中文摘要：

【目的】研究硫肥对外源四价硒条件下土壤硒赋存形态和价态变化的影响,旨在揭示硫调控小麦硒吸收的作用机制。【方法】以郑麦9023为试验材料,通过苗期土培和水培进行,土培试验设3个硫水平,分别为0、150和300 mg·kg-1,硫源为硫磺,2个硒水平,分别为0和5 mg·kg-1,硒源为亚硒酸钠,生长至70 d收获并取土样;水培试验先将幼苗在1/5 Hogland-Arnon营养液中培养2周,然后开始进行处理,设3个硫水平,分别为0、1和2 mmol·L-1,硫源为硫酸镁,硒水平为10μmol·L-1,2种硒源,分别为亚硒酸钠和硒酸钠,培养24 h后收获,土培和水培试验均为完全交互设计,重复4次,采用HG-AFS-8220型双道原子荧光光度计对小麦地上部和根以及土壤中硒含量进行测定,根据与植物硒吸收的相关性,将土壤总硒分成不同赋存形态和价态。【结果】施用适量硒和硫对小麦生长均有一定的促进作用;150 mg·kg-1硫可以显著降低小麦地上部和根中硒含量和硒累积量,降幅分别可达61.7%、34.4%和55.7%、24.7%,但是这种降低不会随施硫量的增加而显著变化;施硫可以显著降低土壤p H值,最高可降低0.50个单位,并增加了土壤有机质含量,最高可增加0.78 g·kg-1。施硫可以显著降低土壤中水溶态硒含量,并显著增加铁锰氧化物结合态硒含量,也增加了有机结合态和残渣态硒含量,而对交换态硒含量无显著影响,表明施硫促使了硒在土壤中的钝化。施硫可以显著降低水溶态中各种价态硒含量,其降幅基本一致,施硫可以增加交换态中四价硒含量而显著减少六价硒含量,表明施硫抑制了硒在土壤中向高效价态的转化。小麦对四价硒和六价硒的吸收差异与是否施硫密切相关,无硫时,六价硒处理下小麦地上部和根中硒含量分别为四价硒处理的44.7和22.4倍,而硫浓度为1 mmol·L-1时,其硒含量迅速降为四价硒处理的2.8倍和51.8%,表明硫可以显著缩小小麦对

英文摘要：

[ Objective ] This study was conducted to investigate the effects of sulfur （S） on the fractions and species of amended selenite in soil by applying S fertilizer, and explore the mechanism through which S controls the selenium （se） uptake of wheat. [Method] Wheat （Triticum aestivum L. cv. Zhengmai 9023） was chosen as the test material, and underwent seedling stage soil cultivation and solution cultivation. A potted soil experiment was performed on wheat and the application amounts of S were 0, 150,and 300 mg＇kg-l, respectively, Sulfur was used as S source, Se source was selenite （Na2SeO3） and it was designated at 0 and 5 mg.kg-1. The wheat seedlings were harvested on the 70th day after sowing and soil samples were taken. The treatments started two weeks after the seedlings were planted in hydroponic experiment which the nutrient solution was made with 1/5 Hogland-Arnon formula. Different amounts of S were added in the experiment： 0, 0.1, and 2 mmol＇Lq; Se was designed at 10 μmol.L-1. Se and S was supplied to plants in the form of sodium selenite （Na2SeO3）, sodium selenate 0Na2SeO4-10H20） and magnesium sulfate （MgSO4.7H20）, respectively. Wheat was harvested after 24 h. A fully interactional design was performed and each treatment was repeated four times in potted soil experiment and hydroponic experiment. The hydride generation atomic fluorescence spectrometer model HG-AFS-8220 was used to measure the Se content in shoot and root of wheat and soil. Based on the Se absorption of plant and the correlation of selenium content in soil, Se content in the soil was divided into different fractions and species. [ Result ] Applications of both Se and S resulted in stimulation to wheat growth with appropriate amount. S was applied at 150 mg-kg-1 significantly reduced the content and accumulation of Se in shoots and roots of wheat by 61.7% and 35.5%, 55.7% and 24.7%, respectively, but such reduction won＇t change significantly with the increasing S application to soil. Application of S sign