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Keywords:

  • Ericoid mycorrhizal fungus;
  • Erica hispidula;
  • dual uptake;
  • phosphate

Summary

Mycelia of the endomycorrhizal fungus of Erica hispidula L. were grown in liquid culture media containing high (6 mM) or low (60 μM) concentrations of orthophosphate. Phosphate uptake rates were measured over the range 1 to 500 μ and were interpreted as being the consequence of a dual uptake system. The Vmax values of low P and high P status mycelia of the low-affinity system (LA) were similar, whereas the Km of high P status mycelia was lower than that of low P status mycelia. The Km values of high P and low P status mycelia of the high-affinity system (HA) were similar, whereas high P status mycelia showed a higher Vmax value than low P status mycelia. In low P status mycelia, the LA contribution to total uptake was 93% at 500μM and 25% at 1 μM external phosphate. The uptake systems were sensitive to pH and 2,4-dinitrophenol. These results are compared with similar studies on saprotrophic fungi and mycorrhizal associations.