,4,*Influence of phosphorus on rice (Oryza sativa L.) grain zinc bioavailability and its relation to inositol phosphate profiles concentration
SU Da1,2, WU Liang-Quan2, S?ren K. Rasmussen3, ZHOU Lu-Jian4, PAN Gang4, CHENG Fang-Min,4,*通讯作者:
收稿日期:2019-06-3接受日期:2019-08-9网络出版日期:2019-09-10
| 基金资助: |
Received:2019-06-3Accepted:2019-08-9Online:2019-09-10
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苏达, 吴良泉, S?ren K. Rasmussen, 周庐建, 潘刚, 程方民. 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[J]. 作物学报, 2020, 46(2): 228-237. doi:10.3724/SP.J.1006.2020.92032
SU Da, WU Liang-Quan, S?ren K. Rasmussen, ZHOU Lu-Jian, PAN Gang, CHENG Fang-Min.
锌是作物生长发育所必需的微量营养元素, 参与作物光合、逆境胁迫、激素合成、种子萌发以及细胞膜建成等多个生理过程[1,2]。全世界范围内土壤缺锌均较为普遍, 碱性石灰土壤中锌虽然不是一个限制因子, 但往往会与碳酸钙结合或被土壤团粒吸附, 降低其被作物吸收利用的有效性[2]。此外, 锌在人体生理代谢中也发挥着重要作用[3], 食源锌摄入不足, 即所谓的“隐性饥饿”, 已经威胁到世界1/3人口的健康, 其中以发展中国家面临的挑战最为严峻[4]。
水稻是重要的粮食作物, 全国有65%的人口以稻米为主粮。与其他禾谷类和豆科作物相比, 水稻籽粒中的锌、铁含量普遍较低, 且集中分布于表皮及糊粉层中[5]。受传统饮食习惯的影响, 水稻籽粒在去麸加工成精米的过程中会造成锌(27%~45%)、铁(60%~76%)等矿质元素的进一步流失[2,6]。而植酸(C6H18O24P6, InsP6, 六磷酸肌醇)作为水稻籽粒中磷的最主要贮存形式, 往往还会与稻米中的锌、铁、钙和镁等矿质营养元素络合, 形成难溶性的植酸盐, 从而降低它们的生物有效性[2]。因此, 生物强化的实现, 除需培育和筛选锌、铁富集的优质作物资源, 还应同时降低作物籽粒中植酸等“抗营养元素”的水平。
磷素对水稻籽粒中锌和植酸的合成和积累都有显著的调控效应[7,8,9]。首先, 磷素是稻米中植酸积累最直接的调控因子。前人在不同作物(小麦、燕麦、玉米、水稻、大豆等)中已广泛证明外源磷供应对作物籽粒植酸的积累有显著促进作用[10,11,12,13], 且籽粒不同部位的植酸积累对外源磷的响应还存在一定的空间区位特异性[14,15]。其次, 磷也是影响作物籽粒中锌含量的重要环境生态因子[16], 但由于磷肥对作物籽粒锌的调控同时还受到土壤特性、土壤中菌根数量、根系形态特征、作物类型以及气候条件等因子互作的影响[9,17], 使得磷肥对作物籽粒锌积累的影响规律还存在不一致甚至相互矛盾的地方。尤其是在目前集约化栽培体系下, 施磷量普遍较高[16], 过量磷肥投入在可能影响稻米植酸含量的同时, 对籽粒锌含量以及锌的生物有效性的影响, 目前还少见相关报道。
本研究利用大田磷肥长期定位试验, 结合稻穗离体磷培养, 旨在阐明磷营养对籽粒锌的生物有效性的影响及其与籽粒不同价位磷酸肌醇含量之间的关系, 为稻米品质改良及合理磷肥运筹提供理论依据。
1 材料与方法
1.1 大田磷肥长期定位试验
大田试验地点是浙江省海宁市杨渡村浙江省农业科学院肥料长期定位试验基地。该基地从2011年起开始连续用于磷肥长期定位试验, 土壤类型为水稻土类、黄松田土属。2016年水稻播种前土壤速效氮和速效钾含量分别为126.6 mg kg-1和135.9 mg kg-1, 2017年水稻播种前土壤速效氮和速效钾含量分别为151.7 mg kg-1和126.5 mg kg-1。供试水稻材料为秀水134。采用随机区组设计, 设3个磷肥处理水平, 分别为不施磷处理(0 kg hm-2, LP)、中磷处理(75 kg hm-2, MP)和高磷处理(150 kg hm-2, HP)。磷肥于水稻播种前一次性基施, 设每个磷处理3个重复小区, 小区面积30 m2。其中, 不施磷处理的3个小区土壤速效磷的本底值为43.2 mg kg-1 (2016年)和37.4 mg kg-1 (2017年), 中磷处理的3个小区土壤速效磷的本底值为151.5 mg kg-1 (2016年)和146.7 mg kg-1 (2017年), 高磷处理的3个小区土壤速效磷的本底值为206.3 mg kg-1 (2016年)和214.6 mg kg-1 (2017年)。在2016和2017年的试验期间, 不同磷肥处理小区的氮肥(尿素)和钾肥(氯化钾)用量一致, 分别为180 kg hm-2和120 kg hm-2。其中, 氮肥按基肥∶分蘖肥∶穗肥比例5∶2∶3施用, 分蘖肥于移栽后7 d一次性施用, 穗肥于倒四叶时期施用。钾肥分别于移栽前和穗肥期等量施入。各小区之间用水泥埂隔开, 并包被防水薄膜, 独立排灌。播种日期分别是2016年5月20日和2017年5月21日, 采用常规湿润育秧, 25 d左右的秧龄时手工移栽于大田, 栽插密度为25 cm × 13 cm, 每穴2株苗。水稻大田生长期间田间进行常规水分管理, 及时防治病虫杂草。待水稻生长至齐穗期, 选同日开花的单穗挂牌标记, 并在水稻成熟收获时取标记稻穗籽粒。1.2 稻穗离体培养试验
为进一步明确外源磷与水稻籽粒锌的生物有效性及植酸磷等磷酸肌醇谱含量之间的关系。我们在大田磷肥长期定位试验的基础上, 利用多磷梯度水平的稻穗离体培养试验, 对其调控规律做了进一步探讨。稻穗离体培养试验在浙江大学紫金港校区控温培养室进行。供试水稻品种为秀水110, 单季稻种植, 播种日期与田间试验一致, 6月中旬单本插栽于大田, 常规高产水作管理。参照已授权发明专利(专利授权号: CN103355169B)的稻穗离体培养方法。抽穗期选择生育时期一致(长势、生育进程及外观)的水稻主茎进行培养。离体主茎需保留2个完整节间, 同时保留5 cm长旗叶和旗叶鞘。暴露于培养瓶中的主茎部位需依次用70%乙醇和1%次氯酸钠分别消毒45 s和15 min。其后迅速转移至已灭菌的培养基及培养瓶中, 并用无菌脱脂棉包裹固定, 便于与外界环境隔绝, 离体培养过程中培养瓶内部全程保持无菌。将培养瓶统一置1~2℃冰台的浅层冷水浴中。由室内控温控湿控光装置调控, 穗层温度为24~26℃, 湿度为75%。16 h光照/8 h黑暗, 光强为300 μmol m-2 s-1。培养过程每6 d更换一次培养基, 并重复前期稻株和培养基的灭菌过程。离体培养试验以NaH2PO4·2H2O为磷源, 设0、1、3、6和12 mmol L-1五个磷梯度处理(分别标记为P0、P1、P3、P6、P12)。不同处理间除磷水平差异外, 培养基的其他成分保持一致。1.3 籽粒不同磷组分(植酸磷、不同价位磷酸肌醇谱、总磷)含量分析
