Hawkins, HJ; George, E. 1997. Hydroponic culture of the mycorrhizal fungus Glomus mosseae with Linum usitatissimum L., orghum bicolor L. and Triticum aestivum L. Plant Soil 196: 143-149.

Address:

E George; UNIV HOHENHEIM; INST PLANT NUTR 330; STUTTGART; GERMANY; D-70593 BC

Linum usitatissimum, Sorghum bicolor and Triticum aestivum plants were further colonised by the arbuscular mycorrhizal fungus, Glomus mosseae, during a four week period of hydroponic culture after a pre-culture period of three weeks with the fungus in perlite substrate. The viability of mycorrhizal colonisation of T. aestivum was indicated by an initial experiment where G. mosseae from mycorrhizal plants colonised non-mycorrhizal plants when the plants were grown together in the same hydroponic container using modified Long Ashton nutrient solution. Intermittant aeration of the plant roots (2 h periods, four times per day) provided a compromise between adequate aeration and minimal disturbance of the fungus. In a second experiment, two nutrient media, modified Long Ashton and modified Knop plus Hoagland medium were compared for culturing G. mosseae on T. aestivum. A significantly higher root dry weight was found for the mycorrhizal versus the non-mycorrhizal wheat plants in modified Long Ashton nutrient medium, which contained 10 mu M P and an organic buffer. Modified Knop plus Hoagland nutrient medium contained a high P concentration (0.9 mM) and did not produce viable cultures of mycorrhizal colonisation. In a third experiment, modified Long Ashton medium was used for hydroponic culture of mycorrhizal L. usitatissimum, S. bicolor and T. aestivum. The root colonisation percentages for T. aestivum (73%), S. bicolor (36%) and L. usitatissimum (65%) were within the range of colonisation rates obtained with solid substrate culture in perlite. Viability of the mycorrhizal structures in hydroponic culture was assessed by monitoring activity of fungal succinate dehydrogenase and found to be similar to cultures in perlite. No difference in the P concentration of mycorrhizal and non-mycorrhizal plants was observed, possibly owing to the lack of diffusion limits for P in hydroponic solution. This report describes a system for the viable culture of G. mosseae with different plant species where a high mycorrhizal colonisation rate was produced under conditions of a short culture period using intermittent aeration, a low concentration of P supply and an organic buffer.

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VEJSADOVA H; CATSKA V; HRSELOVA H; GRYNDLER M . 1993. INFLUENCE OF BACTERIA ON GROWTH AND PHOSPHORUS-NUTRITION OF MYCORRHIZAL CORN . JOURNAL OF PLANT NUTRITION . 16 (9):1857-1866 .

Address:

VEJSADOVA H, CZECHOSLOVAK ACAD SCI,INST MICROBIOL,VIDENSKA 1083,CS-14220 PRAGUE 4,CZECHOSLOVAKIA

Corn plants were grown in a non-sterile soil in a greenhouse or in hydroponic culture in a growth chamber. We studied the influence of chitinolytic, pectinolytic, P-solubilizing bacterial isolates, and a collection of bacterial strains on the development of native vesicular-arbuscular mycorrhizal (VAM) populations, colonization of roots by the VAM fungus Glomus fasciculatum and their influence on the phosphorus (P) nutrition and growth of plants. As compared with VAM native control, the most potent stimulants for root colonization of soil-grown plants by the VAM native population was a strain of Agrobacterium radiobacter and isolate H30. All bacteria used significantly supressed shoot fresh weight of mycorrhizal plants (-13% up to -37%), with the exception of Agrobacterium. Under hydroponic conditions, the P-solubilizing isolate F27 significantly stimulated the intensity of mycorrhiza, the number of arbuscules in roots, and increased both the P concentration and P content in corn shoots (+30% and +35%), than did the VAM fungus alone. Isolate F27 significantly increased shoot dry weight as compared with the mycorrhizal control. The other bacteria did not influence biomass production of corn.

