RADIOISOTOPES

Photosynthates are translocated into the plant tissue mainly in the form of sucrose. To determine whether there are differences in translocation between internally produced photosynthates and externally applied sucrose, ¹⁴CO₂ or ¹⁴C-sucrose was supplied to specific soybean leaves and the ¹⁴C activity distribution was compared. The distribution rates were almost the same among the above-ground tissues, but different in the roots. Care should be taken when using ¹⁴C-sucrose as a photosynthate, especially when focusing on roots.