UPTAKE RATE OF TRACE-ELEMENTS BY SOYBEAN PLANTS

The uptake rate of Tc-95m, Rb-83, and Zn-65 by soybean plants cultivat ed in soil was measured during 2-247 hrs by a multitracer technique. T he uptake amount in most of the leaves and stems increased up to 150-2 00 hrs after the administration of the multitracer and then decreased with time. The uptake amount of Zn-65 in the youngest fruit increased until 120 hrs and then decreased with time, and Rb-83 uptake reached a lmost a constant amount after 120 hrs. On the other hand, the uptake a mount of Tc-95m in the youngest fruit increased continuously up to 247 hrs. The behavior of elements in the leaves and stems was analyzed ma thematically with the second order function, A(r) = c+k(1)t+k(2)t(2), 0<t = 247, where A is the amount of uptake or translocation of element r in each part of plants, c is a constant, t is cultivating time afte r the multitracer has been added, k(1) and k(2) are coefficient of t a nd t(2), respectively.