Quantifying the Impact of Arbuscular Mycorrhiza on Plant Competition

Glyphosate-based herbicides are used extensively in forestry and agriculture to control broadleaf plant competition. A review of the literature offers conflicting results regarding the impact of glyphosate on fungal growth. This study investigated the effects of 7 glyphosate concentrations (1, 2, 5, 10, 50, 100, and 1000 µg·mL–1) of Roundup (35.6% glyphosate) on the number of colony-forming units (CFUs) of soilborne microfungi from a boreal forest soil sample and on the in vitro linear growth of 20 selected species of microfungi representative of this boreal forest soil. Concentrations of glyphosate at 50 µg·mL–1and higher significantly decreased the number of CFUs observed. At glyphosate concentrations equal to 5 µg·mL–1, 13 fungal species exhibited colony diameters less than 50% than that of their respective controls. Several species showed an inhibition of pigmentation and sporulation when subjected to glyphosate concentrations of 1 µg·mL–1. Differential sensitivity was observed among species at the various concentrations, suggesting the possibility of a shift towards tolerant species of fungi when they are exposed to glyphosate.

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Brief Overview of Arbuscular Mycorrhiza Research Conducted in Russia Over the XXTH Century

Revista Gestão Inovação e Tecnologias ◽

10.47059/revistageintec.v11i2.1645 ◽

2021 ◽

Vol 11 (2) ◽

pp. 71-92

Author(s):

Andrey P. Yurkov ◽

Lidija M. Jacobi ◽

Alexey A. Kryukov ◽

Lidija G. Perevedentseva ◽

Maria F. Shishova

Keyword(s):

Species Composition ◽

Arbuscular Mycorrhiza ◽

Biological Diversity ◽

Physiological Role ◽

Ecological Factors ◽

Am Fungi ◽

Soviet Period ◽

Agricultural Plants ◽

The Impact

Arbuscular mycorrhiza (AM) is one of the most common terrestrial plant-microbe symbioses. The interest in studying AM is caused by its importance for the growth and nutrition of plants and its ecological role in preserving biological diversity. At present, 92% of plant families are known to form AM. Fungi in AM are obligate symbionts and belong to a monophyletic group – Glomeromycotina subdivision. Some researchers believe that formation of AM-symbiosis with fungi by ancient plants allowed them to inhabit land, which has led to the formation of the biosphere as we know it. AM is studied by researchers from around the world including Russia. This overview presents in brief the results of AM research in Russia during the Soviet period which did not receive international coverage due to its classified nature; the most prominent research schools and works of AM researchers are identified; main stages and lines of this research are listed, such as: distribution of AM in plant communities and different climatic zones, mycorrhiza anatomy and morphology, fungi species composition on different soils, collection of AM fungi and growing AM in vitro, physiological role of AM for agricultural plants, the impact different ecological factors have on AM fungi species composition and AM development, conditions for effective use of Am fungi to increase productivity and quality of agricultural plants as well as to perform biological recultivation of toxic soils and restore the fertility of degraded soils.

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IMPACT OF BRACHIARIA, ARBUSCULAR MYCORRHIZA, AND POTASSIUM ENRICHED RICE STRAW COMPOST ON ALUMINIUM, POTASSIUM AND STABILITY OF ACID SOIL AGGREGATES

Indonesian Journal of Agricultural Science ◽

10.21082/ijas.v13n1.2012.p27-34 ◽

2013 ◽

Vol 13 (1) ◽

pp. 27

Author(s):

Bariot Hafif ◽

Supiandi Sabiham ◽

Iswandi Anas ◽

Atang Sutandi Sutandi ◽

Suyamto Suyamto

Keyword(s):

