Resumen de Accumulation of potassium in grapevine rootstocks (Vitis) as affected by dry matter partitioning, root traits and transpiration
Shreevatsa Kodur, J. M. Tisdall, Caixian Tang, Rob R. Walker
Background and Aims: A high concentration of potassium (K) in grape juice can lead to high juice pH (e.g. >3.8) and, in turn, wine of lower quality. The concentration of K in grapevine can be controlled by rootstocks. However, the differences between rootstocks in the accumulation of K in grapevines and mechanisms of regulation of K are not well known. The current study addresses these issues.
Methods and Results: Rootstocks (on own‐roots) Freedom, Schwarzmann, 1103 Paulsen, 110 Richter, 140 Ruggeri and 101‐14 Millardet et de Grasset were grown in sand for 56 days in a glasshouse and watered daily with 3 mM K. At Day 56, rootstock 1103 Paulsen had the highest total K uptake, while 101‐14 Millardet et de Grasset and 140 Ruggeri had the highest concentration of K in shoot and roots, respectively. Total K uptake in rootstocks was positively related to the dry weight of the whole grapevine, relative growth rate, total root length and total root surface area. Translocation efficiency of K in rootstocks was positively related to shoot : roots dry weight and shoot demand for K per unit root weight. Total K uptake and accumulation of K into the shoot were not affected by transpiration, but concentration of K in the shoot was positively related to the concentration of K in the xylem sap.
Conclusions: The results show genetic differences between grapevine rootstocks in K uptake and transport, and highlight the importance of growth, dry matter partitioning, root traits and root pressure, and the lack of significance of transpiration, in the accumulation of K.
