盐胁迫对东北薄荷种子萌发的影响

为了研究4种单盐对东北薄荷Mentha sachalinensis(Briq.)Kudo.种子萌发特性的影响,明确种子萌发期对4种盐胁迫的耐受性。人工模拟不同浓度NaCl、Na_2SO_4、NaHCO_3和Na_2CO_3胁迫条件,采用双层滤纸法培养各胁迫处理种子,测定发芽率、发芽势、发芽指数、活力指数、平均发芽时间等发芽指标,并通过相对发芽率与盐浓度建立的函数方程确定东北薄荷种子萌发期对4种盐胁迫的耐盐适宜浓度、耐盐半致死浓度和耐盐极限浓度。结果表明,随着盐浓度的升高,4种盐胁迫处理下的平均发芽时间逐渐延长,发芽率、发芽指数和活力指数逐渐下降;Na_2CO_3胁迫处理下的发芽势呈逐渐下降趋势,而其他3种盐处理下的发芽势均呈现先升高后下降的趋势。东北薄荷种子萌发期对NaCl、Na_2SO_4、NaHCO_3和Na_2CO_3的耐盐适宜浓度为119.44、64.64、64.32和19.27 mmol·L~(-1),耐盐半致死浓度为153.36、66.70、86.54和22.23 mmol·L~(-1),耐盐极限浓度为191.21、105.33、108.07和25.07mmol·L~(-1);东北薄荷种子对4种盐胁迫的耐受性由大到小依次为NaCl、NaHCO_3、Na_2SO_4、Na_2CO_3。

Effects of Salt Stress on Seed Ge rminat ion of Mentha sa chalinensis(Briq.)Kudo

We investigated the effects of four kinds of salt stress on seed germination of Mentha sachalinensis(Briq.)Kudo.,and confirmed the salt-tolerance of seeds during germination period.The salt stress environment was simulated with different concentrations of NaCl, Na2SO4, NaHCO3and Na2CO3, and seeds were cultured adopting a double-layer filter paper method under four kinds of salt stress.Several indexes of seed germination were measured such as germination rate,germi-nation potential,germination index,vigor index and mean germination time,and through the function equation established by relative germination rate and salt concentrations, the salt-tolerance appropriate content, salt-tolerance half-lethal and salt-tolerance limit concentrations of NaCl,Na2SO4,NaHCO3and Na2CO3were determined at seed germination period of M.sachaline nsis.With the increasing salinity, the mean germination time was gradually extended, and the germination rate,germination index and vigor index were all reduced under four kinds of salt stress.Under Na2CO3stress,the germina-tion potential was decreased with increasing salinity,while the germination potential was increased,and then decreased un-der NaCl,Na2SO4and NaHCO3stress.The appropriate contents of salt-tolerance for NaCl,Na2SO4,NaHCO3and Na2CO3 were 119.44,64.64,64.32 and 19.27 mmol· L-1at seed germination period,the salt-tolerance half-lethal concentrations were 153.36,66.70,86.54 and 22.23 mmol· L-1,and the salt-tolerance limit concentrations were 191.21,105.33,108.07 and 25.07 mmol· L-1,respectively.The descending tolerance order of M.sachalinensis seeds for four kinds of salt stress was NaCl,NaHCO3,Na2SO4and Na2CO3.