水稻对~(14)CO_3~(2-)的吸收和积累动态

用同位素示踪技术研究水稻对14CO32-的吸收和积累动态,及其在水稻田中的行为特性。结果表明:通过水稻根系和浸于水中的茎杆下部吸收的14CO32-离子会向上部组织输送并形成积累趋势;在上部组织中,叶和茎杆上部的14C比活度随时间呈逐渐上升的趋势,而穗中的比活度于14d达最大值(271.9Bq/g)后又呈下降趋势;茎杆下部由于直接浸于水中,表现出对14CO32-离子的快速吸收、吸附,此后随时间呈下降趋势,根部表现出上升过程迟后于茎杆下部,其14C比活度也低于茎杆下部。上部组织(穗、叶和茎杆上部)中14C的百分含量随时间上升,而下部组织(茎杆下部和根)则相反,至试验后期(21~35d),其百分含量基本持平(约各占50%),14C从下部组织向上部组织输送的特征非常明显。

ABSORPTION AND ACCUMULATION DYNAMICS OF ~(14)CO_3~(2-) IN RICE

Dynamics of absorption and accumulation of ()~(14)CO~(2-)_3 in rice were studied by isotope-tracer technology in order to study the behavior of ()~(14)CO~(2-)_3 in rice paddy. The results showed that: ()~(14)CO~(2-)_3 ions absorbed by roots and lower part of stems (LPS) in water were transferred to upper part of rice plant(UPR), and presented a tendency of accumulation. In UPR, the specific activity of ()~(14)C in leaves and upper part of stems (UPS) slowly increased with time while it in tassels tended to decrease after reaching the maximum (271.9Bq/g) at the 14th day. ()~(14)CO~(2-)_3 ions were absorbed quickly in LPS dipping in water, and then slowly declined. Compared with LPS, the increasing tendency in roots was slowly and the specific activity of ()~(14)C was also lower as roots embed in soil. The percentage of ()~(14)C in UPR (tassels, leaves and UPS) was increscent with time, but reversed in LPR. During the late stage of experiment (21～35d), percentage in both UPR and LPR were almost equal, about 50% respectively. The characteristic of ()~(14)C transferred from LPR to UPR was greatly evident.