Abstract:

【Objective】 Effect of chlorimuron-ethyl on biochemical mechanism in tolerant sugar beet was investigated to provide basic data on using the tolerant genotype to chlorimuron-ethyl properly. 【Method】 Tolerant sugar beet was used to analyze its biochemical mechanism under chlorimuron-ethyl stress with frame culture in field and water culture. 【Result】 Glutathione S-transferase (GST) activity in leave of tolerant sugar beet was remarkably increased as chlorimuron-ethyl was used at 0.5 ga.i.ha-1 and 1.5 ga.i.ha-1 field dose , at the same time glutathione (GSH) content increased by 50.0-490.1 μg g-1. GST activity of sensitive sugar beet decreased by 122.6 U?(min?mg)-1 compared with tolerant sugar beet and GSH content only increased by 7.4 μg g-1 as chlorimuron-ethyl was at 0.5 ga.i.?ha-1 field dose in sensitive sugar beet. The higher GST activity and GSH content could conjugate chlorimuron-ethyl which had been absorbed in tolerant sugar beet and made it lost activity. Acetolactate synthases (ALS) activity of the tolerant sugar beet increased by 62.5% and 70.6%, respectively, in seedling and leaf growth period, at the same time ALS activity of the sensitive variety decreased by 36.8% and 64.8%, respectively. 【Conclusion】 The rapid enhancement of GST,GSH and the target enzyme activity of ALS is the important reason for the tolerant sugar beet enduring to chlorimuron-ethyl.

Key words: sugar beet, chlorimuron-ehtyl, glutathione S-transferase, glutathione, acetolactate synthases