乙草胺对小麦生理机能的影响与生物标记物识别

Effects of Herbicide Acetochlor on Physiological Mechanisms in Wheat and Biomarkers Identification

对乙草胺胁迫下小麦幼苗叶片的超氧化物歧化酶(SOD)、过氧化物酶(POD)活性、可溶性蛋白含量、丙二醛(MDA)以及叶片中叶绿素含量的变化进行了研究.结果表明,乙草胺处理小麦幼苗1d后,叶片MDA含量显著增加,说明了乙草胺处理诱导有毒活性氧(AOS)生成,但随着处理时间的延长,不同浓度处理与对照的差异逐渐减小.对小麦叶片中POD活性变化的研究表明,在乙草胺胁迫的开始阶段,植物有能力抵抗低浓度乙草胺污染所产生的氧化胁迫,但是,随着暴露时间的延长和污染物浓度的增加,这种抵抗能力将会消失.对小麦SOD活性的研究表明,小麦叶片中POD酶活的上升可能与其它途径而不是SOD诱导产生的H2O2有关.小麦叶片中MDA含量和POD活性不能作为土壤乙草胺污染的生物标记物.小麦叶片中SOD酶活性有着作为乙草胺污染土壤生物标记物的潜力,但还需要进一步研究.小麦叶片叶绿素含量和可溶性蛋白含量可以作为乙草胺污染胁迫的生物标记物,并且小麦幼苗叶片可溶性蛋白含量与土壤乙草胺浓度之间具有较好的剂量-效应关系.

Changes of the activity of antioxidant enzymes including peroxidases （POD） and superoxide dismutases （SOD） and the contents of chlorophyll （CHL）, malondialdehyde （MDA）, and soluble proteins （SP） in wheat （ Triticum aestivum L. ） under the stress of acetochlor in soil were examined. The increased MDA level detected in the leaves of wheat after 1 day exposure of acetochlor indicated the presence of poisoning AOS. However, the difference of MDA levels in leaves of different concentrations of acetochlor decreased with the prolonged exposure. The data of POD could suggest that the plant had the capacity to counteract the oxidative stress caused by lower concentration of acetochlor, but the capacity would be lost with exposure time. It is indicated that the increase of POD activity in the leaves may be caused by H2O2 produced from sources other than SOD. The activity of POD and contents of MDA could not he considered as biomarkers of stress by acetochlor in soil. While the activity of SOD could be considered as biomarkers of stress by acetochlor in soil need farther research. But the contents of CHL and SP could be considered as biomarkers of stress by acetochlor in soil and there are dose-response relationships between the SP content in leaves and the concentration of acetochlor in soil.