水稻对~(134)Cs的吸收和~(134)Cs在水稻-土壤中的分配

试验表明,水稻对~(134)Cs的吸收,孕穗期吸收速率最快;土壤理化性质不同,吸附~(134)Cs的能力有差异;不同生育期灌溉~(134)Cs溶液,水稻对其吸收量不同,离成熟期近,吸收得多;灌溉次数多和灌溉水中~(134)Cs活度高,水稻吸收的~(134)Cs也多。糙米经精白加工后,可使~(134)Cs的污染减少22.6—45.6％;~(134)CS在水稻各部位比活度大小的顺序为糠>根>稻草>谷壳>精白米;活度以稻草中最高,占水稻植株总活度的51.4％,糙米、根和谷壳分别占28.4％。11.8％和8.4％:~(134)Cs在土壤中移动很少,有95.1％集中在0—2.5cm的表土层内;~(134)Cs在水稻-土壤中的分配为6.1％:93.9％;K~+抑制水稻对~(134)Cs的吸收,K~+浓度与水稻中~(134)Cs比活度之间呈指数回归形式。

THE ABSORPTION AND DISTRIBUTION OF CESIUM-134 IN RICE-SOIL SYSTEM

Dynamics of absorption of 134Cs by rice shows that absorption rate is the fastest at boot stage;absorption capacities of 134Cs in soils are different with the different physical-chemical properties of soils;absorption amounts vary with the time of irrigating 134Cs the closer the irrigation time to mature stage is,the more the absorption amount of 134Cs in rice will be the more the irrigating times are,and the higher the radioactivity of 134Cs in irrigating water is,the more the absorption amount in rice will be.After brown rice is polished,contamination of 134Cs can be decreased by 22.6-45.6%.The order of specific activity in rice is:bran >root>straw>husk>polished rice.Percentage activity of straw,brown rice,root and husk is 51.4%,28.4%,11.8% and 8.4% respectively.The migration of 134Cs is very slow in soil and 95.1%.of 134Cs is concentrated in surface soil.(0-2.5cm).The distribution ratio of 134Cs in the rice and soil is 6.1%:93.9% Potassium ion can inhibit the absorption of 134Cs by rice.There is an exponential function between the concentration of potassium ion and specific activity of 134Cs in rice.