不同稗草种群对五氟磺草胺的敏感性差异

为探讨不同地区稗草种群对五氟磺草胺的敏感水平,采用室内整株生测法测定五氟磺草胺对不同稗草种群的生物活性以及对不同稗草种群叶绿素含量、光合特性、叶绿素荧光参数和Rubisco活性的影响。结果表明,五氟磺草胺影响稗草Rubisco活性、最大光化学效率以及光合速率等生理指标,但不同稗草种群的变化略有差异。其中五氟磺草胺处理后4 d对安徽潜山稗草种群生理指标影响较大,五氟磺草胺3.75~60.00 g a.i./hm~2处理剂量下稗草Rubisco活性较相同种群空白对照显著降低24.45%~61.09%,15.00~60.00 g a.i./hm~2剂量下,稗草叶片净光合速率较对照显著降低30.04%~58.56%,60.00 g a.i./hm~2剂量下,稗草叶绿素含量和最大光化合效率分别较对照显著降低13.10~28.82%和6.64%~11.29%,而湖北武汉稗草种群叶绿素含量、叶绿素荧光参数以及Rubisco活性无显著变化,只是叶片净光合速率较相同种群空白对照显著降低18.82%~28.49%。整株生物活性测定结果表明,五氟磺草胺处理21 d后安徽潜山稗草地上部鲜质量ED90值最低,为14.936 g a.i./hm~2,而湖北武汉稗草的ED90值最高,为201.679 g a.i./hm~2,显著超过了五氟磺草胺生产使用的推荐剂量。可见湖北武汉稗草种群对五氟磺草胺敏感性明显低于其他地区稗草种群,生产中需要密切注意其抗药性水平的发展变化,及时调整化学防除策略。

The Sensitivity of Different Echinochloa crus-galli Populations to Penoxsulam

The differential sensitivity of Echinochloa crus-galli from different regions to penoxsulam was assessed with whole plant bioassays conducted to measure the effects of this herbicide on biological activity,chlorophyll content,photosyntheticcharacteristics,chlorophyllfluorescenceparametersandRubisco activity.Penoxsulam can affect Rubisco activity,the maximal photochemical efficiency and photosynthetic rate and other physiological indicators,but the responses of Echinochloa crus-galli from different regions were only slightly different.The physiological indicators of Qianshan biotype had great influence after 4 days of spraying penoxsulam.Compared with the control from the same region,the increase in penoxsulam dosage from 3.75 g a.i./hm2 to 60 g a.i./hm2 significantly decreased the Rubisco activity by 24.45%~61.09%,and when penoxsulam dosage from 15 g a.i./hm2 to 60 g a.i./hm2,the net photosynthetic rate of Qianshan biotype significantly decreased by 30.04%~58.56%,the chlorophyll content and the maximal photochemical efficiency decreased by 13.10%~28.82% and 6.64%~11.29% at the dose of 60 g a.i./hm2.There had no significant difference on the chlorophyll content,chlorophyll fluorescence parameters and Rubisco activity of Wuhan biotype,but,the net photosynthetic rate of Wuhan biotype significantly decreased by 18.82%~28.49%.In the whole-plant bioassays,Qianshan and Wuhan biotypes had the lowest (14.9 g a.i./hm2) and highest (201.7 g a.i./hm2) ED90 values to penoxsulam,respectively;the latter being far above the recommended field dose.The sensitivity of Wuhan biotype to penoxsulam was the lowest compared to that of biotypes from other regions.Therefore,proper attention shoud be paid to the possible evolution and levels of resistance to make the required adjustments to the chemical control strategy timely.