镉对籽粒苋耐性生理及营养元素吸收积累的影响

Effect of cadmium on tolerance physiology and nutrient accumulation in Amaranthus hypochondriacus L.

初步阐明了镉对籽粒苋耐性生理及营养元素吸收积累的影响,为进一步揭示籽粒苋的镉耐性与镉富集机理奠定了基础。通过对生物量的监测,对叶绿素、蛋白质、游离氨基酸、大量元素及微量元素等的含量的测定,阐明镉胁迫对籽粒苋生长生理、抗胁迫耐性、营养元素吸收分配的影响。研究结果显示,镉胁迫对籽粒苋的生长抑制作用不明显,植株生物量随着镉浓度的提高而轻微降低。随着镉处理浓度的提高,叶绿素含量下降幅度显著;蛋白质和游离氨基酸含量变化幅度不明显;钾含量无大幅变化;镉、磷、钙、镁、锌、铁、锰、铜含量变化幅度较显著。镉、钾、磷、锰的迁移系数随着镉处理浓度的提高无显著变化;钙的迁移系数呈上升趋势;镁、锌、铁、铜的迁移系数均呈下降趋势。这些结果表明:镉胁迫降低籽粒苋叶绿素含量,抑制植株光合作用,继而抑制了植株的生长,但其程度不明显;镉胁迫条件启动活性氧防御机制;引起植株体内部分养分代谢紊乱。结论:低浓度镉处理条件下,籽粒苋受镉离子影响,抗氧化能力下降。在高浓度镉处理条件下,籽粒苋调节了营养元素的吸收和分配,启动了一系列活性氧防御机制,提高了抗胁迫能力。

This paper illustrated the tolerance physiology of cadmium and the impact of cadmium on nutrient uptake and accumulation in Amaranthus hypochondriacus L.Through monitoring the biomass,chlorophyll content,protein content,free amino acids content,macro-elements content and micro-elements content,the paper can determined the effect of cadmium stress on amaranth.The results were： cadmium stress inhibited growth of amaranth slightly.As the cadmium concentration increased,there was a significant decrease in chlorophyll content.Change in protein content and free amino acids content is not obvious as the cadmium concentration elevated.With the increased cadmium concentration,potassium content showed no significant change.Significant change in phosphorus,calcium,magnesium,zinc,iron,manganese,copper content appeared with the cadmium concentration increased.Transfer factor of cadmium,potassium,phosphorus,manganese changed slightly with the cadmium concentration increased.Transfer factor of calcium rise with the cadmium concentration increased;Transfer factor of magnesium,zinc,iron,copper showed a downward trend as the cadmium concentration increased.These results suggest that cadmium stress reduced chlorophyll content,and then inhibited photosynthesis and growth of plant;triggered defense mechanisms against reactive oxygen stress;caused metabolic nutrients disorders in plant.Conclusion： Under low cadmium concentration treatment conditions,cadmium ion damaged anti-oxidation system;decreased antioxidant capacity in plant.Under high cadmium concentration treatment conditions,amaranth has been adapted to the stress of cadmium ions,launched a series of defense mechanisms against active oxygen,improve the ability of anti-stress.