INVESTIGATIONS ON THE PHOTOSYNTHETIC SYSTEM OF SPRUCE AFFECTED BY FOREST DECLINE AND OZONE FUMIGATION IN CLOSED CHAMBERS

Investigations using chlorophyll fluorescence induction kinetics provide the parameters R(fd), L, and A(p) to characterize different specifications of the photosynthetic system (PS). The application of ozone, with concentrations between 100 mug m-3 and 2000 mug m-3 to spruce in closed chambers yields a reduction of R(fd) between 6% and 23% for the current year's needles, which indicates a reduced potential photosynthetic capacity. Further measurements on the current year's needles of spruce of the damage classes S0/S1, S2 and S3 show also a reduction of R(fd) of between 7% and 14% in 2 successive Years. In addition, the parameter L increases for damaged trees by between 11% and 49%, indicating a change of the chlorophyll content and of the internal energY distribution between PSI and PSII. As no effect of L can be observed with ozone fumigation, it is concluded that the change of some specifications of the PS can be simulated well by ozone fumigation (e.g. R(fd)) while Other Specifications cannot (e.g. L).