根表铁氧化物胶膜对水稻吸收诺氟沙星的影响

采用水培法研究了水稻根表铁氧化物胶膜对水稻吸收诺氟沙星的影响.结果表明,水稻根表的铁氧化物胶膜生成量随溶液中Fe2+质量浓度的增加而增加.营养液中添加诺氟沙星之后,根表铁膜量不同程度地降低,且随着添加诺氟沙星质量浓度的增加铁膜减少量有所增加.根表诺氟沙星含量与根表铁膜含量具有相关性,且相关性系数为0.959(诺氟沙星=10 mg·L-1)和0.987(诺氟沙星=50 mg·L-1),根内诺氟沙星含量以及地上部诺氟沙星含量,与根表铁膜含量没有显著相关性.添加不同质量浓度的诺氟沙星,水稻根表、根内以及地上部所含诺氟沙星的质量分数:水稻根表为87.7%~97.6%,根内为0.8%~4.8%,地上部为1.5%~7.5%,根表诺氟沙星远远大于根内以及地上部的诺氟沙星含量.因此,水稻根表形成的铁氧化物胶膜在一定程度上是一个诺氟沙星富集库,但是并没有对诺氟沙星迁移到水稻根内和地上部起到明显的促进或抑制作用.

Effect of Root Iron Plaque on Norfloxacin Uptake by Rice

In anaerobic condition, release of oxygen by roots to rhyzosphere caused the formation of red plaque of iron oxides or hydroxides on the root surface of rice. The effect of iron plaque on norfloxacin uptake was investigated with solution culture in greenhouse, and the results are showed in the following. The content of iron plaque increased with the increase of Fe²⁺ concentration in medium. After the addition of norfloxacin in nutrient solution, the content of iron plaques on the root surface decreased to different degree, and the reduction of iron plaques was increasing with the increase of norfloxacin mass concentration. Significant relationships were found between the iron plaques and norfloxacin on the root surface, and the correlation coefficients were 0.959 (norfloxacin mass concentration was 10 mg·L^-1) and 0.987 (norfloxacin mass concentration was 50 mg·L^-1), respectively, however, the norfloxacin contents in roots and shoots had no significant correlation with the iron plaques. After addition of different mass concentrations of norfloxacin, the quality distribution percentages of norfloxacin on the root surface and in roots and shoots were 87.7%-97.6%, 0.8%-4.8%, 1.5%-7.5%, respectively, the norfloxacin content on the root surface was far greater than those in roots and shoots. It was therefore concluded that iron plaque on roots was a norfloxacin reservoir for rice plant but had no significant effect on the transfer of norfloxacin to roots and shoots of the rice plant.