FREE AMINO ACIDS IN ROOT EXUDATES OF CEREALS DURING THE PROCESS OF GROWTH STIMULATION AND PHYTO REMEDIATION

Key words: amino acids, phytoremediation, cereals

Amino acid content of root exudates of some cereals in usual conditions of j growth and under application of growth stimulation was studied. Genetic ] regulation of exudative process, high content of basic amino acids in exudates of some species and perspectivness of application of the growth stimulators are j shown. Some aspects of amino acids root exudation now are considered in connection with arising problem of phytoremediation. As it was recently shown organic acids in soil may act as phytosiderophores - metal-chelating molecules being secreted into risosphere chelated and solubilized soil-bound metals (Salt et al. 1995). Role of free amino acids is not studied in this aspect but it was reasonable to suppose that these chemically active substances in root exudates will play role of phytosiderophores. Also, amino acids in soils are nutritive elements that increase living status of a region. The purpose of our work is to investigate the process of amino acid exudation during the first germination days of some cereals and influence growth regulators on that process. Several inbred lines of maize {Zea mayz L) and wild cereals (Festuca rubra L., Lollium perenne L.) were studied. Amino acid content of root exudates under application of heteroauxine (HA) (Lethman et al. 1978) and mixed succinate- fumarate of iron (TSFe) (Tananaeva 1981), content of Pb, Cd and Zn were measured in three layers of soil in these experiments according to usually accepted procedures. We showed that cereals studied by us had different quantity and content of amino acids in root exudates and different reply to growth stimulation (Tab. 1).