匍茎翦股颖对Cu2+、Zn2+、Cd2+与Pb2+ 胁迫的生长响应与阈限浓度

Growth response and threshold concentration of Agrostis stolonifera to Cu2+,Zn2+,Cd2+or Pb2+ stress

关键词:  重金属胁迫  匍茎翦股颖  生长响应  阈限浓度

Key words:  heavy metal stress  Agrostis stolonifera  growth response  threshold concentration

摘要:

采用砂培法,研究了匍茎翦股颖对Cu²⁺、Zn²⁺、Cd²⁺与Pb²⁺胁迫的生长响应及阈限浓度,结果表明:种子萌发率随着4种重金属浓度的增加而下降。对株高的影响是当重金属浓度小于100 mg/L时会促进株高生长,高于100 mg/L则产生抑制作用。Cu²⁺显著抑制根系生长,并随浓度的增加抑制效应愈加显著; 在Cu²⁺浓度为600 mg/L时匍茎翦股颖的根长比对照下降了93.75%。Cu²⁺、Zn²⁺、Pb²⁺浓度小于200 mg/L时会促进地上生物量的增加,但高于200 mg/L时,地上生物量会随着3种重金属的增加而减少。Cu²⁺、Zn²⁺浓度小于100 mg/L或Cd²⁺、Pb²⁺浓度小于200 mg/L会增加叶绿素的含量,高浓度会降低叶绿素的含量; Cd²⁺在浓度为600 mg/L时显著降低叶绿素含量,与对照相比,下降了43.55%。匍茎翦股颖生长的综合效应分析表明,匍茎翦股颖对Cu²⁺胁迫最敏感,具有较低的阈限浓度,而Zn²⁺胁迫对匍茎翦股颖的生长影响最小,阈限浓度相对较高。

Abstract:

By sand cultural method,the experiment was conducted to investigate growth response and threshold concentration of Agrostis stolonifera to Cu²⁺,Zn²⁺,Cd²⁺ or Pb²⁺ stress. It was found that rate of seed germination decreased with increasing supply of Cu²⁺,Zn²⁺,Cd²⁺ or Pb²⁺. Heavy metal supply at concentration ≤100 mg/L increased plant height of A.stolonifera,whereas Cu²⁺,Zn²⁺,Cd²⁺or Pb²⁺supply higher than 100 mg/L decreased plant height. Cu²⁺ inhibited root growth significantly,and root length decreased with increasing Cu²⁺ supply. Compared with the control,root length of A.stolonifera was lowered by 93.75% at Cu²⁺ concentration of 600 mg/L. Aboveground biomass increased at Cu²⁺,Zn²⁺ or Pb²⁺ concentration ≤200 mg/L,but decreased with increasing concentrations when their concentrations were higher than 200 mg/L. Chlorophyll content increased at Cu²⁺,Zn²⁺ concentration ≤100 mg/L or Cd²⁺,Pb²⁺ concentration ≤200 mg/L,but tended to decrease at Cu²⁺,Zn²⁺ concentration ≥100 mg/L or Cd²⁺,Pb²⁺ concentration ≥200 mg/L. Only Cd²⁺ significantly lowered chlorophyll content of A.stolonifera by 43.55% at concentration of 600 mg/L. Synthetical effect of heavy metal on A.stolonifera growth indicated that A.stolonifera was most sensitive to Cu²⁺ stress with low threshold,but the effect of Zn²⁺ stress on A.stolonifera growth was the least.