Single and Combined Effects of Continuous and Discontinuous O₃ and SO₂ Immission on Norway Spruce Needles: II. Metabolic Changes

Abstract

The analysis of the cytological effects of SO₂, O₃ or SO₂/O₃ exposure on the structure of spruce needles (Picea abies Karst.) revealed an extremely high amount of phenolic compounds in the vacuoles of the mesophyll cells of primary needles (see part 1 of this study). This observation prompted us to identify and quantify different spruce needle phenolics, their changing amount during SO₂, O₃, or SO₂/O₃ exposure as well as their effect on the adenylate energy charge (AEC) as an integrate stress index of the plant cell.

Discontinuous fumigation with O₃ combined with low constant-concentration exposure to SO₂, overlapped by occasional peak concentration of SO₂, seems to affect the phenolic metabolism and the adenylate energy charge the most. The high phytotoxicity of this fumigation pattern is indicated by a drastically reduced adenylate energy charge and extremely high levels of distinct intermediates of the phenolic pathway.

Key Words:

• Forest die-back
• ozone
• sulfur dioxide
• needle phenolics
• adenine nucleotides