Plant and Soil

, Volume 294, Issue 1–2, pp 125–136

Mycorrhizas in agroforestry: spread and sharing of arbuscular mycorrhizal fungi between trees and crops: complementary use of molecular and microscopic approaches

Original Article


The spread of arbuscular mycorrhizal (AM) fungi from tree to crop roots was examined by molecular and microscopic methods in a glasshouse study. Growth of Calliandra calothyrsus Meissner trees inoculated with isolates of the AM fungi Glomus etunicatum Becker and Gerdemann and Gigaspora albida Schenck and Smith was monitored over an 18-month period. Three successive ‘intercrops’ of beans or maize were sown at 25, 50 and 75 cm distances from the tree and harvested during this period. At each crop harvest, the distribution of tree and crop roots and the spread of the inoculant fungi were determined using traditional microscopic methods and fungal specific primers. Both inoculants greatly improved the growth of the trees and colonization spread to the crops once the trees were 6 months old. However, benefits of inoculation to crop growth were not observed due to increased competition from the larger inoculated trees growing in a restricted soil volume. Of the two inoculant fungi, Glomus etunicatum appeared to be more mobile as it spread more rapidly, formed higher levels of colonization at increasing distances from the tree and was responsible for most of the mycorrhizal cross-contamination. In contrast, colonization of tree and crop roots by Gigaspora albida was higher nearest the tree. This work demonstrated the benefits of mycorrhizal fungus inoculation for tree growth and confirmed that trees and crops share the same AM fungi. Trees may therefore act as reservoirs of mycorrhizal fungi, either inoculant or indigenous, for surrounding crops or other annual vegetation. It was also shown that tree pruning, the normal practice in agroforestry systems, did not reduce mycorrhizal colonization or prevent spread to crops. However, the slow rates of inoculant spread found here suggest that it may take years before inoculants benefit the growth of crops sown several metres from the tree. The work also demonstrated that microscopic quantification of mycorrhizal colonization and the use of molecular probes to identify specific fungi within roots can complement each other effectively. Molecular probes were more sensitive at detecting mycorrhizal fungi than microscopic methods, but did not discriminate between full mycorrhizal structures and traces of hyphae.


Calliandra calothyrsus Gigaspora albida Glomus etunicatum Molecular probes Tree-crop linkages 



