Vesicular-arbuscular Mycorrhizal Infection Research Articles

Influences of mycorrhizal inoculum on Cd and Pb uptake by wheat plant

Influences of mycorrhizal inoculum on Cd and Pb uptake by wheat plant

Development and Activity of Vesicular–Arbuscular Mycorrhizal Infection of Trifolium pratense L. in the Course of a Meadow Phytocoenosis Succession

This paper describes symbiotic relationships at various succession stages of a meadow phytocoenosis using the example of vesicular–arbuscular mycorrhiza of Trifolium pratense L. It is established that the functional potential of symbiotic relationships changes in the course of the succession, and it is fully realized in undisturbed climax communities. It is shown that discriminant analysis of biometric parameters of a single leguminous plant performed taking into account its symbiotic potential can be used for biological diagnostics of the phytocoenosis state (i.e., succession stage).

Effects of fertilizers and vesicular–arbuscular mycorrhizas on the growth and photosynthesis of Azadirachta excelsa (Jack) Jacobs seedlings

Azadirachta excelsa (Jack) Jacobs is a fast growing indigenous species being promoted as a plantation species in Malaysia. However, the low fertility of most native soils is a primary constraint for good establishment of this species. The effects of fertilizer and vesicular–arbuscular mycorrhizal infection on growth and rate of photosynthesis in A. excelsa seedlings were assessed in a pot experiment. The mycorrhizal inoculated plants (without fertilizer) grew more slowly than control (uninoculated without fertilizer) seedlings, despite the higher percentage of infection. These results suggest that introduced mycorrhizal inoculum was not effective enough to improve seedling growth. Mycorrhizal development was depressed under high levels of fertilizer application. Fertilizer had the strongest effect on growth, biomass and photosynthetic rate, and leaf nutrient concentrations of A. excelsa seedlings. Plants supplied with slow release fertilizer (20N–10P 2O 5–5K 2O) alone gave the most vigorous growth and higher rates of photosynthesis among the fertilizer treatments. These results demonstrate the potential of using slow release fertilizer in promoting seedling growth.

Vesicular-arbuscular mycorrhizal infection of Quercus rubra seedlings.

• The influence of vesicular-arbuscular mycorrhizal (VAM) host plants is reported on VAM infection of Quercus rubra seedlings, a predominately ectomycorrhizal species. • In a field experiment, Q. rubra seedlings were planted near Quercus montana and Acer rubrum (a VAM host) stump sprouts and near dead Quercus spp. stumps. In a subsequent glasshouse study, seedlings of Q. rubra were grown with or without VAM inoculum (±V) and with or without Sorghum bicolor (±S), a VAM host. • In the field experiment, seedlings planted near A. rubrum had greater VAM infection than other seedlings; ectomycorrhizal infection was greatest on seedlings near Q. montana. In the glasshouse experiment, VAM infection was increased in both extent (proportion of root length infected in roots of infected seedlings) and frequency (number of seedlings with infection) in the presence of S. bicolor. Seedling mass and N concentration were reduced in the+V treatment; however, these variables were not correlated with extent of VAM infection. • VAM infection of Q. rubra is greatly enhanced in the presence of VAM hosts in both field and glasshouse conditions. No evidence for positive effects of VAM infection on Q. rubra seedlings was found.

Effect of Citrus Juice Pomace Extracts on in vitro Hyphal Growth of Vesicular-Arbuscular Mycorrhizal Fungi and their in vivo Infections of Citrus Roots.

The effect of citrus juice pomace extracts on in vitro hyphal growth of vesicular-arbuscular mycorrhizal (VAM) fungi and the mycorrhizal formation on trifoliate orange (Poncirus trifoliata Raf.) seedlings and Citrus iyo Tanaka trees was investigated. One hundred μl [equivalent to 6.5 g dry weight (DW) of satsuma mandarin (Citrus unshiu Marc.) and 4.3 gDW of Citrus hassaku Tanaka] of the 25% MeOH eluates of citrus juice pomace extracts significantly increased in vitro hyphal growth of Gigaspora ramisporophora Spain, but a 100% MeOH eluates inhibited it. In a plot where the solution consisting of 25% MeOH eluates of satsuma mandarin juice pomace extracts (equivalent to 10 gDW) and liquid fertilizers was applied to the soil inoculated with the spores of Gigaspora ramisporophora, the percentage of VAM infection in trifoliate orange roots was six times higher than that in the control (water only) after one week. When the above mixed solution was administered to a Citrus iyo orchard via a sprinkler irrigation system, VAM development was markedly stimulated as compared to the untreated plots (liquid fertilizer only) and the control (solid fertilizer only). These results show that 25% MeOH eluates of citrus juice pomace extracts contain stimulatory substances for VAM fungi. Furthermore, the application of the 25% MeOH eluates to the soil is very effective in stimulating VAM development.