风干水稻籽粒样品经去离子水冲洗3次并吸干水分, 于60℃烘干至恒重后, 人工去壳, 用研钵手工研磨成米粉, 并过0.25 mm筛后放入聚乙烯离心管中低温保存, 用于品质相关的理化指标分析。籽粒植酸含量采用Liu等[18]和Bi等[19]铁沉淀法分析, 植酸磷含量 = 植酸含量 × 0.2815; 总磷含量参照Wilcox等[20]方法测定。不同价位磷酸肌醇含量参照Zhou等[21]方法利用HPLC-ESI-MS测定。1.4 籽粒锌含量及锌的生物有效性分析
籽粒锌含量参照Wei等[22]的电感耦合等离子体质谱法(ICP-MS)分析。锌的生物有效性(TAZ)参照Miller等[23]的三元模型分析:
$\text{TAZ}=0.5\times 65\times 100\times \left\{ {{A}_{\text{MAX}}}+\text{TDZ}+{{K}_{\text{R}}}\times \left( 1+\frac{\text{TDP}}{{{K}_{\text{P}}}} \right)-{{\sqrt{\left[ {{A}_{\text{MAX}}}+\text{TDZ}+{{K}_{\text{R}}}\times \left( 1+\frac{\text{TDP}}{{{K}_{\text{P}}}} \right) \right]}}^{2}}-4\times {{A}_{\text{MAX}}}\times \text{TDZ} \right\}$
其中, 每日摄入锌的生物有效性(TAZ, mg Zn d-1), 即有效锌指数, 将根据每日膳食中植酸(TDP, mmol PA d-1)和锌(TDZ, mmol Zn d-1)的含量拟合后获得。与肠内锌稳态和生物利用率相关的3个常数为AMAX (最大锌吸收) = 0.091; KR (Zn受体结合反应的平衡解离常数) = 0.680; KP (Zn和PA结合反应的平衡解离常数) = 0.033。以平均每日稻米摄入量400 g作为Zn和PA的来源[24]。
此外, 用能谱扫描电镜分析籽粒中磷和锌的空间分布, 参照戴云云等[25]方法, 直接用镊子掰断稻穗离体培养的典型磷处理的糙米样品(P0、P3、P12), 保留自然状态下断裂的横截面, 朝上将样品沾于铜样台上, 用离子溅射喷镀仪对断面镀金处理后, 在场发射扫描电子显微镜(XL30 ESSM-TMP)上观察照相。
1.5 数据统计分析
采用Microsoft Excel 2016对数据进行录入、整理和计算, 运用SPSS 16.0 (SPSS, Inc., Chicago, IL, USA)软件对试验数据进行方差分析, 以Turkey多重比较分析处理间差异显著性, 显著水平设定为P=0.05 (One-way ANOVA, Turkey’s Multiple Range Test), 以GraphPad Prism软件绘图。并用R统计软件进行相关性分析(R分析包为pheatmap)。最终结果以平均数±标准差表示。2 结果与分析
2.1 大田长期磷肥定位试验中不同磷肥处理对水稻籽粒植酸、锌含量和锌生物有效性的影响
由图1可见, 磷肥施用量对水稻籽粒植酸磷含量和总磷含量有显著的影响。其中, 籽粒植酸磷含量和总磷含量均随磷肥施用量的增加呈上升趋势, 且高磷(HP)处理 > 中磷(MP)处理 > 不施磷(LP)处理(其中2017年中磷和高磷处理的籽粒植酸磷含量差异不显著), 但籽粒植酸磷与总磷的比值(PAP/TP)在高磷处理(HP)却呈下降趋势, 2年大田试验的数据规律基本一致。上述现象说明, 磷肥施用量的增加会引起水稻籽粒中植酸磷和总磷含量的显著提升, 其中总磷相比植酸磷含量受磷肥处理的影响更为显著。图1
新窗口打开|下载原图ZIP|生成PPT图1大田磷肥处理对水稻籽粒植酸磷、总磷含量以及植酸磷/总磷比值的影响
标以相同小写字母的柱值差异未达到0.05的显著水平。LP: 低磷处理; MP: 中磷处理; HP: 高磷处理; PAP: 植酸磷; Total P: 总磷; PAP/total P: 植酸磷/总磷。
Fig. 1Differences in PAP, Total P concentration (mg g-1), and PAP/total P among various phosphorus fertilizer levels in field experiment
Bars indicated by the same letter among treatments are not significantly different at the 0.05 probability level. LP, MP, HP mean the low phosphorus level, medium phosphorus level, and high phosphorus level. PAP: phytic acid-phosphorus; Total P: total phosphorus; PAP/total P: phytic acid-phosphorus/total phosphorus.
水稻籽粒中的锌和铁含量随磷肥施用量增加呈明显下降趋势(图2)。2年数据中, 与LP相比, HP处理下水稻籽粒中锌含量降低了9.0%~10.7%, 铁含量降低了15.4%~17.1%。磷肥处理对水稻籽粒中锰含量的影响效应不明显, 而籽粒铜含量在年际间的变化不一致。受籽粒植酸磷和锌含量共同变化的影响, 不同磷肥处理下水稻籽粒锌的有效性的变异系数进一步加大(其中, 2016和2017年间植酸和锌的变异系数分别为4.0%~5.7%和4.4%~5.2%, 而锌的生物有效性的变异系数为8.7%~9.8%)。与LP处理相比, HP处理下籽粒锌的生物有效性降低了18%~20%。
图2
新窗口打开|下载原图ZIP|生成PPT图2大田磷肥处理对水稻籽粒锌、铁、锰、铜含量以及锌的生物有效性的影响
标以相同小写字母的柱值差异未达到0.05的显著水平。LP: 低磷处理; MP: 中磷处理; HP: 高磷处理。TAZ: 锌的生物有效性。
Fig. 2Effects of different phosphorus levels on grain Zn, Fe, Mn, and Cu concentrations and Zn bioavailability (TAZ) (field phosphorus fertilizer experiment)
Bars indicated by the same letter among treatments are not significantly different at the 0.05 probability level. LP, MP, HP mean the low phosphorus level, medium phosphorus level, and high phosphorus level, respectively. TAZ represents Zn bioavailability.
