Langstreckentransport von Calcium in Stolonen von Kartoffelpflanzen

Long-distance transport of calcium in stolons in potato plants In potato plants grown in water culture the influence of the tuber growth rate and the Ca supply to the tubers as well as the effect of the relative humidity around the stolons and tubers on the ⁴⁵Ca translocation in the stolon was investigated. If the stolon tip or the tuber were supplied with additional exogenous Ca and the relative humidity around the stolon or tuber was very high then ⁴⁵Ca applied to the roots was translocated in a negligible amount into the stolon or tuber. Even when the supply of exogenous Ca to the tubers was low, the tubers exerted no “sink”-effect on the ⁴⁵Ca translocation within the stolon. Under conditions of high relative humidity around the stolon ⁴⁵Ca applied to the stolon surface was nearly exclusively translocated in direction of the shoot. In contrast, under low relative humidity around the stolon or tuber ⁴⁵Ca applied to the stolon surface or to the root system was translocated into the stolon tip and into the tuber. The results indicate that within the stolon Ca is exclusively translocated in the xylem. A “sink”-effect of the tuber on the Ca translocation into the stolon as well as within the stolon was not been observed.