Potassium, calcium and magnesium uptake of Japanese persimmon trees in root restricted culture.

The micropropagated persimmon trees by shoot tip culture were planted in the plastic cloth pots with artificial media, and they were cultured for 3 years. Trees were 2.5 m in height and had over 15 lateral branches at the time of investigation. Potassium, calcium and magnesium were measured by atomic absorption spectrochemical analysis. Leaves had already high potassium content in June 1, and had the same content by August 1. But after that time these contents declined and leaves had fallen in the middle of November with high potassium content in these failed leaves. Roots had low potassium contents by August 1, and after that the amount increased. Potassium contents of shoot and trunk were constant in low level throughout the year. Calcium contents increased after June 1 in leaves and trunk and increased after August 1 in roots. Magnesium content increased after August 1 in roots. Root was storage organ of potassium, magnesium and calcium and leaves that had fallen in the middle November had high content of these elements.