Interactions between nitrogen nutrition and phytohormone levels in festulolium plants

Abstract

This study aims to reveal and to compare effect of two various systems of nitrogen nutrition, namely injection and sidedress application, on the levels of NO-3 and phytohormones (cytokinins, abscisic acid (ABA), indole-3-acetic acid (IAA)) in Festulolium plants. Calcium nitrate (CN) or ammonium sulphate (AS) were used as N source in the pot experiment. The yield of Festulolium above and below ground biomass was more substantially enhanced after sidedress application of both AS or CN in comparison with injection application. The levels of endogenous cytokinins peaked 5 days after application regardless the form of N source and the method of application. The increased concentration of endogenous cytokinins as well as the enhanced content of selected free amino acid suggest that N applied sidedress can maintain better distribution patterns of nutrients and provide improved conditions for growth and nitrogen uptake. The nitrogen application affected ABA concentrations on all tested treatments. The correlation between NO-3 and ABA concentrations ranged from 0.77 to 0.89. A significant IAA increase was recorded in plants after ammonium nitrogen sidedress application and it was confirmed that applications of nitrate reduced IAA concentration (correlation between NO and IAA for AS treatment R2 = 0.77-0.94).