Zemanová Veronika, Pavlík Milan, Pavlíková Daniela
Isotope Laboratory, Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
Department of Agro-Environmental Chemistry and Plant Nutrition, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences, Prague, Czech Republic.
PLoS One. 2017 May 19;12(5):e0177963. doi: 10.1371/journal.pone.0177963. eCollection 2017.
Cadmium (Cd) toxicity affects numerous metabolic processes in plants. In the presence of Cd, plants accumulate specific amino acids which may be beneficial to developing Cd tolerance. Our study aimed to characterize the changes in the metabolism of selected free amino acids that are associated with Cd tolerance, and investigate the levels of selected microelements in order to relate these changes to the adaptation strategies of two metallophytes-Noccaea caerulescens (Redlschlag, Austria) and Noccaea praecox (Mežica, Slovenia). The plants were exposed to Cd contamination (90 mg Cd/kg soil) for 120 days in a pot experiment. Our results showed higher Cd accumulation in N. praecox compared to N. caerulescens. Cadmium contamination reduced the zinc and nickel levels in both species and a mixed effect was determined for copper and manganese content. Differences in free amino acid metabolism were observed between the two metallophytes growing under Cd-free and Cd-loaded conditions. Under Cd-free conditions, aromatic amino acids (phenylalanine, tryptophan and tyrosine) and branched-chain amino acids (leucine, isoleucine and valine) were accumulated more in the leaves of N. praecox than in N. caerulescens. Cd stress increased the content of these amino acids in both species but this increase was significant only in N. caerulescens leaves. Marked differences in the responses of the two species to Cd stress were shown for alanine, phenylalanine, threonine and sarcosine. Cadmium contamination also induced an increase of threonine as alanine and sarcosine decrease, which was larger in N. caerulescens than in N. praecox. All these factors contribute to the higher adaptation of N. praecox to Cd stress.
镉（Cd）毒性会影响植物中的众多代谢过程。在镉存在的情况下，植物会积累特定的氨基酸，这可能有助于形成对镉的耐受性。我们的研究旨在表征与镉耐受性相关的选定游离氨基酸代谢变化，并研究选定微量元素的水平，以便将这些变化与两种金属植物——奥地利红施拉格的天蓝遏蓝菜和斯洛文尼亚梅日察的早熟遏蓝菜的适应策略联系起来。在盆栽试验中，将这些植物暴露于镉污染（90毫克镉/千克土壤）环境中120天。我们的结果表明，与天蓝遏蓝菜相比，早熟遏蓝菜中镉的积累量更高。镉污染降低了两个物种中的锌和镍含量，并且确定了铜和锰含量存在混合效应。在无镉和镉负载条件下生长的两种金属植物之间，观察到游离氨基酸代谢存在差异。在无镉条件下，早熟遏蓝菜叶片中积累的芳香族氨基酸（苯丙氨酸、色氨酸和酪氨酸）和支链氨基酸（亮氨酸、异亮氨酸和缬氨酸）比天蓝遏蓝菜更多。镉胁迫增加了两个物种中这些氨基酸的含量，但这种增加仅在天蓝遏蓝菜叶片中显著。对于丙氨酸、苯丙氨酸、苏氨酸和肌氨酸，两个物种对镉胁迫的反应存在明显差异。镉污染还导致苏氨酸增加，同时丙氨酸和肌氨酸减少，早熟遏蓝菜中的这种变化比天蓝遏蓝菜更大。所有这些因素都促使早熟遏蓝菜对镉胁迫具有更高的适应性。
