Impact of pea growth and arbuscular mycorrhizal fungi on the decomposition of 15N-labeled maize residues
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A pot experiment was carried out (1) to compare C and N yield of different plant parts, nutrient concentrations, and root colonization between the non-mycorrhizal mutant P2 (myc −) and the symbiotic isoline Frisson (myc +), (2) to investigate the effects of arbuscular mycorrhizal fungi and growing pea plants on microbial decomposition of 15N-labeled maize residues, and (3) to follow the distribution of the added substrate over different soil fractions, such as particulate organic matter, soil microbial biomass, and microbial residues. Yields of C in straw, grain, and roots of myc + peas were significantly higher by 27%, 11%, and 92%, respectively, compared with those of myc − peas. The δ13 C values in the different plant parts were significantly higher in myc + than in myc − tissue with and without maize. Application of labeled maize residues generally resulted in 15N enrichment of pea plants. At the end of the experiment, the ergosterol concentration in roots of mature peas did not differ between the two isolines, indicating similar colonization by saprotrophic fungi. The decomposition of added maize residues was significantly reduced by the myc − peas, but especially by myc + peas. The formation of microbial residue C was increased and that of microbial residue N was reduced in the presence of plants. The insufficient N supply to soil microorganisms reduced decomposition of maize residues in the presence of peas, especially myc + peas.
KeywordsArbuscular mycorrhizal fungi Peas Maize residues Decomposition Microbial biomass Particulate organic matter δ13C δ15N
We greatly appreciate the technical assistance of Gabriele Dormann. This project was supported by a grant from the University of Al-Baath, Homs, Syria and in part also by a grant of the Research Training Group 1397 “Regulation of soil organic matter and nutrient turnover in organic agriculture” from the German Research Foundation (DFG).
- Balesdent J, Mariotti A (1996) Measurement of soil organic matter turnover using 13C natural abundance. In: Boutton TW, Yamasaki SI (eds) Mass spectrometry of soils. Marcel Dekker, New York, pp 83–111Google Scholar
- Cernusak LA, Tcherkez G, Keitel C, Cornwell WK, Santiago LS, Knohl A, Barbour MM, Williams DG, Reich PB, Ellsworth DS, Dawson TE, Griffiths H, Farquhar GD, Wright IJ (2009) Why are non-photosynthetic tissues generally 13C enriched compared to leaves in C3 plants? Review and synthesis of current hypotheses. Funct Plant Biol 36:199–213CrossRefGoogle Scholar
- Dormaar JF (1990) Effect of active roots on the decomposition of soil organic materials. Biol Fertil Soils 10:121–126Google Scholar
- Haider K, Heinemeyer O, Mosier AR (1989) Effects of growing plants on humus and plant residue decomposition in soil; uptake of decomposition product by plants. Sci Tot Environ 81(82):661–670Google Scholar
- Müller J (1999) Mycorrhizal fungal structures are stimulated in wildtype peas and in isogenic mycorrhiza-resistant mutants by tri-iodo-benzoic acid (TIBA), an auxin-transport-inhibitor. Symbiosis 26:379–389Google Scholar
- Querejeta JI, Barea JM, Allen MF, Caravaca F, Roldán A (2003) Differential response of δ13C and water use efficiency to arbuscular mycorrhizal infection in two aridland woody plant species. Oecol 135:510–515Google Scholar
- Ruschel AP, Vose PB, Victoria RL, Salati E (1979) Comparison of isotope techniques on nodulating and non-nodulating isolines to study the effect of ammonium fertilization on dinitrogen fixation in soybean, Glycine max (L). Merrill Plant Soil 53:513–525Google Scholar
- Shearer G, Kohl DH (1986) N2 fixation in field settings: estimations based on natural 15N abundance. Aust J Plant Physiol 13:699–756Google Scholar
- Smith SE, Read DJ (2008) Mycorrhizal symbiosis, 3rd edn. Academic, LondonGoogle Scholar
- Vestberg M, Kahiluoto H, Wallius E (2010) Arbuscular mycorrhizal fungal diversity and species dominance in a temperate soil with long-term conventional and low-input cropping systems. Mycorrhiza. doi: 10.1007/s00572-010-0346-y