2.2 稻穗离体培养条件下外源磷处理对水稻籽粒植酸磷、不同价位磷酸肌醇谱、锌含量及其生物有效性的影响
随外源磷处理浓度的上升, 水稻籽粒中的植酸磷和总磷含量呈逐渐增加的趋势(图3)。但外源磷处理浓度对水稻籽粒PAP/TP比值影响不显著。利用能谱扫描电镜对典型磷处理浓度(P0、P3和P12)下水稻籽粒样品磷元素分布观测也表明, 随外源磷水平的上升, 水稻籽粒的表皮及糊粉层、籽粒内部淀粉层的磷积累量均明显增加(图4)。考虑到植酸是籽粒磷的最主要贮存形式, 能谱电镜扫描下籽粒在不同空间的磷分布可近似代表籽粒植酸的变化, 说明外源磷供给对水稻籽粒不同部位的植酸磷积累都有一定的促进作用。图3
新窗口打开|下载原图ZIP|生成PPT图3外源磷处理对水稻籽粒植酸磷、总磷含量以及植酸磷/总磷的比值的影响(稻穗离体培养)
标以相同小写字母的柱值差异未达到0.05的显著水平。P0、P1、P3、P6、P12分别代
Fig. 3Effects of different phosphorus levels on grain PAP, total P concentration, and the ratio of PAP to total P (detached panicle culture experiment)
Bars indicated by the same letter among treatments are not significant at the 0.05 probability level. P0, P1, P3, P6, P12 mean the P (NaH2PO4·2H2O ) levels of 0, 1, 3, 6, and 12 mmol L-1, respectively. PAP, total P, PAP/total P mean phytic acid-phosphorus, total phosphorus, and phytic acid-phosphorus/total phosphorus, respectively.
图4
新窗口打开|下载原图ZIP|生成PPT图4稻穗离体培养体系中不同磷浓度水平下水稻籽粒中的磷分布(5000倍光镜下稻米横断面扫描, 100 μm)
A: P0处理; B: P3处理; C: P12处理。
Fig. 4Effect of exogenous phosphorus treatments on grain P distributions in brown rice in detached panicle culture experiment (scanning electron microscopic images of brown rice with 5000 ×; scale bars are 100 μm)
A, B, C represent P0, P3, and P12 treatments, respectively.
利用HPLC-ESI-MS对水稻籽粒中植酸合成过程中不同价位的磷酸肌醇谱(InsP1、InsP2、InsP3、InsP4、InsP5、InsP6)含量进行测定(图5), 表明外源磷处理影响水稻籽粒植酸磷与总磷含量的同时, 对水稻籽粒中的不同价位的磷酸肌醇谱的含量也会产生显著的影响。随外源磷处理浓度的上升, InsP6、InsP5和InsP4含量(mg g-1)呈明显上升趋势。与低价磷酸肌醇衍生物(InsP1、InsP2)相比, 高价磷酸肌醇(InsP4-6)在不同磷浓度处理下的差异幅度更大。此外, 水稻籽粒中的不同价位磷酸肌醇在不同磷浓度处理下的相对比例均表现为InsP6 > InsP5 > InsP4 > InsP(1-3)。其中, InsP6、InsP5和InsP4分别占水稻籽粒总磷酸肌醇含量的70%~79%、17%~20%和2%~8%, 但外源磷处理对水稻籽粒不同价位磷酸肌醇组分所占比例的影响规律不显著(图6)。
图5
新窗口打开|下载原图ZIP|生成PPT图5外源磷处理对水稻籽粒不同价位磷酸肌醇含量的影响(稻穗离体培养)
P0、P1、P3、P6、P12分别代
Fig. 5Effects of different phosphorus levels on grain inositol phosphate (InsP1-6) concentrations (detached panicle culture experiment)
P0, P1, P3, P6, P12 mean the P (NaH2PO4·2H2O) levels of 0, 1, 3, 6, and 12 mmol L-1, respectively.
图6
新窗口打开|下载原图ZIP|生成PPT图6外源磷处理下水稻籽粒中不同价位磷酸肌醇占总磷酸肌醇含量的比例(稻穗离体培养)
Fig. 6Ratio of inositol phosphate composition/total inositol phosphate in different exogenous phosphorus treatment (detached panicle culture experiment)
A: P0; B: P1; C: P3; D: P6; E: P12.
稻穗离体培养下, 外源磷供给对水稻籽粒锌的积累也有显著影响。对最适磷浓度处理(P3)和极端磷处理样品(无磷, P0; 极高磷, P12)的能谱扫描电镜分析显示, 高磷浓度处理下, 籽粒中锌的含量在籽粒不同的横切面都表现为显著降低(图7)。ICP-MS的定量分析结果也表明(图8), 相较于适宜P浓度处理(P3), 高磷浓度水平(P12)下水稻籽粒中锌的含量降低了26.4%。由于极高磷(P12)水平相比无磷处理(P0)籽粒植酸磷含量增加了4.5倍, 因此受籽粒植酸磷和锌含量共同变化的影响, 高磷浓度水平下锌的生物有效性相比无磷处理(P0)降低了81.3%。说明籽粒锌的生物有效性相比籽粒锌含量受外源磷的影响更为显著(图8)。
图7
新窗口打开|下载原图ZIP|生成PPT图7稻穗离体培养体系中不同磷浓度水平下水稻籽粒中锌的分布(5000倍光镜下稻米横断面扫描, 标尺为100 μm)
A: P0处理; B: P3处理; C: P12处理。
Fig. 7Effect of exogenous phosphorus treatment on grain Zn distributions in detached panicle culture experiment (scanning electron microscopic images of brown rice with 5000 ×; scale bars are 100 μm)
A, B, C represent P0, P3, and P12 treatment, respectively.
图8
新窗口打开|下载原图ZIP|生成PPT图8外源磷处理水稻籽粒锌的含量及其有效性的影响(稻穗离体培养)
标以相同小写字母的柱值差异未达到0.05的显著水平。P0、P1、P3、P6、P12分别代
Fig. 8Effects of different phosphorus levels on grain Zn concentration and its bioavailability (TAZ) (detached panicle culture experiment)
Bars indicated by the same letter among treatments are not significant at the 0.05 probability level. P0, P1, P3, P6, P12 mean the P (NaH2PO4·2H2O) levels of 0, 1, 3, 6, and 12 mmol L-1, respectively. TAZ: Zn bio-availability.
2.3 不同磷素处理下各种指标之间的相关性
大田磷肥试验表明(图9左), 籽粒植酸磷和总磷之间呈极显著正相关(0.944**), 与籽粒锌的生物有效性之间呈极显著负相关(-0.692**)。综合田间长期磷肥定位试验和稻穗离体培养进行相关性分析(图9右)表明, 籽粒植酸磷和锌的生物有效性之间呈现极显著的负相关(-0.780**)。说明外源磷处理可显著增加水稻籽粒植酸磷和总磷含量, 同时降低籽粒锌的生物有效性。图9
新窗口打开|下载原图ZIP|生成PPT图9不同磷肥处理水平下水稻籽粒磷组分和锌的生物有效性之间的相关性分析(左: 大田试验; 右: 大田试验+稻穗离体培养试验)
PAP: 植酸磷; TP: 总磷; TAF: 锌的生物有效性。
Fig. 9Correlation of grain phosphorus components and Zn bioavailability under P treatment (left: heatmap of field phosphorus fertilizer experiment; right: correlation in both field and detached rice panicle culture systems)
PAP: phytic acid phosphours; TP: total phosphours; TAF: Zn bio-availabiity. ** P < 0.01.
