carbon cost of phosphorus uptake

Abstract Plants allocate substantial amounts of carbon (C) below‐ground to obtain nutrients and other resources. Increasing nutrient availability typically reduces the C investment in root growth and mycorrhizal fungi, hence reducing the C cost of nutrient acquisition. This C cost of nutrient acquisition, however, remains poorly quantified. In a P fertilization experiment with Zea mays, we examined below‐ground C allocation and the C cost of phosphorus (P) uptake. In addition, we compared plants inoculated with arbuscular mycorrhizal fungi (AMF) to those growing in pasteurized soil to examine the same measures in the absence of AMF. P fertilization tended to increase above‐ground plant growth more than it increased the total below‐ground C flux (TBCF; root growth plus rhizosphere respiration), suggesting a reduced investment in nutrient acquisition. This was confirmed by a negative fertilization effect on the TBCF‐to‐total plant P ratio (~25% reduction for high vs. low P fertilization). Soil pasteurization increased this proxy for the C cost of P uptake (~50% increase). This novel quantification of the influence of P availability and mycorrhizal fungi on plant–soil C partitioning can guide the incorporation of these processes in vegetation models. A free Plain Language Summary can be found within the Supporting Information of this article.

Stimulation of corn zinc efficiency in the soil polluted with petroleum hydrocarbons and lead using Arbuscular mycorrhizal fungi and zinc oxide nanoparticles

Zinc (Zn) deficiency is among the main concerns regarding human nutrition. The present study aimed to evaluate the effects of zinc oxide (ZnO) nanoparticles and Arbuscular mycorrhizal fungi (AMF) on the changes of Zn concentration in the corn plant grown in the soil contaminated with petroleum hydrocarbons and lead (Pb). Treatments consisted of applying 0% (Zn0) and 1% (w/w) Zn oxide nanoparticles (Zn1), soil pollution with zero (Pb0), 400 (Pb400), and 600 (Pb600) mg Pb/kg soil and 0% (P0), 1.5% (P1.5), and 3% (W/W) of crude oil (P3) in the presence (AMF+) and absence of AMF (AMF-). After the corn harvesting, plant Zn and Pb concentrations were measured using atomic absorption spectroscopy (AAS). Also, total petroleum hydrocarbons (TPHS) degradation in the soil was measured via gas chromatography. The least significant difference (LSD) test was used to determine the statistical differences between the mean values. According to the findings, the presence of AMF in soil containing 1.5% (W/W) crude oil and polluted with 400 mg Pb/kg soil caused a significant increase in plant Zn concentration by 52%. However, increasing soil pollution to petroleum hydrocarbon or Pb caused a significant decreasing in the plant Zn concentration. The highest TPHS degradation has belonged to the soil treated with 1% (W/W) ZnO nanoparticles nanoparticle in the presence of AMF that containing 1.5 % (W/W) crude oil. The results of this study showed that regardless of pollution type, application of AMF in soil treated with ZnO nanoparticles nanoparticle can increase plant Zn concentration.

Impacts of arbuscular mycorrhizal fungi on nutrient uptake, N2 fixation, N transfer, and growth in a wheat/faba bean intercropping system.

Arbuscular mycorrhizal fungi (AMF) can play a key role in natural and agricultural ecosystems affecting plant nutrition, soil biological activity and modifying the availability of nutrients by plants. This research aimed at expanding the knowledge of the role played by AMF in the uptake of macro- and micronutrients and N transfer (using a 15N stem-labelling method) in a faba bean/wheat intercropping system. It also investigates the role of AMF in biological N fixation (using the natural isotopic abundance method) in faba bean grown in pure stand and in mixture. Finally, it examines the role of AMF in driving competition and facilitation between faba bean and wheat. Durum wheat and faba bean were grown in pots (five pots per treatment) as sole crops or in mixture in the presence or absence of AMF. Root colonisation by AMF was greater in faba bean than in wheat and increased when species were mixed compared to pure stand (particularly for faba bean). Mycorrhizal symbiosis positively influenced root biomass, specific root length, and root density and increased the uptake of P, Fe, and Zn in wheat (both in pure stand and in mixture) but not in faba bean. Furthermore, AMF symbiosis increased the percentage of N derived from the atmosphere in the total N biomass of faba bean grown in mixture (+20%) but not in pure stand. Nitrogen transfer from faba bean to wheat was low (2.5–3.0 mg pot-1); inoculation with AMF increased N transfer by 20%. Overall, in terms of above- and belowground growth and uptake of nutrients, mycorrhization favoured the stronger competitor in the mixture (wheat) without negatively affecting the companion species (faba bean). Results of this study confirm the role of AMF in driving biological interactions among neighbouring plants.

Physiological response of Physalis peruviana L. seedlings inoculated with Funneliformis mosseae under drought stress

Physalis peruviana L. is gaining importance in international markets due to its nutritional properties; however, the production regions are increasingly susceptible to drought periods due to global climate change. A sustainable tool against this abiotic constraint is the association with arbuscular mycorrhizal fungi (AMF). The aim of this work was to evaluate the effects of AMF inoculation with Funneliformis mosseae on the early development and some physiological parameters of P. peruviana under drought stress. The tested treatments were three soil water conditions (30%, 40% and 80% of field capacity) and the presence or absence of AMF. In this sense, root colonization quantification, root andshoot dry weight, relative water content (RWC), leaf water potential, net photosynthesis (A), transpiration (E), stomatal conductance (gs), electrolyte leakage, chlorophyll content and fluorescence were evaluated. The treatments representing 30% and 40% of field capacity had a negative effect on all the evaluated parameters; nevertheless, AMF plants presented enhanced values of root dry weight, RWC, A, gs and chlorophyll content in comparison to non-inoculated stressed plants. Despite this, mycorrhization did not affect stress indicators as chlorophyll fluorescence and electrolyte leakage, revealing that, although AMF is a promising strategy, it is not enough to relieve drought stress deleterious effects, and need to be integrated with other management strategies.