不同形态硫叶面喷施对水稻镉积累影响

Effect of foliar spraying different forms of sulfur on cadmium accumulation in rice

为研究叶面喷施不同形态硫对水稻镉的阻控效果,以“湘早籼45号”为材料,采用盆栽试验及田间试验的方法,设计两种不同喷施次数(分蘖盛期喷施一次,分蘖盛期与孕穗期共喷施两次),3种不同形态硫元素(-SH形态的半胱氨酸、SO_(4)^(2-)形态的硫酸钾及S^(2-)形态的硫化钾)的叶面喷施试验。盆栽试验以叶面硅肥、硝酸钾(KNO_(3))及自来水为对照,田间试验以自来水为对照。结果表明:3种形态的硫及硅较自来水对照对糙米降镉效果显著,降镉能力为半胱氨酸(Cys)>硫化钾(K_(2)S)>硅(Si)>硫酸钾(K_(2)SO_(4)),其盆栽试验喷施两次叶面肥的糙米镉含量分别降低53.57%、46.43%、39.29%和28.57%,KNO_(3)对水稻无降镉效果。田间试验喷施两次叶面肥Cys、K_(2)S、K_(2)SO_(4)的糙米镉含量依次降低47.18%、39.49%和27.69%。喷施不同形态叶面硫肥及硅肥是通过降低茎部向叶部镉转运系数,进而降低糙米镉含量。研究表明,3种不同形态的硫对水稻糙米的降镉效果为Cys>K_(2)S>K_(2)SO_(4),喷施Cys和K_(2)S能使盆栽试验和田间试验糙米的镉含量在0.2 mg·kg^(-1)以下,且喷施两次效果更好。

The effect of foliar spraying different forms of sulfur(S)on reducing the cadmium(Cd)uptake of the brown rice"Xiangzaoxian 45"were carried out through pot and field experiments.Three forms of sulfur[cysteine(Cys)in—SH form,potassium sulfate(K_(2)SO_(4))in SO_(4)^(2-) form,and potassium sulfide(K_(2)S)in S^(2-)form]were sprayed on the surface of leaves of"Xiangzaoxian 45"(once at the tillering stage,and twice at tillering stage and booting stage).In the pot experiment,silicon(Si)fertilizer,potassium nitrate(KNO_(3)),and tap water were used as a control,while in the field experiment,tap water was used as a control.The results showed that the three forms of sulfur and silicon had significant effects on reducing Cd uptake in the brown rice compared with the tap water control,and KNO_(3) had no effect on reducing Cd in rice.The ability the different forms of sulfur to reduce the Cd concentration in the rice was in the following order:Cys>K_(2)S>Si>K_(2)SO_(4),and the Cd concentration in the rice decreased by 53.57%,46.43%,39.29%,and 28.57%,respectively,after spraying the leaf fertilizers twice in the pot experiment.In the field experiment,the Cd concentration in the brown rice decreased by 47.18%,39.49%,and 27.69%by spraying Cys,K_(2)S,and K_(2)SO_(4),respectively.Spraying different forms of S and Si foliar fertilizer reduced the Cd concentration in the brown rice by reducing the Cd transfer coefficient from stem to leaf.The results of the pot and field experiments suggested that the effect of the three different forms of S on reducing the Cd concentration in brown rice was Cys>K_(2)S>K_(2)SO_(4),while Cys and K_(2)S can reduce the Cd content to<0.2 mg·kg^(-1),and spraying twice was better.