施氮、锌对镉污染小麦产量及籽粒锌、镉含量的影响

Effects of nitrogen and zinc application on yield,zinc and cadmium concentration in wheat grain under cadmium pollution

为了明确氮、锌、镉处理及其互作对小麦产量和籽粒锌、镉含量的影响,本研究设置盆栽裂区试验,以扬麦25为供试材料,主区氮处理设常氮(1.6 g·盆^(-1))和减氮(0.8 g·盆^(-1)),裂区锌、镉处理设对照、锌处理(150 mg·kg^(-1))、镉处理(5 mg·kg^(-1))和锌+镉处理,测定小麦产量性状,籽粒不同组分(面粉、次粉和麸皮)氮、锌、镉含量以及籽粒锌、镉有效富集系数。结果表明:与常氮相比,减氮处理使小麦籽粒产量显著降低,这主要与产量构成因子、生物产量和收获指数均显著下降有关;减氮条件下小麦成熟籽粒氮含量(不同组分10%~15%)、镉含量(12%~16%)以及镉有效富集系数亦显著降低。与不施锌相比,土壤施锌对籽粒产量和氮含量均无显著影响,但使籽粒锌含量大幅增加(14%~30%),使镉含量(18%~28%)以及锌、镉有效富集系数均显著下降。土壤镉处理对籽粒产量和氮含量均无显著影响,使籽粒镉含量(38~42倍)以及锌、镉有效富集系数均显著增加,而使锌含量显著下降(3%~12%)。籽粒组分及其与镉、锌处理的互作对小麦籽粒锌和镉含量影响均达显著。研究表明,5 mg·kg^(-1)镉污染条件下小麦产量无明显变化,但籽粒各组分镉含量大幅增加,减施氮肥或/和增施锌肥均可显著减少小麦籽粒不同组分镉含量。

To investigate the effects of nitrogen,zinc,and cadmium treatments and their interactions on yield,the zinc and cadmium concentration in grain was examined.A pot experiment was carried out using wheat cultivar Yangmai 25.The main plots had nitrogen application levels of normal nitrogen fertilizer(1.6 g·pot^(−1))and reduced nitrogen fertilizer(0.8 g·pot^(−1)).The split plots contained the control,zinc treatment with a soil zinc application of 150 mg·kg^(-1),cadmium treatment with a soil cadmium application of 5 mg·kg^(-1),and a combination treatment with zinc and cadmium.At plant maturity,the wheat grains were separated into three fractions of bran,shorts,and flour.The grain yield,nitrogen,zinc,and cadmium concentration of the grain fractions,zinc,and the cadmium bioconcentration factor(BCF)of wheat were studied.The results showed that nitrogen reduction significantly reduced the grain yield.This was mainly related to the significant decreases in yield components,biomass,and the harvest index.Meanwhile,the concentrations of nitrogen(10%-15%)and cadmium(12%-16%)in different grain fractions and BCFCd were significantly decreased.The soil zinc treatment had no significant effect on the yield and nitrogen concentration of grain.However,the zinc concentrations of different grain fractions significantly increased by 14%-30%.The soil zinc treatment significantly decreased the cadmium concentration by 18%-28%,BCFZn,and BCFCd.The soil cadmium treatment had no significant effect on grain yield and the nitrogen concentration of the grain.However,cadmium concentrations of the different grain fractions of BCFZn and BCFCd were significantly increased(38-42 folds).The soil cadmium treatment decreased zinc concentrations of different grain fractions by 3%-12%.ANOVA results showed that the grain fraction and its interactions with zinc or cadmium treatment had significant effects on grain zinc and cadmium concentrations.These results suggest that soil cadmium pollution of 5 mg·kg^(-1)has no effect on wheat grain yield,but substantially increase the cadmium concentrations of different grain fractions.Nitrogen reduction,soil zinc application,and the combination of the two measures significantly reduce the cadmium concentrations of grain fractions.