【摘要】 本文研究了铜(Cu)胁迫下玉米(Zeamays)幼苗生长、叶绿素含量、叶绿素荧光参数和抗氧化酶活性的变化。研究结果表明,5￣20μmol.L-1Cu处理10天明显抑制玉米幼苗根系生长,并减少玉米幼苗的干物重,以及增加玉米幼苗地上部和根系含Cu量;玉米幼苗吸收的Cu大部分积累在根系,在地上部分布较少。Cu处理还降低玉米叶片的叶绿素含量和Fv/Fm、ETR、qP和qy值。在10天的Cu处理期间,根系中SOD、POD、CAT和GR活性呈现先上升后下降的趋势。而叶片中的SOD、POD、CAT和GR活性在处理前期不受Cu胁迫的显著影响,处理后期则因Cu胁迫而增强。实验表明抗氧化酶在抵御过量Cu引起的氧化胁迫中发挥了一定的作用。更多还原

【Abstract】 Growth, chlorophyll content, chlorophyll fluorescence parameters and activity of antioxi- dant enzymes in corn seedlings were investigated under hydroponics supplied with different concen- trations of Cu. Root growth of corn seedlings was significantly inhibited and dry weight was de- creased with 5-20 μmol.L-1 Cu. Chlorophyll content and Fv/Fm, ETR, qP and qy in leaves were also significantly decreased under excess Cu. The Cu concentrations in shoots and roots increased with increasing Cu concentration in the nutrient solution. However, most absorbed Cu by corn seedling was located in roots. At all levels of Cu treatment, the amount of Cu was substantially higher in roots than in shoots. During the 10-day Cu treatment, the activities of SOD, POD, CAT and GR initially increased and then decreased in roots. But for the leaves, short-term treatment with excess Cu had no significant effect on these enzyme activities. Prolonged exposure for 4 days resulted in increased enzyme activities. Thus, antioxidant enzymes have functions to alleviate the toxic effects of oxidative stress caused by excess Cu.更多还原