摘要:
提要：对苏锡常地区416套稻米-耕层土样品Cd等元素含量的解剖研究，证实了土壤Cd、Zn、Se、pH、OM、CEC等是控制稻米Cd的重要地球化学因素。相关统计分析结果显示：1）酸性土壤环境中当稻米Cd的BCF值大于10%时，稻米Cd与土壤Cd、Zn呈显著正相关，相关系数大于0.67。土壤Cd的生物有效量普遍较高，土壤中酸可溶态Cd与稻米Cd含量的相关系数大于0.7，接近或稍高于稻米与土壤Cd的相关性；2)土壤Se、OM、CEC均能抑制水稻对土壤Cd的吸收，在一定条件下稻米Cd与土壤Se、OM、CEC之间显著负相关，相关系数均小于-0.5；3）土壤酸化可促进稻米对土壤Cd的吸收，当土壤Cd＞0.2 mg/kg、OM变化于2.5%~6.5%时，稻米Cd与土壤pH呈显著负相关，相关系数为-0.6；4）水稻不同器官中Cd含量不同，从根部→地上部→稻米Cd含量渐次降低，指示根部水稻器官在稻米从土壤吸收Cd的过程中发挥了更大作用、水稻根系吸收的Cd多积聚于根部。
关键词:
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水稻
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吸收
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Cd
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地球化学控制因素
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土壤
Abstract:
Abstract: On the basis of collecting and testing about 416 couples of rice seeds and the cultivated soil samples from Suxichang typical area of Jiangsu Province, a series of geochemical data related to Cd distribution and other relative elements concentrations since 2011 was obtained. By studying and analyzing these data, the authors confirmed that rice uptake of Cd from soil is mainly controlled by such geochemical factors as cadmium, zinc, selenium, pH, organic matter (OM) and cation exchange capacity (CEC) within the cultivated soil. Some conclusions have been reached: 1) When the pH is lower than 7.0 in soil and BCF (Bioconcentration Factor) is larger than 10% in milled rice, there exists obvious positive correlative relationship between Cd concentration of milled rice and Cd and Zn content within soil, and their correlation coefficients are above 0.67; bioactivity of cadmium in farmland soils is higher in most cases; there exists more significant correlative relationship between Cd of rice and bioavailable Cd of soil than total Cd within soil if cadmium content from the cultivated soil reflects only exchangeable and weak acid-soluble fraction, with the correlation coefficient larger than 0.7; 2) Se, OM and CEC could inhibit the rice uptake of Cd from the cultivated soil, and there exists a significant negative correlation between Cd concentration of milled rice and Se, OM and CEC concentrations within the soil under some limited conditions, with the correlation coefficients being less than -0.5; 3) Soil acidification could stimulate the increase of Cd content in the milled rice, when Cd concentration of milled rice is larger than 0.2mg/kg and its OM is equal to 2.5%~6.5%, and there yet exists significant negative correlation between Cd concentration of milled rice and pH in the cultivated soil, with the correlation coefficient smaller than -0.6; 4) the Cd distribution in different rice organs is not uniform, from the roots to the upper rice organs, the Cd content in rice gradually reduced, and it is obvious that root rice organs could play a greater role in absorption of Cd from the cultivated soil during the rice growth.
百度学术
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