Effect of potassium supply on cation uptake and distribution in grafted Vitis champinii and Vitis berlandieri x Vitis rupestris rootstocks

The effect of different potassium (K) supply levels (1 and 10 mmol/L) on cation uptake and distribution was investigated in a nutrient solution trial using Vitis champinii var. Ramsey and Freedom and V. berlandieri x V. rupestris var. 1103 Paulsen and 140 Ruggeri grafted with Djandjal Kara. While dry matter production was not affected by K supply or rootstock, greater K supply increased K contents in the various plant parts by 25-32%. Vines grafted on Freedom had the highest K content in the scion parts, and those grafted on 1103 Paulsen had the lowest. Potassium and magnesium (Mg) accumulation, expressed as the relative contribution to total cations, clearly distinguished between V. champinii (Ramsey and Freedom) and V. berlandieri x V. rupestris (1103 Paulsen and 140 Ruggeri), with higher K and lower Mg accumulation in vines grafted on V. champinii rootstocks. Results indicate that K accumulation in the scion parts of grafted vines is affected by the genotype of the rootstock.