镉胁迫下草地早熟禾离子吸收及生理响应特征分析

Analysis of ion absorption characteristics and physi⁃ ological response characteristic of kentucky blue⁃ grass under cadmium stress

摘要:

为探究草地早熟禾(Poa pratensis)对镉(Cd)胁迫下的生理响应及离子吸收情况，采用砂培法育苗，对不同浓度 Cd 胁迫下的草地早熟禾株高、根长、叶片及根系鲜重、光合指标、抗氧化酶活性、叶片激素水平及离子含量进行测定。结果表明：Cd 胁迫抑制草地早熟禾生长并造成草地早熟禾萎蔫、失绿，显著减少草地早熟禾光合色素含量，抑制叶片的蒸腾速率、气孔导度、净光合速率、胞间二氧化碳浓度。随着 Cd 胁迫浓度的增加，草地早熟禾叶片 CAT 和 POD 活性逐渐降低，而根系 CAT 和 POD 活性增加。另外，Cd 胁迫降低草地早熟禾叶片 IAA 和 GA3含量，增加 ZT 含量。离子吸收方面，大部分 Cd 富集在根部而较少转移至叶片，且 Cd 胁迫导致草地早熟禾 Zn2⁺ 含量降低，叶片 Mg2⁺ 含量升高，根系 Mg2⁺含量降低。综上，Cd 胁迫抑制草地早熟禾生长发育、光合作用及离子吸收，可通过调控抗氧化酶活性和激素水平缓解 Cd 毒害。

Abstract:

To investigate the physiological response and ion absorption of Poa pratensis to cadmium (Cd) stress，seedlings were raised by sand culture method，and plant height，root length，leaf and root fresh weight，pho‐ tosynthetic indexes，antioxidant enzyme activities，leaf hormone levels and ion content of Poa pratensis under differ‐ ent concentrations of Cd stress were measured. The results showed that Cd stress inhibited the growth of Kentucky bluegrass，caused wilting and chlorosis，significantly reduced the contents of photosynthetic pigment，inhibited leaf transpiration rate，stomatal conductance，net photosynthetic rate and intercellular carbon dioxide concentration. The To investigate the physiological response and ion absorption of Poa pratensis to cadmium (Cd) stress，seedlings were raised by sand culture method，and plant height，root length，leaf and root fresh weight，pho‐ tosynthetic indexes，antioxidant enzyme activities，leaf hormone levels and ion content of Poa pratensis under differ‐ ent concentrations of Cd stress were measured. The results showed that Cd stress inhibited the growth of Kentucky bluegrass，caused wilting and chlorosis，significantly reduced the contents of photosynthetic pigment，inhibited leaf transpiration rate，stomatal conductance，net photosynthetic rate and intercellular carbon dioxide concentration. The