中文摘要：

在当前除草剂品种繁多而谷子田可用除草剂稀缺的条件下,探讨二甲四氯除草剂在谷子田施用时的安全性。采用大田试验研究谷子3-4叶期喷施不同剂量二甲四氯对‘张杂谷10号’光合作用、叶绿素荧光参数以及产量构成的影响。结果表明：供试除草剂处理后,谷子叶片的叶绿素质量分数、净光合速率（Pn）、气孔导度（Gs）、气孔限制值（Ls）、PSⅡ最大光化学效率（Fv/Fm）、PSⅡ潜在活性（Fv/Fo）、PSⅡ有效量子产量[Y（Ⅱ）]、电子传递速率（ETR）和光化学猝灭系数（qP）均出现不同程度的降低;而胞间CO2摩尔分数（Ci）和非光化学淬灭系数（NPQ）的变化呈相反趋势,且表现出一定的剂量效应关系。此外,除草剂对谷子植株光合特性的影响效应随着施药时间的延长逐渐减弱,表现为喷施除草剂后15d之前较为显著,其后多数指标可恢复至对照水平。谷子产量随供试除草剂剂量的增加呈先增后降的趋势。可见,在二甲四氯喷施剂量超过1 500g/hm2时,会对谷子造成不可逆的伤害,降低谷子产量。

英文摘要：

The security of application of MPCA in foxtail millet was studied under in the conditions of a wide variety of herbicides but scarce available for foxtail millet. Field trial was carried out to study the effect of different levels of MPCA,sprayed at the 3th or 4th leaf stages,on photosynthetic charac- teristics,chlorophyll fluorescence parameters and yield component of ＂Zhangzagu 10＇ in experiment site of Shanxi Agricultural University. The results showed that after spraying MPCA,photosynthetic pigment mass fraction, the photosynthetic rate（Pn）, stomatal conductance（Gs）, stomatal limitation val- ue（Ls） ,Fv/Fm ,F.,/Fo ,Y（ Ⅱ ） ,ETR and qe were varying decreased; however,the internal CO2 concen- tration（C） and NPQ were presented a tendency of opposite, which displayed remarkable dose-re- sponse. Furthermore,the impact of herbicide on the photosynthetic characteristics of foxtail millet was more obvious at the initial of the treatment, followed by a gradually slowing effect, at the late of the treatment most of the indicators could be restored to the control level. Yield showed a trend of increas- ing at first and then decreasing. The above results suggested that a irreversible damage will be pro- duced and reduce the yield of foxtail millet,when the level of MPCA exceed 1 500 g/hm2.