3 讨论
针对水稻和小麦等大宗粮食作物籽粒锌、铁的生物强化, 是目前农业研究中作物品质改良以及对抗“隐性饥饿”的主要方向。实现生物强化的目标, 除要通过育种和栽培管理措施提高籽粒微营养含量外, 还需要同步降低以植酸为主的“抗营养元素”水平, 只有这样才能保障或提高锌等微营养在人体内的真正有效吸收。本试验在大田磷肥梯度长期定位试验的基础上, 进一步利用稻穗离体培养体系, 通过拉大外源磷梯度效应和精确控制区分“源”中磷素供应量, 试图进一步明确外源磷素对水稻籽粒锌的生物有效性的影响及其与籽粒植酸等磷酸肌醇谱含量之间的关系。与前人关于外源磷调控籽粒植酸合成的研究结果相似[16,26], 本试验也表明外源磷(肥)可显著提高籽粒中植酸磷和总磷的含量(图1、图3、图4和图5), 大田和离体培养试验的结果相似。然而大田磷肥调控下, 水稻籽粒中总磷含量的增幅相比植酸磷变化更为显著, 使得高磷处理水平(HP)下水稻籽粒植酸磷与总磷的比值(PAP/TP)显著降低, 说明植酸磷、无机磷以及其他磷组分在高磷处理下的变化规律并不完全一致。Sompong等[27]对绿豆籽粒磷组分含量相关的QTL分析表明, 控制籽粒不同磷组分含量的基因位点不一致。其中, 有3个位点参与植酸磷(PAP)的合成, 另有2个和1个位点分别控制总磷、无机磷的合成。Taliman等[28]研究表明, 对低植酸大豆品系(LP-F10)而言, 高磷浓度处理下籽粒无机磷含量的显著提高是总磷含量升高的主要原因, 植酸磷对外源磷浓度的响应不显著。而常规品种(Enrei)的植酸磷和其他磷组分表现为同步增加, 无机磷变化不显著。说明磷(肥)对作物籽粒中不同磷组分的影响, 可能同时还受到籽粒植酸遗传背景、磷肥梯度以及基因型差异等综合因素的影响。此外, 长期磷肥定位试验中, 施入土壤中的磷肥有效性除与肥料投入量密切相关外, 还受到土壤特性和土壤菌根数量的影响[29,30], 这可能是不同磷水平调控下, 籽粒磷的不同形态及其比例变化不一致的原因之一。同时, 大田栽培和离体培养体系中, 水稻在磷吸收、运转过程中的差异也可能是本试验PAP/TP在高磷浓度水平下变化规律不一致的原因之一。
前人已广泛证明氮肥可显著促进作物籽粒锌、铁积累[31,32]。Kutman等[33]对硬粒小麦的研究表明, 氮素营养无论是对锌获取还是锌向籽粒中的转运都起到关键的作用。然而目前关于磷肥对作物锌等微营养品质影响的结论尚不完全一致。Bolland等[34]的结果表明, 缺磷土壤补充磷肥后, 小麦籽粒中锌含量变化并不显著。Orabi等[35]的结果表明, 磷肥促进锌从叶片向籽粒的转运, 并增加籽粒锌的积累。而Zhang等[36]研究表明, 磷肥会限制茎鞘中的锌积累, 继而减少锌向籽粒的转运, 成熟期小麦锌含量降幅可达17%~56%, 但在Zhang等[16]的研究中这种抑制效应在磷梯度超过100 kg hm-2时变化开始不显著, 说明高磷对籽粒锌吸收的抑制效应还与具体的磷水平设置有关。此外, Ova等[9]认为外源磷供应降低小麦根系锌吸收、营养器官锌转移以及籽粒中的锌积累, 主要与土壤中的菌根种类和数量有关。在缺乏菌根的培养基中没有发现籽粒磷与锌的负向调控效应。本试验结果表明(图2、图7和图8), 磷(肥)供应下水稻籽粒中锌含量显著降低。不同的磷供应试验(大田和离体培养)的结果一致。说明菌根种类和数量的差异并不是磷素抑制籽粒锌积累的唯一原因, 相关磷锌互作的生理机制有待进一步研究。
由于锌在人体和非反刍动物体内最终被吸收的量(即锌的生物有效性)同时还会受胃肠分泌的影响, 并不仅仅只是一个简单的量的吸收过程[37]。传统以植酸和锌的摩尔比([PA]/[Zn])来表征锌的有效性的方法, 在高植酸背景研究中因其高抑制效应不具有真实评价意义。同时也忽略了其他高价磷酸肌醇盐(InsP4和InsP5)对以锌为主的矿质元素的络合效应。因此, 本研究在外源磷调控籽粒锌相对含量的基础上, 利用三元模型, 通过模拟锌在人/单胃动物肠胃内的消化吸收过程, 进一步分析不同磷浓度处理下籽粒锌的生物有效性的变化。大田试验和稻穗离体培养结果均表明高磷处理会显著降低锌的生物有效性。其中长期磷肥定位试验在相对较小的磷肥梯度水平内, 锌的生物有效性降低了18%~20% (图2)。而稻穗离体培养体系通过拉大磷供应梯度, 极高磷浓度梯度(P12)相较无磷(P0)处理, 籽粒中锌的生物有效性降幅高达81.3% (图8)。相关性分析结果也表明, 植酸磷和籽粒锌的生物有效性之间呈极显著负相关(图9)。因此从稻米营养品质角度考量, 过量磷水平会显著降低人体对锌的有效吸收。
水稻籽粒植酸合成是以光合产物葡萄糖-6-磷酸(G-6-P)为起始底物不断顺序磷酸化的过程[15]。在不同价位的磷酸肌醇中间产物(InsP1-6)中, 低价磷酸肌醇的磷酸基团较少, 络合矿质离子的能力相对较弱。而高价磷酸肌醇(InsP4, InsP5)具有与植酸(InsP6)相似的多羟基生化结构, 同样可以络合矿质离子并降低它们的生物有效性[15,37-39]。前人关于植酸对矿质元素有效性影响的定量分析, 往往只关注磷酸肌醇合成的终产物, 即植酸(InsP6, 六磷酸肌醇)的含量水平, 忽略了其他高价磷酸肌醇(InsP4-5)对锌等矿质元素的络合效应。基于这样的研究背景, 本研究首次利用HPLC-ESI-MS分析了外源磷对不同价位磷酸肌醇含量/比例的影响, 试图进一步明确外源磷素调控下籽粒植酸等磷酸肌醇谱系的分布变化特征。试验结果表明, 不同磷处理水平下, 磷酸肌醇谱系中均表现为高价磷酸肌醇的含量显著高于低价磷酸肌醇, 总体表现为InsP6 > InsP5 > InsP4 > InsP1-3, 其中籽粒植酸InsP6占到了磷酸肌醇总含量的70%以上(图2)。外源磷处理可以显著提高不同价位的磷酸肌醇含量, 其中以高价磷酸肌醇(InsP4-6)对外源磷的响应最为显著。本试验中高磷浓度处理下高价磷酸肌醇(InsP4和InsP5)的相对高比例(19%~24%), 说明高磷浓度处理下籽粒锌的生物有效性, 即真正被人体有效吸收的锌比例, 可能被普遍低估。因此, 在保障水稻产量优势的同时适当降低磷肥投入, 对改善作物以锌为主的微营养品质, 解决“隐性饥饿”具有重要的借鉴意义。
4 结论
外源磷可显著提高作物籽粒的植酸磷、不同价位磷酸肌醇以及总磷含量, 同时降低籽粒锌含量。外源磷供应下稻米植酸磷和锌含量的同步变化, 最终导致锌的生物有效性进一步显著降低。过量磷肥投入对籽粒锌营养的负向调控效应显著。参考文献 原文顺序
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被引期刊影响因子
DOI:10.1016/j.jtemb.2018.02.009URLPMID:29472130 [本文引用: 1]
A basic knowledge of the dynamics of zinc (Zn) in soils, water and plants are important steps in achieving sustainable solutions to the problem of Zn deficiency in crops and humans. This paper aims at reviewing and discussing the relevant aspects of the role of Zn in the soil-water-plant agro biological system: from the origins of Zn in soils and water to soil Zn deficiency distribution and the factors affecting soil Zn availability to plants, therefore to elucidate the strategies potentially help combating Zn deficiency problems in soil-plant-human continuum. This necessitates identifying the main areas of Zn-deficient soils and food crops and treating them with Zn amendments, mainly fertilizers in order to increase Zn uptake and Zn use efficiency to crops. In surface and groundwater, Zn enters the environment from various sources but predominately from the erosion of soil particles containing Zn. In plants is involved in several key physiological functions (membrane structure, photosynthesis, protein synthesis, and drought and disease tolerance) and is required in small but nevertheless critical contents. Several high revenue food crops such as beans, citrus, corn, rice etc are highly susceptible to Zn deficiency and biofortification is considered as a promising method to accumulate high content of Zn especially in grains. With the world population continuing to rise and the problems of producing extra food rich in Zn to provide an adequate standard of nutrition to increase, it is very important that any losses in production easily corrected so as Zn deficiencies are prevented.
