| 摘要: |
| 【目的】探讨东北薄荷(Mentha sachalinensis (Briq.) Kudo.)种子萌发期对盐碱混合胁迫环境的响应特征，明确其对混合盐胁迫的耐受性。【方法】将4种单盐（NaCl、Na2SO4、NaHCO3和Na2CO3）按5种摩尔比（A.1∶9∶9∶1，B.1∶1∶1∶1，C.9∶1∶1∶9，D.1∶1∶9∶9，E.0∶0∶1∶1）人工模拟pH分别为8.82，9.58，10.28，11.18和11.25的盐碱混合胁迫条件，每组内又设置5个盐浓度（20，30，40，50，60 mmol/L），以蒸馏水为对照（CK），比较混合盐胁迫下种子萌发及幼苗生长状况，并通过建立的函数方程确定东北薄荷种子和幼苗对混合盐胁迫的耐受阈值。【结果】随着混合盐浓度的升高，A~E处理组的平均发芽时间总体呈延长趋势，而相对盐害率总体呈增加趋势。与对照相比，A~E处理组5个盐浓度胁迫下的发芽指数、活力指数、胚芽长和胚根长均显著降低；D处理组（pH 11.18）的发芽率则呈现“低促高抑”现象，而其他4个处理组的发芽率均低于对照。A、B、E处理组的发芽势逐渐下降，而C、D处理组的发芽势呈先上升后下降的趋势。混合盐胁迫条件下，混合盐浓度是引起东北薄荷种子萌发指标和胚芽生长受抑的主导因素，而pH则是引起胚根生长受抑的主要胁迫因素，二者之间的交互作用影响较弱。解除盐胁迫后，仍有部分种子恢复萌发。东北薄荷种子萌发阶段和幼苗生长阶段对A~E处理组的耐受阈值分别为43.72，45.39，63.73，55.70，44.92 mmol/L和17.96，13.60，6.76，19.26，12.69 mmol/L。【结论】东北薄荷种子萌发阶段对混合盐胁迫的耐受性强于其初生幼苗生长阶段，且东北薄荷对pH为11.18的混合盐胁迫具有较强的耐受性。 |
| 关键词: 东北薄荷 混合盐胁迫 种子萌发 幼苗生长 耐盐性 |
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| 基金项目:吉林省重点科技成果转化项目（20170307011NY）；吉林省大学生创新创业训练计划项目（2017093032）；吉林师范大学博士科研启动项目（吉师博2016031号） |
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| Effects of mixed salt stress on seed germination and seedling growth of Mentha sachalinensis (Briq.) Kudo. |
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LI Yumei,FENG Ying,JIANG Yuntian,et al
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| Abstract: |
| 【Objective】This paper explored the responses of seed germination of Mentha sachalinensis (Briq.) Kudo.to saline alkaline mixed stresses,and identified its tolerance to mixed salt stress.【Method】Four single salts (NaCl,Na2SO4,NaHCO3 and Na2CO3) were combined in five different ratios (A.1∶9∶9∶1，B.1∶1∶1∶1，C.9∶1∶1∶9，D.1∶1∶9∶9 and E.0∶0∶1∶1) to artificially simulate mixed stresses with pH of 8.82,9.58,10.28,11.18 and 11.25,respectively.In each treatment group,five salt concentrations were set at 20，30，40，50,and 60 mmol/L.The seed germination and seedling growth were compared with distilled water as control,and functional equations were established to determine tolerance thresholds of seeds and seedlings to mixed salt stresses.【Result】As the concentration of mixed salts increased,average germination time generally prolonged in groups A-E,and relative salt-injury rate increased.Compared with the control,germination index,vigor index,embryo length and radicle length decreased significantly in groups A-E under all five concentrations.The germination rate was promoted in group D with pH of 11.18 under low salt concentrations and was inhibited under high concentrations,while those of other groups were lower than the control group.The germination potentials in groups A,B and E gradually decreased,while those of groups C and D increased first and then decreased.Under mixed salt stress,mixed salt concentration was the dominant factor in inhibiting seed germination indexes and embryo growth,and pH was the major stress factor in inhibiting radicle growth.The interaction between salt concentration and pH was weaker than single stress factor.After salt stress was released,some seeds still germinated.The tolerance thresholds of Mentha sachalinensis to treatment groups A-E were 43.72,45.39,63.73,55.70 and 44.92 mmol/L during seed germination,and 17.96,13.60,6.76,19.26 and 12.69 mmol/L during seedling growth,respectively.【Conclusion】The tolerance of Mentha sachalinensis seeds to mixed salt stress in germination stage was stronger than in primary seedling stage,and Mentha sachalinensis seed had stronger tolerance to mixed salt stress with pH of 11.18. |
| Key words: Mentha sachalinensis (Briq.) Kudo. mixed salt stress seed germination seedling growth salt tolerance |
