Effects of Co-Contamination of Microplastics and Cd on Plant Growth and Cd Accumulation

Microplastics (MPs) occur widely in terrestrial ecosystems. However, information on the interaction of MPs with metals in terrestrial ecosystems is lacking in the literature. The present study investigated the effects of two types of MPs (high-density polyethylene (HDPE) and polystyrene (PS)) with different dosages (i.e., 0, 0.1%, 1%, and 10%) on the uptake and effects of Cd in maize plants grown in an agricultural soil. Results showed that addition of Cd at a 5 mg/kg caused inhibited plant growth and resulted in high Cd accumulation in plant tissues. Polyethylene alone showed no significant phytotoxic effects, but a high-dose of HDPE (10%) amplified Cd phytotoxicity. Polystyrene negatively affected maize growth and phytoxicity further increased in the presence of Cd. Both HDPE and PS caused soil diethylenetriaminepentaacetic acid (DTPA)-extractable Cd concentrations to increase but did not significantly affect Cd uptake into plant tissues. In the soil without Cd addition, HDPE decreased soil pH, while PS did not significantly alter soil pH. However, in the soil spiked with Cd, both HDPE and PS increased pH. Overall, impacts on plant growth and Cd accumulation varied with MP type and dose, and PS induced substantial phytotoxicity. In conclusion, co-occurring MPs can change Cd bioavailability, plant performance, and soil traits. Our findings highlight the ecological impacts that could occur from the release of MPs into soil.

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Tire abrasion particles negatively affect plant growth even at low concentrations and alter soil biogeochemical cycling

10.1101/2021.04.19.440468 ◽

2021 ◽

Author(s):

Eva F Leifheit ◽

Hanna L Kissener ◽

Erik Faltin ◽

Masahiro Ryo ◽

Matthias C Rillig

Keyword(s):

Plant Growth ◽

Soil Respiration ◽

Litter Decomposition ◽

Soil Ph ◽

Terrestrial Ecosystems ◽

Plant Performance ◽

Soil Parameters ◽

Potential Hazard ◽

Terrestrial Environment ◽

Low Concentrations

Tire particles (TPs) are a major source of microplastic on land, and considering their chemical composition, they represent a potential hazard for the terrestrial environment. We studied the effects of TPs at environmentally relevant concentrations along a wide concentration gradient (0 - 160 mg g-1) and tested the effects on plant growth, soil pH and the key ecosystem process of litter decomposition and soil respiration. The addition of TPs negatively affected shoot and root growth already at low concentrations. Tea litter decomposition slightly increased with lower additions of TPs but decreased later on. Soil pH increased until a TP concentration of 80 mg kg-1 and leveled off afterwards. Soil respiration clearly increased with increasing concentration of added TPs. Plant growth was likely reduced with starting contamination and stopped when contamination reached a certain level in the soil. The presence of TPs altered a number of biogeochemical soil parameters that can have further effects on plant performance. Considering the quantities of yearly produced TPs, their persistence, and toxic potential, we assume that these particles will eventually have a significant impact on terrestrial ecosystems.

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Tire abrasion particles negatively affect plant growth even at low concentrations and alter soil biogeochemical cycling

Soil Ecology Letters ◽

10.1007/s42832-021-0114-2 ◽

2021 ◽

Author(s):

Eva F. Leifheit ◽

Hanna L. Kissener ◽

Erik Faltin ◽

Masahiro Ryo ◽

Matthias C. Rillig

Keyword(s):

