| 卢媛媛,张学洪,刘 杰,伍婵翠.超富集植物李氏禾根系对Cr（Ⅵ）吸收机制的研究[J].农业环境科学学报,2013,32(11):2140-2144. |
| 超富集植物李氏禾根系对Cr（Ⅵ）吸收机制的研究 |
| Mechanism of Cr（Ⅵ） Uptake by Hyperaccumulator Leersia hexandra Swartz |
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| DOI：10.11654/jaes.2013.11.006 |
| 中文关键词: 李氏禾 Cr（Ⅵ） 吸收 能量抑制剂 SO２－4 |
| 英文关键词: L. hexandra Cr（Ⅵ） uptake metabolic inhibitors SO2-4 |
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| 中文摘要: |
| 通过盆栽试验，研究了超富集植物李氏禾根系对Cr（Ⅵ）的吸收特征。结果表明，解偶联剂２，４－二硝基苯酚（ＤＮＰ），ＡＴＰ酶抑制剂（Ｎａ３ＶＯ４）和低温（２ ℃）处理均显著地抑制了李氏禾根对Cr（Ⅵ）的吸收（P＜０．０５）。其中，低温处理的抑制作用最明显，李氏禾根中铬的浓度较对照降低６９．８％，说明李氏禾根对Cr（Ⅵ）的吸收是需要能量的主动过程。此外，李氏禾根系对Cr（Ⅵ）的吸收符合Ｍｉｃｈａｅｌｉｓ－Ｍｅｎｔｅｎ方程，其米氏常数（Ｋｍ）为９１．０８ μｍｏｌ·Ｌ－１。在５ ｍｍｏｌ·Ｌ－１ ＳＯ２－4处理下，该米氏常数是对照的１．２７倍；而在ＳＯ２－4缺失的条件下，李氏禾根对Cr（Ⅵ）吸收的米氏常数较对照减少了２４．３％。这种拮抗关系表明李氏禾根对Cr（Ⅵ）的吸收可能与硫酸根吸收体系有关。 |
| 英文摘要: |
| Leersia hexandra Swartz, present in Southern China, has been found to be a chromium hyperaccumulator. Under hydroponic conditions, the mechanisms of Cr（Ⅵ） uptake by roots of L. hexandra were studied at 30 μmol Cr（Ⅵ）·L-1. Absorption of Cr（Ⅵ） by the plant was significantly reduced by uncoupler 2, 4-dinitrophenol（DNP）, ATPase inhibitor（Na3VO4） and low temperature（2 ℃）, with the greatest inhibition（69.8% reduction） by low temperature, implying that Cr（Ⅵ） uptake by roots of L. hexandra was an active process associated with energy metabolism. In addition, Cr（Ⅵ） absorption followed Michaelis-Menten kinetics and was competitively inhibited by sulfate. Sulfate（SO2-4） did not affect the maximum absorption rate of Cr（Ⅵ）（0.143~0.148 μmol·g-1 DW·h-1）, but increased the constant Km values by 27.6% compared with the control（the plants grown in 25% Hoagland solution）. However, sulfate-deficiency decreased the Km by 24.3%. This result suggested that the Cr（Ⅵ） uptake by the roots of L. hexandra may be partially carried via sulfate transporters. |
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