Drying–submergence alternation enhanced crystalline ratio and varied surface properties of iron plaque on rice (Oryza sativa) roots
Drying–submergence alternation enhanced crystalline ratio and varied surface properties of iron plaque on rice (Oryza sativa) roots
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DOI：
10.1007/s11356-017-0509-x
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发表时间：
2018-02
影响因子：
5.8
通讯作者：
Xujian Yang;Zhihong Xu;Hong Shen
中科院分区：
文献类型：
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作者：
Xujian Yang;Zhihong Xu;Hong Shen
铁膜能吸附多种营养元素和有毒离子，在水稻的营养管理和污染耐性研究中具有重要价值。结晶比（CR）可以定义为结晶铁（Cl）与总IP的比例，以描述IP结晶度。虽然对IP的认识已经很丰富，但关于IP的形成条件、表面性质和CR之间的关系的信息仍然不足。以石英砂土为材料，研究了不同时间、不同阶段干淹交替（DSA）对水稻CI、无定形铁（AI）、CR、根系氧化能力（ROC）和IP表面性质的影响。14天DSA治疗使CI增加到连续潜水（CS）后的2.20倍，AI下降到CS后的72.3%。相应地，CR从4.08%提高到6.89%。DSA后IP的CR分别为6.89%和4.23%。此外，14天DSA后的ROC比CS后的ROC提高了一倍。扫描电镜结果显示，与CS后相比，14 d DSA诱导IP中的薄片更薄，颗粒更细。从X射线衍射结果显示，IP含有较高比例的针铁矿，纤铁矿，磁铁矿，赤铁矿后DSA比CS后。DSA后IP的可变电荷和表面积分别为CS后的26.5%和32.0%。结果表明，适当强度的DSA促进了IP的ROC和AI向CI的转化，从而提高了IP的CR，同时改变了其表面性质。
Iron plaque (IP) is valuable in nutrient management and contaminant tolerance for rice (Oryza sativa) because it can adsorb various nutrients and toxic ions. Crystalline ratio (CR) can be defined as the proportion of crystalline iron (CI) to total IP to describe IP crystallinity. Although the knowledge on IP has abounded, the information on the relationship among its formation condition, surface properties, and CR remains insufficient. In this study, quartz sand–soil cultivation with rice was conducted to explore the effect of drying–submergence alternation (DSA) on CI, amorphous iron (AI), CR, root oxidizing capacity (ROC), and surface properties of IP with different treatment durations and at different stages. Fourteen-day DSA treatment increased CI to 2.20 times of that after continuous submergence (CS) but decreased AI to 72.3% of that after CS. Correspondingly, CR was raised to 6.89% from 4.08%. Remarkably, CR of IP after DSA ending in submergence and ending in drying was 6.89% and 4.23%, respectively. In addition, ROC after 14-day DSA was enhanced to twice of that after CS. Results from scanning electronic microscope suggested that 14-day DSA induced thinner sheets with finer particles in IP compared to that after CS. Results from X-ray diffraction revealed that IP contained higher proportions of goethite, lepidocrocite, magnetite, and hematite after DSA than those after CS. Variable charge and surface area of IP after DSA were only 26.5% and 32.0% of those after CS, respectively. Together, our results indicated that proper strength DSA promoted ROC and transformation from AI to CI, and consequently increased CR of IP, while it changed its surface properties.