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Mycorrhiza

, Volume 4, Issue 1, pp 11–15 | Cite as

The mycorrhizal status of vascular epiphytes in Bale Mountains National Park, Ethiopia

  • Anders Michelsen
Original Papers

Abstract

Roots of 28 species of epiphytic vascular plants were collected on tree trunks and branches at six afromontane forest sites between 1700 and 3300 m above sea level in Bale Mountains National Park, Ethiopia. Seven of the 28 epiphyte species were colonized by vesicular-arbuscular mycorrhizal fungi (VAM). Mycorrhizal colonization only occurred at two of the six sites examined, at 2900 m and 3300 m, but more than one type of VAM endophyte was present in each case. Three facultative epiphytic species were all highly colonized by VAM on the forest floor, whereas roots from epiphytic habitats were weakly colonized. No correlations were found between VAM colonization, fine root diameter and root hair length, but VAM colonization and root hair abundance were negatively correlated. The lack of VAM colonization of potential, epiphytic host species at the majority of the sites examined points to the dispersal of VAM propagules as the factor limiting mycorrhizal colonization of epiphytic habitats. It is suggested that root systems of hemiepiphytic tree species serve as corridors between forest floor and tree trunks through which VAM may spread via hyphal growth.

Key words

Afromontane forest Epiphytic plants Fine root Tropics Vesicular-arbuscular mycorrhizal fungi 

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References

  1. Baylis GTS (1975) The magnoliod mycorrhiza and mycotrophy in root systems derived from it. In: Sanders FE, Mosse B, Tinker PB (eds) Endomycorrhizas. Academic Press, London, pp 373–389Google Scholar
  2. Benzing DH (1990) Vascular epiphytes. General biology and related biota. Cambridge University Press, CambridgeGoogle Scholar
  3. Bermudes D, Benzing DH (1989) Fungi in neotropical epiphyte roots. BioSystems 23:65–73Google Scholar
  4. Friis I (1992) Forests and forest trees of northeast tropical Africa. Their natural habitats and distribution patterns in Ethiopia, Djibouti and Somalia. Kew Bull Addit Ser 15:1–396Google Scholar
  5. Harley JL, Harley EL (1987) A checklist of mycorrhiza in the British flora. New Phytol 105 [Suppl]:1–102Google Scholar
  6. Janos DP (1987) VA mycorrhizas in humid tropical ecosystems. In: Safir GR (ed) Ecophysiology of VA mycorrhizal plants. CRC Press, Boca Raton, Fla, pp 108–134Google Scholar
  7. Johansson DR (1989) Vascular epiphytism in Africa. In: Lieth H, Werger MJA (eds) Tropical rainforest ecosystems. Elsevier, Amsterdam, pp 183–194Google Scholar
  8. Leerdam A van, Zagt RJ, Veneklaas EJ (1990) The distribution of epiphyte growth — forms in the canopy of a Colombian cloud-forest. Vegetatio 87:59–71Google Scholar
  9. Lesica P, Antibus RK (1990) The occurrence of mycorrhizae in vascular epiphytes of two Costa Rican rain forests. Biotropica 22:250–258Google Scholar
  10. Michelsen A (1992) Mycorrhiza and root nodulation in tree seedlings from five nurseries in Ethiopia and Somalia. For Ecol Manage 48:335–344Google Scholar
  11. Michelsen A (1993) Growth improvement of Ethiopian acacias by addition of vesicular-arbuscular mycorrhizal fungi or roots of native plants to nonsterile nursery soil. For Ecol Manage 59:193–206Google Scholar
  12. Michelsen A, Rosendahl S (1990) The effect of VA mycorrhiza, phosphorus and drought stress on the growth of Acacia nilotica and Leucaena leucocephala seedlings. Plant Soil 124:7–13Google Scholar
  13. Putz FE, Holbrook NM (1986) Notes on the natural history of hemiepiphytes. Selbyana 9:61–69Google Scholar
  14. SAS Institute (1988) SAS/STAT user's guide, Release 6.03. SAS, Cary, NCGoogle Scholar
  15. St John TV (1980) Root size, root hairs and mycorrhizal infection: a re-examination of Baylis's hypothesis with tropical trees. New Phytol 84:483–487Google Scholar
  16. Tester M, Smith SE, Smith FA (1987) The phenomenon of “non-mycorrhizal” plants. Can J Bot 65:419–431Google Scholar
  17. Zerihun W, Feoli E, Lisanework N (1989) Partitioning an elevation gradient of vegetation from southeastern Ethiopia by probabilistic methods. Vegetatio 81:189–198Google Scholar

Copyright information

© Springer-Verlag 1993

Authors and Affiliations

  • Anders Michelsen
    • 1
  1. 1.Department of Plant EcologyUniversity of CopenhagenCopenhagen KDenmark

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