| In order to explore the effect of compound antibiotics on lettuce and oil wheat,this paper uses two cultivation methods,hydroponic and peat cultivation,to study the changes of biomass and chlorophyll of lettuce and Indian lettuce under the influence of different concentrations of compound antibiotics,and the characteristics of antibiotic enrichment.The main results are as follows:（1）A combined method of ultra high performance liquid chromatography tandem mass spectrometry（UPLC-MS/MS）capable of simultaneously detecting three types of 12 antibiotics was established.Methods methanol-mcllvaine-Na2EDTA solution with p H=3 as extraction solution,HLB solid phase extraction column as purification method,and ultra high performance liquid chromatography tandem mass spectrometry as detection method.It can be used for the rapid determination of 12 antibiotics in leafy vegetable.The RSD（Relative standard deviation）was less than8.68%.The detection limit is 0.4-1 ng·g-1and the quantitative limit is 1.5-3 ng·g-1.Except for a few kinds of antibiotics,the recovery rate is more than 50%.This method is easy to operate and has strong applicability,which can better meet the current detection needs of antibiotics in leafy vegetables.（2）The effects of compound antibiotics on plant growth and development are different.Higher than a certain concentration of compound antibiotics can inhibit the growth of the underground part of plants,which shows that the high concentration of compound antibiotics significantly reduces the quality of the underground roots of Hydroponic Lettuce,soil culture Indian lettuce and Hydroponic Indian Lettuce.For Indian lettuce,the concentration of compound antibiotics had little effect on the quality of the above ground part and the whole plant,but there was no significant effect on the quality of each part.The effect on the Hydroponic Lettuce was great.The quality of the whole plant was significantly lower than that of the blank control when the concentration of compound antibiotics was higher than 0.1mg·L-1.However,there was no significant change in the quality of each part of soil culture lettuce with the change of the concentration of compound antibiotics.The number of leaves did not change significantly with the concentration of compound antibiotics and the type of matrix. （3）High concentration(5mg·L-1)of compound antibiotics can accelerate the aging of old leaves of two kinds of hydroponic vegetables,and reduce the content of initial antibiotics in new leaves.Low concentration(1mg·L-1,0.1mg·L-1,0.01mg·L-1)of antibiotics can increase the initial content of chlorophyll in new leaves.The content of chlorophyll in the soil culture medium showed regular differences.The compound antibiotics of different concentrations could increase the content of chlorophyll in the old leaves of lettuce and the initial content of chlorophyll in the new leaves in a certain period of time,while in the soil culture Indian lettuce,the application of compound antibiotics could accelerate the reduction of the content of chlorophyll in the old leaves and the initial content of new leaves in a certain period of time about Chlorophyll content.（4）With the decrease of the concentration of compound antibiotics,the detection concentration of antibiotics in the above ground and underground parts of most treatment groups decreased.When the concentration of compound antibiotics in the environment is lower than a certain concentration,the relevant antibiotics will not be detected in the plants.However,the adsorption of antibiotics in different parts of plants is greatly affected by the culture medium.The enrichment effect of different vegetables on antibiotics in the same substrate is not the same.In the hydroponic media,the adsorption effect of the two vegetables is greatly affected by the concentration of compound antibiotics.Under the influence of 5mg·L-1,1mg·L-1,and 0.1mg·L-1,the adsorption effect of the underground part of lettuce on antibiotics is stronger than that of the underground part of Indian Lettuce.when 5mg·L-1and 1mg·L-1,the enrichment effect of antibiotics in the above ground part of lettuce is higher than that of Indian Lettuce,0.1mg·L-1,At the concentrations of 0.01mg·L-1and 0.01mg·L-1,the enrichment effect of Indian Lettuce above ground was better than that of lettuce.In the soil culture medium,lettuce and Indian Lettuce showed a preference for different types of antibiotics.The above ground and underground part of Indian Lettuce had higher enrichment coefficient of sulfanilamide antibiotics than lettuce,while the above ground part of lettuce had higher enrichment coefficient of quinolones in most of the low and medium concentration antibiotics,while the underground part of lettuce had higher enrichment effect of quinolones and macrocyclic lipids than Indian Lettuce in most cases.The content of antibiotics in the underground part of plants is higher than that in the above ground part.Compared with the hydroponic medium,the content of antibiotics in the underground and above ground part of plants can be greatly reduced by the soil culture medium.However,with the decrease of the concentration of composite antibiotics,the transport effect of antibiootics in lettuce and Indian lettuce in the soil culture medium increases.Therefore,when the composite antibiotic is 0.1mg·L-1,the content of most antibiotics in the above ground part is higher The state of being underground.（5）Compared with hydroponics,soil culture can significantly reduce the amount of antibiotics absorbed by plants.Therefore,in the environment of high antibiotics,planting lettuce or lettuce,soil culture can reduce the amount of antibiotics accumulated by plants.At present,the content of antibiotics in the water is less than0.1mgmg·L-1,so cultivating lettuce is more conducive to reduce the harm to human body caused by the enrichment of antibiotics than cultivating oilwheat.When the detection amount of sulfanilamide antibiotics in organic fertilizer is high,planting lettuce can effectively reduce the enrichment of antibiotics.When the detection of quinolone antibiotics is high,oilwheat lettuce is the best choice... |
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