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GRYNDLER M; LIPAVSKY J. 1995. EFFECT OF PHOSPHATE FERTILIZATION ON THE POPULATIONS OF ARBUSCULAR MYCORRHIZAL FUNGI. ROSTLINNA VYROBA 41(11) 533-540.

Address:

GRYNDLER M, ACAD SCI CZECH REPUBL,INST MICROBIOL,VIDENSKA 1083,CR-14220 PRAGUE 4,CZECH REPUBLIC

The tolerance of four populations of arbuscular mycorrhizal fungi to the increased long-term phosphate fertilization was studied in hydroponic experiment with four levels of phosphate and maize as a host. The levels of mycorrhizal infection indicators (frequency of infection, intensity of infection and arbuscule abundance in the infected root) decreased with increased concentration of phosphate in nutrient solution. The intensity of infection was slightly lower in treatments inoculated with the soil overfertilized with phosphate for 10 years. The interaction between field fertilization and concentration of phosphate in the nutrient solution as sources of variability was not found, indicating the equal tolerance of populations from phosphate fertilized and unfertilized soil to phosphorus. Parallel cultivation of fungal populations in soil under two nutritional regimes, using leek as a host, showed the significant influence of long term phosphate overfertilization to the species composition of populations.

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Interaction of arbuscular mycorrhizal fungi (AMF) with heavy metals:

Fungal isolates indigenous and non-indigenous in contaminated soils.

  M. Vosátka, R. Malcová, M. Žilová, J. Rydlová
Institute of Botany, Academy of Sciences, Pruhonice, Czech Republic

A series of experiments was conducted to study the adaptation abilities of AMF to elevated concentrations of heavy metals (HM). Indigenous AMF isolates from soils contaminated with Mn or Pb were compared with the same species from unpolluted soils to determine their tolerance to HM. Results suggest differences in HM-tolerance between indigenous and non-indigenous AMF isolates. Nevertheless, some non-indigenous isolates were found to have a high resistance to HM pointing out to a high adaptability to HM. Two linia of each AMF isolate were maintained for 2-3 years either in inert media or in original soil. Process of losing the tolerance to HM when cultivated in inert media was compared to gaining HM-tolerance of non-indigenous strains when exposed to HM-stress. Indigenous isolates of Glomus intraradices and G. fistulosum from Mn-contaminated soil showed higher sporulation in original soil in comparison with non-indigenous isolates of the same species. Better development of indigenous G. intraradices compared with non-indigenous one was also found in hydroponic experiment where Mn was supplied. While indigenous isolate maintained in original soil survived elevated Mn concentration, the isolate maintained in inert substrate was suppressed. Similarly, indigenous G. intraradices showed better performance as compared to non-indigenous one in Pb-contaminated soil, but no difference was observed between the two linia. These linia represent unique material for ecophysiological comparison, however, the studies should be supported by use of biochemical and molecular techniques to find out principles of changed HM-tolerance.

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Respiratory metabolism of rhizosphere dissolved inorganic carbon in arbuscular mycorrhizal roots under P starvation

  A. J. Valentine and M. D. Cramer
Department of Botany, University of Stellenbosch, South Africa

  Inorganic C in the soil exists not only as gaseous CO₂ but also as a pH dependent combination of dissolved CO₂ (i.e. H₂CO₃), HCO₃^– and CO₃^2-, collectively referred to as dissolved inorganic C (DIC). Rhizosphere DIC concentrations play a vital role in root respiratory C metabolism. During P stress, a suite of respiratory bypass reactions are initiated, which includes a glycolytic step that favours DIC incorporation and the engagement of an alternative pathway of mitochondrial electron transport. The influence of AM colonization on DIC utilisation was studied in terms of P supply. Root respiration and DIC metabolism were measured in six week old P-sufficient (2 mM) and P-stressed (2 mM) arbuscular mycorrhizal (AM) tomato plants, grown in hydroponic culture. The roots were supplied with elevated root zone DIC, by aerating the nutrient solution with 5000 ppm co₂. During P stress, AM roots had higher DIC incorporation than non-AM roots, while roots supplied with high P, showed no difference between AM and non-AM roots. In the AM plants under P stress, the majority of the incorporated DIC was in the organic acid fraction in the roots and after subsequent xylem translocation, also in the shoots. Under P stress, the higher % cytochrome pathway (Vcyt) and the lower % alternative pathway (Valt) activities in the AM roots relative to non-AM roots, indicate that AM colonisation can reduce the engagement of mitochondrial respiratory bypasses under P stress. It is concluded that the engagement of glycolytic and mitochondrial respiratory bypass reactions in P starved roots are strongly influenced by root AM status.

