Extraradical mycelium of arbuscular mycorrhizal fungi radiating from large plants depresses the growth of nearby seedlings in a nutrient deficient substrate (original) (raw)
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The influence of arbuscular mycorrhizal colonization and environment on root development in soil
European Journal of Soil Science, 2003
With the objective of determining whether arbuscular mycorrhizal (AM) colonization would alleviate salt stress on the growth of cape gooseberry plants, a saline soil (ECs of 5.65 dS m -1 , available phosphorous of 48.1 mg kg -1 ) was inoculated with AM fungi (Mycoral®) (+AM) and compared to a non-inoculated saline soil (-AM). The openfield experiment was conducted over the course of 131 days on the Marengo farm of the Universidad Nacional de Colombia (near Bogotá, 4º42' N, 74º12' W, 2543 m a.s.l., 14ºC mean temperature, and 800 mm a -1 precipitation) where the plants were irrigated with water (ECs of 1.65 dS m -1 ) from the salt-contaminated Bogota river. Mycorrhizal dependence, AM colonization, relative field mycorrhizal dependency (RFMD 100 ), dry matter (DM) accumulation and growth parameters (unit leaf rate [ULR], leaf area ratio [LAR] and specific leaf area [SLA]) were determined. The percentage of AMcolonization was 29.7% in +AM plants, but only 12.5% in -AM plants. The RFMD 100 index peaked at day 61 (42.5%) and decreased to 7.8% by day 89. Inoculation with AM fungi increased plant dry matter accumulation by 7%, especially stem DM, compared to -AM plants. Generally, growth rates were higher in the +AM plants; ULR increased more in the second half of the experiment in inoculated plants compared to noninoculated. The mycorrhizal infection enhanced leaf area growth, which resulted in increased LAR and SLA, especially during the initial phases of the experiment.
Emirates Journal of Food and Agriculture, 2016
As a result, soil CMN had the functioning for healthy growth of the receptor plants (Barto et al., 2012). Soil aggregation, as an ecological variable, strongly affects the global climate and soil degradation, gas exchanging, and nutrient cycling (Piotrowski et al., 2004). Soil aggregate stability depends on a number of biological factors, Common mycelium networks (CMNs) of arbuscular mycorrhizas link neighbour plants and thus exhibit important roles in underground communication of substances between plants. In this study, a two-compartmented rootbox separated by 37-μm (mycelium, but not root, can pass through the size mesh) or 0.45-μm (both mycelium and root can't pass through the size mesh) mesh was used, where one compartment was inoculated with Paraglomus occultum. We confirmed whether CMNs establish between trifoliate orange seedlings and have the roles in improving both plant growth and soil properties in receptor plant (the plant inoculated without mycorrhizal fungi but infected by mycorrhizal mycelium of another inoculated plant). A CMN was formed between trifoliate orange seedlings under separation of 37-μm but not 0.45-μm mesh, resulting in a moderate root colonization of receptor plant. The mycorrhizal inoculation significantly increased leaf, stem, and root fresh weight and rhizospheric three glomalin-related soil protein (GRSP) concentrations, soil organic carbon, and mean weight diameter in the donor plant (the inoculated plant with mycorrhizal fungi). The CMN under 37-μm mesh condition had significantly positive effects on the above growth and soil properties in the receptor plant. Under 0.45-μm mesh, the AMF inoculation in donor plant considerably inhibited biomass production of receptor plant, but increased easily-extractable GRSP, total GRSP, soil organic carbon, and mean weight diameter in receptor plant. It suggested that AMF inoculation and the subsequent CMN establishment would benefit improvement of plant growth and soil aggregation and fertility in donor and receptor plant.
Plant development in a mycorrhizal field-grown mixture
Soil Biology and Biochemistry, 1991
In the field, a mycorrhiil mixture of corn and soybean was compared to non-mycorrhixal and to P-compensated plant mixtures. The extent of "N-transfer from soybean to corn was assess&. Plant development and the competitive relationship between the components of the mixtures were also examined. After having labelled selected soybean plants with isotopic NH,NO, by feeding roots induced on their stems, a greater amount of i5N-transfer to corn was measured in mycorrhixa inoculated plots than in control plots. The growth of both corn and soybean plants was greatly enhanced when inoculated with Glomur intraradix, and the effect of the fungus could not be replicated by fertilization. Inoculation and P fertilization had similar effects on P, K and Mg uptake by plants, but their effects differed regarding Ca absorption. Inoculation with the mycorrhixal fungus favoured the grass component of the mixture over the legume. Even if more N appeared to be transferred from soybean to corn when plants were mycorrhixal, the nutrient status of the plants suggests that the growth increase can be attributed mainly to a better P uptake by mycorrhizal plants, and that the significance of interspecific mycorrhixae-mediated N-transfer may be limited.
