Influence of Composition of Zosteran–Boric Acid Supramolecular Complexes on the Efficiency of Growth Processes of Cereals

Abstract

Background. Boron is recognized as an important trace element for the processes of functioning of higher plants. The role of boron is specific, it is an indispensable element of nutrition, without which the life of plants is impossible. The main source of boron for plant nutrition is boric acid, which in interstitial water is in the form of non-dissociated molecules and is characterized by rather low solubility and bioavailability. Pectin, which forms boric acid complexes with 1:1 and 2:1 molar ratios, can be used to transport boric acid to a plant. Determining the bioavailability of each of these complexes will optimize the process of boron fertilizers introduction.Objective. The aim of the paper is introduction of boron into plants in the form of supramolecular complexes of boric acid with pectin in order study of bioactivity of such complexes depending on their composition.Methods. Pectin was extracted from leaves of hydrobiont of Zostera marina. Distribution area of this higher plant in Ukraine is the Black Sea coast of the Odessa region. Test cultures of corn and wheat were used as the objects of the study of biological activity effect of zosteran-boron supramolecular complexes on the growth function of the root and the ground part. The mass of the root system and the ground part of the plant was measured according to original methodology in 96 hours after the experiment was started (seed soaking in distilled water for 24 h and in the solution of the supramolecular complex zosteran–boric acid for 72 h).Results. As a result of seed germination on the solutions of supramolecular complexes of different composition, it was found out that complexes have a significant activating effect on the growth processes of aboveground part of plants. It was demonstrated that the biological activity of solutions substantially depends on the nature of culture. Corn showed a higher overall biological activity of supramolecular complexes (up to 108%) compared with wheat (60%). Solution of the supramolecular complex of zosteran–boric acid in a 1:1 molar ratio was found to be effective for both cultures. Zosteran–boric acid complexes in the molar ratio of 2:1 did not demonstrate high biological activity.Conclusions. High biological activity (107.87% for corn and 60.35% for wheat) was demonstrated by complex with zosteran–boric acid mass ratio of 1:20. In such instance, the formation of zosteran–boric acid complexes with molar ratio of 1:1 is the most probable case. It is caused by smaller sizes and therefore better bioavailability of such complexes. Complexes with pectin-boric acid 2:1 molar ratio demonstrated lower biological activity (103.33% for corn and 11.18% for wheat). It can be explained by steric restrictions during penetration into the plant.