The effects of sulphur gas and elemental sulphur dust deposition on Pinus contorta x Pinus banksiana: cell walls and water relations

Abstract

The bulk modulus of elasticity (E) for Pinus contorta (lodgepole pine) x Pinus banksiana (jack pine) hybrids was compared between a site (AI) close to a sour gas processing plant and a control site (AV). The mean bulk modulus of elasticity for branches from AI was 47.5 MPa vs 18.5 MPa for the control site (AV). Site AI had been exposed to S-gas emissions and large amounts of elemental S deposition and had an acidic soil (pH 4.0 at 10 cm depth). During 1981 the needles at AI had more aluminum and iron compared to those at AV (900 ppm vs 390 ppm AI in the 3-year-old needles). Mean leader growth was measured over a 3-year period and was observed to be greater at AI than AV (46+/-7 cm vs 29+/-9 cm for 1988). Histochemically, the needles at AI had higher phenol and lignin content than AV. These results suggest that the S-gas fumigation, S-dust deposition, plus increased concentrations of soluble aluminum and iron had altered the cell wall elastic properties resulting in altered water relations. The implications of this on leaf diffusive resistance and photosynthesis are discussed.