SO2对大蒜根尖细胞遗传损伤作用的研究

第22卷第5期2002年5月生 态 学 报A CTA ECOLO G I CA S I N I CAV o l .22,N o.5M ay,2002S O 2对大蒜根尖细胞遗传损伤作用的研究仪慧兰,孟紫强3(山西大学环境医学与毒理学研究所,生命科学与技术学院,太原030006)基金项目:国家自然科学基金资助项目(39770634);山西省自然科学基金资助项目3通讯联系人A utho r fo r co rrespondence 收稿日期:2001202217;修订日期:2001208224作者简介:仪慧兰(1963～),女,山西人,博士,副教授。

主要从事生态环境毒理学方面的研究。

shxh lanyi @ho tm ail .com摘要:研究SO 2(14,35,84m g m 3)对大蒜幼根细胞的遗传损伤效应。

结果表明:大蒜幼苗短时间暴露于高浓度SO 2环境中,或者长时间生长在低浓度SO 2环境中,均可导致根尖细胞微核和双核频率明显增高,并引起根尖部分细胞核固缩。

SO 2的上述效应具有明显的时间2效应和剂量2效应关系,细胞中的微核、双核及核固缩率与SO 2浓度间呈线性相关。

研究结果表明:SO 2可引起植物细胞遗传物质的损伤,大蒜根尖细胞有可能用作监测SO 2污染的生物计量计。

关键词:SO 2;大蒜;微核;双核;核固缩Cytogenetic Damage of A .sa tivum Root Cells I nduced by Sulfur D iox ideY I H u i 2L an ,M EN G Zi 2Q iang 3　(Institu te ofE nv ironm entalM ed icine and T ox icology ,S chool of L if e S cienceand T echnology ,S hanx i U niversity ,T aiy uan 030006,Ch ina ).A cta Ecolog ica S in ica ,2002,22(5):709～714.Abstract :H um an expo su re to the environm en tal po llu tan t su lfu r di ox ide (SO 2)has becom e increasingly w idesp read due to the com bu sti on of fo ssil fuels .Con sequen tly ,it has becom e i m po rtan t to study the tox ic effects of SO 2in the environm en t to hum an .T he p lan t m icronucleu s (M CN )assays ,w h ich are con sider 2ab ly less expen sive and si m p licity ,have been validated in the in ternati onal co llabo rative study and p roven to be efficien t tests fo r geno tox icity mon ito ring of environm en tal po llu tan ts.Fo r these reason s ,the M CN induced by SO 2in A .sa tivum roo t ti p s w ere investigated ,m eanw h ile b inucleate cells and pycno sis in the roo t ti p s w ere also ob served .Garlic bu lb s ,after removing o ld roo ts and scales ,w ere su spended over a con tainer of tap w ater andkep t in an incubato r at 25℃±1℃.A fter 2days ,roo ts had reached 1.0～2.0c m in length .Garlic bu lb s divided in to five group s.O ne group fo r po sitive con tro l ,one group fo r negative con tro l ,o ther th ree group s u sed fo r SO 2expo su re w ith differen t concen trati on s (14,35,84m g m 3)and vari ou s du rati on (4,8,12,16h ).Cyclopho spham ide (CP )w as u sed fo r the po sitive con tro l at the concen trati on of 5Λg m l .T he garlic bu lb s ,w h ich w ere incubated in tap w ater and unexpo sed to SO 2,w ere u sed fo r negative con tro ls .Fo r SO 2group s ,mon ito ring p lan ts w ere kep t in po ts du ring the expo su re ti m e and w atered daily w ith tap w ater .T he SO 2du rati on w as 4h daily ,afterw ards the p lan ts w ere left fo r 20h recovery .T he roo ts after treatm en t (on ly fo r M CN )o r a recovery peri od (24h )w ere fixed overn igh t in fresh ly p repared 1:3aceto 2ethano l so lu ti on ,and then tran sferred to 70%ethano l fo r sto rage .T hey w ere hydro lyzed in 1N HC l at 60℃fo r 8～10m in and stained w ith Sch iff reagen t fo r 40～60m in ,1mm of the m ito tic zone from w ell 2stained roo t ti p w ere i m m ersed in a drop of distilled w ater on a clean slide and squashed under a cover glass .A bou t 4000cells w ere exam ined from 10separate A .sa tivum seedlings per experi m en tal group .M CN ,b inucleate cells and pycno sis