Mycologia, 1989
In six soils of varied phosphorus availability, spore germination of Glomus epigaeum was higher in non-sterile soil than in steamed soil and this was not altered by P amendment. In contrast, in all six soils without phosphorus amendment, spore germination of four other Glomus species was higher in steamed than in non-sterile soil. Amendment of phosphorus to steamed soil decreased percentage spore germination, whereas P amendment increased spore germination in non-sterile soil. To study the relationship between suppression of spore germination in non-sterile soil and subsequent plant growth response to mycorrhizal symbiosis and root colonization, plants were inoculated and grown in steamed soil, non-sterile soil, or steamed soil amended with non-sterile soil sievings. After 5 wk, seedlings were transplanted into additional soil of each treatment in all possible combinations. Exposure to the soil microftora and microfauna in the initial phase of the experiment was not deleterious to plant dry weight, but exposure after transplanting significantly reduced dry weight. However, significant reductions in root colonization by mycorrhizal fungi were imposed by both the initial and the post-transplant exposure to the soil microorganisms. Apparently, root colonization is a more sensitive measure of microbial suppression than dry weight, since relatively large changes in root colonization were necessary before dry weight was affected. Suppression of spore germination is a possible mechanism, though probably not the sole mechanism, explaining reduced plant growth and root colonization observed in non-sterile, low fertility soils.
Field Crops Research, 2012
The potential effect of indigenous and selected mycorrhizal fungal inoculation and phosphorus (P) treatment on plant growth, yield, root infection and inoculation effectiveness (IE) were tested with and without methyl bromide (MBr) for three successive years under field conditions. In 1997-1999, twelve plant species were used as host plants in a Menzilat soil series (Typic Xerofluvents) in the Mediterranean coastal region of Turkey. Compared to non-inoculated control plants, mycorrhizal inoculation increased yield in some years, but not in others. The mycorrhizal inoculum increased the root colonization of garlic, horsebean, soybean, chickpea, melon, watermelon, cucumber, maize, cotton, pepper, eggplant and tomato plants compared with the non-inoculated treatments. Compared to fumigation, plant roots grown in non-fumigated soil and successfully infected by indigenous mycorrhiza, resulted with better plant growth. Plant species belonging to the Solanaceae, Leguminosae, and Cucurbitaceae showed high responses to the mycorrhizal inoculation effectiveness under both fumigated and non-fumigated soil conditions. In general, IE was higher under low P supply than under high P supply. The effects of mycorrhizal inoculation on plant P and Zn concentrations were determined: mycorrhiza-inoculated plants had a higher nutrient content than non-inoculated plants, and this was most pronounced under fumigated soil conditions. After 3 years of field experiments, it has been concluded that for (seeded) field crops, soil and plant management systems make a great contribution to indigenous mycorrhiza to improve plant development. Whereas for horticultural plants, on the other hand, (plants transplanted into the field as seedlings), mycorrhizal inoculation makes it easy to use for large agricultural areas compared with the non-inoculated plants. It can be suggested to the farmers that arbuscular mycorrhizal fungus inoculated seedlings can be used under field conditions for high yield and quality.
Applied Soil Ecology, 2005
Arbuscular mycorrhizal (AM) fungi influence interactions among plant species through enhancing nutrient uptake and possibly facilitating nutrient transport among plants. However, the effects of one plant species on coexisting plant species with regard to mycorrhizal colonization are not well understood. We examined root mycorrhizal colonization and phosphorus (P) acquisition of plants in a highly P-limiting soil in Lanxi city, Zhejiang, China from the year 2000 to 2002. Three dominant native plant species with different mycorrhizal properties, Digitaria ciliaris (poorly mycorrhizal species), Ixeris denticulate (moderately mycorrhizal species) and Kummerowia striata (highly mycorrhizal species), were planted in experimental plots. In the monocultures, K. striata was found to have the highest infection and D. ciliaris the lowest mycorrhizal infection, but shoot P-concentration was higher in both I. denticulate and D. ciliaris than that in K. striata. In the mixtures, D. ciliaris and I. denticulate did not significantly affect the mycorrhizal colonization, spore production and shoot P-concentration of K. striata plants, but K. striata and I. denticulate significantly increased root mycorrhizal colonization and shoot P-concentration of D. ciliaris. K. striata enhanced but D. ciliaris reduced mycorrhizal infection and shoot P-concentration of I. denticulate. These results suggested that highly mycorrhizal plant species may positively impact coexisting species with respect to mycorrhizal colonization and P acquisition, but the effects on poorly mycorrhizal species are less predictable. #