金属镉及温度胁迫对紫根水葫芦植株几种生理指标的影响

Effects of Cadmium Stress and Temperature Stress on Several Physiological Indicators of Eichhornia crassipes

以紫根水葫芦植株为试材,采用水培方式,研究了不同质量浓度镉梯度0(CK)、0.5、1.0、5.0、10.0 mg·L^-1和不同温度梯度28、24、20、16、10℃下紫根水葫芦生理响应机制,测定了抗氧化酶(POD、CAT)活性、叶绿素含量、丙二醛(MDA)含量以及根系活力。结果表明:不同质量浓度、温度和时间的镉胁迫下,植物上述指标表现出不同的变化规律,不同条件下紫根水葫芦对镉胁迫的耐受存在不同的阈值。质量浓度为0.5 mg·L^-1时,随着胁迫时间的增加,紫根水葫芦叶片的CAT活性、POD活性和MDA含量均呈先下降后上升的趋势,叶绿素含量和根系活力均呈先上升后下降的趋势,表明低浓度镉胁迫条件下紫根水葫芦植株细胞的保护机制可抵御镉离子对植株的伤害。高浓度的镉胁迫会对紫根水葫芦产生毒害作用,对植株的生长发育造成严重伤害。低温与镉的复合胁迫对抑制紫根水葫芦的生长有协同作用,同时复合胁迫对紫根水葫芦的伤害大于单一胁迫;低温胁迫会影响紫根水葫芦镉胁迫的耐受能力,温度越低,紫根水葫芦对镉胁迫的耐受能力越低。

Using hydroponic method,according to the response laws of physiological indices of Eichhornia crassipes under different cadmium stress,0mg·L^-1(CK),0.5,1.0,5.0,10.0mg·L^-1 and different temperature,28,24,20,16,10℃.By observing the changes of the indexes including the activity of antioxidant enzymes(POD,CAT),the level of chlorophyll,malondialdehyde(MDA)and the root activity.The results showed that under different cadmium stress,temperature and time,the above indexes of plants showed different changes.Under different conditions,the tolerance of cadmium stress to cadmium stress had different thresholds.When the mass concentration was 0.5mg·L^-1,the CAT,POD activity and MDA content decreased first and then increased.While the chlorophyll content and root activity increased first and then they showed a downward trend with the increase of time.This phenomenon indicated that the protective mechanism of cells of Eichorniacrassipes plants under low concentration of cadmium stress could resist the damage of cadmium ions to plants.High concentration of cadmium stress could cause toxic effects on purple root water hyacinth,causing serious damage to plant growth and development.The combined stress of low temperature and cadmium had synergistic effect on the growth of purple root water hyacinth.At the same time,the combined damage to the purple root water hyacinth was greater than the single stress;low temperature stress could affect the tolerance of cadmium stress in purple root water hyacinth.And the lower the temperature was,the lower tolerance of purple root water hyacinth to cadmium stress was indicated.