Plant Growth ◽

Soil Respiration ◽

Litter Decomposition ◽

Soil Ph ◽

Terrestrial Ecosystems ◽

Plant Performance ◽

Soil Parameters ◽

Potential Hazard ◽

Terrestrial Environment ◽

Low Concentrations

AbstractTire particles (TPs) are a major source of microplastic on land, and considering their chemical composition, they represent a potential hazard for the terrestrial environment. We studied the effects of TPs at environmentally relevant concentrations along a wide concentration gradient (0–160 mg g−1) and tested the effects on plant growth, soil pH and the key ecosystem process of litter decomposition and soil respiration. The addition of TPs negatively affected shoot and root growth already at low concentrations. Tea litter decomposition slightly increased with lower additions of TPs but decreased later on. Soil pH increased until a TP concentration of 80 mg g−1 and leveled off afterwards. Soil respiration clearly increased with increasing concentration of added TPs. Plant growth was likely reduced with starting contamination and stopped when contamination reached a certain level in the soil. The presence of TPs altered a number of biogeochemical soil parameters that can have further effects on plant performance. Considering the quantities of yearly produced TPs, their persistence, and toxic potential, we assume that these particles will eventually have a significant impact on terrestrial ecosystems.

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Remediation of Cr(VI)-Contaminated Soil by Nano-Zero-Valent Iron in Combination with Biochar or Humic Acid and the Consequences for Plant Performance

Toxics ◽

10.3390/toxics8020026 ◽

2020 ◽

Vol 8 (2) ◽

pp. 26 ◽

Cited By ~ 3

Author(s):

Yuhuan Sun ◽

Fangyuan Zheng ◽

Wenjie Wang ◽

Shuwu Zhang ◽

Fayuan Wang

Keyword(s):

Humic Acid ◽

Plant Growth ◽

Contaminated Soil ◽

Crop Production ◽

Agricultural Soils ◽

Synergistic Effects ◽

Zero Valent Iron ◽

Plant Performance ◽

High Dose ◽

Nano Zero Valent Iron

Nano-scale zero-valent iron (nZVI) is among the most common nanoparticles widely used for the treatment of various environmental contaminants. However, little is known about the combined effects of nano-zero-valent iron (nZVI) and other soil amendments on soil remediation and plant performance. For the first time, we studied the remediation of Cr(VI)-contaminated soil using bare nZVI (B-nZVI) and starch-supported nZVI (S-nZVI) in combination with either biochar (BC) or humic acid (HA), and the consequent effects on plant growth and Cr accumulation. Both S-nZVI and B-nZVI decreased the contents of Cr(VI) and available Cr in soil, but increased available Fe content, with S-nZVI generally showing more pronounced effects at a higher dose (1000 mg/kg). B-nZVI exerted no inhibition and even stimulation on plant growth, but 1000 mg/kg S-nZVI produced significant phytotoxicity, resulting in decreased plant growth, low chlorophyll content in leaves, and excessive accumulation of Fe in roots. Each nZVI decreased shoot and root Cr concentrations. BC and HA produced synergistic effects with nZVI on Cr(VI) removal from soil, but HA decreased soil pH and increased the availability of Cr and Fe, implying a potential environmental risk. Addition of BC or HA did not alter the effects of either nZVI on plant growth. In conclusion, combined application of 100 mg/kg nZVI and BC could be an ideal strategy for the remediation of soil contaminated with Cr(VI), whereas high-dose S-nZVI and HA are not recommended in the remediation of agricultural soils for crop production or in the phytostabilization of Cr(VI).

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Effects of selenium on the growth and photosynthetic characteristics of flue-cured tobacco (Nicotiana tabacum L.)

Acta Societatis Botanicorum Poloniae ◽

10.5586/asbp.2015.006 ◽

2015 ◽

Vol 84 (1) ◽

pp. 71-77 ◽

Cited By ~ 27

Author(s):

Chaoqiang Jiang ◽

Chaolong Zu ◽

Jia Shen ◽

Fuwen Shao ◽

Tian Li

Keyword(s):

