期刊：Rice
主題：通氣促進水稻根部Cd滯留
標題：Aeration Increases Cadmium (Cd) Retention by Enhancing Iron Plaque Formation and Regulating Pectin Synthesis in the Roots of Rice (Oryza sativa) Seedlings
影響因子：3.513
檢測指標：O2、Cd2+流速
檢測部位：距離根尖200微米、500微米，木質部
O2、Cd2+流實驗處理方法：
3周齡水稻幼苗，50uM CdCl2及充空氣（每小時30分鐘）處理14天
O2、Cd2+流實驗測試液成份：
0.01mM CdCl2,0.1mM KCl, 0.1mM CaCl2 and 0.3mM MES , pH 5.4
作者：浙江理工大學熊杰、李滬波
英文摘要
Aeration and water management increasingrhizosphere oxygen amount significantly promote rice (Oryza sativa) growth andyield, but the effect of root aeration on cadmium (Cd) toxicity andaccumulation in rice seedlings under hydroponic culture remains unclear.
Results showed that aeration promoted riceseedling growth and alleviated Cd toxicity. Transverse section discovered thatCd accelerated root mature and senescence while aeration delayed the mature andsenescence of roots. Non-invasive Micro-test Technology (NMT) showed thataeration increased net O2 and Cd2+ influxes on the surface of roots whiledecreased net Cd2+ influx in xylem. Perls blue staining showed that aerationand Cd treatments increased iron plaque formation on the surface of roots.Results of metal concentration analysis showed that besides increasing Cdretention in iron plaque, aeration also increasing Cd retention in the cellwall of rice roots. Cell wall component analysis showed that aeration not onlyincreased pectin content but also decreased pectin methylesterification degree(PMD) by increasing pectin methylesterase (PME) activity.
Conclusions
All of these results indicate that aerationnot only delays root mature and senescence but also increases Cd retention in rootsby enhancing iron plaque formation and regulating pectin synthesis in the rootsof rice seedlings.
中文摘要（谷歌機翻）
曝氣和水分管理增加根際氧氣量顯著促進了水稻（Oryza sativa）的生長和產量，但根系曝氣對水培過程中水稻幼苗鎘（Cd）毒性和積累的影響仍不清楚。
結果表明，曝氣促進了水稻幼苗生長，減輕了Cd的毒性。橫切面發現Cd加速根成熟和衰老，而通氣延遲了根的成熟和衰老。非損傷微測技術（NMT）顯示，通氣增加了根表面的凈O2和Cd2+流入，同時降低了木質部中的凈Cd2+流入。Perls藍染色顯示通氣和Cd處理增加了根表面的鐵斑塊形成。金屬濃度分析結果表明，除了增加鐵斑塊中Cd的保留外，還可以增加水稻根細胞壁中Cd的保留。細胞壁成分分析表明，通氣不僅可以增加果膠含量，還可以通過增加果膠甲酯酶（PME）活性來降低果膠甲酯化程度（PMD）。
所有這些結果表明，通氣不僅可以延緩根系成熟和衰老，還可以通過增強水稻幼苗根系中鐵斑塊形成和調節果膠合成來增加根中Cd的保留。
Fig. 3 Effects of aeration or/and 50 μM CdCl2 treatments on net O2 and Cd2+ fluxes in the roots of rice seedling. a Time-course of Net O2 flux on the surface of root at 500?μm from root apex (elongation zone); b Time-course of Net Cd2+ flux on the surface of root at 500?μm from apex (elongation zone); c Statistical results of steady-state net O2 and Cd2+ fluxes on the surface of root at 500?μm from apex (elongation zone); d Time-course of Net O2 flux on the surface of root at 200?μm from root apex (meristematic zone); e Time-course of Net Cd2+ flux on the surface of root at 200?μm from apex (meristematic zone); f Statistical results of steady-state net O2 and Cd2+ fluxes on the surface of root at 200?μm from apex (meristematic zone); g Time-course of Net O2 flux in the xylem of root at 500?μm from root apex (elongation zone); h Time-course of Net Cd2+ flux in the xylem of root at 500?μm from apex (elongation zone); i Statistical results of steady-state net O2 and Cd2+ fluxes in the xylem of root at 500?μm from apex (elongation zone). The 3-week-old rice seedlings under hydroponic culture were aerated with air pump (30?min per hour) in the absence or presence of 50 μM CdCl2 for 14 d. The values are means ± SE (n?=?100). Different letters on bar indicate significant differences at P < 0.05
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