| 摘要: |
| 【目的】探讨等渗盐胁迫下油菜素内酯（BR）对番茄生长及渗透调节特性的影响，为施用外源BR应对设施土壤盐渍化问题和设施番茄抗逆栽培提供理论依据。【方法】以番茄为试材，以日本山崎番茄配方营养液（对照）添加100 mmol/L Ca(NO3)2和150 mmol/L NaCl模拟等渗盐胁迫环境，通过水培法研究等渗盐胁迫下BR（0.1 μmol/L）对番茄幼苗干鲜质量、叶片相对含水量、根系活力及渗透调节特性（组织汁液渗透势以及可溶性蛋白、可溶性糖、游离氨基酸和脯氨酸含量）的影响。【结果】与对照相比，等渗Ca(NO3)2和NaCl胁迫下番茄植株生长均受到显著抑制，叶片相对含水量均显著降低，NaCl胁迫显著降低番茄根系活力，且NaCl胁迫对植株生长的抑制效应更为明显；同时，等渗盐胁迫下，随处理时间延长叶片渗透势呈先降低后升高的“V”形变化，而可溶性糖含量则呈先升高后降低的倒“V”形变化，可溶性蛋白含量随处理时间延长在NaCl胁迫下含量积累、在Ca(NO3)2胁迫下含量有所降低，游离氨基酸和脯氨酸含量随时间延长呈不同程度的增加趋势。等渗盐胁迫下，外源BR显著提高了盐胁迫植株的干鲜质量、叶片相对含水量，且处理第3天时，与对照相比，等渗盐胁迫下施用外源BR番茄叶片渗透调节物质含量均显著升高；处理第5天时，Na+BR处理渗透调节物质含量显著升高，Ca+BR处理脯氨酸和游离氨基酸含量显著降低。【结论】等渗盐胁迫下外源BR可有效增强番茄幼苗渗透调节能力，改善叶片水分状态，促进植株生长，且对NaCl胁迫的整体缓解效应更显著，等渗盐胁迫条件下外源BR诱导渗透调节物质积累应答Ca(NO3)2、NaCl胁迫的具体模式存在差异。 |
| 关键词: 番茄 等渗盐胁迫 油菜素内酯 渗透调节特性 |
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| 基金项目:旱区作物逆境生物学国家重点实验室开放课题(CSBAA2017004)；国家自然科学基金青年科学基金项目（31501807，31501750，31501806） |
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| Effects of brassinolide on seedling growth and osmotic regulation characteristics of tomato under iso-osmotic salt stress |
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LI Shuo,ZHANG Yi,YAO Qi,et al
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| Abstract: |
| 【Objective】This study explored the effects of brassinolide (BR) on seedling growth and osmotic regulation characteristics of tomato (Solanum lycopersicum L.) under iso-osmotic salt stress to provide basis for the application of exogenous BR to facility soil salinization and stress-resistant cultivation of facility tomato.【Method】In this experiment,100 mmol/L Ca(NO3)2 and 150 mmol/L NaCl were applied to tomato plants to simulate the iso-osmotic salt stress environment.The effects of exogenous BR (0.1 μmol/L) on dry and fresh weights,relative water content,root activity and osmotic regulation characteristics (including osmotic potential,soluble protein,soluble sugar and free amino acid) of tomato seedlings exposed to iso osmotic salt stress were then investigated.【Result】Compared with control treatment,growth of tomato plant was inhibited significantly by iso-osmotic Ca(NO3)2 and NaCl stress.Leaf relative water contents were decreased,and root activity under NaCl stress was lowered significantly.The effect was severer with NaCl stress.Under iso-osmotic salt stress,leaf osmotic potential decreased with the increase of treating time first followed by increasing with a ‘V’ shape,while soluble sugar content showed opposite trend.With the prolonging of treating time,soluble protein content increased under NaCl stress,while decreased under Ca(NO3)2 stress.Contents of free amino acids and proline were improved differently.Exogenous BR significantly increased dry and fresh weights and relative water content of stressed plant under iso osmotic salt stress.It also significantly improved contents of osmotic substances under iso-osmotic salt stress at the third day of treatment.At the fifth day under stress,osmotic substances increased significantly in Na+BR treatment,while contents of free amino acids and proline were significantly decreased in Ca+BR treatment.【Conclusion】Under iso-osmotic salt stress,exogenous BR could effectively enhance osmotic regulation capacity of tomato seedlings,improve leaf water status and promote plant growth with more marked effect on alleviation of NaCl stress.There were differences in osmotic substances mechanism mediated by exogenous BR in response to salt-induced damage caused by Ca(NO3)2 and NaCl stress. |
| Key words: tomato iso-osmotic salt stress brassinolide (BR) osmotic adjustment |
