Effets of Sulfur Dioxide on Three Eucalyptus Species

Abstract

Eucalyptus punctata, E. moluccana and E. crebra were exposed continuously to low concentrations of sulfur dioxide, up to 10.1 pphm, for durations of up to 40 days in open-top fumigation chambers.

Foliar injury and accelerated leaf senescence were found in E. punctata but no symptoms of visible injury were detected in E. moluccana or E. crebra. Sulfur dioxide exposure significantly depressed leaf chlorophyll concentrations in E. crebra and exposure to 4.3 pphm sulfur dioxide significantly depressed total chlorophyll concentrations in E. moluccana. Sulfur dioxide had no significant effect on leaf chlorophyll in E. punctata. Exposure to sulfur dioxide significantly increased leaf sulfur concentrations in all three species, with the exception of the exposure of E. punctata to 3.8 pphm sulfur dioxide which did not result in foliar sulfur accumulation. Sulfur dioxide had no significant effects on tree growth parameters in E. moluccana or E. crebra.

Although all three Eucalyptus species were sensitive to continuous exposure to low concentrations of sulfur dioxide, the response is species-dependent.