中文摘要：

为系统研究六价铬[C（rVI）]对玉米幼苗生长及抗氧化系统的影响,采用水培方法,在培养液中加入不同浓度重铬酸钾（0、10-6、10-5、10-4mol.L-1）,胁迫不同时间（6、12、18d）后对幼苗进行各项指标检测。结果表明,低浓度铬（10-6mol.L-1）对幼苗生长有一定刺激作用,且对地上部分刺激作用更明显;对叶片抗氧化酶活性及抗坏血酸含量没有显著影响。中浓度铬（10-5mol.L-1）胁迫明显抑制根部生长（n=15,P〈0.01）,对地上部分干重积累无显著影响,使幼苗含水量有明显下降（n=15,P〈0.01）;MDA含量明显升高（n=5,P〈0.01）;18d后,SOD和ASA-POD活性分别升高50.9和125.0,POD活性下降72.3,抗坏血酸含量上升约2倍。高浓度铬（10-4mol.L-1）胁迫下幼苗生长几乎停止,含水量明显下降（n=15,P〈0.05）。铬在玉米幼苗中的积累明显影响其生长,造成植株含水量下降,冠根比增大,叶片抗氧化酶活性剧烈变化并受到严重的氧化胁迫。

英文摘要：

The influence of Cr（Ⅵ） to the growth and antioxidant system of maize（Zea mays L.） was studied systematically.Seedlings were cultivated in Hoagland liquid medium,which contained different concentrations of K2Cr2O7（0,10-6,10-5,10-4 mol·L-1）.After 6,12 and 18 days of stress,physiological parameters of seedlings were measured.In the concentration of 10-6 mol·L-1,the growth of seedlings was promoted and whereas that of parts above the earth more notably;and the activities of antioxidant system and content of ascorbic acid were almost the same as those of control.Under the stress of 10-5 mol·L-1,the root growth was restrained markedly and however the dry weight above the earth was almost not inhibited,which made the increase of the ratio of part above the earth to root;the content of water decreased obviously;after 18 days,the activity of SOD increased by 50.9%,that of ASA-POD increased by 125.0% and that of POD decreased by 72.3%;the contents of ascorbic acid and MDA increased obviously.In the concentration of 10-4 mol·L-1,the seedlings almost did not grow and the content of water decreased notably.In brief,the accumulation of Cr in Zea mays made the decrease of water content and the increase of the ratio of part above the earth to root,which affected the normal growth of seedlings.It also caused notable change of antioxidant system in leave,and however,leave of seedling was damaged severely by the oxidant stress.