Soil Fertility ◽

Arbuscular Mycorrhiza ◽

Rice Straw ◽

Soil Aggregates ◽

Acid Soil ◽

Aggregate Stability ◽

Low Fertility ◽

Exchangeable Al ◽

Cassava Stem ◽

The Impact

<p>Acid soil is commonly grown with cassava, which in general, tolerate low soil fertility and aluminum (Al) toxicity. However, without any improvement efforts such soil will become worse. Intercropping cassava with <em>Brachiaria decumbens </em>(BD) which adapts to acid soil and tolerates low fertility soils as well as application of arbuscular mycorrhiza (AM) and organic matters are among the important efforts to rehabilitate this soil. The experiment was conducted to examine the impact of BD, AM, and potassium (K) enriched rice straw compost on exchangeable Al, available K, and stability of soil aggregates. Experiment was arranged in a completely randomized design with three factors and three replications. The first factor was BD as cassava intercropping, the second factor was AM, and the third factor was 2 t ha-1 rice straw compost enriched with 0 kg, 50 kg, 100 kg, and 200 kg KCl ha-1. Brick pots (1 m length x 1 m width x 0.45 m depth) filled with Kanhapludult soil was used for growing cassava in which row of BD was planted at 60 cm from cassava stem. K-enriched rice straw compost and AM (10 g per stem) were applied around cassava stem at 2 and 12 days after planting, respectively. BD was cut every 30 days and the cutting was returned to the soil. Soil exchangeable Al was analyzed at 0, 3, 6 and 9 months after planting (MAP), while Al and K contents as well as aggregate stability were measured at 6 MAP. The results showed that planting BD decreased 33% exchangeable Al, which means that the root exudates of this grass was effective in detoxifying Al3+. Treatment of BD and/or in combination with AM was effective in preserving K added to the soil, increasing total polysaccharides, and improving soil aggregate stability. This indicated that planting BD and applying AM and Kenriched rice straw compost improved acid soil fertility, and therefore can be recommended in cassava cultivation.</p>

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Interactions between Plant Competition and Herbivory on the Growth of Hypericum Species: a Comparison of Glasshouse and Field Results

Australian Journal of Botany ◽

10.1071/bt97025 ◽

1998 ◽

Vol 46 (6) ◽

pp. 707 ◽

Cited By ~ 15

Author(s):

Anthony J. Willis ◽

Richard H. Groves ◽

Julian E. Ash

Keyword(s):

Biological Control ◽

Field Experiment ◽

Native Species ◽

Field Experiments ◽

Plant Competition ◽

Plant Productivity ◽

Combined Effects ◽

The Impact ◽

Hypericum Species

The combined effects of interspecific plant competition and herbivory by a mite, Aculus hyperici Liro, on the growth of two Hypericum species were compared in separate glasshouse and field experiments. The impact of mites on H. perforatum L. was slightly greater than their effect on H. gramineum Forst. In both the glasshouse and the field, competition affected Hypericum growth more adversely than herbivory. There was little evidence that combinations of competition and herbivory caused complex synergistic reductions in plant productivity. In combination, herbivory and competition caused proportional reductions in growth, approximately equivalent to the product of the proportional growth under competition and herbivory individually. Broadly similar results were achieved in both the glasshouse and the field experiment. The results are discussed in relation to the biological control of H. perforatum by A. hyperici, and the impact of this arthropod on the growth of H. gramineum, a non-target native species.

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Interactions between plant genome size, nutrients and herbivory by rabbits, molluscs and insects on a temperate grassland

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2018.2619 ◽

2019 ◽

Vol 286 (1899) ◽

pp. 20182619 ◽

Cited By ~ 3

Author(s):

Maïté S. Guignard ◽

Michael J. Crawley ◽

Dasha Kovalenko ◽

Richard A. Nichols ◽

Mark Trimmer ◽

...

Keyword(s):

Plant Species ◽

Plant Competition ◽

Plant Genome ◽

Total Biomass ◽

Nutrient Inputs ◽

Nutrient Quality ◽

Path Analyses ◽

Plant Herbivore ◽

Herbivore Pressure ◽

The Impact

Angiosperm genome sizes (GS) vary ca 2400-fold. Recent research has shown that GS influences plant abundance, and plant competition. There are also tantalizing reports that herbivores may select plants as food dependent on their GS. To test the hypothesis that GS plays a role in shaping plant communities under herbivore pressure, we exploit a grassland experiment that has experimentally excluded herbivores and applied nutrient over 8 years. Using phylogenetically informed statistical models and path analyses, we show that under rabbit grazing, plant species with small GS generated the most biomass. By contrast, on mollusc and insect-grazed plots, it was the plant species with larger GS that increased in biomass. GS was also shown to influence plant community properties (e.g. competitive strategy, total biomass) although the impact varied between different herbivore guilds (i.e. rabbits versus invertebrates) and nutrient inputs. Overall, we demonstrate that GS plays a role in influencing plant–herbivore interactions, and suggest potential reasons for this response, which include the impact of GS on a plant's response to different herbivore guilds, and on a plant's nutrient quality. The inclusion of GS in ecological models has the potential to expand our understanding of plant productivity and community ecology under nutrient and herbivore stress.

