In this study,we evaluated the effects of different concentrations of NaCl on seed germination and seedling growth of Chenopodium quinoa.Seeds and seedlings of C.quinoa were exposed to different concentrations of NaCl,and seed germination,physiological indexes,and biochemical indexes were determined.The germination percentage,germination energy,germination index,and vigor index of C.quinoa seeds decreased as the concentration of NaCl increased.When the concentration of NaCl was 3.0％,none of the quinoa seeds germinated.As the concentration of NaCl increased,the leaf water content decreased,the contents of soluble sugars,proline,malondialdehyde,relative conductance,and O2-· production rate increased,and the activities of superoxide dismutase,peroxidase,and catalase increased and then decreased.The plant height and stem diameter decreased as the NaCl concentration increased,but root lengths increased and then decreased.The longest root length was in the 1.8％ NaCl treatment.In conclusion,seedling growth of C.quinoa was promoted by low concentrations of NaCl,but inhibited by high concentrations of NaCl.The threshold of salt tolerance was 1.8％ NaCl.%本研究报道了不同浓度NaCl处理对藜麦种子萌发及幼苗生理特性的影响,以确定藜麦的耐盐阈值,为藜麦在盐渍土地种植提供理论依据.结果表明,不同浓度NaCl处理对藜麦种子萌发和幼苗生理特性均产生显著影响,主要表现为,1)随着NaCl浓度的升高,藜麦种子的发芽率、发芽势、发芽指数和活力指数均呈逐渐降低的趋势,当NaCl浓度达到3.0％时,藜麦种子几乎不发芽;2)幼苗叶片含水量逐渐降低,可溶性糖、脯氨酸、丙二醛含量、相对电导率及O2-·产生速率呈逐渐升高的趋势,叶绿素含量、超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性在NaCl浓度为1.8％时达到最大值,而后随着NaCl浓度的升高呈降低的趋势;3)NaCl胁迫显著抑制了藜麦幼苗株高、茎粗的增加,根长的生长随着NaCl浓度的升高呈先增加后减少的趋势,在NaCl浓度为1.8％时根长最长,达到11.73 cm.说明低浓度(≤1.8％)NaCl处理对藜麦幼苗生长具有促进作用,而高浓度的NaCl处理则对其有抑制作用.藜麦耐盐阈值为1.8％.
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