Soil Science, School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide , Urrbrae, SA 5064, Australia.
J Agric Food Chem. 2012 Jun 13;60(23):6037-44. doi: 10.1021/jf3005788. Epub 2012 Jun 5.
This study examined the effects of applied selenium (Se) species, time of application, method of application, and soil water management regimen on the accumulation of Se in rice plants. Plants were grown to maturity in a temperature- and humidity-controlled growth chamber using three water management methods: field capacity (FC), submerged until harvest, and submerged and drained 2 weeks before harvest. Two Se species, selenate (SeO4(2-)) and selenite (SeO3(2-)), were applied at a rate equivalent to 30 g ha(-1). Four application methods were employed as follows: (i) Se applied at soil preparation, (ii) Se-enriched urea granules applied to floodwater at heading; (iii) foliar Se applied at heading; and (iv) fluid fertilizer Se applied to soil or floodwater at heading. Total Se concentrations in rice grains, husks, leaves, culms, and roots were measured, as well as Se speciation in grains from the Se-enriched urea granule treatment. Highest Se concentrations in the grain occurred with SeO4(2-) and with fertilizer applied at heading stage; SeO4(2-)-enriched urea granules applied at heading increased grain Se concentrations 5-6-fold (by 450-600 μg kg(-1)) compared to the control (no fertilizer Se applied) in all water treatments. Under paddy conditions other Se fertilization strategies were much less effective. Drainage before harvesting caused Se to accumulate in/on rice roots, possibly through adsorption onto iron plaque on roots. Rice grains contained Se mainly in the organic form as selenomethionine (SeM), which comprised >90% of the total grain Se in treatments fertilized with SeO4(2-)-enriched urea granules. The results of this study clearly show that of the fertilizer strategies tested biofortification of Se in rice grains can best be achieved in lowland rice by broadcast application of SeO4(2-)-enriched urea granules to floodwater at heading stage.
本研究考察了应用硒（Se）物种、应用时间、应用方式以及土壤水分管理方案对水稻植株中硒积累的影响。采用三种水分管理方法（田间持水量（FC）、淹没至收获期和淹没并在收获前 2 周排水），在温度和湿度受控的生长室中使植物生长至成熟。使用两种硒物种，硒酸盐（SeO4(2-)）和亚硒酸盐（SeO3(2-)），以相当于 30 g ha(-1)的速率施用。采用了四种应用方法，如下所述：（i）在土壤准备时施用硒，（ii）在抽穗期将富硒尿素颗粒施用于洪水，（iii）在抽穗期叶面施硒，以及（iv）在抽穗期将液体肥料硒施用于土壤或洪水。测量了水稻籽粒、稻壳、叶片、茎秆和根中的总硒浓度，以及富硒尿素颗粒处理中籽粒中的硒形态。籽粒中硒浓度最高的是硒酸盐（SeO4(2-)）和在抽穗期施用水肥；在所有水分处理中，与对照（未施用水肥硒）相比，在抽穗期施用的富硒尿素颗粒使籽粒硒浓度增加了 5-6 倍（增加了 450-600μg kg(-1))。在稻田条件下，其他施硒策略效果要差得多。收获前排水导致硒在水稻根系中积累，可能是通过吸附在根系上的铁斑来实现的。水稻籽粒中的硒主要以硒代蛋氨酸（SeM）的有机形式存在，在施用富硒尿素颗粒的处理中，SeM 占总籽粒硒的 90%以上。本研究的结果清楚地表明，在所测试的施肥策略中，通过在抽穗期向洪水播撒富硒尿素颗粒，可以在低地水稻中最好地实现硒的生物强化。
