Ascorbic Acid and Glutathione Contents of Spruce Needles from Different Locations in Bavaria

In 1980 a “mysterious” spruce decline was ob­ served for the first time at higher altitudes in the East Bavarian mountains (Fichtelgebirge and Bavarian Forest). As a typical symptom, the oldest needles became chlorotic with the exception of the current year needles [1] a symptom which has never been described in earlier times. In most cases light ex­ posed needles or needle segments exhibit stronger symptoms as compared to shaded needles. The gaseous air pollutant S 0 2 and photooxidants with ozone as the main component are discussed as possible param eters in spruce decline [2, 3]. Sulfur dioxide may display its toxic activity during the photooxidation of sulfite to sulfate within the chloro­ plasts. Sulfite radicals and reactive oxygen species may be formed which can start lipidperoxidation and pigmentcooxidation [4, 5]. Furthermore the toxic effect of S 0 2 may also involve the inhibition of the enzyme ribulose-l,5-bisphosphate-carboxylase [6]. Ozone toxicity involves either catalysis of free radical formation [7] or ozone molecules themselves [8, 9] causing lipidperoxidation and pigmentcooxida­ tion [10]. Within the stroma of the chloroplasts a detoxifica­ tion cycle is localized which reduces different re­ active oxygen species to water at the expense of N A DPH via ascorbic acid and glutathione [11]. Sev­ eral workers demonstrate that different conifers as well as herbaceous plants increase their antioxidants after fumigation with S 0 2 or 0 3 [12—15]. Our inten­