This thesis provides insight into the influence of IPPs on the IAA and JA-Ile perception in Arabidopsis thaliana. Different transgenic plant lines were created and physiological and transcriptional studies performed. In the scope of physiological experiments, the basal IPP concentrations, phosphoinositide levels and phytohormone concentrations were determined. Additionally, dynamic changes of the IPP concentrations upon mechanical wounding and heat stress were studied. In phenotypic studies, root growth, leaf growth and gravitropic bending responses of the transgenic lines were analyzed. Furthermore, the expression of IAA- and JA-Ileinducible genes was investigated in the context of modulated IPP concentrations. The relationship between varying IPP concentrations and physiological effects of the transgenic lines was visualized with correlation graphs. Additionally, the subcellular localization of the IPP-synthesizing enzymes IPK1 and IPK2 and its reason was investigated. Overall, this work provides a comprehensive picture of the influence of IPPs on growth and defense processes in Arabidopsis thaliana.