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Opposing community assembly patterns for dominant and non-dominant plant species in herbaceous ecosystems globally

10.22541/au.162486571.19454366/v1 ◽

2021 ◽

Author(s):

Carlos Alberto Arnillas ◽

Elizabeth Borer ◽

Eric Seabloom ◽

Juan Alberti ◽

Selene Baez ◽

...

Keyword(s):

Dominant Species ◽

Plant Competition ◽

Environmental Filtering ◽

Environmental Drivers ◽

Environmental Constraints ◽

Dominant Plant Species ◽

Evolutionary Consequences ◽

Abiotic Influences ◽

The Impact ◽

Phylogenetic Dispersion

Dominant and non-dominant plants could be subject to different biotic and abiotic influences, partially because dominant plants modify the environment where non-dominant plants grow, causing an interaction asymmetry. Among other possibilities, if dominant plants compete strongly, they should deplete most resources forcing non-dominant plants into a more constrained niche space. Conversely, if dominant plants are constrained by the environment, they might not fully deplete available resources but instead ameliorate some of the environmental constraints limiting non-dominants. Hence, the nature of the interactions between the non-dominants could be modified by dominant species. However, when plant competition and environmental constraints have similar effects on dominant and non-dominant species no difference is expected. By estimating phylogenetic dispersion in 78 grasslands across five continents, we found that dominant species were clustered (underdispersed), suggesting dominant species are likely organized by environmental filtering, and that non-dominant species were either randomly assembled or overdispersed. Traits showed similar trends, but insufficient data prevented further analyses. Furthermore, several lineages scattered in the phylogeny had more non-dominant species, suggesting that traits related to non-dominants are phylogenetically conserved and have evolved multiple times. We found some environmental drivers of the dominant—non-dominant disparity. Our results indicate that assembly patterns for dominants and non-dominants are different, consistent with asymmetries in assembly mechanisms. Among the different mechanisms we evaluated, the results suggest two complementary hypotheses seldom explored: (1) Non-dominant species include lineages adapted to thrive in the environment generated by the dominant species. (2) Even when dominant species reduce resources to non-dominant ones, dominant species could have a stronger effect on—at least—some non-dominants by ameliorating the impact of the environment on them, than by depleting resources and increasing the environmental stress to those non-dominants. The results show that the dominant–non-dominant asymmetry has ecological and evolutionary consequences fundamental to understand plant communities.

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Impact of Competition on the Growth of Pinus Tabulaeformis in Response to Climate on the Loess Plateau of China

10.21203/rs.3.rs-619294/v1 ◽

2021 ◽

Author(s):

Rumeng He ◽

Xuhu Wang ◽

Tao Liu ◽

Lijun Guo ◽

Baitian Wang ◽

...

Keyword(s):

Plant Competition ◽

Small Diameter ◽

Stand Density ◽

Climate Variation ◽

Pinus Tabulaeformis ◽

Biotic Factor ◽

Small Diameter Trees ◽

Stand Density Index ◽

The Impact ◽

The Relationship

Abstract With climate change, understanding tree responses to climate is important for predicting trees’ growth, and plant competition as a nonnegligible biotic factor plays a key role in such response. However, few studies have investigated how competition affects the response of Pinus tabulaeformis plantations to climate . In our study, we investigated nine 29-year-old P. tabulaeformis plantation plots (three density gradients). The dendroecological method was used to analyze the impact of competition on trees response to drought and interannual climate variation. Stand density index was used to indicate the intensity of competition. The results showed that competition modified the climate-growth relationship. Competition increased trees’ sensitivity to drought but the relationship between competition and sensitivity to drought was nonlinear. The competition effect slightly increased under intense competition conditions. Additionally, competition reduced trees’ sensitivity to interannual climate variation. After 1999, the effect of competition was obvious. The sensitivity of small-diameter trees, especially those in middle- and high-density stands, declined. Thus, in the future these trees presumably may exhibit a reduced sensitivity to interannual climate variation and a greater sensitivity to drought.

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