DOI:10.1186/1471-2148-11-253URLPMID:21917168 [本文引用: 4]
A major goal of molecular evolutionary biology is to understand the fate and consequences of duplicated genes. In this context, aphids are intriguing because the newly sequenced pea aphid genome harbors an extraordinary number of lineage-specific gene duplications relative to other insect genomes. Though many of their duplicated genes may be involved in their complex life cycle, duplications in nutrient amino acid transporters appear to be associated rather with their essential amino acid poor diet and the intracellular symbiosis aphids rely on to compensate for dietary deficits. Past work has shown that some duplicated amino acid transporters are highly expressed in the specialized cells housing the symbionts, including a paralog of an aphid-specific expansion homologous to the Drosophila gene slimfast. Previous data provide evidence that these bacteriocyte-expressed transporters mediate amino acid exchange between aphids and their symbionts.
DOI:10.1111/pbr.2019.138.issue-1URL [本文引用: 1]
DOI:10.1016/j.jcs.2017.09.004URL [本文引用: 1]
DOI:10.1007/s11240-014-0510-8URL [本文引用: 1]
DOI:10.1016/j.jcs.2007.08.003URL [本文引用: 1]
Abstract
Milling and polishing are important operations during the production of white rice. The degree of milling and polishing has a significant effect on the nutritional aspects of white rice, especially on minerals, due to a non-uniform distribution of nutrients in the kernel. Information on the distribution of nutrients in rice will greatly help in understanding the effect of milling and aid in designing procedures that improve technological and sensory properties of rice while retaining its essential nutrients as much as possible. In this study, three kernel shapes (short-, medium- and long-grain) of rice were selected for the study of milling characteristics and distribution of zinc (Zn) and phytic acid using abrasive milling and X-ray fluorescent microscope imaging approaches.Milling characteristics differed with kernel shapes and cultivars. Mass loss (y, %) correlated well with milling duration (x, s) and was fitted using a polynomial equation of y=ax2+bx+c (R2=0.99). Different kernel shapes of rice resulted in different patterns. Breakage in milling increased with longer duration of milling. The relation between breakage (y, %) and milling duration (x, s) fitted the exponential equation y=aebx. Levels of phytic acid, as well as Zn, decreased with prolonged milling. Phytic acid decreased at a higher rate than Zn. The analysis of different milling runs showed that the concentration of phytic acid decreased from the surface region inward, whereas X-ray fluorescent images indicated that the highest concentration of phosphorus was at the interface of the embryo and perisperm.
Our results help in understanding the milling characteristics of different rice cultivars. Understanding these characteristics offers opportunities to optimize milling procedures for maximum phytate removal at minimum mineral losses and yield loss.
DOI:10.1186/s12284-018-0200-yURLPMID:29327163 [本文引用: 1]
Myo-inositol hexaphosphate, also known as phytic acid (PA), is the most abundant storage form of phosphorus in seeds. PA acts as a strong chelator of metal cations to form phytate and is considered an anti-nutrient as it reduces the bioavailability of important micronutrients. Although the major nutrient source for more than one-half of the global population, rice is a poor source of essential micronutrients. Therefore, biofortification and reducing the PA content of rice have arisen as new strategies for increasing micronutrient bioavailability in rice. Furthermore, global climate change effects, particularly rising atmospheric carbon dioxide concentration, are expected to increase the PA content and reduce the concentrations of most of the essential micronutrients in rice grain. Several genes involved in PA biosynthesis have been identified and characterized in rice. Proper understanding of the genes related to PA accumulation during seed development and creating the means to suppress the expression of these genes should provide a foundation for manipulating the PA content in rice grain. Low-PA rice mutants have been developed that have a significantly lower grain PA content, but these mutants also had reduced yields and poor agronomic performance, traits that challenge their effective use in breeding programs. Nevertheless, transgenic technology has been effective in developing low-PA rice without hampering plant growth or seed development. Moreover, manipulating the micronutrient distribution in rice grain, enhancing micronutrient levels and reducing the PA content in endosperm are possible strategies for increasing mineral bioavailability. Therefore, a holistic breeding approach is essential for developing successful low-PA rice lines. In this review, we focus on the key determinants for PA concentration in rice grain and discuss the possible molecular methods and approaches for manipulating the PA content to increase micronutrient bioavailability.
DOI:10.1093/aob/mcw164URLPMID:27590335 [本文引用: 1]
In cultivated rice, phosphorus (P) in grains originates from two possible sources, namely exogenous (post-flowering root P uptake from soil) or endogenous (P remobilization from vegetative parts) sources. This study investigates P partitioning and remobilization in rice plants throughout grain filling to resolve contributions of P sources to grain P levels in rice.
DOI:10.5696/2156-9614-9.24.191212URLPMID:31893173 [本文引用: 3]
High concentrations of total petroleum hydrocarbons (TPH), iron (Fe), and manganese (Mn) were identified in soil samples from two shipyards where vessel dismantling activities take place in Tanjungjati Village, Indonesia, and subjected to bioremediation.
[本文引用: 1]
[本文引用: 1]
DOI:10.1104/pp.75.4.1094URLPMID:16663741 [本文引用: 1]
The relationships between nutrient P and Zn levels and the phytic acid, P, and Zn concentrations in soybean (Glycine max L. Merr. cv ;Williams 79') seed were studied. Phytic acid increased linearly from 4.2 to 19.2 milligrams per gram as nutrient P treatment was varied from 2.0 to 50 milligrams per liter and Zn was held constant at 0.05 milligrams per liter. Leaf P concentration during seed development was found to be closely related to the concentrations of seed P and phytic acid. Leaf and seed Zn concentrations both responded positively to increasing nutrient Zn treatment. The effects of P treatment on plant and seed P and phytic acid were largely independent of the effects of Zn treatment on leaf and seed Zn. Phytic acid to Zn molar ratios ranging from 3.6 to 33.8 were observed.The effects of nutrient P treatments on the concentrations of phytic acid, seed P, and leaf P were also studied in the P-sensitive (gene np) cultivars ;Harosoy' and ;Clark' and their respective P-tolerant (gene Np) near-isogenic lines L66-704 and L63-1677. In general, the positive relationships observed among nutrient P, leaf P, seed P, and phytic acid concentrations were similar to those observed in the studies with Williams 79. When fertilized with low or moderate nutrient P (2.5 and 25.0 milligrams P per liter, respectively) no significant differences in any parameter were observed between Harosoy or Clark and their respective P-tolerant isolines. When fertilized with high nutrient P (100 milligrams P per liter), Harosoy seed had a significantly higher concentration of phytic acid (30 milligrams per gram) than did seed of its P-tolerant near-isogenic line L66-704 (24.2 milligrams per gram phytic acid), whereas no significant difference was observed between Clark and its P-tolerant near-isogenic line L63-1677 (22.8 and 21.6 milligrams per gram, respectively). Variation in the phytic acid concentrations in the mature seed of the cultivars and isolines more closely paralleled leaf P concentrations observed during seed development (49 days after flowering), than those observed at the onset of seed development (14 days after flowering). Electrophoresis and ion-exchange chromatography revealed that partially phosphorylated intermediates do not appear when phytic acid accumulation is greatly reduced by limiting the nutrient P or when accumulation is greatly accelerated by excess P.
