engleski

Recovery of black pine (Pinus nigra Arn.) needles in response to the lowering of SO2 concentrations in the air - a case study of thermal power plant Plomin (Croatia)

The impact of SO2 emitted from the thermal power plant Plomin (Croatia) was monitored for about fifteen years by measuring the S-concentration in the needles of Black pine grown at different distances from the power plant. Since 1999 the emission of SO2 was significantly lowered, but expected decrease of S-concentrations in needles was not observed in the same and the next (2000) year. The aim of present study, conducted in 2001, was to determine the time needed for the recovery of Black pine needles regarding the S-concentration. The performed chemical and biochemical analysis included the measurement of N, P, K, Ca, Mg and S concentrations, percentage of dry weight, total soluble proteins and photosynthetic pigments content. Although S-concentrations decreased in comparison to the values reported for previous years, they were still elevated in current-year needles, while in previous-year needles S- concentrations belong to low level class. Values for K, Ca and Mg were adequate to optimal, while the P-content for all sample plots was low. The results of soluble proteins and photosynthetic pigments content, as well as percentage of dry weight further confirmed that physiological status of investigated needles was not disturbed. It can be concluded that the lowering of S-concentrations in Black pine needles started about two years after the drop of SO2 concentrations. The mineral nutrition can not be considered as the main reason for slow lowering rate of S-concentrations in needles. Measured biochemical parameters confirmed that there were no significant differences in physiological status of black pine needles at various distances from the Plomin thermal power plant.

Pinus nigra; air pollution; SO2; mineral nutrition; photosynthetic pigments; proteins

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