摘要
为研究抗生素环丙沙星(ciprofloxacin,CIP)和土霉素(oxytetracycline,OTC)对烤烟生长的影响,以“红花大金元”为试材,采用漂浮育苗方式,分析不同质量浓度(0、5、15、30、45、60 mg/L)的抗生素处理下,烤烟幼苗生长情况、叶绿体结构与色素含量变化、光合指标变化及抗生素在烤烟体内累积情况。结果显示:低质量浓度(CIP<15 mg/L,OTC<5 mg/L)的抗生素处理能刺激烤烟幼苗的生长,而高质量浓度处理则表现出抑制效果;透射电镜(TEM)观察结果显示,2种抗生素低质量浓度处理均会破坏烤烟幼苗叶绿体结构;随着2种抗生素处理质量浓度的增加,烤烟幼苗叶片叶绿素含量均逐渐降低且净光合速率Pn、蒸腾速率Tr、气孔导度Gs逐渐减小,而细胞间CO2浓度Ci逐渐增加;烤烟幼苗不同部位对CIP和OTC的累积量都表现出根>叶>茎的规律。研究结果表明:低浓度抗生素能促进烤烟幼苗生长,但抗生素对叶片叶绿体结构的破坏造成了色素含量的减少及光合能力的下降,最终会影响烤烟生长及品质;生产中应减少抗生素的使用,避免可能增加的植物富集风险。
我国是抗生素使用大国,抗生素带来的环境问题受到人们越来越多的关
烟草是我国重要的经济作物之一,种植面积广泛,烟叶品质严重影响其经济产出,研究表明,土壤等的抗生素残留会对烟叶品质产生不利影响,如毛
试验于2023年4—8月在云南农业大学烟草学院试验温室大棚进行,烟草育苗基质育苗。待出苗25 d后(四叶一心),挑选长势一致的烟苗移至改良霍格兰营养液(14 L)中水培并施加不同质量浓度(0、5、15、30、45、60 mg/L)抗生素处理,每个处理3次重复。抗生素处理后第10天取样,进行生理生化指标及抗生素含量测定分析。调节温室大棚气温,白天(28±2) ℃,夜间21 ℃。
1)农艺性状及根系构型。采用随机取样法,每个处理组选取长势一致的3棵(n=3)植株样品,参考YCT142—2010《烟草农艺性状调查测量办法》,测定叶片最大叶长、最大叶宽、株高和茎围。根系扫描采用EPSON Scan根系扫描仪,数据分析采用WinRHIZO Reg根系扫描分析系统。测量烟苗总根长、平均直径、根表面积和根系体积。
2)烟株抗生素质量浓度。烤烟幼苗中抗生素测定在浙江大学智达N2000色谱工作站进行,采用日本岛津shimadzu 20AT高效液相色谱系统,色谱柱采用安捷伦ODSC 18 column(5 µm,250 mm×4.6 mm)。CIP测定方法:流动相为甲醇︰1%乙酸=20︰80(V/V),流速1.0 mL/min,柱温35 ℃,紫外检测波长277 nm。OTC检测方法为:流动相为乙腈︰0.05 mol/L柠檬酸=15︰85(V/V),流速1.0 mL/min,柱温40 ℃,紫外检测波长280 nm,具体方法参考文献[
3)叶片叶绿素含量。取0.2g新鲜叶片,放入研钵,加入少量石英,再加入95%乙醇2~3 mL,研磨匀浆,加入95%乙醇10 mL继续研磨至组织变白,静置3~5 min,过滤到25 mL棕色容量瓶中,用95%乙醇定容到25 mL。将色素提取液倒入比色皿内,以95%乙醇为对照(n=3),分别在波长665、649和 470 nm处测定吸光值,并计算叶片的叶绿素a、叶绿素b和类胡萝卜素浓
4)叶绿体结构观察。参考Khan
5)光合参数。使用Li-6400便携式光合仪(Li-Cor Inc,USA)测定每片烟叶的净光合速率[Pn,µmol/(
2种抗生素对烤烟幼苗生长的影响如

图1 不同质量浓度抗生素处理下的烤烟生长差异
Fig.1 Growth difference of flue-cured tobacco under different concentrations of antibiotics

图2 CIP和OTC对烤烟幼苗农艺性状的影响
Fig.2 Effects of CIP and OTC on agronomic index of tobacco seedlings
同列中不同小写字母表示组间差异有统计学意义(P<0.05);图例中字母‘C’和‘O’表示CIP和OTC,后边数字表示浓度,单位mg/L,下同。Different lowercase letters in the same column indicate significant differences among different treatments(P<0.05). In the illustration, the letters C and O denote CIP and OTC, followed by numbers indicating concentration, mg/L, the same as follows.
