Abstract
Plant specialized metabolites are small molecules known for their role in abiotic and biotic stress tolerance. Understanding of the individual functions of most of these metabolites remains unknown. A border of the root of annual plants is especially attractive to clarity how the plant roots withstand biotic and abiotic challenges. A main part of the metabolites in the root the plant Scutellaria baicalensis consists of the wide variety of methylated flavones. Eight most abundant of its, mono- and polymethylated, which present the beginning and end of the plant flavone biosynthesis pathway, respectively, were detected as phenoxide-ions over the root organs (bark, cambium, xylem and decayed core) by LС-MS. This inspection recovers their location within cambium and bark. The disposition of mono-methylated wogonin and oroxylin A with it’s the putative potency to form the o-quinon anions (reductants) provide chemical protection of the root from reactive oxygen species. The tetra- and penta-methylated flavones arrange a passive hydrophobic physical barrier of the root bark. Environment threats necessitate the plant to produce the methylated flavones, which resistance mechanisms are embedded in the structures of their molecules.