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GRYNDLER M; VEJSADOVA H; VANCURA V. 1992. THE EFFECT OF MAGNESIUM-IONS ON THE VESICULAR ARBUSCULAR MYCORRHIZAL INFECTION OF MAIZE ROOTS. NEW PHYTOLOGIST. 1992. 122 (3):455-460.

Address:

GRYNDLER M, CZECHOSLOVAK ACAD SCI,INST MICROBIOL,VIDENSKA 1083,CS-14220 PRAGUE 4,CZECHOSLOVAKIA.

The effect of magnesium sulphate on the colonization of maize roots by a vesicular-arbuscular mycorrhizal fungus was studied in hydroponic culture. Increased concentration of MgSO4 in the nutrient solution caused an increase in the percentage of root length infected. The highest infection levels were found when nutrient solutions contained 5.84-11.68 mmol l-1 of MgSO4. Root colonization was stimulated by the increased concentration of magnesium but not calcium or potassium ions in the nutrient solution. No significant difference occurred in the percentage of root length infected when magnesium chloride was replaced by magnesium sulphate. A broad range of magnesium sulphate concentrations did not cause significant differences in plant biomass. The stimulation of root colonization by magnesium cannot be explained by changes in pH or osmotic pressure of the nutrient solution.

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Mycorrhiza

ISSN: 0940-6360 (printed version)
ISSN: 1432-1890 (electronic version)

Table of Contents

Abstract Volume 5 Issue 4 (1995) pp 279-282

Growth of Glomus intraradices and its effect on linseed (Linum usitatissimum L.) in hydroponic culture

D. G. Dugassa , G. Grunewaldt-Stöcker , F. Schönbeck

Institut für Pflanzenkrankheiten und Pflanzenschutz der Universität Hannover, Herrenhäuser Strasse 2, D-30419 Hannover, Germany, Fax: (49) 511-7623015

Abstract This paper presents a hydroponic system for culturing and maintaining the VAM fungus Glomus intraradices in symbiosis with linseed (Linum usitatissimum L.) under greenhouse conditions in pure nutrient solution. It was possible to obtain large quantities of mycorrhizal host plant roots as well as extramatrical mycelium and chlamydospores free of impeding residues of solid substrate components. Starting from linseed donor plants inoculated in sand and transferred to the nutrient solution, new infections arose within the fast growing root system, hyphae spread out into the liquid and infected mycorrhiza-free receptor plants. Data for infection rates and plant growth parameters are presented. In comparsion to other culture systems for VAM fungi, the advantages of this hydroponic system are discussed and potential uses suggested.

Key words VA mycorrhiza · Glomus intraradices · Linum usitatissimum · Hydroponic culture · Extramatrical hyphae

Article not available online

Online publication: December 2, 1997
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==============================

Mycorrhiza

ISSN: 0940-6360 (printed version)
ISSN: 1432-1890 (electronic version)

Table of Contents

Abstract Volume 9 Issue 4 (1999) pp 191-197

The mycorrhizal status of an emergent aquatic, Lythrum salicaria L., at different levels of phosphorus availability

J. A. White , I. Charvat

University of Minnesota, Plant Biology Department, 220 Biological Sciences Center, 1445 Gortner Avenue, St. Paul, MN 55108, USA e-mail: charv001@tc.umn.edu, Fax: +1-612-625-1738

