Abstract: In order to investigate the physilogical reason for potassium content increasing in leaves of AtNHX1 tobacco,  using positive AtNHX1 gene homozygous strain N7, N9, N10 and non-transgenic control K326 as material under field and hydroponic condition, this paper studied the potassium content, root system morphology and physiological characteristics of AtNHX1-expressing tobacco lines. The results showed that AtNHX1-expressing tobacco lines grew with unanimous vigor in the fields. The potassium content on leaves at 10~70 d was remarkably higher than that of the control under filed condition. In hydroponic experiment, the AtNHX1-expressing tobacco lines exhibited strong potassium absorption capability and larger maximum potassium absorption rate. The root system morphology and vigor, cation exchange capacity and ATPase activity were significantly higher than that of the control. These results indicated that AtNHX1-expressing tobacco lines had  effective potassium absorption and accumulation characteristics. Therefore, the potassium content in tobacco leaf was greatly increased.

Key words: AtNHX1-expressing tobacco lines, potassium content, root system morphology, physiological characteristics

摘要： 为了探明转AtNHX1基因提高烟叶钾含量的生理原因，利用大田和水培试验，以3个转AtNHX1基因阳性纯合株系N7、N9和N10，以及未转化烟草K326(对照)为材料，研究了转AtNHX1基因烟草钾含量、根系形态和生理特性。结果表明，转AtNHX1基因烟草在大田中长势一致，烟叶含钾量在10~70 d叶龄始终显著高于对照；在水培实验中，转AtNHX1基因烟草吸收K+能力强，具有较大的K+吸收速率，其根系形态、根系活力、阳离子交换量和ATPase 活性均显著高于对照。转AtNHX1基因烟草具有富钾基因型烟草钾高效吸收和积累的特征，因而钾含量大大提高。

关键词: 转AtNHX1基因烟草, 钾含量, 根系形态, 生理特性