Tolerance and translocation of heavy metals in young grapevine (Vitis vinifera) grown in sandy acidic soil with interaction of high doses of copper and zinc

Vineyard soils may have high levels of copper due to frequent applications of Bordeaux mixture for the control of fungal diseases. Therefore, many winegrowers have used zinc-based fungicides instead of copper-based fungicides, resulting in high levels of Cu and Zn in vineyard soils. The aim of the study was to evaluate the tolerance of young grapevines grown in soil with interaction of high contents of Cu and Zn, and the translocation of these heavy metals from roots to shoots. We collected soil of a natural field of Rio Grande do Sul, the southernmost state of Brazil. Soil treatments were addition of 0, 30, and 60 mg Cu kg(-1), and addition of 0, 15, 30, 60, 120, and 180 mg Zn kg(-1) for each copper dose. A seedling of grapevine per pot was grown for 60 days. After that, we measured root and shoot dry matter, Cu and Zn content in roots and shoots, chlorophyll a fluorescence, photosynthetic pigments, and peroxidase and superoxide dismutase activity. Young grapevines showed tolerance mechanisms to high concentrations of Cu and Zn by retaining these metals in the roots, decreasing translocation to the shoots. However, at the highest doses of Cu and Zn, we observed decrease in plant growth and in photochemical efficiency associated with the decrease in photosynthetic pigment content. Furthermore, the activity of antioxidant enzymes increased in intermediate doses of Zn, which indicates activation of the antioxidant system. However, the stress condition in treatments with high levels of Cu and Zn was not reversed.