Identifying Grapevine Rootstocks Tolerant to Copper Excess

The aim of the current study is to identify grapevine rootstocks with the potential to tolerate excessive Cu concentrations. Four grapevine rootstock genotypes were tested: Paulsen 1103, IAC 572, SO4 and Isabel. The plants were cultivated in nutrition solution added to the following treatments: 0.3 µM Cu and 80 µM Cu. Growth, nutrient concentration in tissue and the physiological and biochemical parameters were assessed. Rootstocks showed different growth responses to Cu excess in the solution. SO4, IAC 572 and Isabel markedly reduced growth under Cu excess compared to plants in the control solution, whereas genotype Paulsen 1103 showed a less pronounced effect. The root system of all genotypes presented a Cu increase under a high Cu concentration, as well as higher POD activity and H2O2 concentration than the control. Isabel presented the greatest sensitivity to Cu excess, as shown by leaf wilting and yellowing. Paulsen 1103 rootstock presented smaller changes in the observed parameters in the high Cu concentration solution than in the control solution. Our results indicate that Paulsen 1103 is the most tolerant to Cu excess, whereas Isabel is the most sensitive. There are natural genetic variations in tolerance to this abiotic stress that typically affect grapevine plants.