Translocation and re-distribution of radionuclides from the leaf surface in plants

Abstract

The transcuticular translocation and re-distribution of multitracer from leaf surfaces through the cuticle were examined for a wide range of plants. Those plants used as test samples were red clover (Trifolium pratense), orchard grass (Dactylis glomerata), white radish (Raphanus sativus), and mung bean (Phaseolus mungo) at the 5th leaf stage. It was found that the translocation was a site-sequential process and its stable state distribution was reached 14 days after the application of radionuclides. The radionuclides of Be(sup *), Ca(sup *), Y(sup *), Te(sup *), Ba(sup *), Ce(sup *), Pm(sup *), Ge(sup *), Yb(sup *), Lu(sup *), Hf(sup *), Os(sup *), Ir(sup *), and Pt(sup *) tended to remain on the cuticle. However, the radionuclides of Sc(sup *), Zn(sup *), Co(sup *), Se(sup *), Eu(sup *), Rb(sup *), and Cs(sup *) tended to migrate easily and accumulate in various parts of the plant including roots. Mn(sup *) and Sr(sup *) were slightly ambiguous and intermediate in behavior, but possibly, they would be thought more mobile when viewed over a longer period.

葉表面からの表皮を通してのマルチトレーサの転流と再配置を広い範囲の植物について調べた。アカツメクサ(Triforium pratense)、カモガヤ(Dactylis glomerata)、日本大根(Raphanus sativus)、ヤエナリ(Phaseolus mungo)の第5葉段階のものを試料とした。転流プロセスは場所的に順次起こり、14日で定常状態になることが分かった。放射性核種Be(sup *)、Ca(sup *)、Y(sup *)、Te(sup *)、Ba(sup *)、Ce(sup *)、Pm(sup *)、Ge(sup *)、Yb(sup *)、Lu(sup *)、Hf(sup *)、Os(sup *)、Ir(sup *)およびPt(sup *)は表皮に残っていた。Sc(sup *)、Zn(sup *)、Co(sup *)、Se(sup *)、Eu(sup *)、Rb(sup *)およびCs(sup *)は移動しやすく根を含む植物の色々な場所に蓄積した。Mn(sup *)とSr(sup *)はやや不確実でその挙動は中間的であり、多分長い周期で見るともっと移動しやすいと思われる。