植物光合作用测定法确定灭草松和特丁津混用的最低致死剂量

在荷兰瓦赫宁根国际植物研究所温室内,用植物光合作用测定法研究了光合作用抑制型除草剂灭草松和特丁津桶混防除6种常见阔叶杂草的最低致死剂量。结果表明,药剂对杂草的生长有明显的抑制作用,在施药2 d后可观察到明显的灭草松的防效,在施药8 d后可观察到明显的特丁津的防效。随着施药剂量的增加,杂草叶片的植物光合作用测定(PPM)值和杂草地上部分鲜重显著下降。供试的6种杂草对该混剂的敏感性存在显著差异:红心藜Chenopodium album、龙葵Solanum nigrum和反枝苋Amaranthus retroflexus对该混剂最敏感,ED90值分别为47.65、71.67和29.17 g/hm2;春蓼Polygonum persicaria和苘麻Abutilon theophrasti敏感,ED90值分别为96.91、114.20 g/hm2;而番茄不敏感。比较施药后2、4和6 d时杂草叶片的PPM值与施药后16 d时杂草地上部分鲜重防效的相关性可以发现,施药后4 d杂草叶片的PPM值与鲜重防效的相关性最好,相应的R2为0.924 7。表明PPM值可以较好地预测防效,在本试验条件下,施药后4 d的PPM值的预测效果最好。

The Determination of Minimum Lethal Dosage of Tank Mixture of Bentazone and Terbuthylazine by Plant Photosynthetic Meter Method

The experiment was conducted in the green house of Wageningen in the Netherlands in order to determine the minimum lethal herbicide dosage (MLHD) of photosynthesis-inhibiting herbicide,bentazone and terbuthylazine,on six weed species with plant photosynthetic meter (PPM). The results showed that the diagnostics of weed caused by bentazone could be observed 2 days after treatment and diagnostics of weed caused by terbuthylazine could be observed 8 days after treatment, and weed growth was inhibited later on. Both PPM values of weed leaves and weed biomass (shoot fresh weight) decreased as the herbicide dosage increased. However,the susceptibility of weed species to the tank mixture of bentazone and terbuthylazine was different among weed species.Chenopodium album,Solanum nigrum,and Amaranthus retroflexus were very susceptible to the herbicides.Polygonum persicaria and Abutilon theophrasti were relatively less susceptible to the herbicides,and Lycopersicon esculentum was not susceptible to it.The relationship between reduction rates of weed biomass and PPM values of weed leaves 2,4,and 6 days after treatment was established.The relationship between reduction rates of weed biomass and PPM values 4 days after treatment was the best with the coefficient of determination of 0.924 7.It was concluded that PPM values of weed leaves after treatment could be utilized to predict weed control efficacy and could help to calculate MLHD. PPM value 4 days after treatment could give the best prediction of MLHD of the mixture of bentazone and terbuthylazine.