Effect of foliar application of microelements on chlorophyll content, canopy architecture indicators, and physiological parameters of <i>Hordeum vulgare</i> L. plants

The foliar application of each of the microelements tested caused a significant increase in the chlorophyll content in the leaves and canopy architecture parameters (LAI and MTA) compared to the control. Furthermore, a significant increase in gas exchange parameters was also observed: intercellular CO₂ concentration (<i>C</i> _i), transpiration rate (<i>E</i>), stomatal conductance (<i>g</i> _s), net photosynthetic rate (<i>P</i> _N) and chlorophyll fluorescence parameters, maximum quantum yield of PSII photochemistry (F_v/F_m), fraction of active PSII reaction centers (RC/ABS), potential photochemical efficiency (F_v/F₀), and performance index (PI). The highest results of physiological parameters such as CCI, <i>C</i> _i, <i>E</i>, F_v/F_m, F_v/F₀ and PI were recorded after the application of zinc fertilizer. LAI and MTA were highest in plots with plants sprayed with molybdenum-based fertilizer. The foliar application of Cu caused the greatest increase in C_i and <i>P</i> _N. The experiment showed significant genotypic differences. The RGT Planet cultivar had a higher chlorophyll content, <i>E</i> and <i>P</i> _N parameters among the tested cultivars. The KWS Irina cultivar was characterized by the highest values of canopy architecture parameters and significantly lower values of CCI, F_v/F_m and F_v/F₀ compared to the Baryłka and RGT Planet.