This paper examines the autumn retranslocation of heavy metals (HMs), namely Cu, Zn, and Cd,from the photosynthetic organs of woody plants. This study was carried out in the subtaiga ecosystems in thesouthern part of the Meshchera Lowlands (Ryazan oblast, Russia). It is shown that three factors affect theHM retranslocation from ageing leaves: (1) the properties of the chemical element (degree of biophilicity,mobility in plant tissues depending inter alia on the ability to form complexes in plant transport systems, andthe geochemical similarity of elements with different clarke values determined by the resemblance of theirexternal electronic shells); (2) the species-specific characteristics of the plant; and (3) the concentration ofthe element (in bioavailable forms) in the soil solution. The relationship between the Cu and Zn retranslocationprocess and nitrogen catabolism in autumn leaves was analyzed. The most general trend involves the outflowof Cu from ageing leaves and accumulation of Zn in them. The share of toxic Cd retranslocated fromleaves varies significantly in different species. This article discusses the multifactorial nature of the retranslocationprocess and the reasons behind its variability under different environmental conditions.
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