Differential appearance of vacuolar polyphenols in black pine (Pinus Nigra) needles in response to the lowering of SO2in the air

Abstract

The changes of vacuolar polyphenols appearance in the mesophyll cells of Black pine needles during the second year of their development and the connection of these changes with distance from the pollution source were studied as needle S-content started to decrease two years after the SO 2 concentration in the air approached the level that could be considered as low near the Plomin thermal power plant. Investigation plot was arranged in zones: I — less than 10 km, II — 10 to 20 km, III — 20 to 30 km around the power plant. Seven forms of vacuolar polyphenols were detected: two forms of granules — fine and larger ones, globules, thin and thick ribbons, ribbons occupying the whole cell and homogeneous mass. In the zone I the dominating were ribbon like polyphenols. The most abundant polyphenols in the zone II was the globular type while in the zone III besides large and fine granules thin ribbons were, also, well abundant. According to the linkage clustering zones I and II are more similar to each other than zone III, based on the abundance of different polyphenols types. At this point the hypothesis that vacuolar polyphenols could be considered as some kind of “memory” molecules in the environmental monitoring of the SO 2 effects on plants can be made.