BIMODAL EFFECT OF THE PICOLINIC-ACID DERI VATIVES ON THE RATE OF WHEAT AND PEA GERMINATION

The physiological effects of some picolinic acid derivatives at concen trations of 10(-4) - 10(-14) M On the tate of germination of wheat and pea seeds were studied. Conformations of the molecules were optimized using the molecular mechanics methods and angles of rotation with ref erence to the aromatic cycle were found. The distribution of charges o n the molecule atoms was established by quantum-chemical calculations, Bimodal dose dependence was found for some compounds. These results s uggest that compounds with a small dihedral angle of the substitute ro tation with reference to the pyridine ring with minimal redundant char ges on three substitute atoms closest to C2 and with a sufficiently hi gh dipole moment display bimodal activity. Based on the analysis of el ectron structures and the energetics of reactions of the picolinic aci d compounds, a new mechanism is proposed for the effects of ultra low doses on biological objects.