叶面喷施锌肥对不同镉水平下水稻产量及元素含量的影响

采用外源添加不同浓度镉的盆栽试验,研究在生育后期叶面喷施锌肥对水稻生长、产量以及不同部位锌(Zn)、镉(Cd)、铜(Cu)、铁(Fe)、锰(Mn)和钙(Ca)等元素含量的影响,并进一步分析不同部位各元素含量间的关系。结果表明:镉处理浓度越高,其对植株生长和产量的抑制作用越显著;与对照相比,在镉添加水平为2.5和5mg·kg-1时,植株的鲜质量分别降低了14.0%和15.9%,干物质积累量降低了5.3%和7.6%,产量降低了27.9%和48.4%,而糙米中镉含量分别达到了0.35和0.65mg·kg-1,高于农业部食品安全标准(0.2mg·kg-1);生育后期叶面喷施锌肥对水稻生长和产量无明显影响,植株各部位锌含量显著增加,而Fe、Mn、Cu等元素含量受到了不同程度的影响;在2.5mg·kg-1镉处理下,叶面喷施锌肥后糙米镉含量提高41.9%,而在5mg.kg-1镉处理下,糙米镉含量却降低了15.4%;相关分析表明,糙米中镉与锌无明显相关性,而与Mn、Cu、Mg呈显著正相关。

Effects of foliar Zn application on rice yield and element contents under different Cd levels

A pot experiment was conducted to investigate the effects of foliar zinc(Zn) fertilization at the late developmental stage on rice growth and yields under different cadmium(Cd) levels,as well as the influence on metal contents such as Zn,Cd,iron(Fe),copper(Cu),manganese(Mn),magnesium(Mg) and calcium(Ca) in different plant parts.And the correlations of these elements in rice grains were also analyzed.The results showed that with elevated soil Cd,rice growth was inhibited.The fresh mass of rice plants was decreased by 14.0% and 15.9%,respectively,when 2.5 or 5 mg·kg-1 Cd was added to the soil;accordingly,the dry mass was decreased by 5.3% and 7.6%,respectively;the yield also was decreased by 27.9% and 48.4%,respectively;in brown rice,the Cd content was 0.35 and 0.65 mg·kg-1,respectively,which exceeded the food safety standard(0.2 mg·kg-1 Cd).There were not obvious effects of foliar Zn application on rice growth and yield.However,Zinc contents in all plant parts increased with foliar Zn application under all Cd levels.Cadmium content in brown rice increased by 41.9% with foliar Zn application at 2.5 mg·kg-1 Cd level,while,it was decreased by 15.4% at 5 mg·kg-1 Cd level.Further analysis revealed that Cd was significantly correlated with Cu,Mn and Mg,but not correlated with Zn in brown rice.