Nicotiana Tabacum ◽

Plant Growth ◽

Tobacco Plant ◽

Photosynthetic Characteristics ◽

Carboxylation Efficiency ◽

Plant Tissues ◽

High Dose ◽

High Accumulation ◽

Order Root ◽

Mda Content

The objective of this study was to investigate the effect of Selenium (Se) supply (0, 3, 6, 12, 24 mg kg−1) on the growth, photosynthetic characteristics, Se accumulation and distribution of flue-cured tobacco (Nicotiana tabacum L.). Results showed that low-dose Se treatments (≤6 mg kg−1) stimulated plant growth but high-dose Se treatments (≥12 mg kg−1) hindered plant growth. Optimal Se dose (6 mg kg−1) stimulated plant growth by reducing MDA content and improving photosynthetic capability. However, excess Se (24 mg kg−1) increased MDA content by 28%, decreased net photosynthetic rate and carboxylation efficiency by 34% and 39%, respectively. The Se concentration in the roots, stems, and leaves of the tobacco plants significantly increased with increasing Se application. A linear correlation (R = 0.95, P < 0.01) was observed between Se level and tobacco plant tissue Se concentration. This correlation indicated that the tobacco plant tissues were not saturated within the concentration range tested. The pattern of total Se concentration in the tobacco plant tissues followed the order root > leaf > stem. The Se concentration in the roots was 3.17 and 7.57 times higher than that in the leaves and stems, respectively, after treatment with 24 mg kg−1 Se. In conclusion, the present study suggested that optimal Se dose (6 mg kg−1) improved the plant growth mainly by enhancing photosynthesis, stomatal conductance, carboxylation efficiency and Rubisco content in the flue-cured tobacco leaves. However, the inhibition of excess Se on tobacco growth might be due to high accumulation of Se in roots and the damage of photosynthesis in leaves.

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Gluconacetobacter diazotrophicus Pal5 Enhances Plant Robustness Status under the Combination of Moderate Drought and Low Nitrogen Stress in Zea mays L.

Microorganisms ◽

10.3390/microorganisms9040870 ◽

2021 ◽

Vol 9 (4) ◽

pp. 870

Author(s):

Muhammad Aammar Tufail ◽

María Touceda-González ◽

Ilaria Pertot ◽

Ralf-Udo Ehlers

Keyword(s):

Zea Mays ◽

Plant Growth ◽

Zea Mays L ◽

Growth Promotion ◽

Nitrogen Stress ◽

Rrna Gene ◽

N Fixation ◽

Gluconacetobacter Diazotrophicus ◽

Maize Plants ◽

Low Nitrogen

Plant growth promoting endophytic bacteria, which can fix nitrogen, plays a vital role in plant growth promotion. Previous authors have evaluated the effect of Gluconacetobacter diazotrophicus Pal5 inoculation on plants subjected to different sources of abiotic stress on an individual basis. The present study aimed to appraise the effect of G. diazotrophicus inoculation on the amelioration of the individual and combined effects of drought and nitrogen stress in maize plants (Zea mays L.). A pot experiment was conducted whereby treatments consisted of maize plants cultivated under drought stress, in soil with a low nitrogen concentration and these two stress sources combined, with and without G. diazotrophicus seed inoculation. The inoculated plants showed increased plant biomass, chlorophyll content, plant nitrogen uptake, and water use efficiency. A general increase in copy numbers of G. diazotrophicus, based on 16S rRNA gene quantification, was detected under combined moderate stress, in addition to an increase in the abundance of genes involved in N fixation (nifH). Endophytic colonization of bacteria was negatively affected by severe stress treatments. Overall, G. diazotrophicus Pal5 can be considered as an effective tool to increase maize crop production under drought conditions with low application of nitrogen fertilizer.

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Isolation and Characterization of Fungal Endophytes Isolated from Medicinal Plant Ephedra pachyclada as Plant Growth-Promoting

Biomolecules ◽

10.3390/biom11020140 ◽

2021 ◽

Vol 11 (2) ◽

pp. 140 ◽

Cited By ~ 2

Author(s):

Ahmed Mohamed Aly Khalil ◽

Saad El-Din Hassan ◽

Sultan M. Alsharif ◽

Ahmed M. Eid ◽

Emad El-Din Ewais ◽

...

