Root/soil interfaces are characterized by the deposition of the hydrophobic biopolymer suberin to the plant cell wall.Using gas chromatography and mass spectrometry (GC/MS), chemical composition of suberized plant cell walls can be investigated.Suberin is mostly composed of oxygenated, very long chain fatty acids with chain-lengths ranging from C16 to C30.Fatty acid elongases (FAE) and cytochrome P450 monooxygenases (P450) are essential enzymes for suberin monomer biosynthesis.Using reverse genetic approaches, several knockout mutants of Arabidopsis thaliana with T-DNA insertions in FAE-and P450-genes were isolated, changes in root suberin composition of mutants were identified by GC/MS and a biosynthetic pathway for suberin biosynthesis has been suggested.In response to different environmental stress factors (salt, drought, oxygen deficiency...) acting on roots, suberization is strongly enhanced, thus leading to strengthened apoplastic barriers in roots.This reduces water loss to dry soil, oxygen loss to the environment under water-logged growth conditions and reduces rates of salt uptake.Examples of successful adaptations of Arabidopsis thaliana and rice roots towards these environmental stress factors will be presented and discussed.