Different strategies to deal with the same issue: the case study of four Brazilian native grasses exposed to an excess of Zn availability.

Introduction: The successive applications of fungicides containing zinc (Zn) in vineyards increase the levels of Zn contents in soils, contributing to the reduction of productivity in vineyards in tropical and subtropical regions. Thus, it is necessary to establish sustainable strategies to decrease the toxicity potential of Zn. The selection of tolerant native plants from the Pampa biome present in vineyards can reduce Zn toxicity in vines. Objective: The study aimed to evaluate, considering physiological variables, the grass species native to the Pampa biome that are more tolerant to Zn excess. Methods: The grass species of the Pampa biome used in the experiment were Andropogon lateralis , Axonopus affinis , Paspalum plicatulum and Paspalum notatum . Three Zn doses were added to the solution, corresponding to 2µM (original concentration of the nutrient solution), 150 and 300 µM of Zn in the form of ZnCl 2 for the cultivation of the four grasses. Results: The increase in Zn availability increased the photosynthetic rate in the four species. Andropogon lateralis increased shoot and root dry matter production with increasing Zn concentration in solution. Andropogon lateralis increased phosphorus (P) retention in the root system, contributing to the increase of Zn in the roots. Conclusions: Axonopus affinis , Paspalum notatum , Paspalum plicatulum and Andropogon lateralis presented different values of growth rate, nutritional and photosynthetic parameters, and enzymatic activity, when cultivated in solution with Zn doses.