摘要： 为探究外源硫化氢（Hydrogen sulfide，H₂S）对Cd胁迫下平邑甜茶幼苗根系损伤的影响，及Ca²⁺在H₂S介导重金属胁迫信号传导中的作用，采用营养液培养法，利用外源Ca²⁺以及Ca²⁺螯合剂EGTA、质膜Ca²⁺通道阻断剂La³⁺和钙调素拮抗剂CPZ，研究了平邑甜茶幼苗生长、根系细胞死亡、根系活性氧代谢和线粒体特性的变化。结果表明：与单独Cd胁迫处理相比，添加外源Ca²⁺或H₂S供体硫氢化钠（NaSH）均显著缓解了Cd胁迫对平邑甜茶幼苗生长的抑制，根系细胞死亡数量减少，根系超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）活性显著提高，超氧阴离子产生速率（O₂^·）、过氧化氢（H₂O₂）和丙二醛（MDA）含量明显下降，根系线粒体膜透性（MPT）减小，膜电位（Δψm）提高、细胞色素c（Cyt c）含量增加；添加NaSH的同时添加钙离子专一螯合剂EGTA，钙离子通道阻断剂LaCl₃或钙调素拮抗剂CPZ抑制了H₂S以上的调节作用。可见，外源Ca²⁺或H₂S可稳定线粒体功能，增强活性氧清除能力，减轻Cd对平邑甜茶的伤害，并且在这个过程中H₂S缓解Cd胁迫的作用可能依赖于Ca²⁺。

关键词: 平邑甜茶, 钙, 硫化氢, 活性氧, 线粒体

Abstract: The purpose of this paper is to explore the effects of hydrogen sulfide(H₂S) on root injury of Malus hupehensis Rehd. under Cd stress.The nutrient solution culture was used to study the effects of exogenous Ca²⁺,EGTA(Ca²⁺ chelator),La³⁺(blocker of Ca²⁺ channel in plasma membrane) and CPZ(antagoniston of calmodulin) on the growth of seedling,root cell death,reactive oxygen species metabolism and mitochondrial properties. The results showed that adding exogenous Ca²⁺ or H₂S donor NaSH could obviously alleviate the inhibition to the growth of seedlings,reduced the number of cell death in roots induced by Cd stress;and compared with Cd stress alone,the enzymes(SOD,POD,CAT) activities were significantly increased,the rate of superoxide anion production(O₂^·),contents of hydrogen peroxide(H₂O₂) and malondialdehyde(MDA) were significantly decreased,the mitochondrial membrane permeability(MPT) of root was decreased,the mitochondrial membrane potential(Δψm) of root was increased,the content of cytochrome c(Cyt c) was increased. The alleviative effects of H₂S on cadmium injury were inhibited by addition of Ca²⁺-chelate EGTA,Ca²⁺ channel blocker LaCl₃ or calmodulin inhibitor CPZ. Those indicate that Ca²⁺ or H₂S can stabilize mitochondrial function,enhance the ROS scavenging activity,alleviate the injury of Cd to Malus hupehensis Rehd.,and the effect of H₂S on cadmium stress may be dependent on Ca²⁺ in this process.

Key words: Malus hupehensis Rehd., Cadmium, Hydrogen sulfide, Reactive oxygen species, Mitochondria

中图分类号: 

• S571.01