DOI:10.1007/s11104-013-2015-3URL [本文引用: 1]
As plants approach maturity and start to senesce, the primary sink for phosphorus (P) is the seed but it is unclear how plant P status affects the resulting P concentration and speciation in the seed and remaining plant parts of the residues. This study was established to measure how P speciation in different parts of wheat and canola is affected by plant P status.
Wheat and canola grown in the glasshouse were supplied three different P rates (5, 30 and 60 kg P ha(-1) equivalent). At physiological maturity, plants were harvested and P speciation was determined for all plant parts (root, stem, leaf, chaff/pod and seed) and rates of P application, using solution P-31 nuclear magnetic resonance (NMR) spectroscopy.
Phytate was the dominant form of P in seed whereas orthophosphate was the dominant form of P in other plant parts. The distribution of P species varied with P status for canola but not for wheat. The phytate content of wheat chaff increased from 10 to 45 % of total P as the P rate increased. Canola pods did not show a similar trend, with most P present as orthophosphate.
Although minor differences were observed in P speciation across the three P application rates and plant parts, the effect of this on P cycling from residues into soil is likely to be relatively minor in comparison to the overall contribution of these residues to soil P pools. This glasshouse experiment shows the dominant P form in crop residues that is returned to soil after harvest is orthophosphate, regardless of plant P status.
DOI:10.1021/acs.jafc.7b04883URLPMID:29401375 [本文引用: 1]
Development of rice cultivars with low phytic acid (lpa) is considered as a primary strategy for biofortification of zinc (Zn) and iron (Fe). Here, two rice genotypes (XS110 and its lpa mutant) were used to investigate the effect of P supplies on accumulations and distributions of PA, Zn, and Fe in rice grains by using hydroponics and detached panicle culture system. Results showed that higher P level increased grain PA concentration on dry matter basis (g/kg), but it markedly decreased PA accumulation on per grain basis (mg/grain). Meanwhile, more P supply reduced the amounts and bioavailabilities of Zn and Fe both in milled grains and in brown grains. Comparatively, lpa mutant was more susceptive to exogenous P supply than its wild type. Hence, the appropriate P fertilizer application should be highlighted in order to increase grain microelement (Zn and Fe) contents and improve nutritional quality in rice grains.
DOI:10.1016/s1360-1385(01)02104-5URLPMID:11590064 [本文引用: 3]
myo-Inositol(1,2,3,4,5,6)hexakisphosphate (InsP(6) or 'phytic acid') was first known as the storage form of phosphorus in seeds. Seed-derived dietary InsP(6) can contribute to iron and zinc deficiency in human populations. Excretion of 'phytic acid phosphorus' by non-ruminants such as poultry, swine and fish can contribute to water pollution. Sustainable solutions to these important problems might depend on progress in the molecular biology and genetics of InsP(6) accumulation during seed development. The development of 'low phytate' grain and legume genotypes could help advance our understanding of this biology, and when used in foods and feeds might help to reduce human malnutrition and reduce animal waste phosphorus.
DOI:10.1021/acs.jafc.6b04778URLPMID:28171726 [本文引用: 4]
To supplement human dietary nutrition, it is necessary to evaluate the effects of phosphorus (P) fertilizer application on grain and flour protein contents and especially on the bioavailability of zinc (Zn). A field experiment of winter wheat with six P application rates (0, 25, 50, 100, 200, 400 kg/ha) was conducted from 2013 to 2015. The grain yield increased with P application but was not further enhanced when P rates exceeded 50 kg/ha. As P application increased, the protein concentration in grain and standard flour and the viscosity of standard flour decreased. Phosphorus and phytic acid (PA) concentrations in grain and flours increased and then plateaued, whereas Zn concentration decreased and then plateaued as P application increased from 0 to 100 kg/ha. Estimated Zn bioavailability in grain and flours decreased as P application increased from 0 to 100 kg/ha and then plateaued. Estimated Zn bioavailability was greater in standard flour, bread flour, and refined flour than in grain or coarse flour. Phosphorus supply in the intensive cropping of wheat can be optimized to simultaneously obtain high grain yields, high grain and flour protein contents, and high Zn bioavailability.
DOI:10.1002/jpln.v179.1URL [本文引用: 1]
DOI:10.1016/j.jcs.2004.09.010URL [本文引用: 1]
DOI:10.1007/s11104-012-1561-4URL [本文引用: 1]
This study aims to investigate the effect of nitrogen (N) on grain phosphorus (P) accumulation in japonica rice.
Six cultivars with contrasting agronomic traits were grown for 3 years (from 2008 to 2010) of field experiments under seven N treatments and 1 year (in 2010) of pot experiments with five N treatments to study the effect of N on grain phosphorus accumulation and to explore its physiological foundation.
Grain total P and phytic acid concentration showed a clearly decreasing trend as N rate increased for both field and pot experiments. Pot experiment revealed that application of N increase plant biomass, but tended to lower plant P uptake, especially for the split topdressing treatments. Both harvest index (HI) and P harvest index (PHI) increased with N rate, but PHI was consistently higher than HI, indicating the larger proportion of P translocation to grain than that of dry matter by N. Further, ratio of PHI/HI differed significantly among genotypes, but was stable across contrasting N treatments.
The combination of decreased plant P uptake and dilution effect of increased grain yield by N is proposed as underlying mechanism of the decreased grain P concentration by high N.
DOI:10.2135/cropsci2000.4061601xURL [本文引用: 1]
DOI:10.1007/s10725-018-0402-8URL [本文引用: 1]
DOI:10.1021/jf205025bURLPMID:22273463 [本文引用: 1]
Rice is the staple food for more than half of the world's population and, hence, the main source of a vital micronutrient, zinc (Zn). Unfortunately, the bioavailability of Zn from rice is very low not only due to low content but also due to the presence of some antinutrients such as phytic acid. We investigated the effect of germination and Zn fortification treatment on Zn bioavailability of brown rice from three widely grown cultivars using the Caco-2 cell model to find a suitable fortification level for producing germinated brown rice. The results of this study showed that Zn content in brown rice increased significantly (p &lt; 0.05) as the external Zn concentrations increased from 25 to 250 mg/L. In contrast, no significant influence (p &gt; 0.05) on germination percentage of rice was observed when the Zn supply was lower than 150 mg/L. Zn fortification during the germination process has a significant impact on the Zn content and finally Zn bioavailability. These findings may result from the lower molar ratio of phytic acid to Zn and higher Zn content in Zn fortified germinated brown rice, leading to more bioavailable Zn. Likewise, a significant difference (p &lt; 0.05) was found among cultivars with respect to the capacity for Zn accumulation and Zn bioavailability; these results might be attributed to the difference in the molar ratio of phytic acid to Zn and the concentration of Zn among the cultivars evaluated. Based on global intake of Zn among the world population, we recommend germinated brown rice fortified with 100 mg/L ZnSO(4) as a suitable concentration to use in the germination process, which contains high Zn concentration and Zn bioavailability. In the current study, the cultivar Bing91185 fortified with Zn through the germination process contained a high amount as well as bioavailable Zn, which was identified as the most promising cultivar for further evaluation to determine its efficiency as an improved source of Zn for target populations.
