Effects of copper stress on morphological traits and copper compartmentalization and microstructure of flax (Linum usitatissimum L.) cultivars

Flax ( Linum usitatissimum L.) is a crop plant that has long been used for various purposes, including production of fiber, oil, and food. In addition, it has more recently been studied for its phytoremediation potential to remove and detoxify environmental contaminants. Copper is a heavy metal that can be toxic to plants. In recent years, flax has begun to be used as a phytoremediation tool for phytoextraction of different heavy metals, especially when grown in metal-contaminated soils. The objective of the study was to conduct the efficiency of flax as a phytoremediation plant grown on the soil contaminated with different doses of copper (Cu) (control, 100 and 200 mg L -1 ) metal. The results revealed that a high concentrations of Cu in the soil negatively affected plant growth and development by reducing plant height (30.17-22.33 cm), technical stem length (25.83-18.33 cm) and root length (7.50-4.00 cm) compared with the control (30.17-25.17 cm). The content of Cu in the leaves, stems and roots of flax cultivars was higher at 200 mg L -1 Cu concentration in the Mures and Erkendorfi cultivars. In addition, the two Cu concentrations (100 and 200 mg L -1 ) were highly destructive to the plant, according to the SEM images, and the maximum stem damage was reported. Thus, the soil Cu content should be carefully controlled in order to avoid adverse effects on plant growth and development. Consequently, future research is needed for gaining better understanding of the physiology, biochemistry, anatomy, and molecular biology of flax in order to increase its pollutant removal efficiency.