Handbook of Vitamin C Research

(mgg -1 )Vitamin C as a Stress Bioindicator of Norway Spruce 3193. Results3.1. Mean Annual Content of Vitamin C in Spruce NeedlesPhysiological condition of spruce trees, sampled in the area influenced by the ŠTPP, wasinvestigated by determination of contents of vitamin C and photosynthetic pigments incurrent-year Norway spruce needles. Mean annual concentrations of vitamin C are presentedin Figure 2. Since the content of vitamin C in green parts of higher plants had already beenconfirmed as a suitable bioindicator of oxidative stress caused by air pollution (Perl-Treves &Perl, 2002; Langebartels et al., 2002; Eposito et al., 2009), a determination of relationbetween mean annual contents of vitamin C in needles and mean annual emissions of sulphurdioxide from ŠTPP was emphasized in this study.VITAMIN C9,008,007,006,005,004,003,002,001,000,007,225,625,594,985,574,903,90 3,74 4,534,654,39 4,292,350,58 0,461992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007Figure 2. Mean content of vitamin C in current-year needles of spruce located in the emission area ofthe ŠTPP in the period 1992-2007. The arrows marked the years in which desulphurization deviceswere installed (Unit 4 in February 1995 and Unit 5 in November 2000, respectively).As a rule, the defence mechanism of plants and consequently content of vitamin C intheir tissues should increase with increasing air pollution (Foyer, 1993; Larcher, 1995; Crosset al., 1998; Perl-Trevers and Perl, 2002). However, in the period of the largest emissions ofsulphur dioxide (1991-1994), the lowest mean concentrations of vitamin C in spruce needleswere found (Figure 2). Immediately after the first significant reduction of SO 2 emissions in1995, contents of vitamin C in needles started increasing and reaching the peak in 2000,although emissions remained almost unchanged in that period. Such a trend is comparablewith some previous studies from highly polluted areas (e.g. Grill et al., 1979; Bermadinger etal., 1990; Batič et al., 2001). If spruces trees were exposed to high SO 2 emissions and for along time, the antioxidant defence mechanism would be damaged and the content of vitaminC would not increase as expected. In our study area, previous huge emission of SO 2 werefirstly significantly reduced after the installation of the desulphurization devices on the fourth