不同质量浓度OTC对烤烟的生长影响如
CIP和OTC对烤烟根系的影响如
处理 Treatment | 总根长/cm Total length | 根表面积/c Surface area | 平均直径/mm Average diameter | 根系体积/c Volume | ||||
---|---|---|---|---|---|---|---|---|
CIP | OTC | CIP | OTC | CIP | OTC | CIP | OTC | |
CK | 244.29c | 244.29a | 47.22b | 47.22a | 0.60a | 0.60a | 0.71a | 0.71a |
T5 | 329.25a | 192.38b | 49.16b | 37.07b | 0.48c | 0.62a | 0.58b | 0.57b |
T15 | 320.28a | 174.97c | 54.59a | 37.42b | 0.54b | 0.46b | 0.74a | 0.38c |
T30 | 270.05b | 173.29c | 30.90c | 21.69c | 0.38d | 0.40c | 0.31c | 0.22d |
T45 | 135.14d | 133.67d | 16.06d | 19.45c | 0.37d | 0.38c | 0.16d | 0.23d |
T60 | 121.14d | 129.63d | 15.46d | 20.88c | 0.36d | 0.39c | 0.14d | 0.24d |
注: 表中T表示处理,后边数字表示质量浓度,mg/L,下同。Note: T in the table represents treatment, and the following number indicates concentration, mg/L, the same as follows.
研究结果表明,随着抗生素处理质量浓度的增加,烟苗体内的抗生素含量不断增加(

图3 抗生素在烤烟幼苗器官的累积分布
Fig.3 Content of antibiotics in seedling organs of flue-cured tobacco
不同质量浓度OTC处理下,烟草幼苗不同部位抗生素的含量也有较大的差异,OTC在根中的质量浓度显著高于叶片和茎,叶片中的OTC质量浓度高于茎,且在不同处理下,OTC的含量均为根>叶>茎(
抗生素处理下烤烟叶片叶绿体结构变化如

图4 透射电子显微镜下烟草叶片叶绿体结构变化
Fig.4 Chloroplast structure changes of tobacco leaves under transmission electron microscope
图A、B、C为对照,D、E、F为30 mg/L CIP处理,G、H、I为60 mg/L CIP处理;J、K为5 mg/L OTC处理,L、M为30 mg/L OTC处理,N、O为60 mg/L OTC 处理。PG:质体球;GT:基质类囊体;M:线粒体;TS:类囊体肿胀;ST:淀粉;S:基质;TK:类囊体;RCM:细胞膜破裂。A,B,C are control,D,E,F are 30 mg/L CIP treatments,G,H,I are 60 mg/L CIP treatments,J,K are 5 mg/L OTC treatments,L,M are 30 mg/L OTC treatments,N, O are 60 mg/L OTC treatments.PG: Plasmoglobule;GT:Stroma thylakoid;M:Mitochondria;TS:Thylakoid swelling;ST:Starch;S:Matrix;TK:Thylakoid;RCM:Cell membrane rupture.
