硒对镉胁迫下寒地水稻镉含量与分配的影响  

Effects of Se on Cd content and distribution in rice plant under Cd stress in cold climate

作　　者：刘春梅[1,2] 罗盛国[1] 刘元英[1] 

机构地区：[1]东北农业大学资源与环境学院,黑龙江哈尔滨150030 [2]黑龙江八一农垦大学农学院,黑龙江大庆163319

出　　处：《植物营养与肥料学报》2015年第1期190-199,共10页Journal of Plant Nutrition and Fertilizers

基　　金："十二五"国家科技支撑计划项目(2013BAB20B04)资助

摘　　要：【目的】研究施硒对不同镉污染土壤上镉在水稻各器官中的分配及稻米中镉含量的影响,探讨通过施硒降低水稻镉吸收量及在稻米中分配的可行性。【方法】采用盆栽试验,以垦鉴稻6号为材料,研究添加不同浓度镉(0、2、4和8 mg/kg土壤)的条件下,施硒(0、0.07和0.14 mg/kg土壤)对水稻不同器官镉含量和镉分配的影响。成熟期整盆收获,分别测定叶片、叶鞘、茎秆、根系和糙米、精米镉含量、硒含量和干物重,计算镉积累量和分配比例。【结果】1)当土壤镉浓度在0 4 mg/kg时,水稻各营养器官和糙米、精米中镉含量随土壤镉浓度增高而显著增加,但当土壤中镉浓度>4 mg/kg时,糙米和精米中镉含量增加不显著。未施硒(Se0)时,Cd2(4 mg/kg)和Cd3(8mg/kg)处理糙米中镉含量分别为0.221 mg/kg和0.234 mg/kg,分别是Cd0处理的15.8和16.7倍,均超过我国国家食品安全标准中稻米镉的限量(0.2 mg/kg),精米镉含量未超过国家食品安全规定的限量,Cd3处理精米中镉含量最高,为0.174 mg/kg。2)相同镉浓度下,随着硒浓度的增加,水稻各营养器官和糙米、精米的镉含量和镉积累量均显著下降,糙米和精米的镉含量均低于我国国家食品安全规定的稻米镉限量,且Se2(0.14 mg/kg)处理优于Se1(0.07 mg/kg)处理。其中Cd1(2 mg/kg)浓度时,Se2处理的精米镉含量下降幅度最大,比Se0降低31.5%(P<0.01)。3)镉在各器官中的分配比例为根系>茎鞘>稻谷>叶片。随着硒浓度的增加,镉在根系中的分配比例增加,在地上部的分配比例减少,在稻壳中的分配比例增加,在精米中的分配比例下降。在Cd1浓度时,根系镉分配比例范围为60.9%67.8%,稻谷镉分配比例为12.6%13.8%;Se2处理稻壳中镉分配比例比Se0增加5.2个百分点,而精米中镉分配比例则下降了6.2个百分点。4)相同镉浓度下,随着硒浓度的增加,植株各营养器官干物重均增加,Se2处理对干物重的影响优于Se1处理。【Objectives】Effects of Se application on Cd accumulation and distribution in rice organs and content of Cd in rice grain were studied to explore countermeasures for rice planting in Cd polluted soils. 【Methods】A pot experiment was conducted using rice cultivar Kenjiandao 6 as experimental material. Four levels of Cd additions( 0,2,4 and 8 mg /kg soil) and 3 Se levels( 0,0. 07 and 0. 14 mg /kg soil) for each Cd addition were designed.The rice plants were harvested at the maturity stage,the Cd contents in leaves,stems,sheaths,roots,brown rice and polished rice were determined,Cd accumulation amounts and distribution ratios in rice organs were calculated,and the Se contents in brown rice and polished rice,and dry matter weight were determined as well. 【Results】1)When the added Cd concentration in soil is increased from 0 to 4 mg / kg,the Cd contents in different organs of rice,brown rice and polished rice are increased significantly. When added Cd concentration is higher than 4mg / kg,the increases of the Cd contents in brown rice and polished rice are not significant. The Cd contents in brown rice are 0. 221 mg / kg and 0. 234 mg / kg under the Cd2( 4 mg / kg) and Cd3( 8 mg / kg) treatments without Se application which are 15. 8 and 16. 7 times higher than that of Cd0,higher than the national food safety standards of China for Cd content( 0. 2 mg / kg). The Cd content in polished rice is 0. 174 mg / kg,which conforms to the national food safety standards of China. 2) The Cd contents and Cd accumulation amounts in different organs of rice and brown rice,polished rice are decreased significantly with the increase of Se concentration under the same Cd concentration,and larger declines of the Cd content are observed under the Se2( 0. 14 mg / kg) treatment.Under Cd1( 2 mg / kg),the Cd content in polished rice in the Se2 treatment is reduced by 31. 5%( P < 0. 01)compared to Se0. 3) Sequence of the Cd distribution in rice organs is roots > stems and sheaths > grains >leaves. The Cd distribution portion in root

关 键 词：硒 镉胁迫 寒地水稻 镉含量 镉分配 

分 类 号：S511[农业科学—作物学] X53[环境科学与工程—环境工程] X173