不同菵草种群对甲基二磺隆的敏感性差异

为监测江苏省不同地区菵草种群对甲基二磺隆的敏感性,采用室内整株生测法测定不同菵草种群在叶绿素含量、叶绿素荧光参数、1,5-二磷酸核酮糖羧化酶/加氧酶(rubisco)活性以及生物量积累方面对甲基二磺隆的响应。结果表明,甲基二磺隆影响菵草rubisco活性、最大光化学效率等光合生理指标,但不同地区菵草种群对其的响应存在差异。其中,甲基二磺隆处理10 d后,江苏淮安地区菵草种群生理指标变化较大。在甲基二磺隆36.00 g a.i./hm^2剂量处理下,淮安地区菵草叶片rubisco活性较相应空白对照显著下降48.14%,在9.00~36.00 g a.i./hm^2剂量下,叶绿素含量显著下降26.43%~47.75%,最大光化学效率显著下降1.13%~2.13%。而江苏南京高淳地区菵草叶片rubisco活性与相应空白对照相比下降幅度明显较缓慢,在9.00~36.00 g a.i./hm^2剂量处理下,叶绿素含量显著下降15.37%~32.59%,最大光化学效率则无显著性变化。整株生物活性测定结果表明,甲基二磺隆处理21 d后,淮安地区菵草地上部鲜重ED90值最低,为32.745 a.i./hm^2,高淳地区菵草的ED90值最高,为69.116 g a.i./hm^2,远远超过甲基二磺隆的推荐剂量。可见,高淳菵草种群对甲基二磺隆敏感性明显低于其他地区菵草种群,生产中要密切注意其抗药水平的发展变化,及时调整化学防除策略。

The Sensitivity of Different Beckmannia syzigachne Populations to Mesosulfuron-methyl

The sensitivity to mesosulfuron-methyl of Beckmannia syzigachne on populations from different regions in Jiangsu was determined in whole-plant bioassays by measuring chlorophyll content,chlorophyll fluorescence parameters and rubisco enzyme activity. Mesosulfuron-methyl differentially effected the photosynthetic physiological indexes such as rubisco activity and the maximal photochemical efficiency of B. syzigachne from different regions. The physiological indexes of Huai’an biotype had great influence after 10 days of spraying mesosulfuron-methyl. Compared with the control from the same region,Huai’an biotype rubisco activity decreased by 48% at 36 g a. i./hm^2;at doses from 9 ~ 36 g a. i./hm^2,chlorophyll content decreased by 26. 43%~ 47. 75% and maximum photochemical decreased by 1. 13%~ 2. 13%. Rubisco activity of Gaochun biotype significantly decreased more slowly than that of the control from the same region;the chlorophyll content at 9 ~ 36 g a. i./hm^2 treatment decreased by15. 37%,without change in photochemical efficiency. The ED90 for mesosulfuron-methyl based on whole plant biological activity determination 21 d after treatment for the Huai ’an and Gaochun biotypes were 32. 7 and69. 1 g a. i./hm^2,respectively;the latter being significantly higher than the recommended herbicide dose. The biotype from Gaochun was less sensitive to mesosulfuron-methyl than other biotypes. Therefore,it is important to pay attention to this biotype,and follow up any further decrease in its sensitivity to the herbicide while adjusting the weed control tactics to prevent the evolution ans spread of resistance.