不同质量浓度OTC处理下,与对照相比,烤烟叶片中叶绿体数量变化差异不大(
2种抗生素处理下,烤烟幼苗叶片光合色素变化如

图5 土霉素和环丙沙星对烤烟幼苗叶片色素含量的影响
Fig.5 Effects of oxytetracycline and ciprofloxacin on pigment content in leaves of tobacco seedlings
如

图6 2种抗生素对烤烟幼苗光合特征的影响
Fig.6 Effects of antibiotics of CIP and OTC on photosynthetic characteristic of tobacco seedlings
OTC处理下,与对照组相比,烤烟叶片Pn在T5~T15处理下有所降低,但差异不显著(P<0.05),而Gs、Tr和Ci与对照组相比具有显著差异(P<0.05)。T60处理下,Pn、Gs和Tr分别降低30.1%、59.9%和28.3%,Ci增加34.5%。CIP和OTC处理下显著抑制了烤烟幼苗的气孔开闭导度,表明抗生素可以影响烤烟叶片气孔的开度,进而对蒸腾作用和呼吸作用产生影响,最终对光合效率产生影响。
本研究发现,不同质量浓度(0~60 mg/L)的环丙沙星和土霉素对烤烟幼苗生长的影响均表现为:低浓度促进,高浓度抑制。这与张继旭
本研究中抗生素处理下烟苗叶片叶绿素含量减少,叶绿体形态结构发生变化,叶绿体中类囊体肿胀、片层和垛叠结构发生改变。高浓度CIP和OTC引起烤烟叶片叶绿体数量变少,导致叶绿素的含量降低,这与Zhao
根系是植物从土壤中吸收物质的主要器官,根系吸收是抗生素进入植物的主要途径之一,抗生素通常会在根中大量积
光合作用是植物制造自身生长所需有机物的主要途径,叶绿素和类胡萝卜素均有吸收光能的作用,是植物能够顺利进行光合作用的物质基
综上所述,CIP和OTC显著影响烤烟幼苗的生长发育,虽然低质量浓度对烤烟生长有所促进,但从整体来看,这2种抗生素还是阻碍了烤烟的正常生长发育(根系的影响、叶绿体结构的破坏、色素含量的降低和光合过程的抑制等),对烤烟品质造成严重影响。在烤烟生产中应该减少抗生素的使用,以减少抗生素进入环境的风险,对于抗生素含量高的有机畜禽粪肥等应经过特殊处理后再排放,避免抗生素带来更多的危害。同时未来需要深入研究烤烟对这2种抗生素的吸收作用机制,以期找到降低抗生素对烤烟影响的具体方法。
参考文献 References
杨礼震,刘天琪,王禄禄,等.养猪废水处理工艺对耐药基因迁移影响研究进展[J].华中农业大学学报,2022,41(4):1-9.YANG L Z,LIU T Q,WANG L L,et al.Research progress on transfer effect of antibiotic resistance gene in swine wastewater treatment process[J].Journal of Huazhong Agricultural University,2022,41 (4):1-9(in Chinese with English abstract). [百度学术]
KRUPKA M,PIOTROWICZ-CIEŚLAK A I,MICHALCZYK D J.Effects of antibiotics on the photosynthetic apparatus of plants[J].Journal of plant interactions,2022,17(1):96-104. [百度学术]
ZHANG H,LI X N,YANG Q X,et al.Plant growth,antibiotic uptake,and prevalence of antibiotic resistance in an endophytic system of pakchoi under antibiotic exposure[J/OL].International journal of environmental research and public health,2017,14(11):1336[2023-10-01].https://doi.org/10.3390/ijerph14111336. [百度学术]
ROCHA D C,DA SILVA ROCHA C,SANTOS TAVARES D,et al.Veterinary antibiotics and plant physiology:an overview[J/OL].Science of the total environment,2021,767:144902 [2023-10-01].https://doi.org/10.1016/j.scitotenv.2020.144902. [百度学术]
HOU J,WAN W N,MAO D Q,et al.Occurrence and distribution of sulfonamides,tetracyclines,quinolones,macrolides,and nitrofurans in livestock manure and amended soils of Northern China[J].Environmental science and pollution research,2015,22(6):4545-4554. [百度学术]
脱霞霞.环丙沙星对土壤抗性基因和微生物群落的影响[D].杨凌:西北农林科技大学,2018.TUO X X.Effect of ciprofloxacin on diversity of resistance genes and bacterial communities in soil[D].Yangling:Northwest A & F University,2018 (in Chinese with English abstract). [百度学术]
