Influence of Macroelements’ Uneven Distribution on the Content of Hormones and Extension of the Roots in Wheat Plants

Resumo

Increase in the level of mineral nutrition reduces the relative growth rate of the roots, which adversely affects the drought resistance of plants. This was not observed when fertilizers were locally applied. Local fertilizer treatment caused activation in the elongation of the roots that were not directly in contact with locally applied fertilizers. The goal of this study was identification of features of the association between hormone levels and growth of Triticum durum Desf. seedlings under the influence of changes in the level and distribution of mineral nutrition elements in the environment. For this purpose, a model with a split root system imitating local fertilization was used, when part of the roots is in contact with high (HC) concentration of macronutrients and the other part is in contact with a low concentration of macronutrients (LC). It was shown for the first time using immunohistochemical localization that the inhibition of elongation of HC roots occurred at the increased content of cytokinins in the cells of the root tips, which can explain the inhibition of root elongation under the influence of an increased concentration of mineral nutrition elements. Differences in the content of ABA in the shoots of plants grown in the presence of uneven (heterogeneous, Het-plants) and uniform (homogeneous, Hom-plants) distribution of macronutrients were not found. This indicates that there is no stress effect of a local increase in the osmotic concentration in the root area (HC) on the plant in general.