Use of phosphorus fertilization and mycorrhization as strategies for reducing copper toxicity in young grapevines

Abstract

Abstract Established vineyard soils may have high copper (Cu) contents due to the ongoing foliar applications of copper-based fungicides. In viticulture, the replacement of old vineyards with new vines is common practice, however, limited by Cu excess in soil and its toxicity to young grapevines. The application of phosphorus (P) and arbuscular mycorrhizal fungi (AMF) inoculation are potential strategies to reduce Cu toxicity to young grapevines. This study aimed to assess the effects of phosphorus fertilization and AMF (Rhizophagus clarus) inoculation on growth and physiological parameters of young grapevines grown in soil with high Cu content. The experiment was conducted in a greenhouse, where natural grassland soil was artificially contaminated by the addition of 60\u2009mg\u2009kg−1 Cu. The soils were treated with and without AMF inoculation, combined with additions of 0, 40 and 100\u2009mg\u2009P kg−1. After 90 days of cultivation, grapevine plants were assessed for chlorophyll a fluorescence, photosynthetic pigment contents, superoxide dismutase (SOD) activity, plant height, plant biomass, and concentrations of Cu and P in roots and shoots. Phosphorus fertilization promoted increases in seedling growth (related to the increase of total P concentration in roots and shoots), soluble Pi concentration in leaves, and the quantum yield of the PSII (YII) (associated with a reduction in shoot Cu concentration). The AMF inoculation increased the concentration of P in roots and shoots, soluble Pi in leaves and electron transport rate (ETR). Phosphorus fertilization and inoculation of grapevines with AMF are strategies capable of reducing Cu toxicity in young grapevines.