镉胁迫对洋常春藤叶绿素荧光特性的影响

以洋常春藤扦插苗作为实验对象，分别对其进行不同浓度的CdCl₂溶液水培处理，测定并分析镉胁迫对其叶绿素含量及荧光参数的影响。结果表明：在镉胁迫下，洋常春藤叶片的叶绿素a、叶绿素b以及总叶绿素含量均显著降低，叶绿素a/b比值显著升高，且变化程度随着镉胁迫浓度的增大而增大。在浓度20、80 μmol/L的镉胁迫下，洋常春藤的叶绿素荧光参数光系统Ⅱ潜在最大光化学效率、光系统Ⅱ实际光化学效率、非光化学淬灭、光化学淬灭、电子传递速率无显著变化，说明在浓度小于80 μmol/L的镉胁迫下洋常春藤叶绿素荧光参数光系统Ⅱ光合机构功能状态良好。而在浓度200、400 μmol/L的镉胁迫下，尤其是400 μmol/L时，可导致其光合机构受损，表现为潜在最大光化学效率、光系统Ⅱ实际光化学效率、非光化学淬灭和电子传递速率的显著降低，叶片初始荧光显著升高，说明此浓度的镉胁迫对洋常春藤的叶绿素荧光参数光系统Ⅱ光合机构功能有抑制作用。

Effects of Cadmium Stress on Chlorophyll Fluorescence Characteristics of Hedera helix

The Hedera helix cuttings seedlings were used as experimental objects, and hydroponic treatment of different concentrations of CdCl2 solution was carried out. The effects of cadmium stress on its chlorophyll content and fluorescence parameters were determined and analyzed. Results show that the chlorophyll a, chlorophyll b and total chlorophyll content decrease significantly under cadmium stress, and the chlorophyll a/b ratio increase significantly. Moreover, the chlorophyll a/b ratio increase largely with the increase of the concentration of cadmium stress. Under the cadmium stress of 20 and 80 μmol/L, the maximum optical efficiency, the non-photochemical quenching, the actual photosynthetic efficiency, the photochemical quenching, and the photosynthetic electron transport rate show no significant change, indicating that the chlorophyll fluorescence parameters photosynthetic apparatus of H. helix can keep well stability under the this cadmium concentration. While under the cadmium stress of 200, 400 μmol/L, especially the 400 μmol/L Cd2+, can cause damage to its photosynthetic apparatus, manifested by potential maximum photochemical efficiency, actual photochemical efficiency of photosystem Ⅱ, non-photochemical quenching, and significant reduction in electron transport rate. Leaf initial fluorescence is significantly increased. This indicates that cadmium stress at this concentration has an inhibitory effect on the photosynthetic system function of chlorophyll fluorescence parameters of H. helix.