甲基二磺隆对小麦药害的早期诊断

Early diagnosis of mesosulfuron-methyl phytotoxicity on wheat

对当茬和后茬作物的药害是磺酰脲类除草剂应用的重要限制因素。甲基二磺隆是麦田常用的磺酰脲类除草剂之一,为了早期诊断其对小麦的药害,采用温室盆栽试验测定了不同剂量甲基二磺隆对小麦株高、地上部分鲜重、丙二醛(MDA)含量、脯氨酸(Pro)含量、可溶性糖含量、叶绿素含量、最大光量子产量(Fv/Fm)和根系形态的影响。结果表明:30 g/L甲基二磺隆可分散油悬浮剂(OD)按有效成分剂量9~45 g/hm^(2)施用后10 d,小麦才表现出肉眼可见的矮化和生长抑制症状;但其MDA含量、Pro含量、可溶性糖含量、Fv/Fm和根系形态在喷施甲基二磺隆后5 d就已经表现出明显的变化,其中小麦MDA和Pro含量随甲基二磺隆施用剂量的加大而增加,当施药剂量≥27 g/hm^(2)时,MDA和Pro含量均显著高于清水对照;可溶性糖和Fv/Fm对甲基二磺隆胁迫的响应更敏感,当施药剂量≥9 g/hm^(2)时,可溶性糖含量显著高于清水对照,而Fv/Fm则显著低于清水对照;喷施甲基二磺隆9~45 g/hm^(2)各剂量处理均可抑制小麦根尖数、总根长、总根表面积和总根体积。综合以上结果,MDA、Pro、可溶性糖、Fv/Fm和根系形态可作为早期诊断甲基二磺隆对小麦药害的敏感指标。

The phytotoxicity to current and subsequent crops is an important factor affecting the application of sulfonylurea herbicides.Mesosulfuron-methyl is one of the commonly used herbicides in wheat fields.For early diagnosis of phytotoxicity on wheat by mesosulfuron-methyl,the plant height,shoot fresh weight,malondialdehyde(MDA)content,proline(Pro)content,soluble sugar content,chlorophyll content,Fv/Fm,and root morphology were determined by a dose-response experiment in the greenhouse.The results showed that the wheat seedlings did not show dwarfing and inhibition until 10 days after mesosulfuron-methyl 30g/L OD(9-45 g/hm^(2))application.However,the contents of MDA,Pro,and soluble sugar,Fv/Fm,and root morphology had shown obvious changes 5 days after mesosulfuron-methyl application.The contents of MDA and Pro increased with the increase of mesosulfuron-methyl dosages.After being treated with mesosulfuron-methyl at 27 g/hm^(2) or more,the contents of MDA and Pro were significantly higher than control.The content of soluble sugar and Fv/Fm were more sensitive to the stress of mesosulfuron-methyl.After being treated with mesosulfuron-methyl at 9 g/hm^(2) or more,the soluble sugar content was significantly higher than control,while the Fv/Fm was significantly lower than control.Mesosulfuron-methyl applied at 9-45 g/hm^(2) also reduced the number of root tips,total root length,total root surface area,and total root volume of wheat seedlings.MDA,Pro,soluble sugar,Fv/Fm,and root morphology can be used as sensitive indicators for early diagnosis of mesosulfuron-methyl phytotoxicity on wheat seedlings.