Studies On Physiological And Biochemical Mechanism To Chlorimuron-Ethyl In Tolerant Sugarbeet

Development and applying of some kinds of super high effective herbicides such as sulfonlureas occupied the herbicide market after the year1990 in 20th century.It represented the direction of herbicide development. Sulfonlureas herbicides were have been widely used in five big crops such as corn,soyben,wheat and rapeseed.Some kinds of sulfonlureas herbicides was long residue in soil and seriously damaged the sensitive rotation crops.Sugarbeet(Beta vugaris L) is the most sensitive crop .Widely use of sulfonlureas had brought obstacle in sugarbeet rotation and in the same time restricted the application of this super high effective herbicides also.In this paper,we used china and outside sugarbeet varieties to select tolerant sugarbeet gene type to sulfonlureas herbicides and studied on its tolerant mechanism in order to resolve the obstacle in sugarbeet rotation and provide theory basis in reasonable use of the tolerant gene. We concluded following results:l.One tolerant sugarbeet variety had been firstly selected.Its growth was unaffected after a year when soil chlorimuron-ethyl was under3.7ppb,but the sensitive variety was damaged seriously, while chlorimuron-ethyl was sprayed in 7.5ga.i./hm2 on the leaf of tolerant sugarbeet, its growth can remain normally after several days.2.Root activity of tolerant variety NE02-1 was slightly decreased when soil chlorimuron-ethyl was 0.5ga.i./hm2-1.0 ga.i./hm2.Chlorophll content showed increasing trend and made the tolerant variety had higher photosynthesis ability.Three days after spraying chlorimuron-ethyl , chlorophll content of the tolerant sugarbeet was increased and recovered formal level in short time. The root activity slightly decreased and recovered formal growth after 6 days.3.Under the stress of chlorimuron-ethyl in root, POD and SOD activity in the tolerant sugarbeet seedlings showed firstly decreasing and then increasing trend;MDA content was firstly increased and then decreased in short time.Three days after spraying chlorimuron-ethyl, SOD activity in the leaf of tolerant variety showed decreasing trend then SOD activity begin increasing and arrive at normal level.At the same time, SOD activity of the sensitive sugarbeet was continuously decreased and MDA content showed increasing trend,but the increasing scope of the tolerant variety was little compare with the sensitive sugarbeet varieties.lt is one course that resistant oxidant enzyme keep high activity in tolerant sugarbeet variety so as to clarify the super oxide which is harmful to sugarbeet4.Endogenous hormones content of the tolerant variety recovered in short time and remained relatively balance under chlorimuron-ethyl stress .three advancing hormons 1AA,GA and Zr remained higher content compare with sensitive sugarbeets, ABA content was lower relatively.On the contrary the endogenous hormons of sensitive sugabeets maintain lowerlevel and ABA content was striking increased.Three advancing endogenous hormons content divided by ABA content in tolerant sugarbeet was distinct higher than the sensitive sugarbeet.It remained the balance of endogenous hormons content relatively and it is important to the tolerant variety remain formal growth under stress of soil chlorimuron-ethyl.5.There was no difference in chlorimuron-ethyl absorption by root system and leaf between the tolerant and sensitive variety,but the sensitive variety transferred more chlorimuron-ethyl to its root after spraying chlorimuron-ethyl.6.Chlorimuron-ethyl degradation in tolerant variety was quicker than sensitive variety. Rapid degradation of chlorimuron-ethyl in tolerant variety at short time makes tolerant sugarbeet uninjured and it was the important cause to increase tolerance to chlorimuron-ethyl.7.The tolerant sugarbeet has higher GST activity and GSH content in root and leaf under stress of Chlorimuron-ethyl.This increased the conjugation ability to chlorimuron-ethyl..It is important way to dispel toxin of chlorimuron-ethyl in tolerant sugarbeet variety.8.The tolerant variety remained higher amino acid content under c...