[目的]研究La3+和pH值对拟南芥种子萌发和主根生长的影响,优化拟南芥抗La3+突变体的筛选条件.[方法]通过人工控制pH值研究低pH值和La3+对拟南芥种子萌发及主根生长的影响.[结果]拟南芥种子萌发的适宜pH值范围较宽,但过低pH值会推迟种子发芽,降低种子萌发率.随着酸度的增加,主根生长受到抑制.pH=5.5时,拟南芥种子萌发和主根生长受到的影响较小.La3+浓度为5 mg/kg及以下时刺激种子萌发,为10 mg/kg及以上时推迟种子萌发,为1 mg/kg 时刺激主根生长,为5 mg/kg及以上时显著抑制主根生长.随着La3+浓度的增加,种子萌发和主根生长受到的抑制作用增强.在去P培养基与纯La培养基中,拟南芥种子萌发和主根生长对La3+的反应趋势基本相同.[结论]过低pH值和不低于5 mg/kg 的La3+浓度对拟南芥种子萌发和主根生长有负面影响.%[Objective] The aim was to study the influences of La3+ and pH on the seed germination and taproot growth of Arabidopsis thaliana and optimize the screening condition of its mutants with resistance to La3+. [Method] The influences of low pH and La3+ on the seed germination and taproot growth of A. thaliana were studied through controlling pH manually. [Result] The pH range suitable for the seed germination of A. thaliana was quite wide, but too low pH value would delay its seed germination and decrease its seed germination rate. As the acidity was increased, its taproot growth was inhibited. When pH value was 5.5, the influences on the seed germination and taproot growth of A. thaliana were less. When the concn. of La3+ was 5 mg/kg or lower, the seed germination was promoted; when it was 10 mg/kg or higher, the seed germination was delayed; when it was 1 mg/kg, the taproot growth was promoted; when it was 5 mg/kg or higher, the taproot growth was inhibited significantly. As the concn. of La3+ was increased, the inhibition effects on the seed germination and taproot growth were enhanced. On the medium without phosphorous and pure La-medium, the response tendencies of seed germination and taproot growth of A. thaliana to La3+ were basically same. [Conclusion] When the pH was too low or the concn. of La3+ was no lower than 5 mg/kg, it had negative influences on the seed germination and taproot growth of A. thaliana.
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