DOI:10.1093/jn/137.1.135URLPMID:17182814 [本文引用: 1]
The quantities of zinc and phytate in the diet are the primary factors determining zinc absorption. A mathematical model of zinc absorption as a function of dietary zinc and phytate can be used to predict dietary zinc requirements and, potentially, enhance our understanding of zinc absorption. Our goal was to develop a model of practical and informative value based on fundamental knowledge of the zinc absorption process and then fit the model to selected published data to assess its validity and estimate parameter values. A model of moderate mathematical complexity relating total zinc absorption to total dietary zinc and total dietary phytate was derived and fit to 21 mean data from whole day absorption studies using nonlinear regression analysis. Model validity, goodness of fit, satisfaction of regression assumptions, and quality of the parameter estimates were evaluated using standard statistical criteria. The fit had an R(2) of 0.82. The residuals were found to exhibit a normal distribution, constant variance, and independence. The parameters of the model, A(MAX), K(R), and K(P), were estimated to have values of 0.13, 0.10, and 1.2 mmol/d, respectively. Several of these estimates had wide CI attributable in part to the small number and the scatter of the data. The model was judged to be valid and of immediate value for studying and predicting absorption. A version of the model incorporating a passive absorption mechanism was not supported by the available data.
DOI:10.1016/j.foodchem.2016.07.064URLPMID:27507486 [本文引用: 1]
Rice is known to accumulate methylmercury (MeHg) in the rice grains. MeHg as a neurotoxin impacts on the human central nervous systems and especially on the developing brain. In this exploratory study, 87 commercial rice products sold in Europe, including nine baby-rice products, were analyzed for total Hg and MeHg content. MeHg concentration in all rice products investigated range from 0.11 to 6.45μgkg(-1) with an average value of 1.91±1.07μgkg(-1) and baby-rice is not significantly different from other rice products. Total Hg ranges from 0.53 to 11.1μgkg(-1) with an average of 3.04±2.07μgkg(-1). MeHg concentrations in all rice products studied in this work would not exceed the provisional tolerable weekly intake (PTWI). 30% of all commercial market rice products exceeded 10% of the PTWI calculated for toddlers or 13% of products for adults with rice based diet.
DOI:10.3969/j.issn.1001-7216.2009.04.12URL [本文引用: 1]
以武育粳3号为材料，在开放环境下使用远红外加热器对水稻穗部进行增温处理，研究了灌浆结实期穗部日间或夜间增温对稻米品质的影响。结果表明，夜间增温降低了糙米率、精米率和整精米率，增加了垩白发生，降低了稻米的加工品质和外观品质，与日间增温影响一致。夜间增温提高了稻米蛋白质含量，与日间增温相似，但夜间增温有降低稻米直链淀粉含量的趋势，与日间增温相反。夜间增温处理淀粉结构与日间增温差异较分明，尤其是胚乳腹部，夜间增温胚乳腹部的淀粉粒个体较大，棱角分明，排列紧密；而日间增温淀粉体较小，呈圆形和椭圆形，但数量较多。夜间增温对淀粉相对结晶度的影响与日间增温相似，但夜间增温增幅较小。总体来说，灌浆结实期夜间增温对稻米的加工品质、外观品质、营养品质影响与日间增温一致，对蒸煮食味品质和淀粉结构的影响与日间增温存在很大的差异，且夜间增温对稻米品质的影响程度整体上小于日间增温。
DOI:10.3969/j.issn.1001-7216.2009.04.12URL [本文引用: 1]
以武育粳3号为材料，在开放环境下使用远红外加热器对水稻穗部进行增温处理，研究了灌浆结实期穗部日间或夜间增温对稻米品质的影响。结果表明，夜间增温降低了糙米率、精米率和整精米率，增加了垩白发生，降低了稻米的加工品质和外观品质，与日间增温影响一致。夜间增温提高了稻米蛋白质含量，与日间增温相似，但夜间增温有降低稻米直链淀粉含量的趋势，与日间增温相反。夜间增温处理淀粉结构与日间增温差异较分明，尤其是胚乳腹部，夜间增温胚乳腹部的淀粉粒个体较大，棱角分明，排列紧密；而日间增温淀粉体较小，呈圆形和椭圆形，但数量较多。夜间增温对淀粉相对结晶度的影响与日间增温相似，但夜间增温增幅较小。总体来说，灌浆结实期夜间增温对稻米的加工品质、外观品质、营养品质影响与日间增温一致，对蒸煮食味品质和淀粉结构的影响与日间增温存在很大的差异，且夜间增温对稻米品质的影响程度整体上小于日间增温。
DOI:10.1590/S1677-04202002000100007URL [本文引用: 1]
DOI:10.1270/jsbbs.62.87URLPMID:23136518 [本文引用: 1]
Phytic acid (PA) is the storage form of phosphorus (P) in seeds and plays an important role in the nutritional quality of food crops. There is little information on the genetics of seed and seedling PA in mungbean [Vigna radiata (L.) Wilczek]. Quantitative trait loci (QTL) were identified for phytic acid P (PAP), total P (TP), and inorganic P (IP) in mungbean seeds and seedlings, and for flowering, maturity and seed weight, in an F(2) population developed from a cross between low PAP cultivated mungbean (V1725BG) and high PAP wild mungbean (AusTRCF321925). Seven QTLs were detected for P compounds in seed; two for PAP, four for IP and one for TP. Six QTLs were identified for P compounds in seedling; three for PAP, two for TP and one for IP. Only one QTL co-localized between P compounds in seed and seedling suggesting that low PAP seed and low PAP seedling must be selected for at different QTLs. Seed PAP and TP were positively correlated with days to flowering and maturity, indicating the importance of plant phenology to seed P content.
DOI:10.3390/plants8050119URLPMID:31071932 [本文引用: 1]
Crop seed phosphorus (P) is primarily stored in the form of phytate, which is generally indigestible by monogastric animals. Low-phytate soybean lines have been developed to solve various problems related to seed phytate. There is little information available on the effects of P fertilization on productivity, physiological characteristics, and seed yield and quality in low-phytate soybeans. To address this knowledge gap, studies were conducted with a low-phytate line and two normal-phytate cultivars from western Japan when grown under high- and low-P fertilization. The whole plant dry weight, leaf photosynthesis, dinitrogen fixation, and nodule dry weight at the flowering stage were higher in the higher P application level, but were not different between the low-phytate line and normal-phytate cultivars. As expected, seed yield was higher in the higher level of P application for all lines. Notably, it was higher in the low-phytate line as compared with the normal-phytate cultivars at both levels of fertilizer P. The total P concentration in the seeds of the low-phytate line was the same as that of the normal-phytate cultivars, but the phytate P concentration in the low-phytate line was about 50% less than that of the normal-phytate cultivars. As a result the molar ratio of phytic acid to Zn, Fe, Mn, and Cu in seed were also significantly lower in the low-phytate line. From these results, it can be concluded that growth after germination, leaf photosynthesis, nitrogen fixation, yield and seed quality were not less in the low-phytate soybean line as compared with two unrelated normal-phytate cultivars currently grown in Japan, and that low-phytate soybeans may improve the bioavailability of microelements.
