| The experiment was conducted in the main building of Shanxi Agricultural University and Shenfengcun experimental base from 2017 to 2018.Taking Zhangzagu 10 and Jingu.21 as experimental materials,field combined with pot culture was used to spray herbicides(10% nitrosulfurone)with different concentrations(CK 0 ml/hm2,T1 75 ml/hm2,T2 150 ml/hm2,T3 300 ml/hm2,T4 600 ml/hm2)on foxtail millet at 3-5 leaf stage.Chlorophyll content,chlorophyll a,chlorophyll b,carotenoids,net photosynthetic rate and photosynthetic rate of Foxtail Millet were determined.Influences of transpiration rate,stomatal conductance,intercellular CO2 concentration,chlorophyll fluorescence of millet,agronomic traits of millet(plant height,stem diameter,leaf area,leaf length,leaf width),1000-grain weight,grain weight per panicle and yield of millet).The effects of different concentrations of sulfonylurone on photosynthesis,physiological characteristics and yield components of millet were comprehensively analyzed,and the optimum concentration of sulfonylurone was explored to provide theoretical basis and technical support for the efficient utilization of sulfonylurone in Millet fields and the high yield and high quality cultivation of millet.1.Effects of foliar spraying of nitrosulfadone on Millet safety and agronomic traits.The results showed that after spraying nitrosulfonate on the leaves,the morphological indexes at jointing stage were greatly affected,and the effects on the morphological indexes at heading and filling stages were gradually alleviated,and the effects on the morphological indexes of Jingu 21 were greater than those of Zhangzagu 10.After spraying nitrosulfonate on the leaves for 30 days,the symptoms of plant injury could be alleviated.2.Effects of foliar spraying of nitrosulfadone on chlorophyll content of millet.The results showed that the contents of carotenoids and chlorophyll a and B were significantly affected by spraying nitrosulfonate on leaves 3,5 and 7 days after spraying,and there were significant differences among treatments compared with CK.After spraying nitrosulfonate on leaves 9 and 15 days,the effects of T1,T2 and T3 treatments on chlorophyll content were gradually alleviated,and the effects of T4 treatment on chlorophyll content were greater.3.Effects of foliar spraying of nitrosulfadone on Photosynthetic Characteristics of millet.The results showed that the net photosynthetic rate(Pn),stomatal conductance(Gs)and transpiration rate(Tr)of Foxtail Millet decreased and intercellular CO2 concentration(Ci)increased after spraying for 3,5 and 7 days.There were significant differences between T1,T2,T3 and T4 treatments and CK treatments.With the increase of concentration,the net photosynthetic rate,stomatal conductance,transpiration rate and intercellular CO2 concentration of foxtail millet were affected.The greater the difference was,the less significant the difference was between T1,T2 and T3 treatments than CK at 9 and 15 days after spraying,and the effect on photosynthetic parameters was gradually alleviated.T4 treatment had more significant difference than CK,and had greater influence on net photosynthetic rate,stomatal conductance,transpiration rate and intercellular CO2 concentration.In summary,with the increase of the concentration of sulfonylurea,the influence on photosynthetic parameters is greater,but with the increase of spraying days,the influence on light and parameters under T1,T2 and T3 treatments is gradually alleviated,but the influence on light and parameters under T4 treatment can not be alleviated.4.Effects of foliar spraying of nitrosulfadone on fluorescence parameters of millet.Actual photochemical efficiency Y(II),electron transfer rate(ETR),photochemical quenching coefficient q P and non-chemical quenching coefficient(NPQ)of the first two leaves of millet were measured 3,5,7,9 and 15 days after spraying.The results showed that the actual photochemistry efficiency Y(II),electron transfer rate(ETR),photochemistry quenching coefficient q P fluorescence parameters decreased with the increase of spraying concentration,while the non-chemical quenching coefficient(NPQ)increased with the increase of spraying concentration,and there were significant differences among treatments compared with CK 9 days after spraying.On days 1 and 15,there was no significant difference between T1,T2 and T3 treatments and CK,and the effect on fluorescence parameters was gradually alleviated.T4 treatment had significant difference compared with CK,and had greater influence on fluorescence parameters.In summary,with the increase of the concentration of nitrosulfonate,the influence of fluorescence characteristics is greater,but with the increase of spraying days,the influence of T1,T2 and T3 treatment on fluorescence parameters is gradually alleviated,but the effect of T4 treatment on light and parameters can not be alleviated.5.Effects of foliar spraying of nitrosulfadone on Millet Yield and yield components.The results showed that there was no significant difference in yield and yield components between T1,T2 and T3 treatments after spraying nitrosulfadone on leaf surface,but there was no significant difference in yield and yield components between T1,T2 and T3 treatments.In conclusion,the safe use of mesotrione in the millet field is 75-300 ml/hm2. |
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