张天莹,余彬彬,林文轩,等.磺胺二甲基嘧啶与环丙沙星对小麦种子萌发和幼苗生长的影响[J].农业资源与环境学报,2021,38(2):176-184.ZHANG T Y,YU B B,LIN W X,et al.Effects of sulfadimidine and ciprofloxacin stress on seed germination and seedling growth of wheat[J].Journal of agricultural resources and environment,2021,38(2):176-184 (in Chinese with English abstract). [百度学术]
BOXALL A B A,JOHNSON P,SMITH E J,et al.Uptake of veterinary medicines from soils into plants[J].Journal of agricultural and food chemistry,2006,54(6):2288-2297. [百度学术]
毛迎.生物炭对环丙沙星胁迫下烤烟生长和品质的影响[D].昆明:云南农业大学,2022.MAO Y.Effects of biochar on growth and quality of flue-cured tobacco under ciprofloxacin stress[D].Kunming:Yunnan Agricultural University,2022 (in Chinese with English abstract). [百度学术]
年夫照,孙永波,顾勇,等.烟草幼苗中土霉素含量的检测方法:CN106770804B[P].2019-07-12.NIAN F Z,SUN Y B,GU Y,et al.Method for detecting content of oxytetracycline in tobacco seedling:CN106770804B[P].2019-07-12(in Chinese). [百度学术]
LIU B Y,LIU W Q,NIE X P,et al.Growth response and toxic effects of three antibiotics on Selenastrum capricornutum evaluated by photosynthetic rate and chlorophyll biosynthesis[J].Journal of environmental sciences,2011,23(9):1558-1563. [百度学术]
KHAN K Y,ALI B,STOFFELLA P J,et al.Study amino acid contents,plant growth variables and cell ultrastructural changes induced by cadmium stress between two contrasting cadmium accumulating cultivars of Brassica rapa ssp.chinensis L.(pak choi)[J/OL].Ecotoxicology and environmental safety,2020,200:110748[2023-10-01].https://doi.org/10.1016/j.ecoenv.2020.110748. [百度学术]
邓世杰,马辰宇,严岩,等.3种抗生素对黑麦草种子萌发的生态毒性效应[J].生态毒理学报,2019,14(3):279-285.DENG S J,MA C Y,YAN Y,et al.Ecotoxicological effects of three antibiotics on seed germination of Lolium perenne[J].Asian journal of ecotoxicology,2019,14(3):279-285 (in Chinese with English abstract). [百度学术]
张继旭,申国明,孔凡玉,等.四环素对烤烟生长发育及光合作用的影响研究[J].农业环境科学学报,2017,36(1):48-56.ZHANG J X,SHEN G M,KONG F Y,et al.Effect of tetracycline on the growth and photosynthesis of flue-cured tobacco[J].Journal of agro-environment science,2017,36(1):48-56 (in Chinese with English abstract). [百度学术]
李通,金彩霞,朱雯斐,等.环丙沙星与Cu复合污染对玉米萝卜和小白菜3种作物生态毒性研究[J].农业环境科学学报,2013,32(1):15-20.LI T,JIN C X,ZHU W F,et al.Joint toxicity of CPFX and Cu on seed germination and root elongation of corn,radish and Chinese cabbage[J].Journal of agro-environment science,2013,32(1):15-20 (in Chinese with English abstract). [百度学术]
HAN T,LIANG Y P,WU Z N,et al.Effects of tetracycline on growth,oxidative stress response,and metabolite pattern of ryegrass[J/OL].Journal of hazardous materials,2019,380:120885[2023-10-01].https://doi.org/10.1016/j.jhazmat.2019.120885. [百度学术]
ZHAO H M,HUANG H B,DU H,et al.Intraspecific variability of ciprofloxacin accumulation,tolerance,and metabolism in Chinese flowering cabbage (Brassica parachinensis)[J].Journal of hazardous materials,2018,349:252-261. [百度学术]
