The Influence of Foliar Fertilizing on the Structural and Optical Properties of Wheat

Throughout its life cycle a plant receives nutrients from the soil and fertilizers that are introduced into it and then absorbed by the roots. Higher plants have an additional ability to absorb nutrients when their leaves are sprayed with a solution of a certain concentration. The amount of fertilizers applied to the soil must be determined in accordance with the analysis of its composition. However, it’s not obligatory when we apply foliar fertilization method, since the properties of the leaves depend not only on the type of plant, but also on the conditions in which it grew. This study for the first time introduces a method for determining optimal concentrations of foliar fertilization based on the structure and optical properties of the plant leaf. In 2023, Kuraginskoe production farm was chosen as a site of a field experience aimed at studying foliar fertilization of Novosibirskaya 31 spring soft wheat ( Triticum L.). The experiment was conducted in 4 ways: 1) control; 2) one-time foliar fertilizing in the tillering phase; 3) two times foliar fertilizing: in tillering and shooting phase; 4) triple fertilizing: in tillering phase, the shooting, and the beginning of earing. We used electron microscopy pictures to assess the standard deviation of thylakoids size as a degree of ordering. Based on models of one-dimensional photonic crystals, graphs of the density of photonic states were calculated. From the analysis of the obtained fluorescent spectra of the flag leaves, changes in the intensity and width of the spectrum lines are visible. Comparison of contours of the peak corresponding to photosystem (PS) II shows a difference in half-widths, which indicates a more active pumping of energy in a plant treated with triple fertilizing. The methods used in the study let us calculate a correlation coefficient equal almost to 1, which means strong link of these parameters. The study has shown that the main mechanism for increasing crop yield when applying foliar fertilizing is a more efficient transfer of energy from PS II to PS I.

photosynthesis, chloroplast, photonic crystal, electron microscopy, fluorescence spectroscopy, numerical modeling