SEASONAL DYNAMICS OF THE PHOTOSYNTHETIC PIGMENTS CONTENT IN <i>Populus tremula</i> L. LEAVES AT THE ADAPTATION ON AN OPEN-PIT COAL MINE REVEGETATING DUMP
Seasonal dynamics of the basic photosynthetic pigments (<i>a</i> and <i>b</i> chlorophylls, carotenoids) content in the samples of aspen <i>Populus tremula</i> during natural regeneration on a revegetating pit dump of a worked-out coal pit has been studied. The studies were conducted every ten days during the vegetation period in 2015 (June-September) on the territory of «Yuzhniy» dump of «Kedrovskiy» open-pit coal mine (Kemerovo region). The pigment content was identified by the means of spectrophotometric detection. The content of photosynthetic pigments in aspen leaves was calculated on oven-dry weight of the leaves, as moisture aspen leaves can greatly vary, and the determination of accuracy of dry matter content higher than the for specific gravity of the sheet. No changes in visible absorption spectrum of acetone extracts indicating pheophytin formation in chlorophylls have been identified. For all variants the larger amount of <i>b</i> chlorophyll was contained in control samples. The largest differences in <i>a/b</i> chlorophylls and chlorophylls/carotenoids ratio were observed in the end of vegetation period. The ratio between <i>a</i> and <i>b</i> chlorophylls of aspen leaves in both cases by the end of the season was considerably lower. The adaptation of aspen photosynthetic system to the revegetating dump conditions was performed due to decrease in the total pigment content and the percent of <i>b</i> chlorophyll in their composition.