Arbuscular mycorrhizal fungi inoculation as strategy to mitigate copper toxicity in young field-grown vines

Frequent applications of foliar fungicides on grapevines increase copper (Cu) levels in soils, which may cause toxicity to young grapevines transplanted to eradicated old vineyards, especially because they are more sensitive. Therefore, it is necessary to adopt strategies to mitigate Cu toxic effects, such as grapevine seedlings inoculation with arbuscular mycorrhizal fungi (AMF), which establish symbiosis association with plants roots, preferably in field experiments. The present study we objective to evaluate AMF pre-inoculation effects on growth and mineral absorption of grapevine seedlings in a field experiment using sandy soil contaminated with Cu. The experiment was conducted in Santana do Livramento (RS), in a Typical Hapludalf soil. Initially, grapevine seedlings from 'Paulsen 1103' (Vitis berlandieri x Vitis rupestris) rootstock were AMP pre-inoculated and then transplanted into the field in area containing high Cu levels. Experimental design was a randomized complete block design, with a 4 x 2 factorial scheme: four seedlings pre-inoculation treatments (control = uninoculated seedlings; Rhizophagus clarus UFSC-14; Rhizophagus intraradices UFSC-32; Dentisculata heterogama UFSC-08); two soil Cu concentrations (62 mg/kg and 118 mg/kg (Mehlich-I), with five replications. Pre-inoculation did not favor growth of young vines in field after 316 and 500 days of transplantation (DAT). However, seedlings from pre-inoculated vines with R. intraradices UFSC-32 and R. clarus UFSC-14 presented lower Cu levels in leaves in the soils with high Cu levels. Thus, pre-inoculation of young vines seedling with selected AMF may represent a strategy to reduce Cu toxicity, contributing to plants establishment in contaminated soils.

Automated summary

Frequent applications of foliar fungicides on grapevines increase copper levels in soils, potentially causing toxicity to young grapevines transplanted to old vineyards. A field experiment was conducted to evaluate the effects of pre-inoculation with arbuscular mycorrhizal fungi (AMF) on growth and mineral absorption of grapevine seedlings in Cu-contaminated sandy soil. The results showed that pre-inoculation did not promote the growth of young vines, but reduced copper levels in the leaves of seedlings in soils with high copper concentrations. Therefore, pre-inoculation with selected AMF may be a strategy to reduce copper toxicity and promote plant establishment in contaminated soils.