Strategy of chemical design of phytoregulators and stress protectors with the given properties

Abstract

Phytohormonal regulation of the growth and development of plants is chosen as a physiological model for developing the strategy of chemical design of effective phytoregulators and stress protectors. The strategy [1 − 3] is based on the following assumptions.(1) Several, rather than one, life-supporting systems participate in the formation of the response of living organisms to any external influence. Even weak but simultaneous stimulating influence on some systems, forming a given character can cause a strong responding effect.(2) It is necessary that these influences should be complementary and coordinated.(3) The physiological activity of a molecule is a result of the interaction of its effector chemical fragments with the receptors of those systems which form the given character (quality).(4) Physical and chemical properties of the effector fragments and the whole molecule (their topochemistry and molecular parameters, including the affinity for proton, water and lipids) do not determine the regulation influence qualitatively. Instead, they strengthen or weaken it quantitatively to the degree corresponding to the structural requirements of structure the receptors of regulatory systems.Auxins and gibberellins, as natural phytohormones, carry out complementary functions in two key processes in the life of a plant: (a) the germination of a seed and rooting of the sprout and (b) the formation and development of fruits and seeds [4,5]. During germination, auxins provide rhizogenesis and gibberellins, the growth of the above-ground part of a plant. Additional stimulation of sprout rooting by auxins accompanied by a slight inhibition of the development of the aboveground part would allow redistributing stocks of nutrients of a seed for the benefit of rhizogenesis, which, in turn, would increase the stability and efficiency of crops. The same auxins together with abscisins control the flow of plastic substances from the feeding flag leaf to the developing seeds and fruits during fructification. Shortage of auxin largely determines the heterogeneity of maturing fruit ripening and slows down their development. During fructification, the inhibition of an excessive growth of the above-ground part of a plant is useful for crop, because it allows redistributing mineral and water for fruit development. Hence, phytoregulators to be designed should have two complementary growth-regulation activities: auxin and antigibberellin (retardant).On the basis of the developed strategy, compounds I, II and III [6] were selected (Table 1). They combine chemical fragments with auxin (the O-benzyl fragment) and with retardant (the quaternary ammonium group) activities favors fast and effective rooting of sprouts developing from seeds subjected to preceding processing. This raises the efficiency of a plant and its stability to stresses and phytopathogens, whereas the radionuclide carry-over from the ground is decreased [7,8]. During the preharvest processing of a plant with solutions of salts I, II and III, developing fruits receive additio...

New Structural Fragments of Molecules of Chemical Regulators of Plant Growth and Development Stimulating Rhizogenesis

“…Previously, it was reported that the compounds under study being quaternary ammonium derivatives also displayed a retardant activity similar to that of chlorocholine chloride [13]. Therefore, the physiological activity of these compounds is a sum of rhizogenic and retardant activities of their effector fragments [24].…”

“…The goal of this work was the generation of quantitative data on the auxin activity of some stress-protectors-phytoregulators using current highly sensitive analytical methods. Later, we planned to increase the number of such compounds by the synthesis based on the chemical design strategy [13], measure the auxin activity of the synthesized compounds, and evaluate the structure-auxin activity relationship for this group with QSAR methods. It had been previously done for the determination of the antigibberellin activity of the retardant group [14].…”

Route to Novel Auxin: Auxin Chemical Space toward Biological Correlation Carriers

“…According to Gafurov, 186 weak but simultaneously stimulating influences on some systems with a given character can cause a strong response in case that the physical and chemical properties of the effector fragment and the whole molecule themselves do not determine the regulation influence qualitatively. We are facing a phenomenon where the cause-effect relationship is a statistical regularity.…”