MORPHOLOGICAL AND STRUCTURAL MODIFICATION INDUCED BY AIR POLLUTANTS IN ACER CAMPESTRE L. LEAVES

Abstract: The study estimated modification in morphology and structure of Acer campestre L. leaf
blades under two diverse levels of industrial air contamination. The samples have been collected from
the same trees growing on the identical place but in two separated with long time periods: 1990, 1991 –
first period and 2004 – second; that are characterized with great difference of pollutant levels,
especially for SO2 at least twice in amount through heavy polluted period. The structure and developing
of winter buds and leaves lamina have been monitoring through severe contamination to reveal any
adaptation responses. Increasing of palisade tissue and decreasing of spongy parenchyma have been
detected, during high levels of industrial contamination, but not in the period with relatively low
pollution levels, that correlated with increasing the palisade ratio. Augmented palisade ratio stated for an adaptive response of tolerant plants toward the stress factor.