| 摘要: |
| 【目的】研究低温胁迫下NO缓解辣椒幼苗伤害的可能机理，为外源NO在蔬菜生产上的应用提供参考依据。【方法】以‘津福803’辣椒为试验材料，采用叶面喷施外源NO供体硝普钠（SNP）和内源NO抑制剂L-NAME（N-硝基-L-精氨酸甲酯盐酸盐）处理低温胁迫下的辣椒幼苗，首先筛选出最佳SNP处理浓度，共设6个处理，分别为常温（喷施蒸馏水，25 ℃/17 ℃）、低温（喷施蒸馏水，15 ℃/5 ℃）、SNP处理（设置SNP浓度依次为0.05，0.1，0.2，0.3 mmol/L，15 ℃/5 ℃），然后以筛选出的SNP最佳浓度（0.2 mmol/L）为处理，另设L-NAME处理（0.2 mmol/L，15 ℃/5 ℃），SNP+L-NAME（0.2 mmol/L SNP+0.2 mmol/L L-NAME，15 ℃/5 ℃），以及上述常温和低温处理为对照进一步试验，研究不同处理对辣椒幼苗的生长情况、光合参数、活性氧积累、抗氧化酶活性和渗透调节物质含量的影响。【结果】与常温处理相比，低温胁迫下辣椒幼苗的生长受到明显抑制，冷害指数为62.8。与低温处理相比，喷施0.2 mmol/L SNP能显著提高辣椒幼苗的生物量、根系活力、叶绿素含量、净光合速率、抗氧化酶活性，增加可溶性蛋白、可溶性糖和游离脯氨酸等渗透调节物质的含量，显著降低细胞膜透性，抑制O-·2产生和H2O2积累，冷害指数为33.1。与低温处理相比，L-NAME处理则使辣椒幼苗的生物量、光合作用、抗氧化酶活性、渗透调节物质含量显著下降，活性氧积累显著上升，冷害指数达到79.2；而SNP+L-NAME处理则使辣椒幼苗的生物量、光合作用、抗氧化酶活性、渗透调节物质含量和活性氧积累均高于L-NAME处理，但低于SNP处理，冷害指数为65.1。【结论】NO对提高辣椒低温耐受性有着积极作用，可通过增强光合作用、抑制活性氧积累、提高抗氧化酶活性、增加渗透调节物质含量等途径，缓解低温胁迫对辣椒幼苗造成的伤害。 |
| 关键词: 辣椒幼苗 一氧化氮(NO) 低温胁迫 光合作用 抗氧化酶 渗透调节 |
| DOI： |
| 分类号: |
| 基金项目:松原市宁江区“北方寒地无公害设施蔬菜基地建设及规范化生产技术科技示范项目” |
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| Mechanisms of spraying external nitric oxide to alleviate injury of pepper seedlings caused by low temperature |
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LIU Xiyuan,WU Chunyan,ZHANG Guangchen,et al
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| Abstract: |
| 【Objective】The possible mechanisms of using NO to alleviate pepper seedling injury under low temperature stress were studied to improve NO application.【Method】Seedlings of Capsicum annuum L.‘Jinfu 803’ were treated under low temperature stress before foliar application of exogenous NO donor sodium nitroprusside (SNP) and endogenous NO inhibitor L-NAME (N-nitro-L-arginine methyl ester hydrochloride).First,a total of 6 treatments were set including normal temperature (H2O,25 ℃/17 ℃), low temperature (H2O,15 ℃/5 ℃),and SNP treatments with concentrations of 0.05,0.1,0.2, and 0.3 mmol/L (15 ℃/5 ℃) to determine the best SNP concentration.Then,with the obtained optimal concentration (0.2 mmol/L),L NAME (0.2 mmol/L,15 ℃/5 ℃) and SNP+L-NAME (0.2 mmol/L SNP+0.2 mmol/L L-NAME,15 ℃/5 ℃) treatments were conducted using above normal temperature and low temperature treatments as control to study the effects of different treatments on seedling growth,photosynthetic parameters,active oxygen accumulation,antioxidant enzyme activity and contents of osmotic adjustment substances.【Result】The growth of seedlings was significantly inhibited under low temperature stress,and the cold injury index reached 62.8.Compared with low temperature treatment,spraying 0.2 mmol/L SNP significantly increased biomass,root activity,chlorophyll content,net photosynthetic rate,antioxidase activity,contents of osmotic adjustment substances such as soluble protein,soluble sugar and free proline,significantly reduced cell membrane permeability,and inhibited O-·2 production and H2O2 accumulation with cold damage index of 33.1.Compared with low temperature treatment,L-NAME treatment significantly reduced biomass,photosynthesis,antioxidant enzyme activity and contents of osmotic adjustment substances,and significantly increased reactive oxygen accumulation with cold damage index of 79.2.SNP+L-NAME treatment resulted in higher biomass,photosynthesis,antioxidant enzyme activity,contents of osmotic adjustment substances and active oxygen accumulation than L-NAME treatment with chilling injury index of 65.1.【Conclusion】NO had positive effects on improving low temperature tolerance of pepper,and it alleviated the damage caused by low temperature stress on pepper seedlings by enhancing photosynthesis,inhibiting accumulation of active oxygen,and increasing activities of antioxidant enzymes and contents of osmotic adjustment substances. |
| Key words: Capsicum annuum nitric oxide (NO) low temperature stress antioxidase photosynthesis osmotic adjustment |
