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.