The objective of the study carried out at Botanical Garden of Southern Federal University (Rostov-on-Don, Russia) was to assess the seasonal changes in photosynthetic pigments contents in the leaves of the maples Acer campestre L., A. negundo L., and A. saccharinum L. Leaves samples were collected from selected maple trees once a week. The contents of chlorophylls and carotenoids were determined spectrophotometrically and expressed per leaf area (mg/dm2). Similar seasonal changes in chlorophylls a and b in A. campestre, A. saccharinum, and A. negundo have been found. At the same time, the seasonal changes in carotenoids contents in A. campestre differs from those in A. saccharinum and A. negundo. The qualitative and quantitative parameters of the seasonal changes in chlorophylls a and b and carotenoids differ from each other, regardless of species. All maple species differ significantly in the mean contents of photosynthetic pigments, the highest one featured by A. campestre. Using the analysis of variance, variations in the contents of photosynthetic pigments during a season were assessed. Chlorophyll variability is highest in A. campestre and lowest in A. negundo. A very large difference of A. campestre from A. saccharinum and A. negundo was found in the variation of carotenoid contents. The response of photosynthetic pigments to changes in climatic factors is higher in A. campestre than in A. saccharinum and A. negundo. These findings suggest that drought adaptation strategy of A. campestre is active, whereas that of A. saccharinum and A. negundo is passive.
Keywords: chlorophyll, carotenoids, maple, adaptation, climatic factors.