ISHS Acta Horticulturae 512: XXV International Horticultural Congress, Part 2: Mineral Nutrition and Grape and Wine Quality
EFFECT OF ROOTSTOCKS AND K+ SUPPLY ON PH AND ACIDITY OF GRAPE JUICE |
| Author: | E.H. Rühl |
| Keywords: | grapevine, Vitis, rootstocks, quality, potassium, malate, tartrate |
| Abstract:
The pH of grape juice or wine is a the major quality factor. Research has demonstrated that rootstocks can affect grape juice pH by changing grape juice K+ concentration. Field and glasshouse studies indicated that this effect of rootstocks on scion grape juice pH and K+ levels originate from different K+ uptake rates of rootstock varieties. At least with the varieties tested, these genotypic differences in K+ uptake only occurred at high levels of K+ supply, and not at low levels of K+ supply. This indicates that as in the roots of most other plant species, a dual K+ uptake mechanism exists in roots of grapevines, and that only the mechanism operational at high K+ levels is different in the rootstock varieties studied. It therefore appears feasible to breed rootstock varieties, which combine high K+ efficiency at low K+ supply with restricted K+ uptake at high supply. This model is currently being verified under German conditions on a range of rootstock varieties. | |
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