Keyword(s):

Medicinal Plants ◽

Plant Growth ◽

Aspergillus Flavus ◽

Endophytic Fungi ◽

Fungal Endophytes ◽

Penicillium Crustosum ◽

Plant Growth Promoting ◽

Penicillium Commune ◽

Maize Plants ◽

Growth Promoting

Endophytic fungi are widely present in internal plant tissues and provide different benefits to their host. Medicinal plants have unexplored diversity of functional fungal association; therefore, this study aimed to isolate endophytic fungi associated with leaves of medicinal plants Ephedra pachyclada and evaluate their plant growth-promoting properties. Fifteen isolated fungal endophytes belonging to Ascomycota, with three different genera, Penicillium, Alternaria, and Aspergillus, were obtained from healthy leaves of E. pachyclada. These fungal endophytes have varied antimicrobial activity against human pathogenic microbes and produce ammonia and indole acetic acid (IAA), in addition to their enzymatic activity. The results showed that Penicillium commune EP-5 had a maximum IAA productivity of 192.1 ± 4.04 µg mL−1 in the presence of 5 µg mL−1 tryptophan. The fungal isolates of Penicillium crustosum EP-2, Penicillium chrysogenum EP-3, and Aspergillus flavus EP-14 exhibited variable efficiency for solubilizing phosphate salts. Five representative fungal endophytes of Penicillium crustosum EP-2, Penicillium commune EP-5, Penicillium caseifulvum EP-11, Alternaria tenuissima EP-13, and Aspergillus flavus EP-14 and their consortium were selected and applied as bioinoculant to maize plants. The results showed that Penicillium commune EP-5 increased root lengths from 15.8 ± 0.8 to 22.1 ± 0.6. Moreover, the vegetative growth features of inoculated maize plants improved more than the uninoculated ones.

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The complexity of wood ash fertilization disentangled: Effects on soil pH, nutrient status, plant growth and cadmium accumulation

Environmental and Experimental Botany ◽

10.1016/j.envexpbot.2021.104424 ◽

2021 ◽

Vol 185 ◽

pp. 104424

Author(s):

Jesper Liengaard Johansen ◽

Maiken Lundstad Nielsen ◽

Mette Vestergård ◽

Louise Hindborg Mortensen ◽

Carla Cruz-Paredes ◽

...

Keyword(s):

Plant Growth ◽

Soil Ph ◽

Nutrient Status ◽

Cadmium Accumulation ◽

Wood Ash

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Molecular imaging of plant-microbe interactions on the Brachypodium seed surface

The Analyst ◽

10.1039/d1an00205h ◽

2021 ◽

Author(s):

Yuchen Zhang ◽

Rachel Komorek ◽

Jiyoung Son ◽

Shawn Riechers ◽

Zihua Zhu ◽

...

Keyword(s):

Biological Control ◽

Molecular Imaging ◽

Plant Growth ◽

Crucial Role ◽

Plant Growth Promoting Rhizobacteria ◽

Plant Tissues ◽

Seed Surface ◽

Plant Growth Promoting ◽

Microbe Interactions ◽

Growth Promoting

Plant growth-promoting rhizobacteria (PGPR) play a crucial role in biological control and pathogenic defense on and within plant tissues, however the mechanism(s) by which plants associate with PGPR to elicit...

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Protists as main indicators and determinants of plant performance

Microbiome ◽

10.1186/s40168-021-01025-w ◽

2021 ◽

Vol 9 (1) ◽

Author(s):

Sai Guo ◽

Wu Xiong ◽

Xinnan Hang ◽

Zhilei Gao ◽

Zixuan Jiao ◽

...

