不同镉胁迫下施用纳米硅和活性硅对水稻的降镉效应

Effects of the Nano-silicon and Active-silicon Application on Cadmium Reduction of Rice under Different Cadmium Stress

为明确施用纳米硅和活性硅在不同镉污染条件下的降镉效应,选取轻度污染的稻田土壤,盆栽设置双因素试验,即设3个镉水平(Cd1,不添加镉,低镉;Cd2,添加5 mg/kg镉,中镉;Cd3,添加10 mg/kg镉,高镉)和3个硅肥水平(Si0,不施硅肥;Si1,叶片喷施纳米硅20 mg/pot;Si2,叶喷纳米硅20 mg/pot+土施活性硅120 mg/kg)共9个处理。结果表明,随着土壤镉浓度的增加,水稻根系和茎叶生物量降低,有效穗数减少,产量显著下降,与Cd1处理相比,Cd2和Cd3处理水稻产量分别降低7.1%和20.0%;施用硅肥能够降低根系和茎叶镉含量,促进根系和地上部分干物质积累,提高有效穗数,进而增加水稻产量,与Si0处理相比,Si1和Si2处理水稻产量分别增加12.3%和15.4%;与Si0处理相比,Si1和Si2处理还能够降低镉从颖壳向糙米和精米转运,糙米镉含量分别降低26.0%和42.3%,精米镉含量分别降低25.2%和42.0%,Si2处理的降镉效果要优于Si1处理。综上,在中镉和高镉胁迫下,水稻叶片喷纳米硅+土壤施活性硅的处理增产和降镉效果显著,可以作为镉污染稻田降镉的有效措施进一步研究。

Lightly polluted paddy soil was selected and a two-factor pot experiment was conducted in Wuxue County,Hubei Province,to clarify the cadmium reduction effects of applying nano-silicon and active-silicon under different cadmium pollution conditions.Three levels of cadmium(Cd1,no cadmium added,low cadmium;Cd2,add 5 mg/kg cadmium,medium cadmium;Cd3,add 10 mg/kg cadmium,high cadmium)and three levels of silicon fertilizer(Si0,no silicon fertilizer applied;Si1,20 mg/pot nano-silicon sprayed on leaves;Si2,20 mg/pot nano-silicon sprayed on leaves+120 mg/kg active-silicon applied on soil)were set for a total of nine treatments.The results showed that with the increase of soil cadmium concentration,the biomass of rice roots,stems and leaves decreased,the number of effective panicles decreased,and the yield significantly decreased.Compared with Cd1 treatment,the rice yield of Cd2 and Cd3 treatments decreased by 7.1%and 20.0%,respectively.Applying silicon fertilizer could reduce the cadmium content in roots,stems,and leaves,promote the accumulation of dry matter in roots and aboveground parts,increase the number of effective panicles,and thereby increase rice yield.Compared with Si0 treatment,the rice yield of Si1 and Si2 treatments increased by 12.3%and 15.4%,the cadmium content in brown rice decreased by 26.0%and 42.3%,the cadmium content in milled rice decreased by 25.2%and 42.0%,respectively.Si1 and Si2 treatments could reduce the transport of cadmium from chaff to brown rice and milled rice.The cadmium reduction effect of Si2 treatment is better than that of Si1 treatment.In summary,under medium and high cadmium stress,spraying nano-silicon on rice leaves and applying active-silicon to the soil have significant effects on increasing yield and reducing cadmium,which can be further studied as an effective measure for cadmium reduction in cadmium polluted paddy fields.