水稻和稗草ALS活性测定及农美利选择性机理研究

乙酰乳酸合成酶（ＡＬＳ）是除草剂主要作用靶标,新型除草剂农美利（ｂｉｓｐｙｒｉｂａｃ－ｓｏｄｉｕｍ）即是通过抑制ＡＬＳ的活性使支链氨基酸的生物合成受阻而达到除草目的。作者利用ＡＬＳ脱羧产物３－羟基丁酮与肌酸及甲萘酚形成的复合物,采用比色法测定ＡＬＳ活性和农美利的抑制作用,以明确农美利对水稻和稗草的选择性机理。研究结果表明,水稻和稗草体内ＡＬＳ酶促反应复合产物的吸收峰为５２０ｎｍ;ＡＬＳ活性在不同水稻品种和不同杂划体内各不相同,不同水稻品种依次为汕优６３、秀水１１〉样湖８４〈嘉育２９３,不同杂草依次为稗草、鳢肠〉异型莎草〉千金子。体内法测定农美利对植物体内ＡＬＳ的抑制程度结果显示,水稻ＡＬＳ受抑制快于稗草,恢复也快;不同水稻品种ＡＬＳ以嘉育２９３受抑制较快,秀水１１抑制程度较大,而祥湖８４和汕优６３受抑制慢且程度

Study on activity of acetolactate synthase (ALS) and inhibition of bispyribac-sodium in rice and barnyardgrass

Acetolactate synthase (ALS) is the main target of herbicides and bispyribac-sodium prevents biosynthesis of branehed-chain amino acids by inhibition of ALS. In this paper,the activity of ALS was determined by an acetoin-creatine-naphthol complex on spectrophotometer and inhibition of bispyribac-sodium to ALS in rice and barnyardgrass assessed. The results showed absorb peak of the complex for rice and barnyardgrass is 520 nm. Rice varieties Xianyou 63 and Xiushui 11 have the highest ALS activity,Jiayu 293 has the lowest one,and Xianhu 84 with the medium. For different weeds,the order of ALS activity from high to low is Echinochloa crusgalli, Eclipta prostrata, Cyperus difformis, Leptochloa chinensis. By in vivo test, ALS is prevented by bispyribacsodium and then recovered quicker in rice than in bamyardgrass. For rice varieties,ALS is repressed quickly in Jiayu 293, strongly in Xiushui 11,whereas in Xianhu 84 and Xianyou 63 the herbicide has slow and week inhibition to ALS. Byin vitro test, the inhibition of bispyribac-sodium to ALS is stronger than pyanchor.