Copper Stress Enhances the Lignification of Axial Organs in Zinnia elegans

Zinnia elegans Jacq. is an ornamental plant, widely used in landscaping. Heavy-metal pollution urban and rural areas still increasing, which determines the actuality of studying plants’ reactions to pollutants. was not sufficiently studied this regard, so aim our research identify morphophysiological changes species under excess copper concentration soil. For this, we treated a growth substrate with 200 µM CuSO4 solution for 20 days. At end treatment, several morphological, biochemical, molecular genetic traits were evaluated: root shoot size; H2O2 malondialdehyde (MDA), as indicators stress; amount phenolic compounds lignin; level expression genes, encoded their biosynthesis. The Cu zinnia organs quantified using atomic-absorption spectroscopy; hydrogen peroxide, MDA, determined spectrophotometrically, while lignin according Klason. Real-time PCR estimation gene-transcription level. Lignin tissues visualized by fluorescent microscopy. In experimental plants, accumulation higher than stem. This caused increase stress markers decrease stem lengths. first time zinnia, it shown that genes—4-coumarate-CoA ligase (4CL), cinnamoyl alcohol dehydrogenase (CAD), class III peroxidase (PRX)—the increased treatment. rise transcripts’ these genes accompanied thickening lignification cell walls metaxylem vessels. Thus, adaptation medium associated metabolic phenylpropanoid pathway. As result, root, led organ limited its translocation through xylem stem, provided plant growth.