【摘要】 通过溶液培养试验研究了不同Cu2+浓度(0、2、4、6、8mg/L)胁迫下,通过溶液培养试验对浮水植物水鳖叶片矿质营养吸收、活性氧产生、保护酶活性及同工酶的影响.结果表明,(1)随着Cu2+浓度的增加,Cu2+对水鳖的矿质营养吸收产生了影响,主要是促进对Ca2+、Fe3+、Mg2+、Zn2+的吸收,降低对Mn2+、P、K+的吸收.(2)SDS-PAGE蛋白电泳图的条带随Cu2+浓度增加而逐渐减少,亮度也随之减弱,导致了多肽明显丢失.(3)谷胱甘肽还原酶(GR)活性和过氧化氢(H2O2)含量的变化趋势呈单峰曲线,在Cu2+浓度为6mg/L时,均达到最大值,分别为对照的2·51倍和3·74倍.超氧阴离子(O2·-)和丙二醛(MDA)含量的变化呈先缓慢后讯速上升趋势,当Cu2+浓度最高时均达顶峰,分别为对照的342·3%和334·2%;超氧化物歧化酶(SOD)的活性呈下降趋势,过氧化物酶(POD)的活性呈上升趋势,过氧化氢酶(CAT)活性仅略有上升.(4)同工酶酶谱分析显示,随着Cu2+浓度的增加,SOD谱带数和表达量均减少.POD谱带数由少逐渐增多,由4带增加到7带,表达量也呈现上升趋势.CAT酶谱带数无明显变化,表达量略存在差异.Cu2+对水鳖的致死浓度范围在2~4mg/L.更多还原

【Abstract】 Hydrocharis dubia plants exposed to 0, 2, 4, 6, 8 mg/L Cu2+ for 7 d were analyzed with reference to its toxic impact on mineral nutrient adsorption, active oxygen generation, protective enzyme activities and their isozyme expression. The results showed that, with the rise of Cu2+ concentration in culture medium: (1)the mineral nutrient absorption was affected by Cu2+ stress, as it increased the absorption of Ca2+、Fe3+、Mg2+ and Zn2+, and reduced that of Mn2+、P and K+, with increasing the concentration of Cu2+. (2)The amount and intensity of protein/peptide band decreased gradually with augment of Cu2+ concentration was observed in SDS-PAGE, respectively, and many polypeptides disappeared significantly in fronds treated with Cu2+ stress. (3) GR activity and H2O2 content change tendency assume the single peak curve, in Cu2+ concentration to 6 mg/L, their datum up to maximize, respectively better 2.51 times and 3.74 times than the control. The O2-· content and MDA content change assume first slow, and then fast trend of escalation, when Cu2+ concentration to 8 mg/L, their datum reaching the crest, comparing 342.3% and 334.2% to the control; SOD activity assumes the drop tendency, POD activity assumes the trend of escalation, and CAT activity only has slightly rise. (4)Their isoenzymic spectrum analysis demonstration, along with Cu2+ concentration increasing, the SOD isoenzymic band number and the expression quantity reduces. The POD isoenzymic band number gradually increases, increasing from 4 belts to 7 belts, and the expression quantity also presents the trend of escalation. The CAT isoenzymic band number does not obviously change, and the expression quantity has slight difference. The conclusion could be reached that the death of plant resulted from destruction of structure foundation of physiological function, unbalance of ion equilibrium and disorder of physiological metabolism. The lethal concentration scope of Cu2+ to Hydrocharis dubia was 2～4 mg/L based on the experiment results.更多还原