EFFECTS OF FORMALDEHYDE-ENRICHED MISTS ON PSEUDOTSUGA-MENZIESII (MIRBEL) FRANCO AND LOBARIA-PULMONARIA (L) HOFFM

The atmosphere in some areas is polluted with formaldehyde (HCHO); how ever, little is known about effects of HCHO on plants at concentration s resembling those in polluted areas. The effects of simulated fogwate r enriched with HCHO on seedlings of Pseudotsuga menziesii (Mirbel) Fr anco (Douglas fir) and pendants of Lobaria pulmonaria (L.) Hoffm. were assessed. Plants were treated with HCHO-enriched fog (target concentr ations of 100, 500, and 1000 mu M) during five knight mist sessions. G rowth and nitrogenase activity (acetylene reduction rate) for lichens and growth and timing of bud-break for Douglas fir were monitored. Nit rogenase activity was lowest in lichens treated at the highest HCHO co ncentration after all but the first mist session, and it declined sign ificantly with increasing HCHO concentration after the final mist sess ion (R(2)=0.60, p=0.02). However, differences in nitrogenase activity among treatments were generally not statistically significant (most p values from ANOVAs were greater than or equal to 0.20). Formaldehyde d id not affect growth of the lichens. Budbreak of Douglas firs was slig htly delayed and height growth was slightly depressed with increasing HCHO concentration, although effects were not statistically significan t. (C) 1997 Elsevier Science Ltd.