Influence of soil organic matter decomposition on arbuscular mycorrhizal fungi in terms of asymbiotic hyphal growth and root colonization.
Soil organic matter is known to influence arbuscular mycorrhizal (AM) fungi, but limited information is available on the chemical components in the organic matter causing these effects. We studied the influence of decomposing organic matter (pure cellulose and alfalfa shoot and root material) on AM fungi after 30, 100, and 300 days of decomposition in nonsterile soil with and without addition of mineral N and P. Decomposing organic matter affected maize root length colonized by the AM fungus Glomus claroideum in a similar manner as other plant growth parameters. Colonized root length was slightly increased by both nitrogen and phosphorus application and plant materials, but not by application of cellulose. In vitro hyphal growth of Glomus intraradices was increased by soil extracts from the treatments with all types of organic materials independently of mineral N and P application. Pyrolysis of soil samples from the different decomposition treatments revealed in total 266 recognizable organic compounds and in vitro hyphal growth of G. intraradices in soil extract positively correlated with 33 of these compounds. The strongest correlation was found with 3,4,5-trimethoxybenzoic acid methyl ester. This compound is a typical product of pyrolysis of phenolic compounds produced by angiosperm woody plants, but in our experiment, it was produced mainly from cellulose by some components of the soil microflora. In conclusion, our results indicate that mycelia of AM fungi are influenced by organic matter decomposition both via compounds released during the decomposition process and also by secondary metabolites produced by microorganisms involved in organic matter decomposition.
Gryndler
Milan
M
Institute of Microbiology, Academy of Sciences of the Czech Republic, 142 20, Prague, Czech Republic. gryndler@biomed.cas.cz.
Hršelová
Hana
H
Institute of Microbiology, Academy of Sciences of the Czech Republic, 142 20, Prague, Czech Republic.
Cajthaml
Tomáš
T
Institute of Microbiology, Academy of Sciences of the Czech Republic, 142 20, Prague, Czech Republic.
Havránková
Marie
M
Department of Botany, Faculty of Science, Charles University, 128 01, Prague, Czech Republic.|Institute of Botany, Academy of Sciences of the Czech Republic, 252 43, Průhonice, Czech Republic.
Řezáčová
Veronika
V
Institute of Microbiology, Academy of Sciences of the Czech Republic, 142 20, Prague, Czech Republic.
Gryndlerová
Hana
H
Institute of Microbiology, Academy of Sciences of the Czech Republic, 142 20, Prague, Czech Republic.
Larsen
John
J
Department of Integrated Pest Management, Faculty of Agricultural Science, University of Aarhus, DK-4200, Slagelse, Denmark.
D002482:Cellulose / Q000378:metabolism; D055137:Glomeromycota / Q000254:growth & development*; D006812:Humic Substances / Q000382:microbiology; D025301:Hyphae / Q000254:growth & development*; D000455:Medicago sativa / Q000378:metabolism; D038821:Mycorrhizae / Q000254:growth & development*; D018517:Plant Roots / Q000382:microbiology*; D018520:Plant Shoots / Q000378:metabolism; D012987:Soil / Q000032:analysis; D012988:Soil Microbiology; D013997:Time Factors; D003313:Zea mays / Q000254:growth & development / Q000382:microbiology
D006812:Humic Substances; D012987:Soil; D002482:Cellulose