ISHS Acta Horticulturae 381: International Symposium on Natural Phenols in Plant Resistance
EFFECTS OF OZONE AND UV-B RADIATION ON SCOTS PINE. |
| Authors: | J.P. SCHNITZLER, T.P. JUNGBLUT, W. HELLER, C. LANGEBARTELS, M. KÖFFERLEIN, H. SANDERMANN Jr |
| Keywords: | UV-B radiation, tropospheric ozone, Scots pine, flavonoids, stillbenes |
| Abstract:
Most of the experiments investigating the effects of UV-B on plants in closed chambers were performed with artificial radiation differing substantially from that of the solar spectrum. A new sunlight simulator developed at the GSF allowed us to simulate global radiation with a mean spectral deviation of not more than 16%. Scots pine seedlings reacted within 72 hours of UV-B irradiation by accumulating four methanol-extractable flavonoids. The main induced metabolite was identified to be 3",6"-di-O-(4-coumaroyl)-isoquercitrin. It was shown that this flavonoid was retained, up to 50%. in enzymatically isolated epidermal cell layers. Ozone has earlier been shown to affect other pathways of secondary metabolism in the needles leading to the accumulation of the stilbenes. pinosylvin and pinosylvin 3-methylether, the flavan catechin. as well as to the induction of the pertinent biosynthetic enzymes. Season-dependent effects of ozone (ambient and twice ambient) and of two light regimes (high/low UV-B radiation) on secondary metabolism of four-year-old Scots pine saplings were recently investigated in the GSF-Phytotron under meterological conditions simulated according to values measured in 1990 at the Wank, an alpine mountain near Garmisch-Partenkirchen (FRG). Preliminary results of this experiment are presented. | |
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