镧不同施用方式对吸收差异型小白菜镉、铬吸收及生物量的影响

Effects of Lanthanum Different Application Methods on Cadmium and Chromium Absorption and Biomass of Absorption Difference Chinese Cabbage Varieties

为探讨轻稀土La在Cd/Cr复合污染土壤种植条件下作物的生长发育效应和抗重金属胁迫生物效应,进一步为农用稀土肥料的科学施用提供借鉴。选用土壤盆栽方法和不同施肥技术(土壤混施、土壤灌施和叶面喷施),研究La对吸收差异型(低吸收累积型和高吸收累积型)小白菜Cd,Cr吸收和生物量的影响。结果表明:La不同施用方式对吸收差异型小白菜茎叶生物量的增产效应总体表现为低吸收累积型显著高于高吸收累积型,其中低吸收累积型以叶面喷施和土壤灌施处理较对照增产显著,而高吸收累积型均未表现增产效果;La不同施用方式对吸收差异型小白菜Cd,Cr吸收的抑制能力效应分别表现为Cd低吸收累积型高于高吸收累积型,Cr高吸收累积型高于低吸收累积型,其中低吸收累积型以叶面喷施和土壤灌施处理抑制Cd,Cr吸收的效应显著,而高吸收累积型抑制Cr吸收显著,抑制Cd吸收不显著或无抑制;La处理对吸收差异型小白菜Cd和Cr转运系数的降低效应变化规律与Cd和Cr抑制能力效应规律基本一致,转运系数降低效应越大,抑制重金属Cd和Cr的吸收作用越显著;外源La显著影响小白菜植株La的吸收与分布,土壤混施和土壤灌施主要以根系吸收积累为主,叶面喷施主要以茎叶吸收积累为主。表明La对Cd/Cr复合污染土壤种植作物重金属抗胁迫能力大小与作物品种重金属吸收差异和施肥技术作用机制不同有关。

The authors investigated the growth and development effects and biological effects against heavy metal stress in crops under Cd/Cr combined contaminated soil by light rare earth La,and further provided the basic theoretical guidance for scientific application of rare earth fertilizers.The effects of La on the Cd and Cr absorption and biomass in absorption difference Chinese cabbage varieties(low absorption and high absorption accumulation)were evaluated using soil potting methods and different fertilization techniques(soil mix application,soil irrigation application and foliar spray application).The results indicated that the effect of La treatment on the yield increase effect of biomass of absorption of difference Chinese cabbage varieties was significantly lower than that of high absorption accumulation type.Among them,the low absorption accumulation type showed significant yield-increasing effects by foliar application and soil irrigation application.The high absorption cumulative type did not show an increase in yield.The inhibitory effect of three fertilization treatments on the heavy metal absorption of Cd/Cr combined absorption Chinese cabbage varieties showed that the Cd low absorption accumulation type was higher than the high absorption accumulation type.The Cr high absorption accumulation type is higher than the low absorption accumulation type.Among them,foliar application and soil irrigation application treatment showed significant effects on the absorption of Cd and Cr on the low absorption accumulation type.However,the three fertilization methods showed no significant or no inhibition on the Cd absorption inhibition of high absorption accumulation vegetables,but significantly inhibited the absorption of Cr in stems and leaves.The effect of La treatment on the reduction of Cd and Cr transport coefficients of Cd/Cr composite cultivars with different cultivars was consistent with the inhibitory effects of Cd and Cr.The greater the effect of reducing the transport coefficient,the more significant the inhibition of the absorption of heavy metals Cd and Cr.Exogenous La significantly affects La absorption and distribution in Chinese cabbage,root absorption and accumulation are the main factors in mixed soil application and soil irrigation,foliar spraying is mainly based on the absorption and accumulation of stems and leaves.These findings found that the anti-stress effects of light rare earth La treatment on heavy metals in Cd/Cr combined contaminated soil is closely related to heavy metal absorption and difference of fertilization mechanism.