Anatomical Study of Japanese Knotweed (Reynoutria japonica Houtt. Polygonaceae): key Insights for Identifying an invasive species with medicinal traits

The macroscopic and microscopic characteristics of the above- and underground organs, along with features of powdered plant material of the invasive species Reynoutria japonica; Hout., Polygonaceae, as a potential raw material for the pharmaceutical industry, were examined. No specific characteristics of the stem, root, and rhizome were identified that could independently allow for species determination. However, identifying features include the leaf midrib with its protrusions, vascular bundle arrangement and trichomes. The leaf powder is characterized by presence of epidermal cells with wavy walls, anisocytic stomata, numerous crystal druses, and conical unicellular trichomes. The ellements present in the rhizome and root powder are crystal druses, cork fragments, vessels, macrosclereids, and grouped starch grains. The use of R. japonica as medicinal raw material could help to reduce the negative impact of this species on habitats and biodiversity in Serbia.