镉胁迫对水仙根系抗氧化系统的影响

研究不同质量浓度镉(0、0.5、2、4、8、25mg·L~(-1))对水仙根系膜脂过氧化作用、抗氧化酶和非蛋白巯基的影响,以期为水仙栽培和园林绿化中筛选重金属修复植物提供理论参考和依据。结果表明随着镉处理浓度的增加,与对照相比,根系丙二醛含量增加77.5%到653.5%;4~25mg·L~(-1)镉诱导根系过氧化氢含量显著增加,与对照相比,各处理浓度下过氧化氢含量增加13.4%到44.9%;SOD酶活性随着镉处理浓度升高呈现先下降后升高趋势;POD酶活性随着镉处理浓度的增加而降低,4~25mg·L~(-1)镉诱导根系POD活性显著低于对照,降低幅度为18.7%~48.5%;8~25mg·L~(-1)镉处理诱导GSH含量显著升高,与对照相比分别增加78.1到116.2%;0.5、25mg·L~(-1)镉处理显著降低了根系非蛋白巯基含量,与对照相比降低了29.0到5.4%。由此看出低浓度镉胁迫已对水仙造成氧化胁迫,根系氧化胁迫随着镉处理浓度增加而加重;长期镉胁迫下抗氧化酶活性受到抑制,降低植物抗氧化能力;而高浓度镉胁迫下水仙通过合成GSH提高自身抗逆性。

Cadmium-induced Peroxidation and Production of Sulfur-related Complex in Roots of Nardissus tazetta var.chinensis

Effect of varied concentrations (i.e.,0,0.5,2,4,8,and 25 mg · L-1 )of cadmium (Cd)on the membrane lipid peroxidation,superoxide dismutase (SOD),peroxidase (POD),non-protein sulfydryl (NPT),and glutathione (GSH )in the roots of daffodil,Narcissus tazetta var.chinensis,were studied with a hydroponic culture.The study aimed to gain information for the cultivation,as well as selection of appropriate phytoremediation on the heavy metal stresses for the plants.It was found that (a)the content of root malondialdehyde (MDA) increased as Cd concentration increased;(b)at 4 - 25 mg · L-1 ,Cd induced a significant increase on hydrogen peroxidein the roots;(c )as Cd concentration increased,SOD activity decreased initially and followed by an increase,while POD decreased continuously with a significantly lower level than that of control when Cd concentration reached 4-25 mg·L-1 ;(d)GSH greatly increased with 8-25 mg·L-1 Cd,while NPT drastically decreased with the presence of 0.5 mg·L-1 or 25 mg·L-1 Cd.It appeared that,even at low level,Cd already imposed oxidative stress on daffodil.As Cd concentration increased,the stress worsened.Underprolonged Cd stress,the anti-oxidation enzymatic activity was suppressed resulting in a lowered capacity of the plants to resist the stress.On the other hand,when encountered high Cd stress,the daffodil plant would synthesize GSH to improve its resistance to the adverse condition.