KHAN K Y,ALI B,ZHANG S,et al.Effects of antibiotics stress on growth variables,ultrastructure,and metabolite pattern of Brassica rapa ssp. chinensis[J/OL].Science of the total environment,2021,778:146333[2023-10-01].https://doi.org/10.1016/j.scitotenv.2021.146333. [百度学术]
VAN WIJK K J,KESSLER F.Plastoglobuli:plastid microcompartments with integrated functions in metabolism,plastid developmental transitions,and environmental adaptation[J].Annual review of plant biology,2017,68:253-289. [百度学术]
LIU X H,LV Y,XU K,et al.Response of ginger growth to a tetracycline-contaminated environment and residues of antibiotic and antibiotic resistance genes[J].Chemosphere,2018,201:137-143. [百度学术]
贺德春,吴根义,许振成,等.小白菜和白萝卜对四环素类抗生素的吸收累积特征[J].农业环境科学学报,2014,33(6):1095-1099.HE D C,WU G Y,XU Z C,et al.Uptake of selected tetracycline antibiotics by pakchoi and radish from manure-amended soils[J].Journal of agro-environment science,2014,33(6):1095-1099 (in Chinese with English abstract). [百度学术]
徐秋桐,顾国平,章明奎.土壤中兽用抗生素污染对水稻生长的影响[J].农业资源与环境学报,2016,33(1):60-65.XU Q T,GU G P,ZHANG M K.Effects of soil veterinary antibiotics pollution on rice growth[J].Journal of agricultural resources and environment,2016,33(1):60-65 (in Chinese with English abstract). [百度学术]
DODGEN L K,UEDA A,WU X Q,et al.Effect of transpiration on plant accumulation and translocation of PPCP/EDCs[J].Environmental pollution,2015,198:144-153. [百度学术]
HAWKER D W,CROPP R,BOONSANER M.Uptake of zwitterionic antibiotics by rice (Oryza sativa L.) in contaminated soil[J].Journal of hazardous materials,2013,263:458-466. [百度学术]
李燕,张敏,宁朋,等.外源NO对盐胁迫下中华常春藤生理特性的影响[J].植物生理学报,2022,58(1):207-213.LI Y,ZHANG M,NING P,et al.Effects of exogenous NO on physiological characteristics of Hedera nepalensis var. sinensis under salt stress[J].Plant physiology journal,2022,58(1):207-213 (in Chinese with English abstract). [百度学术]
CHEN X N,QIU D Y,LIN H M.Botanical characteristics and medicinal value of five Glycyrrhiza species cultivated in the Hexi region of Gansu[J].Acta prataculturae sinica,2016,25(4):246-253. [百度学术]
WANG X J,WANG Y J,NIAN J W.Accumulation and distribution of oxytetracycline and Chlortetracycline in tobacco seedlings and their effects on tobacco growth[J].The journal of animal and plant sciences,2022,32(3):746-752. [百度学术]
GOMES M P,DE BRITO J C M,BICALHO E M,et al.Ciprofloxacin vs.temperature:antibiotic toxicity in the free-floating liverwort Ricciocarpus natans from a climate change perspective[J].Chemosphere,2018,202:410-419. [百度学术]
LI Z J,XIE X Y,ZHANG S Q,et al.Wheat growth and photosynthesis as affected by oxytetracycline as a soil contaminant[J].Pedosphere,2011,21(2):244-250. [百度学术]