| 摘要: |
| 以改造的大花烟草（Nicotiana alata）即早花烟草为试材,研究在1 500 mmol·L-1氯化钠（NaCl）胁迫下,不同浓度梯度外源水杨酸（SA）处理下早花烟草种子的萌发情况和植株的生长状况,分析其过氧化物酶（POD）酶活性、超氧化物歧化酶（SOD）酶活性和活性氧（ROS）含量,及其作用机制. 研究结果表明,适量外源SA可以缓解盐胁迫对早花烟草萌发的毒害. 经0.05~1.00 mmol·L-1 SA处理,盐胁迫下早花烟草种子的发芽势、发芽率、发芽指数及活力指数上升,但随着SA浓度继续升高,其缓解效应随之降低. 盐胁迫下的早花烟草生长已经受到严重抑制. 喷施0.5~1.5 mmol·L-1 SA 后,叶片大小和鲜重、根系的大小和鲜重都明显升高；且喷施0.5~2.0 mmol·L-1 SA叶片中SOD和POD活性均呈现先降低后上升的趋势；ROS含量呈现先降低后上升的趋势；叶绿素含量呈现出先上升后降低的趋势. 这些结果表明：SA调节耐盐性可能以剂量依赖的方式发生,在外源施加适量浓度的SA提高抗氧化酶活性,能有效地消除过量的ROS,避免ROS积累,降低叶片中叶绿素含量及对光系统和光合碳同化过程中多种酶的伤害,维持较高的光合速率. |
| 关键词: 幼苗生长 生理响应 盐胁迫 种子萌发 水杨酸（SA） 早花烟草 活性氧（ROS） |
| DOI：10.20192/j.cnki.JSHNU(NS).2024.04.009 |
| 分类号:Q947.9 |
| 基金项目:上海花卉产业体系建设项目[沪农科产字（2022）第8号] |
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| SA regulates seed germination and growth in a dose-dependent manner in Nicotiana alata under salt stress |
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ZHANG Ren1, MING Jianlin2, LIU Pengcheng1, MING Feng1
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1.College of Life Sciences, Shanghai Normal University, Shanghai 200234, China;2.Shanghai Middle School, Shanghai 200237, China
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| Abstract: |
| Using the modified Nicotiana alata as the test material, the seed germination and plant germination of Nicotiana alata under different concentration gradient exogenous salicylic acid （SA） treatments under 150 mmol·L-1 NaCl stress were studied. Growth status, peroxidase （POD） enzyme activity, superoxide dismutase （SOD） enzyme activity and reactive oxygen species（ROS） content and the relationship between them were analyzed. The results showed that appropriate amount of exogenous SA can alleviate the toxicity of salt stress to the germination of early flowering tobacco, and 0.05-1.00 mmol·L-1 SA treatment can increase the germination potential, germination rate, germination index and vigor index of early flowering tobacco seeds under salt stress. As the concentration of SA continued to increase, its alleviation effect decreased. Under the stress of 150 mmol·L-1 NaCl, the growth of tobacco has been severely inhibited, while the size and fresh weight of leaves and root system were significantly increased by spraying 0.5-1.5 mmol·L-1 SA； and spraying 0.5-2.0 mmol·L-1 SA The activities of SOD and POD in SA leaves showed a trend of first decreasing and then increasing； ROS content first decreasing and then increasing； chlorophyll content first increasing and then decreasing. It is shown that the regulation of salt tolerance by SA can occur in a dose-dependent manner, and exogenous application of an appropriate concentration of SA to increase the activity of antioxidant enzymes can effectively eliminate excess ROS, avoid ROS accumulation, and can reduce chlorophyll content in leaves and the process of photosystem and photosynthetic carbon assimilation. The damage of a variety of enzymes maintains a high photosynthetic rate. |
| Key words: seedling growth physiological response salt stress seed germination salicylic acid （SA） Nicotiana alata reactive oxygen species （ROS） |
