土壤-水稻系统中镉迁移与阻控  

The transfer and control of cadmium in the soil-rice systems

作　　者：汪鹏 赵方杰[1] WANG Peng;ZHAO Fangjie(College of Resources and Environmental Sciences,Nanjing Agricultural University,Nanjing 210095,China)

机构地区：[1]南京农业大学资源与环境科学学院,江苏南京210095

出　　处：《南京农业大学学报》2022年第5期990-1000,共11页Journal of Nanjing Agricultural University

基　　金：国家自然科学基金项目(41977375);江苏省重点研发专项(BE2021717)。

摘　　要：南方部分地区稻米镉超标问题较为突出,主要与土壤污染、土壤酸化、稻田水分管理以及南方种植的一些镉积累能力较高的水稻品种等因素有关。我国土壤镉总量要比欧美国家土壤低,但我国土壤镉的活性较高,不同省份土壤镉的活性也存在较大差异,其中湖南省土壤镉的活性普遍要高于广西、贵州等地。稻米镉积累关键时期是灌浆期,这个时期常对应的是稻田排水烤田阶段,该阶段土壤镉活性主要受“原电池效应”“自由基氧化效应”和“pH-铁氧化物吸附效应”等过程控制。提高土壤Zn、Mn含量能抑制稻田排水阶段硫化镉的氧化溶解速率,提高土壤pH值能降低镉向土壤溶液相的分配,从而降低土壤镉的活性。水稻镉吸收与转运受多个关键基因控制,一些基因的等位变异使得不同水稻品种籽粒镉积累产生差异。水稻籽粒镉积累阻控可以通过降低土壤镉活性、减少水稻镉吸收转运以及移除土壤镉存量等方式实现。因此,种植低镉积累水稻品种,调酸控镉,施用Zn、Mn肥等是低成本、长效的镉污染农田安全利用的技术措施,而高镉积累水稻品种有潜力发展为土壤镉减存量修复的植物修复技术。Rice grain contaminated with elevated cadmium(Cd)in some areas of Southern China is serious,with this problem attributable to some reasons including increasing inputs of Cd into soils,soil acidification,typical water management of paddy soils,and certain varieties of rice grain with a higher Cd accumulation capacity planted in the South.Soil total Cd concentrations are not worse in China than in other regions of the world,but the bioavailability of Cd is higher in Chinese soils.Soil Cd bioavailability varies largely among different regions in China;soils from Hunan Province are generally higher in Cd bioavailability than those from Guangxi and Guizhou.The grain filling is the key period for the accumulation of Cd in the rice grain,with this period concurrent with soil drainage.The remobilization of Cd during this period is mainly controlled by the voltaic effect,free radical oxidation effect and pH-dependent Fe oxide adsorption effect.Amendment of Zn and Mn fertilizers can suppress the oxidative dissolution of CdS during soil drainage through the voltaic effect.Raising soil pH can reduce the partitioning of Cd into the soil solution,thus decreasing soil Cd solubility.Several key genes involved in Cd uptake,translocation,and sequestration in rice have been cloned.Allelic variations of some genes to some extent explain the variations of grain Cd in different cultivars.The Cd-safe rice grain can be achieved by reducing soil Cd bioavailability,decreasing the uptake/translocation of Cd to the grain,and removing Cd from soils.Hence,the use of low Cd rice cultivars,liming,and applications of Zn/Mn fertilizers are particularly effective and economical for producing safe rice in some Cd-contaminated soils.Rice cultivars with the ability to accumulate high Cd can be used as a feasible phytoremediation method for reducing Cd from the soil.

关 键 词：稻田 镉 水稻 植物修复 农产品安全 

分 类 号：S153[农业科学—土壤学]