Effect of a vesicular-arbuscular mycorrhizal fungus ( Glomus epigaeus ) on herbicide uptake by roots

Vesicular-arbuscular mycorrhizal (VAM) fungi increase root uptake of P and other minerals, but their role in the uptake of herbicides has received far less attention. These experiments were conducted to determine the effect of the VAM fungus, Glomus epigaeus (Daniels and Trappe), on the absorption of atrazine and trifluralin by roots of corn and soybean. Atrazine uptake by excised corn-root segments was consistently increased by the VAM fungus, but VAM enhancement of atrazine uptake by soybeans was less than that observed for corn. Roots from corn grown for 8 weeks in the greenhouse prior to the experiment took up 25 pmol mm–3 root, whereas non-mycorrhizal roots took up only 11 pmol mm–3 root. Soybean and corn root uptake of trifluralin was also enhanced by VAM infection. Addition of P did not increase herbicide uptake by non-VAM plants. The direct role of VAM hyphae on atrazine uptake was demonstrated using a two-chamber system, where only the fungal hyphae had access to 14C-atrazine-treated soil. Hyphal systems of the fungus were able to remove and transfer 14C-atrazine residues from soil to corn plants, demonstrating direct uptake of the herbicide by the fungal hyphae.

海藻抽出物がＶＡ菌根菌の菌糸生長ならびにカラタチ樹の菌根形成に及ぼす影響

海藻抽出物がVAM菌の菌糸生長やカラタチ実生苗のVAM形成に及ぼす影響を, Gigaspora ramisporophora SpainというVAM菌を用いて調査を行った.海藻抽出物として, コンブおよびワカメから75%MeOHを用いて抽出したもの(粗抽出物)とともに, これらの粗抽出物からODSカラム使用のフラッシュクロマトグラフィーによって得られた0, 10, 25, 50および100%MeOH溶出物を本実験に供試した.この結果, コンブおよびワカメの粗抽出物処理区におけるVAM菌の菌糸生長は対照(水)区と比較して差異がみられなかったが, コンブの25%MeOH溶出物(0.1および0.3gDW相当量)と50%MeOH溶出物(0.3gDW相当量), ならびにワカメの10%MeOH溶出物(0.3gDW相当量)と25%MeOH溶出物(0.1および0.3gDW相当量)処理区では有意な生長促進効果が認められた.特に, コンブ, ワカメともに, 25%MeOH溶出物(0.3gDW相当量)処理区での促進効果は顕著であった.一方, 土壌へのコンブおよびワカメの粗抽出物ならびに25%MeOH溶出物の処理によって, カラタチ実生苗の菌根感染率は対照区と比べて良好となる傾向が認められた.特にコンブ, ワカメともに, 25%MeOH溶出物(1.0gDW相当量)処理区におけるVAM形成は顕著であった.これらの結果から, コンブおよびワカメ抽出物, 特に25%MeOH溶出物にはVAM菌生長促進物質が存在しており, これがカラタチ根における菌根形成を良好にさせたものと考えられる.

Effects of vesicular arbuscular mycorrhizal inoculation on growth and phosphorus nutrition of barley in natural or methyl bromide‐treated soil

The growth and phosphorus (P) nutrition of barley (Hordeum vulgare L.) in a soil, methyl bromide fumigated or untreated and supplied with or without mycorrhizal inoculum, was studied in pots placed under a field environment. Inoculation significantly raised the overall levels of vesicular arbuscular mycorrhizal (VAM) infection. The relative increase was significantly greater in sterile than nonsterile soil. Soil sterilization produced significantly higher dry matter throughout the experiment. Inoculation resulted in a significant growth depression earlier in the season which could not be offset by the following mycorrhizal enhancement in P absorption rates. The primary reasons for this yield depression were most probably the root density and available P status of the soil which might have been over the threshold limit for positive mycorrhizal yield response in barley. In this experiment, the result of inoculation could be regarded beneficial considering 17 and 30% higher P concentrations in grain and straw, respectively, but detrimental with respect to 20% loss in grain plus straw yield.