Arbuscular mycorrhizal


Root length density


Polymerase chain reaction


International bank for the glomeromycota


  1. Alvarez-Solis JD, Anzueto-Martinez MD (2004) Soil microbial activity under different corn cropping systems in the highlands of Chiapas, Mexico. Agrociencia 38:13–22Google Scholar
  2. Arihara J, Karasawa T (2000) Effect of previous crops on arbuscular mycorrhizal formation and growth of succeeding maize. Soil Sci Plant Nutr 46:43–51Google Scholar
  3. Brundrett MC, Abbott LK (1994) Mycorrhizal fungus propagules in the jarrah forest. New Phytol 127:539–546CrossRefGoogle Scholar
  4. Diagne O, Ingleby K, Deans JD, Lindley DK, Diaite I, Neyra M (2001) Mycorrhizal inoculum potential of soils from alley cropping plots in Senegal. For Ecol Manage 146:35–43CrossRefGoogle Scholar
  5. Dodd JC, Arias I, Koomen I, Hayman DS (1990) The management of populations of vesicular-mycorrhizal fungi in acid-infertile soils of a savanna ecosystem. I. The effect of pre-cropping and inoculation with VAM-fungi on plant growth and nutrition in the field. Plant Soil 122:229–240Google Scholar
  6. Habte M, Turk D (1991) Response of two species of Cassia and Gliricidia sepium to vesicular-arbuscular mycorrhizal infection. Commun Soil Sci Plant Anal 22:17–18Google Scholar
  7. Haselwandter K, Bowen GD (1996) Mycorrhizal relations in trees for agroforestry and land rehabilitation. For Ecol Manage 81:1–17CrossRefGoogle Scholar
  8. Howeler RH, Sieverding E, Saif S (1987) Practical aspects of mycorrhizal technology in some tropical crops and pastures. Plant Soil 100:249–283CrossRefGoogle Scholar
  9. Ingleby K, Fahmer A, Wilson J, Newton AC, Mason PA, Smith RI (2001) Interactions between mycorrhizal colonisation, nodulation and growth of Calliandra calothyrsus seedlings supplied with different concentrations of phosphorus solution. Symbiosis 30:15–28Google Scholar
  10. Jakobsen I, Abbott LK, Robson AD (1992) External hyphae of vesicular-arbuscular mycorrhizal fungi associated with Trifolium subterraneum L. 1. Spread of hyphae and phosphorus inflow into roots. New Phytol 120:371–380CrossRefGoogle Scholar
  11. Jansa J, Mozafar A, Frossard E (2005) Phosphorus acquisition strategies within arbuscular mycorrhizal fungal community of a single field site. Plant Soil 276:163–176CrossRefGoogle Scholar
  12. Kabir Z (2005) Tillage or no-tillage: impact on mycorrhizae. Can J Plant Sci 85:23–29Google Scholar
  13. Koske RE, Gemma JN (1989) A modified procedure for staining roots to detect VA mycorrhizas. Mycol Res 92:486–505CrossRefGoogle Scholar
  14. Leakey RRB, Wilson J, Deans JD (1999) Domestication of trees for agroforestry in drylands. Ann Arid Zone 38:195–220Google Scholar
  15. Lesueur D, Ingleby K, Odee D, Chamberlain J, Wilson J, Manga TT, Sarrailh JM, Pottinger A (2001) Improvement of forage production in Calliandra calothyrsus: methodology for the identification of an effective inoculum containing rhizobium strains and arbuscular mycorrhizal isolates. J Biotechnol 91:269–282PubMedCrossRefGoogle Scholar
  16. Miller MH (2000) Arbuscular mycorrhizae and the phosphorus nutrition of maize: a review of Guelph studies. Can J Plant Sci 80:47–52Google Scholar
  17. Namirembe S (1999) Tree shoot pruning to control competition for below-ground resources in agroforestry. Ph.D. Thesis, University of Wales, Bangor, UKGoogle Scholar
  18. Odhiambo HO, Ong CK, Wilson J, Deans JD, Broadhead J, Black C (1999) Tree-crop interactions for below-ground resources in drylands: root structure and function. Ann Arid Zones 38:221–237Google Scholar
  19. Olsson PA, Wilhelmsson P (2000) The growth of external AM fungal mycelium in sand dunes and in experimental systems. Plant Soil 226:161–169CrossRefGoogle Scholar
  20. Rao MK, Schroth G, Williams SE, Namirembe S, Schaller M, Wilson J (2004) Managing below-ground interactions in agroecosystems. In: van Noordwijk M, Cadisch G, Ong CK (eds) Below-ground interactions in tropical agroecosystems. Concepts and models with multiple plant components. CABI Publishing, Wallingford, pp 309–328Google Scholar
  21. Read DJ (1991) Mycorrhizas in ecosystems. Experientia 47:376–391CrossRefGoogle Scholar
  22. Sanchez PA, Buresh RJ, Leakey RRB (1997) Trees, soils, and food security. Philos Trans R Soc B Biol Sci 352:949–961CrossRefGoogle Scholar
  23. Sieverding E, Leihner DE (1984) Influence of crop rotation and intercropping of cassava with legumes on VA mycorrhizal symbiosis of cassava. Plant Soil 80:143–146CrossRefGoogle Scholar
  24. Sieverding E (1991) Vesicular-arbuscular mycorrhiza management in tropical ecosystems. GTZ, Eschborn, Germany, p 371Google Scholar
  25. Sokal RR, Rohlf FJ (1995) Biometry: the principles and practice of statistics in biological research. W.H. Freeman, San Francisco, p 887Google Scholar
  26. Stephens MA (1974) EDF statistics for goodness of fit and some comparisons. J Am Stat Assoc 69:730–737CrossRefGoogle Scholar
  27. Tennant D (1975) A test of a modified line intersect method of estimating root length. J Ecol 63:995–1001CrossRefGoogle Scholar
  28. Tilander Y, Ong CK (1999) Conservation of and competition for water and nutrients in semi-arid agroforestry. Ann Arid Zones 38:309–334Google Scholar
  29. van Tuinen D, Jacquot E, Zhao B, Gollotte A, Gianinazzi-Pearson V (1998) Characterization of root colonization profiles by a microcosm community of arbuscular mycorrhizal fungi using 25S rDNA-targeted nested PCR. Mol Ecol 7:879–887PubMedCrossRefGoogle Scholar
  30. Voets L, de la Providencia IE, Declerck S (2006) Glomeraceae and Gigasporaceae differ in their ability to form hyphal networks. New Phytol 172:185–188PubMedCrossRefGoogle Scholar
  31. Whitcomb SA, Stutz J (2001) Effects of pruning on root length density, root biomass, and arbuscular mycorrhizal colonization in two landscape shrubs. In: Proceedings of the 3rd international conference on Mycorrhizas (ICOM3), Adelaide. Abstract, pp 1–157Google Scholar
  32. White TJ, Bruns T, Lee S, Taylor J (1990) Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. In: Innis MA, Gelfand DH, Sminski JJ, White TJ (eds) PCR protocols, a guide to methods and applications. Academic, San Diego, pp 315–322Google Scholar

Copyright information

© Springer Science+Business Media B.V. 2007

Authors and Affiliations

  • K. Ingleby
    • 1
  • J. Wilson
    • 1
  • R. C. Munro
    • 1
  • S. Cavers
    • 1
  1. 1.Centre for Ecology and HydrologyPenicuikUK

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