Keyword(s):

Plant Growth ◽

Organic Fertilizer ◽

Agricultural Practices ◽

Plant Performance ◽

Organic Fertilization ◽

Plant Yield ◽

Growing Seasons ◽

Beneficial Microorganisms ◽

Plant Growth Promoting ◽

Plant Growth Promoting Microbes

Abstract Background Microbiomes play vital roles in plant health and performance, and the development of plant beneficial microbiomes can be steered by organic fertilizer inputs. Especially well-studied are fertilizer-induced changes on bacteria and fungi and how changes in these groups alter plant performance. However, impacts on protist communities, including their trophic interactions within the microbiome and consequences on plant performance remain largely unknown. Here, we tracked the entire microbiome, including bacteria, fungi, and protists, over six growing seasons of cucumber under different fertilization regimes (conventional, organic, and Trichoderma bio-organic fertilization) and linked microbial data to plant yield to identify plant growth-promoting microbes. Results Yields were higher in the (bio-)organic fertilization treatments. Soil abiotic conditions were altered by the fertilization regime, with the prominent effects coming from the (bio-)organic fertilization treatments. Those treatments also led to the pronounced shifts in protistan communities, especially microbivorous cercozoan protists. We found positive correlations of these protists with plant yield and the density of potentially plant-beneficial microorganisms. We further explored the mechanistic ramifications of these relationships via greenhouse experiments, showing that cercozoan protists can positively impact plant growth, potentially via interactions with plant-beneficial microorganisms including Trichoderma, the biological agent delivered by the bio-fertilizer. Conclusions We show that protists may play central roles in stimulating plant performance through microbiome interactions. Future agricultural practices might aim to specifically enhance plant beneficial protists or apply those protists as novel, sustainable biofertilizers.

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The Coevolution of Plants and Microbes Underpins Sustainable Agriculture

Microorganisms ◽

10.3390/microorganisms9051036 ◽

2021 ◽

Vol 9 (5) ◽

pp. 1036

Author(s):

Dongmei Lyu ◽

Levini A. Msimbira ◽

Mahtab Nazari ◽

Mohammed Antar ◽

Antoine Pagé ◽

...

Keyword(s):

Microbial Community ◽

Plant Growth ◽

Stress Resistance ◽

Mycorrhizal Fungi ◽

Plant Tissues ◽

Terrestrial Plants ◽

Plant Host ◽

Symbiotic Relationships ◽

Wide Range ◽

Terrestrial Environments

Terrestrial plants evolution occurred in the presence of microbes, the phytomicrobiome. The rhizosphere microbial community is the most abundant and diverse subset of the phytomicrobiome and can include both beneficial and parasitic/pathogenic microbes. Prokaryotes of the phytomicrobiome have evolved relationships with plants that range from non-dependent interactions to dependent endosymbionts. The most extreme endosymbiotic examples are the chloroplasts and mitochondria, which have become organelles and integral parts of the plant, leading to some similarity in DNA sequence between plant tissues and cyanobacteria, the prokaryotic symbiont of ancestral plants. Microbes were associated with the precursors of land plants, green algae, and helped algae transition from aquatic to terrestrial environments. In the terrestrial setting the phytomicrobiome contributes to plant growth and development by (1) establishing symbiotic relationships between plant growth-promoting microbes, including rhizobacteria and mycorrhizal fungi, (2) conferring biotic stress resistance by producing antibiotic compounds, and (3) secreting microbe-to-plant signal compounds, such as phytohormones or their analogues, that regulate aspects of plant physiology, including stress resistance. As plants have evolved, they recruited microbes to assist in the adaptation to available growing environments. Microbes serve themselves by promoting plant growth, which in turn provides microbes with nutrition (root exudates, a source of reduced carbon) and a desirable habitat (the rhizosphere or within plant tissues). The outcome of this coevolution is the diverse and metabolically rich microbial community that now exists in the rhizosphere of terrestrial plants. The holobiont, the unit made up of the phytomicrobiome and the plant host, results from this wide range of coevolved relationships. We are just beginning to appreciate the many ways in which this complex and subtle coevolution acts in agricultural systems.

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