【摘要】 为探究大气细颗粒物中镉(Cadmium,Cd)沉降对小白菜(Brassica rapa var. chinensis(L.)Kitamura)的毒性效应,本研究模拟不同浓度梯度大气细颗粒物中镉沉降(0、150、300和500μg/m3),分别代表对照、轻度、重度和严重污染,检测幼苗受胁迫后的生长状况、叶绿素相对含量(SPAD)、抗氧化酶活性、丙二醛(MDA)及体内Cd含量。结果显示:在处理第7 d时,3种污染处理均提高了小白菜茎叶长、根长和鲜重,但到第19 d,严重污染处理显著降低了茎叶长、根长和鲜重,较对照分别下降了8.05%、13.82%和9.80%;整个试验期间,重度和严重污染均显著降低SPAD,在第19 d时,严重污染处理组SPAD较对照降低了17.54%;3种污染浓度均显著提高了MDA含量和过氧化物酶(POD)活性;小白菜地上部分Cd积累量随污染浓度的增加而递增。研究结果表明,大气细颗粒物中镉沉降显著影响小白菜生长、叶绿素相对含量、抗氧化酶系统及Cd的累积。更多还原

【Abstract】 This study investigated the toxic effects of different concentrations and gradients of cadmium(Cd)(0,150,300,and 500 μg/m~3)in fine particulate matter following deposition on pakchoi(Brassica rapa var. chinensis(L.)Kitamura). After treatment,the growth status,relative chlorophyll content(SPAD),antioxidant enzyme activity,malondialdehyde(MDA)content,and heavy metal enrichment in pakchoi seedlings were measured. Results showed that mild,heavy,and severe concentrations of Cd deposition in atmospheric fine particulate matter initially promoted stem,root,and leaf length,and fresh weight of pakchoi on day 7. On day 19,compared with the control,the severe pollution conditions significantly reduced stem and leaf length,root length,and fresh weight of pakchoi by 8. 05%,13. 82%,and 9. 80%,respectively. During the whole experimental period,severe pollution significantly reduced the SPAD of pakchoi. On day 19,compared with the control,the SPAD of pakchoi under severe pollution conditions decreased significantly by 17. 54%. Mild,heavy,and severe concentrations of Cd in fine particulate matter significantly increased MDA content and peroxidase(POD)activity. Furthermore,Cd accumulation in the aboveground parts of pakchoi increased with the increase in Cd concentration,and Cd accumulation was the highest under severe pollution conditions. These results indicated that Cd deposition in fine particulate matter significantly affects growth,SPAD,antioxidant enzymes,and Cd accumulation in pakchoi.更多还原