不同浓度Cd对小白菜生长及抗氧化系统的影响

Effects of Different Concentrations of Cadmium on Growth and Antioxid ant System in Brassica Campestris ssp.chinensis

采用温室水培试验方法,研究了不同浓度Cd对小白菜生长、叶绿素含量和叶片中抗氧化系统的影响。结果表明,Cd浓度为0.01mg·L-1时促进小白菜生长;Cd浓度为10mg·L-1时,抑制小白菜生长;与对照相比,0.01、0.1mg·L-1Cd处理后,叶绿素a与叶绿素b的含量增加;Cd浓度达到1mg·L-1时,叶绿素a与叶绿素b的含量显著下降(P<0.05)。超氧化物岐化酶(SOD)的活性随Cd处理浓度的增加而下降;愈创木酚过氧化物酶(GPOD)、抗坏血酸过氧化物酶(APX)在Cd浓度为0.1mg·L-1时活性最高;过氧化氢酶(CAT)在Cd浓度为1mg·L-1时活性达到最高;脱氢抗坏血酸还原酶(DHAR)、谷胱甘肽还原酶(GR)的活性和抗坏血酸(AsA)、还原型谷胱甘肽(GSH)的含量在Cd处理浓度为10mg·L-1时最高。

Effects of different concentrations of cadmium (0.01, 0.1, 1,10 mg ·L-1) on growth, chlorophyll content and antioxidant system in Brassica campes tris ssp.chinensis were studied. Cd below 0.1 mg·L-1 enhanced the growth and chlorophyll content, whereas the growth was seriously inhibited by 10 mg·L-1 Cd. SOD activity increased with increasing Cd concentration in growth medium. The activities of GPOD and CAT increased in the treatment of 0.01 and 0.1 mg·L-1, but dropped dramatically in the treatment of 10 mg·L-1Cd APX, DHAR and GR increased with Cd and AsA and GSH content increased at 10 mg·L-1 Cd. The re existed dosage effect on growth of Brassica campestris ssp.chinensis under Cd stress, Cd increased the growth in low level and prohibited it in high level. B rassica campestris ssp.chinensis probably depended on SOD, GPOD, CAT to eliminat e ROS (reactive oxygen species) under temperate Cd stress, but might depend on A PX, GR, DHAR, AsA and GSH called Halliwell-Asada cycle in chloroplast to relie ve damage of ROS under severer stress of Cd.