w ere exp ressed in term s of the num ber of abno rm al cells per 1000roo t017　生　态　学　报22卷ti p cells.T he studen t’s t statistical test w as u sed fo r analyzing the sign ifican t difference betw een SO2 group s and their negative con tro ls.Cytogenetic dam age in A.sa tivum roo t ti p s induced by SO2w as analyzed.T he resu lts show ed that the M CN frequencies of SO2group increased w ith SO2concen trati on and expo su re peri od.A lthough the M CN decreased after a recovery,the M CN frequencies in all SO2group s w ere h igher than that of the negative con tro l(0182±0131),and at h ighest concen trati on M CN reached9143‰.A t84m g m3expo sed fo r8～16h(p<0105o r0101)o r at35m g m3fo r16h(p<0105)SO2expo su re cau sed a statistically sign ifican t in2 crease of M CN frequencies.T he frequencies of b inucleate cells also had po sitive relati on to du rati on and do se.T he h igher the SO2concen trati on w as,the mo re the b inucleate cells w ere;the longer the du rati on w as,the mo re the b inucleate cells had.T he b inucleate cells frequencies in all treatm en ts and negative con2 tro l w ere117‰～218‰after first4h expo su re,the h ighest frequency of negative con tro l and SO2group w ere3123‰and15147‰respectively.T he p resen t resu lts also show ed that SO2can induce pycno sis,at 84m g m3expo sed fo r at least8h,14m g m3fo r at least16h and35m g m3fo r at least12h,the cells w ith py2 cno sis cou ld be found in roo t ti p s,how ever no pycno sis cells w as ob tained in o ther treatm en ts w ith SO2at low er concen trati on s and sho rter expo su re peri ods and negative con tro ls.Among these nuclear aberra2 ti on s,pycno sis had h ighest increm en t w ith concen trati on increased.Bo th M CN and b inucleate cells w ere equal sen sitive to SO2,bu t the M CN frequencies w ere low er than b inucleate cell frequencies in all treat2 m en ts and negative con tro ls.T he decrease of m ito tic index and cell cycle delay w ere also found in SO2 group s and they w ere po sitive co rrelative to M CN frequencies.T he experi m en tal resu lts indicate that bo th treatm en ts w ith SO2at h igh concen trati on fo r sho rter du rati on and low er concen trati on fo r longer peri ods induced cytogenetic dam age in roo t ti p s.O u r resu lts also indicate that SO2expo su re cau sedM CN,pycno sis and b inucleate cells in a do se2dependen t m anner(r=0194,0197and0190fo r m icronuclei,b inucleate cells and pycno sis,respectively)in A.sa tivum roo t ti p s.A lthough ou r data are still in sufficien t,th is is the first experi m en tal evidence that SO2induce M CN,b inucleate cells,pycno sis in p lan t cells.T hese resu lts w ere si m ilar to ou r p revi ou s ob servati on in hum an lympho id.It w as suggested that SO2cou ld induce cyto2 genetic dam age in p lan t cells and A.sa tivum roo t cells cou ld be u sed as the b i o logical do si m eter to mon ito r SO2po llu tan t in the environm en t.Key words:su lfu r di ox ide;A llium sa tivum;m icronuclei;b inucleate cell;pycno sis文章编号:100020933(2002)0520709206　中图分类号:Q142,Q891　文献标识码:A 二氧化硫作为常见的全球性大气污染物,在燃煤地区和硫酸生产厂空气中含量相当高,生物体吸收后在体内通过对生物大分子的作用影响动植物的生理状况。