Sulfur dioxide injury, sulfur content, and stomatal conductance of birch foliage

Abstract

Seedlings of three birch species were exposed biweekly to 2358 μg/m³ (0.9 ppm) SO₂ for 2 h from May to September 1977. Leaf sulfur content of the birch foliage increased following exposure to SO₂, but sulfur accumulation was not correlated with visible injury. Relative susceptibility was significantly correlated with preexposure leaf conductance rates of Betulanigra L. and B. papyrifera Marsh., but not for B. pubescens Ehrh. Leaf conductance rates were not correlated with sulfur accumulation.