Functional aspects of root architecture and mycorrhizal inoculation with respect to nutrient uptake capacity (original) (raw)
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The Mechanisms of Nutrient Uptake by Arbuscular Mycorrhizae
Mycorrhiza - Nutrient Uptake, Biocontrol, Ecorestoration, 2017
Mycorrhizal fungi are one of the commonly occurring living organism in soil facilitating plants in growth, development, stress tolerance, soil pollutants remediation, C-sequestration, food security and agricultural sustainability. Mycorrhizal fungi assist the plants in nutrient absorption by extending mycorrhizal hyphae network beyond the rhizosphere. Mycorrhizal inoculation alters the root architecture and studies showed that nutrient absorption capacity of inoculated root is much better than non-inoculated. For a long time, it is assumed that roots absorb nutrients only through direct pathway (DP) only while contribution of AM fungi in nutrients uptake by mycorrhizal pathway (MP) has been ignored. But now the development in scientific methods and tools, enabled the researcher to explore MP mechanism for macro and micro nutrients, moreover suppression of heavy metal stress to the plants. Besides that, mycorrhizal fungi obtain around 20% of photosynthesized C from the plant in exchange of nutrients. Moreover, this C triggers nutrient uptake and their translocation. Plant hormones and root exudates also influence the infection formation and development, they also point out new sites for the interaction of mycorrhizal fungi and plant roots. Nutrient mobility by MP is more secure and economical than DP. Understanding about the nutrient exploration, mobilization, and uptake in root-mycorrhizal interaction has been discussed here at molecular level. Contribution of plant and mycorrhizal transporters have been discussed which need further understanding. Also contribution of mycorrhizal inoculation on nutrient uptake compared with non-inoculated roots were discussed.
2006
This study aimed to investigate mycorrhizal colonisation on plant growth and nutrient acquisitions on three crop species, i.e, soybean (Glycine max (L.) Merr cv. Willis), upland rice (Oryza sativa cv. Cirata), and maize (Zea mays cv. Marshall). These crops were inoculated with arbuscular mycorrhiza fungi (AMF) Glomus mosseae BEG 107 grown in a Luvisol (Calcareous soil, pH 7.3 in CaCl2) under glasshouse conditions. Inoculated plants became mycorrhizal while control plants remained non-mycorrhizal. The AM colonisation rates were as high as 60%, 40%, 70% of the total root length, respectively, in soybean, upland rice, and maize. Mycorrhizal crop growth increased 7.5-folds, 4.5-folds, and 5.0-folds relative to non-mycorrhizal crop, respectively, in soybean, upland rice, and maize. Related to nutrient uptake, mycorrhizal colonisation increased P concentrations in shoot 1.6- folds, 3.2-folds, and 1.6-folds; and in root 1.9-folds, 1.9-folds, and 2.6-folds, respectively, in soybean, upland ...
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.
Tree Physiology, 2001
Effects of nitrogen (N) source and concentration on root system architecture and receptivity to mycorrhizal infection were studied in seedlings of Atlas cedar (Cedrus atlantica Manetti) grown in root observation boxes in a controlled-environment chamber. Nitrogen was supplied in a solution containing either NO 3 − or NH 4 + at a concentration of either 0.25 or 5.0 mM. Root extension was recorded twice weekly by tracing the roots growing in contact with the transparent face of the root observation box. Among treatments, lateral root production and branching density were greatest with 5.0 mM NO 3 − . Inoculation with mycelium of Tricholoma cedrorum Malençon was carried out 3 months after the start of the N treatments. The highest percentage of mycorrhizal roots, and the greatest amounts of living mycelium (estimated by the ergosterol assay) were observed in the NO 3 − treatments. Differences in root branching density among the N treatments were insufficient to explain the observed differences among treatments in the extent of mycorrhizal infection of seedlings.
Plant and Soil, 2004
The double compartment technique has been commonly used in studies on nutrient uptake by mycorrhizas whereas the double pot technique has been used to assess the nutritional stress of plants grown in different soils. A combination of the double pot and the double compartment technique was used as a tool to understand the processes involving mycorrhiza and plant nutrition. Maize (Zea mays) and three species of the arbuscular mycorrhizal fungi in the genus Glomus were used to study phosphorus (P) uptake with and without mycorrhiza from the A and B horizons of an Oxisol. The plants were supplied from the lower pot with a nutrient solution without P. The upper pot had a double compartment with either a fine and coarse mesh screen to control the volume of soil explored by the roots, and thereby, limit the amount of soil P accessible to plants from the test soil. There were significant effects of time for plants grown in both soil horizons, and of mycorrhizas for plants grown in the A soil horizon. No effect of mesh size was observed. There were significant effects of horizon and mycorrhiza, but not of mesh size, on the dry weight and P contents of shoots and roots. The P concentration (P g kg −1 of plant) for shoots and roots was similar in the A and B soil horizons. The results showed that the double pot -double compartment system was suitable for the experimental objectives. No differences in plant growth were observed when root growth was not limited vs root growth limited to the inner compartment because the non-mycorrhizal plants did not take up P. Consequently, responsiveness of the maize cultivar was wholly dependent on mycorrhiza for P uptake under these experimental conditions.
