Effects of fluoride on photosynthesis and respiration of some South-East American forest trees

• Published in: Environmental pollution 1975, Vol.8 (2), p.91-96
• Main Authors: McLaughlin, Samuel B., Barnes, Robert L.
• Format: Article
• Language: English
• ISSN: 0013-9327
• DOI: 10.1016/0013-9327(75)90018-X

Experiments with three pine and six hardwood species revealed consistent effects of added fluoride on gas exchange processes of detached pine needles and hardwood leaves. Apparent photosynthesis was commonly depressed when foliage was allowed to take up NaF solutions ranging from 10 −4 to 10 −2 M (1·9 − 190 ppm F). Dark respiration was commonly stimulated at low levels of NaF (10 −4 to 10 −3 M) and higher levels either stimulated the process further (in most hardwoods) or inhibited it (in the pines and some hardwoods). Pines were generally more sensitive than hardwoods and current-year needles were more sensitive than one-year-old needles. Concurrent stimulation of dark respiration and inhibition of apparent photosynthesis suggest that growth reduction could occur in trees accumulating low levels of foliar fluoride.