| 摘要: |
| 【目的】探究气体信号分子H2S和NO在平邑甜茶幼苗抵抗镉胁迫中的调节作用和相互影响，为果树抗逆应用研究提供参考。【方法】以平邑甜茶幼苗为供试材料，采用营养液培养法，以正常Hoagland营养液为对照（CK），在Cd胁迫条件下，分别通过外源施加H2S供体硫氢化钠（NaHS）或清除剂亚牛磺酸（HT）和外源NO供体硝普钠（SNP）或清除剂Carboxy-PTIO盐（c-PTIO），共计8个处理，分别为CK、Cd、Cd+NaHS、Cd+NaHS+HT、Cd+NaHS+c-PTIO、Cd+SNP、Cd+SNP+c-PTIO和Cd+SNP+HT，观测幼苗生长情况的变化，分析幼苗叶片叶绿素含量、叶绿素荧光参数和根系细胞死亡数量、呼吸速率、呼吸代谢关键酶活性、O-·2产生速率、H2O2含量以及抗氧化酶活性等的变化。【结果】与CK相比，单独Cd胁迫明显抑制平邑甜茶幼苗的生长，导致叶片光合能力下降；根系细胞大量死亡，活性氧积累，SOD、POD、CAT活性增加，呼吸速率下降，呼吸代谢关键酶PFK、MDH活性降低，而G-6-PDH活性升高。与单独Cd胁迫处理相比，Cd+NaHS和Cd+SNP处理平邑甜茶叶片叶绿素a、叶绿素b含量分别提高了22.84%，29.66%和16.29%，29.52%；潜在光化学活性（Fv/Fo）、最大光化学效率（Fv/Fm）和实际光化学效率（ΦPSⅡ）均显著升高；根系呼吸速率增加了46.33%和44.93%，PFK、MDH活性提高了11.29%，27.17%和13.70%，17.48%，G-6-PDH活性降低了13.82%和16.98%；根系O-·2产生速率降低了37.75%和35.74%，H2O2含量降低了27.49%和26.66%，SOD、POD和CAT活性显著提高了41.52%，82.22%，49.29%和34.87%，98.90%，78.72%。Cd胁迫条件下，外源H2S和NO均能抑制根系细胞死亡，促进幼苗生长。而添加NO清除剂c-PTIO抑制了外源H2S和NO对平邑甜茶幼苗镉损伤的缓解，添加H2S清除剂HT仅能抑制外源H2S的保护效应，对外源NO的作用基本无影响。【结论】平邑甜茶幼苗遭受镉胁迫时H2S和NO有交互作用，推测H2S的产生先于NO。 |
| 关键词: 硫化氢 一氧化氮 镉胁迫 平邑甜茶 |
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| 基金项目:国家自然科学基金项目(31301733)；山东省高校科技发展计划项目(J18KA157) |
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| Effects of hydrogen sulfide and nitric oxide on resistance of Malus hupehensis Rehd. seedlings against cadmium stress |
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JIANG Qianqian,CAO Hui,YANG Yanhong,et al
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| Abstract: |
| 【Objective】This study investigated the interaction and regulation effects of gaseous signal molecules H2S and NO on resistance of Malus hupehensis Rehd.seedlings against cadmium stress to provide basis for stress resistance researches of fruit trees.【Method】The Malus hupehensis Rehd.seedlings were treated with nutrient solution culture method.Using normal Hoagland nutrient solution as control,exogenous H2S donors sodium sulfide (NaHS),scavenger taurine (HT) and NO donors sodium nitroprusside (SNP),and scavenger carboxy-PTIO salt (c-PTIO) were applied under Cd stress conditions.A total of 8 treatments including CK,Cd,Cd+NaHS,Cd+NaHS+HT,Cd+NaHS+c-PTIO,Cd+SNP,Cd+SNP+c-PTIO and Cd+SNP+HT were included to observe changes in seedling growth and analyze changes in leaf chlorophyll content,chlorophyll fluorescence parameters,number of root cell death,respiratory rate,respiratory metabolism related enzyme activity,O-·2 production rate,H2O2 content and antioxidant enzyme activities.【Result】Compared with the CK,cadmium stress significantly inhibited growth of Malus hupehensis Rehd.seedlings,leading to decrease of photosynthetic capacity,a large number of root cell death and accumulation of reactive oxygen species.It also increased activities of SOD,POD,CAT and G-6-PDH,while decreased respiratory rate and activities of PFK and MDH.Compared with Cd stress treatment alone,contents of chlorophyll a and chlorophyll b in leaves of Malus hupehensis Rehd.treated with Cd+NaHS were increased by 22.84%,29.66% and those treated by Cd+SNP were increased by 16.29% and 29.52%,respectively.The potential photochemical activity (Fv/Fo),maximum photochemical efficiency (Fv/Fm) and actual photochemical efficiency (ΦPSII) were significantly increased.The root respiratory rate was increased by 46.33% and 44.93%,PFK and MDH activities were increased by 11.29%,27.17% and 13.70%,17.48%,and G-6-PDH activity was reduced by 13.82% and 16.98%.Root O-·2 production rate was reduced by 37.75% and 35.74%,H2O2 content was reduced by 27.49% and 26.66%,while SOD,POD,and CAT activities were significantly increased by 41.52%,82.22%,49.29% and 34.87%,98.90%,78.72%,respectively.Under Cd stress,exogenous H2S and NO inhibited root cell death and promoted seedling growth.The addition of NO scavenger c-PTIO reversed the alleviation of cadmium damage in Malus hupehensis Rehd.seedlings by exogenous H2S and NO.The addition of H2S scavenger HT could only reverse protective effect of exogenous H2S and had basically no effect on effect of exogenous NO.【Conclusion】There was an interaction between H2S and NO when Malus hupehensis Rehd.seedlings were under cadmium stress,and it was speculated that the production of H2S preceded NO. |
| Key words: hydrogen sulfide(H2S) nitric oxide(NO) cadmium stress Malus hupehensis Rehd. |
