The effects of ozone and sulfur dioxide on respiration of ectomycorrhizal fungi

Abstract

Oxygen-uptake determinations were made on mycelial mats of four ectomycorrhizal fungal isolates: three of Pisolithustinctorius (Pers.) Coker and Couch and one of Thelephoraterrestris (Erhr.) Fr. following a 1-h exposure to 5 and 50 parts per hundred million (pphm) O₃ or SO₂. Similar determinations were made on mycorrhizal (P. tinctorius and T. terrestris) and nonmyeorrhizal loblolly pine (Pinustaeda L.) root segments exposed to 5 pphm O₃ and SO₂. Both gases caused marked reductions in respiration rates of the pure fungal and root materials with significant species and intraspecies differences observed. However, greater inhibition was observed with SO₂ than with O₃. Ectomycorrhizal loblolly pine root segments were significantly more resistant to the deleterious influences of O₃ and SO₂ on respiration than were nonmycorrhizal roots indicating that ectomycorrhizal development may afford some protection against feeder-root damage from O₃ and SO₂. The greatest protection from O₃ was provided by Thelephoraterrestris while Pisolithustinctorius root sections were most resistant to SO₂ damage.