Effects of excess copper in vineyard soils on the mineral nutrition of potato genotypes

Abstract

The ecotoxicological effects of copper (Cu) are of global concern due to the intensive and long-term application of Cu-based fungicides, which may cause Cu to accumulate in the soil. Relative to the effects of other metals, comparatively little is known about the accumulation and translocation of Cu and its effects on other mineral nutrients in plants. This study determined the mineral nutrient distributions under Cu toxicity in potato genotypes differing in their efficiency of use and response to phosphorus (P). Plants were grown in vineyard soils with varied Cu soil levels (2, 5, 36, 67, 96, 270, and 321 mg/kg) during the fall and spring growing seasons. The increase of Cu concentrations in plant tissues was dependent on the external Cu concentrations, and the highest concentrations were observed in root and stolon tissues. The majority of the Cu taken up by the plants accumulated in the tubers. During the fall growing season, plants classified as NER (P-nonefficient and P-responsive) showed the highest sensitivity to excess Cu in terms of growth and nutrition. The plants showing responses to Cu toxicity included plants without expanded leaves and plants without tuber production, whereas genotypes classified as ENR (P-efficient and P-nonresponsive) were able to expand their leaves and produce tubers in all tested soils. Tissue P and Cu concentrations showed a strong correlation with high Cu concentrations in Cambisols, whereas Fe and K tissue concentrations were more strongly correlated with Cu levels in Ultisols. Our data suggest that the middle and apex leaves should be used to assess Cu toxicity in potato plants. This study also provides evidence of noncompetitive uptake of Cu and Fe by potato plants.