Some aspects of underground organs of spotleaf orchis growth and phenolic compounds accumulation at the generative stage of ontogenesis

For the first time, changes of the growth and accumulation of phenolic compounds (PHCs) in different parts of underground organs of the tuberoid orchid Dactylorhiza maculata during vegetation and the winter dormancy period were studied. It was shown that the replacement of old tuberoids and adventitious roots by new ones is accompanied by active growth, assimilates reallocation, and PHCs accumulation. It was found that the tuberoid performing the function of a storage organ possessed a low PHCs content, which increased at the end of vegetation and was stably high during the winter dormancy period; in spring the content decreased, mosr likely as a result of PHCs catabolism and utilization for growth processes. It was proposed that the higher PHCs content in adventitious roots and tuberoid terminal parts is determined by mycotrophy of the organs.