Observation of Vesicular-Arbuscular Mycorrhizal Formation in the Roots of Some Seasonal Weeds Proliferated in Citrus Orchards.

Weeds were collected from citrus orchards in April and July to investigate vesicular-arbuscular mycorrhizal (VAM) infection. The infection was found to be high in the roots of spring weeds : Rumex acetosa L., Agropyron tsukuhiense (Honda) Ohwi var. transiens (Hack.) Ohwi, Stellaria media Villars., Vicia cracca L., Lamium amplexicaule L., and Medicago polymorpha L., and in the roots of summer weeds : Erigeron canadensis L., Amaranthus lividus L., Cynodon dactylon (L.) Pers., Beckmannia syzigachne (Steud.) Fern., Commelina communis L., Oxalis corniculata L., and Digitaria adscendens Henr. Spore formation was mostly found in the roots of spring weed : Stellaria media, Vicia cracca, and Lamium amplexicaule ; no VAM infection was observed in the roots of Rumex japonicus Houtt., Equisetum arvense L., and Polygonum blumei Meisn.

Nodulation and growth of mycorrhizal Casuarina equisetifolia J.R. and G. First in response to flooding

The influence of vesicular-arbuscular mycorrhizal (VAM) inoculation on nodulation and growth of flooded Casuarina equisetifolia J.R. and G. First was investigated. Casuarina seedlings were grown in sterile soil inoculated with Glomus clarum Nicolson and Schenick and flooding was imposed for 8 weeks. Mycorrhizal Casuarina seedlings adapted to flooding better than non-inoculated seedlings. This was achieved partly by the greater development of adventitious roots and hypertrophied lenticels which increased oxygen availability, and therefore VAM infection in the upper soil zone. The VAM infection led to the suppression of the accumulation of toxic products of anaerobic respiration, such as ethanol. Mycorrhizal inoculation also prevented the total suppression of nodulation in the flooded plants. Nodulation was observed only in the upper soil zone, and its occurrence made dinitrogen fixation possible. The results suggest that mycorrhizal infection is essential for nodulation of Casuarina in flooded soils and is therefore related to the relatively higher dinitrogen accumulation in Casuarina under anoxic conditions.

Analysis of vesicular-arbuscular mycorrhizal colonization data with a logistic regression model

Vesicular-arbuscular mycorrhizal (VAM) infection is usually expressed as percentage of root length colonized. The frequency distributions of the data are often non-normal and may follow a negative binomial distribution. Data transformation, such as an arcsin of percentage colonization, may be used to help colonization data satisfy the normal distribution assumption, but is not always successful. In this paper, we compare ANOVA and logistic regression model (LRM) analysis of data on the effect of phosphorus fertilization and corn cultivar on VAM colonization. Transformed data did not fit a normal distribution, and we propose the LRM as a better model for statistical analysis of VAM colonization. The LRM is more accurate because (1) this model assumes a binomial distribution, (2) it incorporates the original sample size into the probability estimation, and (3) the model uses non-transformed data, which are easier to interpret.

Acidification effects on vesicular-arbuscular mycorrhizal (VAM) infection, growth and nutrient uptake of established heathland herb species

A greenhouse experiment was carried out to determine whether the decline of Arnica montana L. in heathland vegetation in the Netherlands could be caused by a detrimental effect of soil acidification on vesicular-arbuscular mycorrhiza of this species. Arnica montana and two non-declining species from the same habitat, Hieracium pilosella L. and Deschampsia flexuosa (L.) Trin., were grown with and without the vesicular-arbuscular mycorrhizal (VAM) fungus Glomus fasciculatum (Thaxter sensu Gerdemann) Gerd. and Trappe in pots with an extremely nutrient-poor, sandy soil. They were percolated weekly with nutrient solution with different pH values, viz. 5.5, 4.5, 3.5 and 2.5. At intervals of three weeks and up to 12 weeks, measurements were made on growth, nutrient uptake and VAM infection.

