A possible relationship between stalk necrosis and membrane transport in grapevine cultivars

The higher susceptibility to stalk necrosis of the grape (Vitis vinifera L.) cultivar ‘Bonarda’ (clusters with few berries) than the cultivar ‘Barbera’ (clusters with many berries) was correlated to higher ratios in the tissue and to a different functioning of the transport mechanism. At the middle of the meristematic growth phase of the berries, segments excised from grapevine clusters of the more susceptible cultivars showed lower proton extrusion activity, lower K+ and Ca2+ leakage and similar uptake capacity both for K+ and for Ca2+. These results are discussed in regard to the onset of stalk necrosis in grapevine clusters.