大麦根中多胺含量和转化与耐盐性的关系

Relationship between the levels and conversion of polyamines in the roots and salt tolerance in barley seedlings

用0、50、100、200和300mmol·L-1NaCl对2个耐盐性不同的大麦品种鉴4(J4,耐盐性较强)和科品7号(KP7,耐盐性较弱)幼苗处理8d后,其干重均随着NaCl浓度增加而显著下降,叶片MDA含量和相对电导率相应增加。与对照相比,J4干重的降低要小于KP7,MDA含量和相对电导率也比KP7低。在盐胁迫下,大麦幼苗根系的多胺含量和种类也有显著的变化,随NaCl浓度的增加,腐胺(Put)含量先下降后上升,而亚精胺(Spd)含量的变化则相反,这种多胺含量变化的盐浓度阈值J4大于KP7。多胺合成抑制剂D-Arg、二氟甲基鸟氨酸(DFMO)和甲基乙二醛双(鸟嘌呤腙)(MGBG)可以显著降低盐胁迫下多胺含量,不同程度上加重了盐胁迫的伤害,表明植物体内多胺在盐胁迫适应中具有重要的作用。

After 0,50,100,200 and 300 mmol·L -1 NaCl stress for 8 days,the dry weight of barley seedlings decreased as the increase of NaCl concentrations in two cultivars(KP7(salt sensitive)and J4(salt tolerance)),the contents of MDA and the electrolyte leakage increased in leaves.However,the dry weight lost of J4 was less than that of KP7 and the content of MDA and electrolyte leakage were lower in J4 than that in KP7 when compared with the control in the same NaCl concentration.Meanwhile,the polyamine levels and forms were affected significantly under salt stress and their change patterns were similar in two cultivars.Namely Put content in the seedling roots decreased firstly and then increased as the increase of NaCl concentrations,however the change of Spd contents was opposite.But the threshold NaCl concentration leading to the change of the polyamines contents in J4 seedlings was larger than that in KP7.The treatments with polyamine biosynthesis inhibitors,D-Arg,difluoromethylornithine(DFMO)and methylglyoxyl bis(guanylhydrazone)(MGBG),reduced obviously the polyamine contents and caused much more injury to barley seedlings.It is suggested that polyamines play an important role in plant salt tolerance.