Hydrogen Peroxide Dissolved in Acidic Fog as Air Pollutant—Effects on Spruce Needles

Abstract

In fog chamber experiments, 3-year-old spruce trees (Picea abies Karst.) were exposed to acidic fog (pH 4) containing 864±250 ppb H₂O₂ 4 days a week from 4 a.m. to 7 a.m. over a period of 8 weeks. During the remaining time, the chambers were opened and the trees were exposed to natural climatic conditions. This fumigation program was selected after the natural pollutant values of H₂O₂.

As effects of this nebulation experiment, we observed decreases in all histological parameters studied. An increased accumulation of phenols in the central vacuoles of the mesophyll cells of the needles was observed.

HPLC-measurements indicate that acidic fog containing H₂O₂ affects distinct intermediates of the phenolic pathway. The amounts of piceatannolglycoside, kaempferol-glycoside, catechin as well as quinic and shikimic acid increased.

Key Words:

• Forest decline
• fog chamber experiments
• hydrogen peroxide
• needle tissues
• needle phenols