DOI:10.1081/CSS-120038559URL [本文引用: 1]
DOI:10.1016/j.fcr.2015.10.002URL [本文引用: 1]
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DOI:10.1007/s11104-012-1510-2URL [本文引用: 1]
Background and aims Nitrogen (N) nutrition is a critical factor in zinc (Zn) acquisition and its allocation into grain of wheat (Triticum aestivum L.). Most of the information collected about this topic is, however, derived from the pot experiments. It is also not known whether optimal N management by decreasing N input could affect the Zn status in grain and plant in the field. The aim of this research is to investigate the impact of N management on grain and shoot Zn status of winter wheat.
Methods Field experiments were conducted in two cropping seasons.
Results Results showed applying N at optimal rate (198 kg N ha(-1) in 2007-2008 and 195 kg N ha(-1) in 2008-2009) maintained or resulted in significantly higher grain Zn concentration and especially grain content of Zn compared to no or lower N treatments. For example, grain Zn concentration increased from 21.5 mg kg(-1) in the control to 30.9 mg kg(-1) with optimized N supply in 2007-2008 and from 24.7 mg kg(-1) in the control to 29.1 mg kg(-1) with optimized N supply in 2008-2009. Further increasing N supply from optimal to excessive N supply resulted in non-significant increases in grain Zn concentration and content. Generally, similar trends were also found in shoot Zn. Moreover, 72 % to 100 % of the shoot Zn requirement had been accumulated at anthesis, and accordingly 67 % to 100 % of grain Zn content was provided by Zn remobilization from pre-anthesis Zn uptake with N supply. Grain Zn accumulation mainly originates from Zn remobilization and the optimal N management would ensure better shoot Zn nutrition to contribute to increasing Zn remobilization from vegetative tissues and to maintain relatively higher grain Zn for better human nutrition.
DOI:10.1007/s11104-010-0679-5URL [本文引用: 1]
Deficiencies of zinc (Zn) and iron (Fe) are global nutritional problems and caused most often by their limited dietary intake. Increasing Zn and Fe concentrations of staple food crops such as wheat is therefore an important global challenge. This study investigated the effects of varied nitrogen (N) and Zn supply on the total uptake, remobilization and partitioning of Zn, Fe and N in durum wheat throughout its ontogenesis. Plants were grown under greenhouse conditions with high or low supply of N and Zn, and harvested at 8 different developmental stages for analysis of Zn, Fe and N in leaves, stems, husks and grains. The results obtained showed that the Zn and Fe uptake per plant was enhanced up to 4-fold by high N supply while the increases in plant growth by high N supply were much less. When both the Zn and N supplies were high, approximately 50% of grain Zn and 80% of grain Fe were provided by post-anthesis shoot uptake, indicating that the contribution of remobilization to grain accumulation was higher for Zn than for Fe. At the high N and Zn application, about 60% of Zn, but only 40% of Fe initially stored in vegetative parts were retranslocated to grains, and nearly 80% of total shoot Zn and 60% of total shoot Fe were harvested with grains. All these values were significantly lower at the low N treatment. Results indicate that N nutrition is a critical factor in both the acquisition and grain allocation of Zn and Fe in wheat.
DOI:10.1080/00103629309368874URL [本文引用: 1]
DOI:10.1007/BF02374607URL [本文引用: 1]
DOI:10.1007/s11104-012-1238-zURL [本文引用: 1]
Background and aims Malnutrition resulting from zinc (Zn) and iron (Fe) deficiency has become a global issue. Excessive phosphorus (P) application may aggravate this issue due to the interactions of P and micronutrients in soil crop. Crop grain micronutrients associated with P applications and the increase of grain Zn by Zn fertilization were field-evaluated.
Methods A field experiment with wheat was conducted to quantify the effect of P applications on grain micronutrient quality during two cropping seasons. The effect of foliar Zn applications on grain Zn quality with varied P applications was tested in 2011.
Results Phosphorus applications decreased grain Zn concentration by 17-56%, while grain levels of Fe, manganese (Mn) and copper (Cu) either remained the same or increased. Although P applications increased grain yield, they restricted the accumulation of shoot Zn, but enhanced the accumulation of shoot Fe, Cu and especially Mn. In 2011, foliar Zn application restored the grain Zn to levels occurring without P and Zn application, and consequently reduced the grain P/Zn molar ratio by 19-53% than that without Zn application.
Conclusions Foliar Zn application may be needed to achieve both favorable yield and grain Zn quality of wheat in production areas where soil P is building up.
DOI:10.1016/j.foodchem.2008.02.064URLPMID:26047266 [本文引用: 2]
Rice is an important staple food in Asian countries. In rural areas it is also a major source of micronutrients. Unfortunately, the bioavailability of minerals, e.g. zinc from rice, is low because it is present as an insoluble complex with food components such as phytic acid. We investigated the effects of soaking, germination and fermentation with an aim to reduce the content of phytic acid, while maintaining sufficient levels of zinc, in the expectation of increasing its bioavailability. Fermentation treatments were most effective in decreasing phytic acid (56-96% removal), followed by soaking at 10°C after preheating (42-59%). Steeping of intact kernels for 24h at 25°C had the least effect on phytic acid removal (&lt;20%). With increased germination periods at 30°C, phytic acid removal progressed from 4% to 60%. Most wet processing procedures, except soaking after wet preheating, caused a loss of dry mass and zinc (1-20%). In vitro solubility, as a percentage of total zinc in soaked rice, was significantly higher than in untreated brown rice while, in steeped brown rice, it was lower (p&lt;0.05). Fermentation and germination did not have significant effects on the solubility of zinc. The expected improvement due to lower phytic acid levels was not confirmed by increasing levels of in vitro soluble zinc. This may result from zinc complexation to other food components.
DOI:10.1021/jf071191tURLPMID:17696444
Wheat phytase was purified to investigate the action of the enzyme toward its pure substrate (phytic acid - myo-inositol hexakisphosphate) and its naturally occurring substrate (phytate globoids). Phytate globoids were purified to homogeneity from wheat bran, and their nutritionally relevant parameters were quantified by ICP-MS. The main components of the globoids were phytic acid (40% w/w), protein (46% w/w), and several minerals, in particular, K &gt; Mg &gt; Ca &gt; Fe (in concentration order). Investigation of enzyme kinetics revealed that K(m) and V(max) decreased by 29 and 37%, respectively, when pure phytic acid was replaced with phytate globoids as substrate. Time course degradation of phytic acid or phytate globoids using purified wheat phytase was followed by HPIC identification of inositol phosphates appearing and disappearing as products. In both cases, enzymatic degradation initiated at both the 3- and 6-positions of phytic acid and end products were inositol and phosphate.
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