Growth-regulating activity of N-benzyl- and O-benzyl-containing compounds belonging to a new group of synthetic analogues of natural auxins

Abstract

We studied the effect of benzylamine, benzyl alcohol, and their derivatives (constituting a new group of synthetic analogues of natural auxins) on rooting of leaf and stem cuttings, rhizogenesis and growth of barley plantlets and tomato seedlings, and tomato plant productivity. These compounds promoted rooting of leaf and stem bean cuttings, increased rhizogenic activity, and stimulated the development of root systems in barley and tomato seeds. The activity of the compounds studied was similar to that of standard substances (3-indoleacetic acid potassium salt and 2-naphthylacetic acid). The benzyl group attached to the oxygen or nitrogen atom was shown to be the smallest molecular structure which provided auxin activity of the compounds. Derivatives of benzyl alcohol containing the quaternary ammonium fragment possessed auxin and antigibberellin (retardant) properties. They were selected by chemical synthesis of low-molecular-weight bioregulators with desired properties (a combination of chemical fragments with complementary physiological activity in the molecule). Auxin and anti-gibberellin (retardant) activities produced a synergistic effect. Germination of seeds treated with these compounds was accompanied by a more significant increase in the weight and length of roots (compared to standard auxins). The rate of seedling establishment reached 100%. The development of fruits and accumulation of reserve nutrient substances were synchronized and accelerated after spraying vegetating plants with solutions of studied compounds. The synergistic effect underlay a significant increase in the amount and quality of the crop (e.g., tomatoes).

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

“…Using pea seedlings we found that stress-protectors-phytoregulators benzyhol and ethyhol and their analog akvyhol, all containing an oxymethyl fragment, manifested a rhizogenic activity similar to that of IAA, although they do not belong to auxins. It is in agreement with the data on a high rhizogenic activity of the compounds bearing oxybenzyl or aminobenzyl fragments obtained in the test systems of rooting of leaf and stem cuttings of beans and spring barley seed sprouting [8][9][10]. Thus, oxybenzyl OBzl and aminobenzyl NHBzl groups are new structural fragments of molecules of chemical regulators of plant growth and development adding a rhizogenic activity of the non-auxin nature.…”

“…In our experiments we showed that the oxybenzyl group OBzl linked to a quaternary ammonium fragment via a dimethylene linker provided to the compounds under study an essential rhizogenic activity of a non-auxin nature. Previously, it was found that compounds with an aminobenzyl group also displayed a high rhizogenic activity [8][9][10]. Thus, these two chemical fragments are the structural elements giving compounds a high rhizogenic activity.…”

“…It was shown previously that the compounds bearing oxybenzyl OBzl or aminobenzyl NHBzl fragments including benzyl alcohol, benzyl amines and their quaternary salts, for example, stress-protectors-phytoregulators benzyhol and ethyhol, can stimulate rooting of leaf and stem bean cuttings as well as rhizogenesis and development of barley seedlings, with the rhizogenesis activity comparable with that of reference auxins, IAA and 2-naphtylacetic acid [8][9][10]. The studies were performed using a biotest available at that time for auxin activity [11], although some data had already indicated that "biological methods were insufficiently specific and the results depended on hardly controlled variations of sensitivity and reactivity" [12].…”

“…The authors reported that the test on bean cuttings was highly specific and only IAA as a natural auxin caused the active root formation, whereas other phytohormones and inhibitors were either inert or inhibited the process [11]. Based on the results of the biotest, the authors drew a conclusion that oxybenzyl and aminobenzyl fragments provided the auxin activity to the compounds under study [8][9][10].…”

Influence of potassium p-aminobenzene thiosulfate on the membrane potential and ATPase activity of the plasmatic membrane of the embryos of weatherfish (Misgurnus fossіlis)

“…Studying synthesis of new biologically active compounds and subsequent search for new potentially medical drugs are relevant scientifictechnological tasks. Special attention should be paid to the development of synthetic analogues of natural bioregulators (Filimonov, 1999;Steiner, 2001;Gafurov & Makhmutova, 2005;Crowley & Dando, 2022), which would be able to exert higher or lower biological action and thereby regulate the physiological activity of the cell, organ or the organisms in general. The development of chemistry of sulfur-containing organic compounds is of significant scientific and practical importance.…”