Association Euratom-ITAL, P.O. Box. 48, Wageningen.
Planta. 1978 Jan;138(2):145-51. doi: 10.1007/BF00391171.
The internal distribution processes of cadmium ((115m)Cd) in the stems of tomato plants have been investigated using in vivo β-spectrometric measurements with semiconductor detectors. The initial penetration into the xylem after root uptake and the subsequent lateral redistribution in the surrounding tissues were monitored continuously in each individual plant. The kinetics of the lateral migration toward the epidermis can be described by a diffusion process, characterized by an apparent diffusion coefficient of about 10(-8) cm(2) s(-1). After two days of cadmium supply this heavy metal is accumulated in relatively large amounts in the epidermal and cortical layers, from which it can be released only very slowly. On the contrary, the exchange processes with other divalent cations cause in the xylem a quick release, its rate being dependent on the duration of the preceding cadmium treatment.
使用半导体探测器进行体内β光谱测量，研究了镉（(115m)Cd）在番茄植株茎内的内部分布过程。在根系吸收后最初进入木质部以及随后在周围组织中的横向再分配，在每株植物中都进行了连续监测。向表皮横向迁移的动力学可以用扩散过程来描述，其特征是表观扩散系数约为 10(-8) cm(2) s(-1)。在提供镉两天后，这种重金属在表皮和皮层中大量积累，从这些部位中释放出来非常缓慢。相反，与其他二价阳离子的交换过程导致木质部中快速释放，其释放速率取决于之前镉处理的持续时间。
