Colonisation by arbuscular mycorrhizal fungi changes the relationship between phosphorus uptake and membrane potential in leek (Allium porrum) seedlings

Abstract

The effect of colonisation by arbuscular mycorrhizal (AM) fungi on the relationship between phosphorus (P) uptake and root membrane electric potential difference (p.d.) was investigated in leek (Allium porrum L.). Plants were grown, with or without the AM fungus Scutellospora calospora (Nicolson and Gerdemann) Walker and Sanders, in soil. P uptake and root p.d. were correlated; plants with the highest P concentration in the shoot had the most negative p.d. This relationship was strong in non-mycorrhizal leeks (r² = 84–98%), but weaker in mycorrhizal leeks (r² = 55–64%), consistent with the idea that in mycorrhizal roots the fungal hyphae are the principal site of P uptake.