College of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, People's Republic of China.
J Environ Sci Health B. 2010 Jan;45(1):33-9. doi: 10.1080/03601230903404317.
The content and spectral characteristics of cytochrome P450 (Cyt P450) and cytochrome b(5) (Cyt b(5)) extracted from shoots of etiolated maize and rice seedlings were studied by using ultraviolet (UV) difference spectrophotometry. The results showed that fenclorim, rac-metolachlor and S-metolachlor may induce the same P450 isoenzyme with lambda(max) at 453 nm, while naphthalic anhydride (NA) induced another one with lambda(max) at 447 nm. The microsomal Cyt P450 and Cyt b(5) content of maize seedlings was higher than that of rice, and the Cyt b(5) content was higher than that of Cyt P450. Maize and rice microsomal Cyt P450 and Cyt b(5) were induced at different levels by the four chemicals, with the order as follows: NA > fenclorim > rac-metolachlor > S-metolachlor with p < 0.05. When induced by NA, fenclorim, rac-metolachlor and S-metolachlor, the maize Cyt P450 content was, respectively, 5.63-, 3.30-, 3.02- and 2.48-fold that of the control, the rice Cyt P450 content was 8.54-, 2.20-, 1.91- and 1.33-fold that of the control, the maize Cyt b(5) content was 9.89-, 5.49-, 4.69- and 3.40-fold that of the control, and the rice Cyt b(5) content was 7.76-, 4.56-, 2.60- and 1.82-fold that of the control. An enantio-difference existed when rac- and S-metolachlor combined with plant Cyt P450. The interaction of microsomal Cyt P450 with S-metolachlor is higher than that with rac-metolachlor, which may be one of the reasons why S-metolachlor is superior at killing weeds compared with rac-metolachlor. These results will help to develop an understanding of the tolerance for and selectivity of rac- and S-metolachlor.
采用紫外差光谱法研究了不同浓度的乙草胺、异丙甲草胺、甲草胺和萘酐对玉米和水稻幼苗黄化苗微粒体细胞色素 P450（Cyt P450）和细胞色素 b（5）（Cyt b（5））含量和光谱特性的影响。结果表明，乙草胺、异丙甲草胺、甲草胺可能诱导出最大吸收峰在 453nm 的同一种 P450 同工酶，而萘酐则诱导出最大吸收峰在 447nm 的另一种同工酶。玉米幼苗微粒体 Cyt P450 和 Cyt b（5）含量均高于水稻，且 Cyt b（5）含量高于 Cyt P450。4 种化学物质对玉米和水稻微粒体 Cyt P450 和 Cyt b（5）的诱导水平不同，顺序为萘酐＞乙草胺＞异丙甲草胺＞甲草胺，差异达显著水平（P＜0.05）。当用萘酐、乙草胺、异丙甲草胺和甲草胺诱导时，玉米 Cyt P450 含量分别是对照的 5.63、3.30、3.02 和 2.48 倍，水稻 Cyt P450 含量分别是对照的 8.54、2.20、1.91 和 1.33 倍，玉米 Cyt b（5）含量分别是对照的 9.89、5.49、4.69 和 3.40 倍，水稻 Cyt b（5）含量分别是对照的 7.76、4.56、2.60 和 1.82 倍。异丙甲草胺和甲草胺与植物 Cyt P450 结合时存在对映体差异。与 rac-异丙甲草胺相比，S-异丙甲草胺与微粒体 Cyt P450 的相互作用更高，这可能是 S-异丙甲草胺除草活性优于 rac-异丙甲草胺的原因之一。这些结果有助于深入了解 rac-异丙甲草胺和 S-异丙甲草胺的耐药性和选择性。
