磷营养对水稻籽粒锌生物有效性的影响及其与植酸等磷酸肌醇谱含量的关系

作物籽粒锌缺乏所导致的“隐性饥饿”已威胁到全世界1/3人群的健康。为明确磷对水稻籽粒锌的生物有效性的影响,利用大田磷肥长期定位试验,并结合稻穗离体培养技术,探讨了不同外源磷浓度下水稻籽粒锌的生物有效性的变化及其与籽粒植酸等磷酸肌醇谱含量的关系。试验表明高磷处理显著增加水稻籽粒中植酸磷和总磷的含量,以及不同价位磷酸肌醇(InsP1-6)含量,其中以高价磷酸肌醇(InsP4-6)在磷供给下的增幅最为显著。与籽粒植酸的变化趋势相反,高磷水平降低了稻米中锌的含量及其有效性。稻穗离体培养中,高磷(P12)处理相比无磷(P0)对照,籽粒锌的有效性降幅高达81.3%。因此,过量磷肥投入会通过显著提高水稻籽粒中的植酸及高价磷酸肌醇含量,在同步降低籽粒锌含量的同时,进一步显著降低其在水稻籽粒中的生物有效性。

Influence of phosphorus on rice (Oryza sativa L.) grain zinc bioavailability and its relation to inositol phosphate profiles concentration

The hidden hunger caused by grain zinc (Zn) deficiency in crop poses a potential threat to the health of nearly two billion people worldwide, especially in developing countries. In this study, the long-term phosphorus fertilizer experiment and in vitro detached rice panicle culture systems with varied phosphorus levels were conducted to investigate the effect of phosphorus on rice grain Zn bioavailability and its relation of grain inositol phosphates profiles (phytic acid related metabolic derivatives) concentration. In our results, compared with low phosphorus level, high phosphorus supply increased grain phytic acid phosphorus and total phosphorus concentration (mg g ^-1). Moreover, high phosphorus supply also increased different grain inositol phosphate profile concentrations (InsP_1-6), especially for InsP_4-6. On the contrary, grain Zn concentration decreased with phosphorus supply. Both the decrement of Zn and increment of phytic acid phosphorus induced by the higher phosphorus supply in rice grain led to the significant decrement of grain Zn bioavailability. In in vitro detached panicle culture system, the Zn bioavailability in P₁₂ treatment decreased by 81.3% relative to P₀ treatment. In conclusion, higher phosphorus input could significantly decrease grain Zn bioavailability through increased grain phytic acid phosphorus and inositol phosphates derivatives concentration, in addition to the decrement of grain Zn concentration.