Relative effectiveness of phosphorus on narrow‐leaf and broadleaf birdsfoot trefoil growth and the effect of added phosphorus on vesicular arbuscular mycorrhizal infection

Abstract The relative effectiveness of phosphorus (P) applications on growth and the effect of added P on the extent of infection of roots of narrowleaf birsfoot trefoil (Lotus tenuis) and of broadleaf birdsfoot trefoil (Lotus corniculatus) by an indigenous VAM fungi (Glomus sp.) was studied on a P‐deficient soil (Typic Natraquoll). In terms of rate of increase of shoot growth per unit of added P, broadleaf was more efficient than narrowleaf birsdfoot trefoil but they did not differ in the relative effectiveness of P for growth. For the two Lotus species, when increasing the level of added P there was an initial increase in the percentage of root length infected, and then with further additions, there was a consistent decrease of the infection. For narrowleaf, the maximum percentage of root length infected was when plants reached 11% of their maximum shoot growth. Whereas for broafleaf, the maximum percentage of root infected was when plants reached the 66% of their maximum shoot growth. Despite differences in both, the shape of the response curve of shoot growth to P and the extent of infection between Lotus species, they did not differ in their ability to utilize the P that had reacted with the soil for a period of time.

Effect of phosphorus source and rate of application on VAM fungal infection and growth of maize (Zea mays L.)

The effects of two phosphorus (P) sources (triple superphosphate and Ghafsa phosphate rock), applied at rates equivalent to 44kg ha-1 and 22 kg ha-1, on vesicular-arbuscular mycorrhizal (VAM) fungal infection in roots, dry matter yield and nutrient content of maize grown in an oxisol and an alfisol, were investigated in a growth cabinet. The application of 44 kg P ha -1 resulted in root infection by VAM fungi not was significantly different (P<-0.01) from when no P was applied. Root infection was significantly greater when P was applied as triple superphosphate at the rate of 22 kg ha-1 the higher rate. Phosphate rock treatments at both rates of application resulted in significantly greater root infection than in controls with no P or when triple superphosphate was applied at 44 kg ha-1. Plant P uptake increased in all soils with the different P treatments compared with the control. No direct effects of the treatments on the aluminium and zinc contents of maize plants were observed. In the gleyic alfisol, reduced Mn uptake as a result of increased infection of plants with the superphosphate treatments was observed. Higher Mn was also found in plants with the higher rate of superphosphate treatment than with the phosphate rock treatments in the haplustox, although infection rates in plants with the latter treatments were higher. With the exception of plants with the phosphate rock treatment applied at 22kg ha-1, dry matter yields of plants with all P sources were significantly greater than the controls.

Influence of bacteria on vesicular-arbuscular mycorrhizal infection of maize

Bacterial isolates of different capabilities influenced the development of vesicular-arbuscular mycorrhizal infection in the roots of maize cultivated in a hydroponic system. The introduced bacteria influenced different parameters of infection and the effect was specific for the bacterial isolate used. Two phosphate solubilizers and a bacterial chitin decomposing isolate increased the abundance of arbuscules in the root cortex.

Influence of phosphorus nutrition and vesicular–arbuscular mycorrhizal fungi on growth and yield of greenhouse cucumber (Cucumis sativus L.)

This study determined whether beneficial effects obtained with infection by vesicular–arbuscular mycorrhizal (VAM) fungi during early growth of cucumber are maintained through to maturity. Greenhouse cucumbers (Cucumis sativus L. 'Corona' and 'Carmen') were grown in VAM-inoculated (Glomus intraradices Schenck &amp; Smith) or noninoculated autclaved sandy soil with supplemental phosphorus (P) ranging from 90 to 720 mg P plant−1 wk−1. These P treatments resulted in leaf P levels that spanned the range from deficient to sufficient, based on published data for mature cucumber plants. Leaf and mainstem development, number of fruit per plant, and harvest index were enhanced by increasing P levels in all studies. Low levels of P nutrition resulted in deficiency symptoms that were well correlated with deficient concentrations of leaf P. Mature plants maintained a relatively high level of infection by G. intraradices at low and moderate levels of P nutrition; however, depending on the cultivar, VAM infection either had no effect, or slightly depressed leaf and stem growth. The VAM infection stimulated earlier flowering and fruit production, but a longer fruit abortion period precluded increases in final fruit yield. The reduced shoot development and longer interval of fruit abortion characteristic for VAM-infected plants may be due to increased stress imposed by the collective sink requirements of the fungus and developing fruit. Key words:Cucumis sativus L., growth, phosphorus, vesicular-arbuscular mycorrhizal fungi, yield

