Selenate-Enriched Urea Granules Are a Highly Effective Fertilizer for Selenium Biofortification of Paddy Rice Grain

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• 作者：Lakmalie Premarathna ; Mike J. McLaughlin ; Jason K. Kirby ; Ganga M. Hettiarachchi ; Samuel Stacey ; David J. Chittleborough
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2012
• 出版时间：June 13, 2012
• 年：2012
• 卷：60
• 期：23
• 页码：6037-6044
• 全文大小：228K
• 年卷期：v.60,no.23(June 13, 2012)
• ISSN：1520-5118

文摘

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 (SeO₄2鈥?/sup>) and selenite (SeO₃2鈥?/sup>), were applied at a rate equivalent to 30 g ha^鈥?. 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 SeO₄2鈥?/sup> and with fertilizer applied at heading stage; SeO₄2鈥?/sup>-enriched urea granules applied at heading increased grain Se concentrations 5鈥?-fold (by 450鈥?00 渭g kg^鈥?) 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 SeO₄2鈥?/sup>-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 SeO₄2鈥?/sup>-enriched urea granules to floodwater at heading stage.

Keywords:

selenium; selenite; selenate; biofortification; fertilizer; rice; Se-enriched urea