Plant and Soil, 2012
Background and aims Roots and mycorrhizas play an important role in not only plant nutrient acquisition, but also ecosystem nutrient cycling. Methods A field experiment was undertaken in which the role of arbuscular mycorrhizas (AM) in the growth and nutrient acquisition of tomato plants was investigated. A mycorrhiza defective mutant of tomato (Solanum lycopersicum L.) (named rmc) and its mycorrhizal wild type progenitor (named 76R) were used to control for the formation of AM. The role of roots and AM in soil N cycling was studied by injecting a 15 N-labelled nitrate solution into surface soil at different distances from the 76R and rmc genotypes of tomato, or in plant free soil. The impacts of mycorrhizal and nonmycorrhizal root systems on soil greenhouse gas (CO 2 and 14+15 N 2 O and 15 N 2 O) emissions, relative to root free soils, were also studied. Results The formation of AM significantly enhanced plant growth and nutrient acquisition, including interception of recently applied NO 3 −. Whereas roots caused a small but significant decrease in 15 N 2 O emissions from soils at 23 h after labeling, compared to the root-free treatment, arbuscular mycorrhizal fungi (AMF) had little effect on N 2 O emissions. In contrast soil CO 2 emissions were higher in plots containing mycorrhizal root systems, where root biomass was also greater. Conclusions Taken together, these data indicate that roots and AMF have an important role to play in plant nutrient acquisition and ecosystem N cycling.
Plant and Soil, 2011
To investigate whether arbuscular mycorrhizal fungi (AMF)abundant in a phosphatepolluted but nitrogen-poor field siteimprove plant N nutrition, we carried out a two-factorial experiment, including N fertilization and fungicide treatment. Percentage of root length colonized (% RLC) by AMF and tissue element concentrations were determined for four resident plant species. Furthermore, soil nutrient levels and N effects on aboveground biomass of individual species were measured. Nitrogen fertilization lowered % RLC by AMF of Artemisia vulgaris L., Poa compressa L., but not of Bromus japonicus Thunb. Thistogether with positive N addition effects on N status, N:P-ratio and aboveground biomass of most speciessuggested that plants are mycorrhizal because of N deficiency. Fungicide treatment, which reduced % RLC in all species, resulted in lower N concentrations in A. vulgaris and P. hieracioides, a higher N concentration in P. compressa, and did not consistently affect N status of B. japonicus. Evidently, AMF had an influence on the N nutrition of plants in this P-rich soil; howeverpotentially due to differences in their mycorrhizal responsivenessnot all species seemed to benefit from a mycorrhiza-mediated N uptake and accordingly, N distribution.
Arbuscular mycorrhiza enhances nutrient uptake in chickpea
Plant, Soil and Environment, 2011
Arbuscular mycorrhiza fungi (AMF) colonize roots of host plants and promote plant growth due to improved uptake of nutrients. While the effects on P uptake are well known, the relevance of AMF for the uptake of other nutrients is less investigated. In the present paper we studied contents of N, P, K, Ca, Mg, Fe, Mn, Cu, and Zn in the legume chickpea in pot experiments during two seasons. Beside the control, the following treatment combinations: (i) the inoculation with the commercial AMF product ‘Symbivit®’; (ii) soil sterilization before inoculation, and (iii) mineral nitrogen application. A moderate level of AMF colonization (18–55% of roots), enhanced the nutrient uptake of chickpea. With P, Mn, and in 2006 also with K, Cu, and Fe the nutrient concentrations were also elevated, even along with a simultaneous increase in plant biomass. Soil sterilization or fertilization with N showed no significant effect on nutrient uptake and biomass production.
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.
Effect of mycorrhizal inoculation on citrus seedling growth and nutrient uptake
Acta Horticulturae, 2019
Many soils are deficient in available nutrients, especially phosphorus (P), and therefore require considerable fertilizer application in order to obtain optimum plant growth. However, as citrus is strongly mycorrhizal dependent it is important to use an inoculum for enhanced and healthy seedling growth; in addition, mycorrhiza can reduce the requirement of applied P fertilizers. In order to use the optimum P fertilizer level for mycorrhizal inoculation, research on P fertilizer concentrations is still required; hence, the aim of this work was to determine the role of mycorrhizal inoculation on citrus seedling growth at different P concentrations. Sterilized Menzilat series soil was treated with 0, 50, 100, 200 and 400 mg P2O5 per kg soil. Fertilizer and sterilized soil were placed into 3.5 kg pots. Experiments were conducted over a period of five months, and plant height, shoot diameter, shoot and root dry matter, mycorrhizal colonization, and tissue P and Zn concentration were determined. Plant growth and nutrient uptake in mycorrhizae-inoculated plants was significantly increased. As citrus seedlings are mycorrhizal dependent, under sterile and low fertile conditions plant growth was stunted and seedlings did not grow properly. Seedling length, stem diameter and percentages of root inoculation were investigated, along with mycorrhizal dependency. Seedlings inoculated with mycorrhiza were shown to be strongly mycorrhizal dependent. The mycorrhizal inoculum potential of the soil can influence plant root growth, which primarily depends on suitable mycorrhizal partners.