Effect of phosphorus application on the contents of amino acids and reducing sugars in the rhizosphere and VA mycorrhizal infection of white clover

Abstract Vesicular-arbuscular (VA) mycorrhizae accelerate the phosphorus (P) uptake and growth of plants especially in soils with low phosphorus content (Gerdemann 1968; Mosse 1973). Application of phosphate fertilizer to soil, on the contrary, decreases the percentage of infection of roots with VA mycorrhizal fungi (Daft and Nicolson 1966; Mosse and Bowen 1968; Hayman et al. 1975) and inhibit the ameliorating effect on plant growth (Porter et al. 1978; Thomson et al. 1986). The decrease in the percentage of infection with increasing phosphorus concentration may be due to a reduction of fungal growth in soil, inhibition of penetration to roots, and fungal growth within roots. There is little information about the inhibition of mycorrhizal infection at high phosphorus level and also about the compounds which are required for the growth of hyphae.

Effect of vesicular-arbuscular mycorrhizal infection on amino acid composition in roots of onion and white clover

Abstract Vesicular-arbuscular (V A) mycorrhizal infection refers to symbiotic associations between vascular plants and fungi belonging to the order Glomales. The fungi absorb phosphorus from the soil solution and supply it to host cells via arbuscules. In return, the host plant provides its photosynthates as a source of carbohydrates to the fungi (Smith and Gianinazzi-Pearson 1988; Smith and Smith 1990; Saito et al. 1992). However the physiological mechanisms involved in the exchange of nutrients and photosynthates have not been well defined (Smith and Gianinazzi-Pearson 1988; Schwab et al. 1991).

Humid tropical leguminous tree and pasture grass responsiveness to vesicular-arbuscular mycorrhizal infection

Humid tropical leguminous tree and pasture grass responsiveness to vesicular-arbuscular mycorrhizal infection

Humid tropical leguminous tree and pasture grass responsiveness to vesicular-arbuscular mycorrhizal infection

Phosphorus is the major nutrient limiting plant growth in a Costa Rican silvopastoral system located on an acid, high P-retaining, volcanic soil. We investigated plant responsiveness to vesicular-arbuscular mycorrhizal (VAM) inoculation using the leguminous tree species Erythrina berteroana Urban, and the two dominant grass species Paspalum conjugatum Berg and Homolepsis aturensis Chase of this silvopastoral system. We grew grass seedlings in the greenhouse for 15 weeks in a methyl bromide-sterilized study soil to which either mixed-species VAM inoculum (Theobroma cacao feeder roots) or autoclave-sterilized cacao roots (non-inoculated control) were added. E. berteroana was grown from both seedlings and vegetative stakes (40 cm long) for 30 and 19 weeks, respectively. Upon harvest, we measured above and below ground biomass, N and P content, root∶shoot ratio, legume nodulation, and VAM infection levels. The total above-ground and root biomass of mycorrhizae-inoculated P. conjugatum seedlings were 2.5 and 2.8 times greater than those of noninoculated seedlings. In contrast, VAM-inoculated seedlings of H. aturensis produced 8.4 and 5.9 times more total above-ground and root mass than noninoculated seedlings. Mycorrhizae-inoculated E. berteroana seedlings produced 10.6 times greater shoot biomass for inoculated versus noninoculated seedlings, while E. berteroana vegetative stakes exhibited a negative growth response to VAM inoculation (an approximately 16% decrease in shoot biomass for VAM-inoculated cuttings). The difference in responsiveness between Erythrina growth forms is hypothesized to reflect the cost-benefit relationship between plant host and fungal symbiont for energy and nutrient reserves.