四环素对4种叶菜类蔬菜种子发芽及幼苗生长与氧化损伤的影响

Effects of Tetracycline on Seed Germination,Seedling Growth and Oxidative Damage of Four Leafy Vegetables

【目的】探究四环素(TC)胁迫下叶菜类蔬菜生长和生理特性的影响,为抗生素对植物的毒性作用研究提供理论依据。【方法】以上海青、小白菜、菜心和生菜为试验对象,采用室内模拟培养法,研究土壤中不同浓度(0~500 mg/kg)TC对4种叶菜生长指标(发芽率、株高、地上部鲜质量)和生理生化指标(叶绿素、MDA含量以及SOD、POD、CAT活性)的影响。【结果】4种叶菜的发芽率随TC浓度升高逐渐降低,上海青和小白菜的株高和地上部鲜质量在低浓度(10、50、100 mg/kg)TC胁迫下逐渐增加、高浓度(300、500 mg/kg)TC胁迫下逐渐降低,其中在TC 100 mg/kg处理时达到最大值。菜心和生菜的株高和地上部鲜质量则随着TC浓度的升高逐渐降低。菜心、生菜和小白菜的叶绿素含量在低浓度(10、50、100 mg/kg)TC胁迫下存在上升趋势,而上海青的叶绿素含量在TC胁迫时均降低。4种叶菜的MDA活性随着TC浓度的升高逐渐增加,在TC 500 mg/kg处理下,均显著高于对照。上海青、生菜和小白菜在TC10mg/kg处理下CAT活性最高,菜心则在TC50mg/kg处理下CAT活性最高。菜心和上海青的SOD活性在TC100mg/kg处理下最高,分别比对照高21.12%、22.33%,小白菜和生菜的SOD活性则随着TC浓度升高逐渐降低。菜心、生菜、上海青和小白菜的POD活性分别在TC 10、50、100、500mg/kg浓度处理下活性最高,比对照高0.85%、14.16%、8.20%和24.79%。【结论】4种叶菜对TC的敏感程度不同,TC会抑制菜心和生菜的生长,而上海青和小白菜在低浓度(10、50、100mg/kg)TC处理下生长受到促进,在高浓度(300、500mg/kg)TC处理下则会受到抑制,且随着浓度的增加,其抑制作用增强。高浓度TC胁迫下,4种叶菜植物细胞受损程度增大,抗氧化酶系统受到损伤。

【Objective】The study aims to explore the effects of tetracycline(TC)stress on the growth and physiological characteristics of leafy vegetables,and to provide a theoretical basis for researches on the toxic effects of antibiotics on plants.【Method】Shanghai green,pakchoi,Chinese cabbage and lettuce were taken as experimental subjects.The simulated culture method was adopted in the laboratory.The effects of different concentrations of TC in soil(0-500 mg/kg)on the growth(germination rate,plant height,aboveground fresh weight)and physiological and biochemical indexes(chlorophyll,MDA,SOD,POD and CAT)of four vegetables were studied.【Result】The germination rate of the four tested vegetables gradually decreased with the increase of TC concentration,the plant height and aboveground fresh weight of Shanghai green and pakchoi gradually increased under TC stress at low concentrations(10,50,100 mg/kg),and gradually decreased under TC stress at high concentrations(300,500 mg/kg).The maximum value reached at 100 mg/kg TC treatment.The plant height and aboveground fresh weight of Chinese cabbage and lettuce decreased gradually with the increase of TC concentration.The chlorophyll contents of pakchoi,Chinese cabbage and lettuce increased under TC stress at low concentrations(10,50,100 mg/kg),while the chlorophyll content of Shanghai green decreased under TC stress.The MDA activity of four vegetables increased with the increase of TC concentration,and was significantly higher than that of control under 500 mg/kg TC treatment.The CAT activity of Shanghai green,lettuce and pakchoi was the highest under the treatment of 10 mg/kg TC,and the CAT activity of Chinese cabbage was the highest under the treatment of 50 mg/kg TC.The SOD activity of Chinese cabbage and Shanghai green was the highest at 100 mg/kg TC treatment,which was 21.12%and 22.33%higher than that of the control,while the SOD activity of pakchoi and lettuce decreased with the increase of TC concentration.The POD activity of Chinese cabbage,lettuce,Shanghai green and pakchoi was the highest at 10,50,100 and 500 mg/kg TC concentration,respectively,which was 0.85%,14.16%,8.20%and 24.79%higher than that of control.【Conclusion】The four vegetables exhibited different sensitivities to TC.TC inhibited the growth of cabbage and lettuce,while promoting the growth of Shanghai green and Chinese cabbage at low concentrations(10,50,100 mg/kg).However,under high concentrations(300,500 mg/kg),growth inhibition occurred,intensifying with the increase of TC concentration.High TC stress increased plant cell damage in all four vegetable species and led to damage in the antioxidant enzyme system.