镉胁迫对玉米幼苗抗氧化系统及光合作用的影响

采用水培方法,在玉米幼苗进入三叶期后向培养液中加入不同浓度氯化镉(0、10-6、10-5、10-4mol·L-1),胁迫不同时间(5、10、15d)后对幼苗进行各项指标检测。结果表明,低浓度(10-6mol·L-1)及中浓度(10-5mol·L-1)镉胁迫对幼苗生长均有较强刺激作用,而中浓度胁迫对地上部分作用更明显;低浓度镉胁迫对根部及叶片抗氧化酶(SOD、POD、CAT及ASA-POD)活性影响较小,只是根部POD、ASA-POD活性明显升高,而中浓度胁迫对除SOD外其他抗氧化酶活性均有显著促进作用;MDA含量均未有显著升高,可见根部及叶片未受到氧化损伤;两种浓度胁迫下,Fv′/Fm′虽下降,净光合速率有所升高。高浓度镉(10-4mol·L-1)胁迫下幼苗生长几乎停止;根部SOD及CAT活性升高,而POD和ASA-POD被明显抑制,叶片中CAT、POD及ASA-POD活性显著升高;根部受到显著氧化损伤;各项光合参数(Fv/Fm、Fv′/Fm′和净光合速率)均显著降低。

The Influence of Cadmium(Cd~(2+)) to the Antioxidant System and Photosynthesis of Seedling of Zea mays L.

The influence of Cd~(2+) to the antioxidant system and photosynthesis of maize(Zea mays L.) was studied systematically. Seedlings were cultivated in Hoagland liquid medium,and in the three-leave-period were treated with different concentrations of CdCl_2 (0,10~(-6),10~(-4)mol·L~(-1)).After5,10 and 15 days of stress,physiological parameters of seedlings were measured.In the stress of low(10~(-6)mol·L~(-1))and middle(10~(-5)mol·L~(-1))concentration,the growth of seedlings was promoted obviouslllly whereas that of parts above the earth more notably in the stress of 10~(-5)mol·L~(-1);In the stress of 10~(-6)mol·L~(-1),the activities of POD and ASA-POD in root increased and activities of other anti-oxidant enzymes changed little; However, the stress of middle concentration made activities of anti-oxidant enzymes increase obviously except SOD; The content of MDA was not high compared with control, which showed that seedlings were not hurt by oxidation; Fv'/Fm' de-creased and the net photosynthetic rate rose.In the concentration of 10~(-4)mol·L~(-1),the seedlings almost did not grow;The activities of SOD and CAT in root increased and those of POD and ASA-POD were inhibited seriously, and the activities of CAT, POD and ASA-POD in leave in-creased sharply; Root was hurt oxidately; Photosynthetic parameters(Fv/Fm, Fv'/Fm' and net photosynthetic rate) decreased notably.