Accepted: 7 August 1999

Abstract The relationship between nutrient availability and mycorrhizal status has been well studied for terrestrial plant species, but has been examined rarely in aquatic and emergent aquatic species. The purpose of this study was to determine the effect of phosphorus availability on the arbuscular mycorrhizal (AM) status of an emergent aquatic, Lythrum salicaria L. L. salicaria was grown in hydroponic sand culture at five phosphorus concentrations (0, 100, 1000, 10 000, and 47 500 µg PO₄/l nutrient solution) for 49 days with or without mycorrhizal inoculum obtained from wetland soil. Inoculated plants at the lowest three phosphorus concentrations were colonized by AM, whereas there was no colonization of plants grown at the highest two phosphorus concentrations. Colonization by AM fungi occurred in conjunction with symptoms of phosphorus deficiency in L. salicaria under experimental conditions: plants at the lowest three phosphorus concentrations had lower biomass and higher root: shoot weight ratios than plants at the highest two concentrations. However, total biomass and internal phosphorus concentration did not differ between inoculated and control plants. Further studies are needed under conditions more closely mimicking natural dynamics.

Key words Arbuscular mycorrhizae · Lythrum salicaria · Phosphorus · Wetland · Emergent aquatic

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Online publication: December 21, 1999
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Mycorrhiza

ISSN: 0940-6360 (printed version)
ISSN: 1432-1890 (electronic version)

Table of Contents

Abstract Volume 4 Issue 5 (1994) pp 185-191

Growth and nutrient uptake of sorghum cultivated with vesicular-arbuscular mycorrhiza isolates at varying pH

C. A. B. Medeiros (1), R. B. Clark (2), J. R. Ellis (2)

(1) Department of Agronomy, Agricultural Research Service, University of Nebraska, Lincoln, NE 68583, USA
(2) U.S. Department of Agriculture, Agricultural Research Service, University of Nebraska, Lincoln, NE 68583, USA

Abstract. This study was conducted to determine the effects of different pH regimes on root colonization with four vesicular-arbuscular mycorrhiza (VAM) isolates, and VAM effects on host plant growth and nutrient uptake. Sorghum [Sorghum bicolor (L.) Moench] was grown at pH 4.0, 5.0, 6.0 and 7.0 (±0.1) in hydroponic sand culture with the VAM isolates Glomus etunicatum UT316 (isolate E), G. intraradices UT143 (isolate I), G. intraradices UT126 (isolate B), and an unknown Glomus isolate with no INVAM number (isolate A). Colonization of roots with the different VAM isolates varied differentially with pH. As pH increased, root colonization increased with isolates B and E, remained unchanged with isolate I, and was low at pH 4.0 and high at pH 5.0, 6.0, and 7.0 with isolate A. Isolates E and I were more effective than isolates A and B in promoting plant growth irrespective of pH. Root colonization with VAM appeared to be independent of dry matter yields or dry matter yield responsiveness (dry matter produced by VAM compared to nonmycorrhizal plants). Dry matter yield responsiveness values were higher in plants whose roots were colonized with isolates E and I than with isolates A and B. Shoot P concentrations were lower in plants colonized with isolates E and I than with isolates A and B or nonmycorrhizal plants. This was probably due to the dilution effect of the higher dry matter yields. Neither the VAM isolate nor pH had an effect on shoot Ca, Mg, Zn, Cu, and Mn concentrations, while the VAM isolate affected not only P but also S, K, and Fe concentrations. The pH×VAM interaction was significant for shoot K, Mg, and Cu concentrations.

Key words: Dry matter yields - Sand culture - Shoot concentrations of P, K, Ca, Mg, S, Mn, Fe, Cu, and Zn - Sorghum bicolor

Correspondence to: R. B. Clark

Article not available online

Present address: USDA-ARS, Department of Agronomy, University of Nebraska, Lincoln, NE 68583, USA

Online publication: December 2, 1997
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