离子组学挖掘影响小麦镉吸收和转运的关键营养元素

Ionomics Analysis Reveals the Key Nutrient Elements Influencing Cadmium Uptake and Translocation in Wheat (Triticum aestivum)

  • 摘要: 为解析影响小麦对镉(Cd)吸收和转运的关键营养元素, 通过室内水培试验研究不同浓度Cd胁迫处理下, 10个品种小麦幼苗体内离子组(Cd、Fe、Mn、Cu、Zn、P、S、K、Ca、Mg)的变化特征及其与小麦幼苗对Cd吸收和转运的关系。结果显示: 与不进行Cd胁迫处理相比, 5 μmol·L-1(低浓度)的Cd胁迫处理9 d对小麦幼苗根系和地上部生长无显著影响, 20 μmol·L-1(高浓度)的Cd胁迫处理9 d则显著抑制小麦幼苗生长; 小麦幼苗根系对Cd的吸收、根系向地上部Cd转运均存在显著的品种间差异, 在低浓度的Cd胁迫处理下, 小麦幼苗根系对Cd的吸收、根系向地上部Cd转运的品种间最大差异分别为1.58和1.95倍, 这种差异在高浓度的Cd胁迫处理下扩大至2.15和2.44倍; 与低浓度的Cd胁迫处理相比, 高浓度的Cd胁迫处理不同程度地改变了小麦幼苗根系和地上部营养元素的含量, 且在不同浓度的Cd胁迫处理下, 小麦幼苗对Cd的吸收、转运与营养元素间的相关性存在差异。Cd胁迫处理干扰了植物体内离子网络的构成。相关性分析和冗余分析发现, 在低浓度的Cd胁迫处理下, Zn、P、Mg是影响小麦幼苗对Cd吸收和转运的主要营养元素; 在高浓度的Cd胁迫处理下, 除了Zn、P、Mg之外, S、Mn、Fe、K也显著影响小麦幼苗对Cd的吸收和转运。影响小麦对Cd吸收和转运的关键营养元素与小麦幼苗受到的Cd胁迫程度相关, 小麦幼苗根据Cd胁迫程度, 通过生理生化过程调整体内元素的含量以适应Cd胁迫环境。

     

    Abstract: To explore the key nutrient elements influencing cadmium (Cd) uptake and translocation in wheat plants, a hydroponic experiment was conducted to investigate the characteristics of the ionome (including Cd, Fe, Mn, Cu, Zn, P, S, K, Ca and Mg) in seedlings of ten wheat cultivars under different concentrations of Cd stress treatments. The relationships of ionomic variations with Cd uptake and translocation were also analyzed. The results reveal that, in comparison to the control group (no Cd stress), a 9-day exposure to 5 μmol·L-1 Cd (low-concentration Cd stress) did not significantly impact the root and shoot growth of wheat seedlings. In contrast, 20 μmol·L-1 Cd (high-concentration Cd stress) treatment for the same duration of exposure resulted in substantial inhibition of plant growth. Notably, considerable variability in Cd uptake and translocation was observed across the studied cultivars. Under low Cd stress, the differences in Cd uptake and the translocation factor among the ten wheat cultivars were 1.58 and 1.95 fold, respectively. These differences were further expanded to 2.15 and 2.44 fold, respectively, under high Cd stress. Compared with low Cd stress, high Cd stress altered one or more nutrient concentrations in the roots and shoots of some wheat cultivars. Moreover, the correlations of Cd uptake and translocation with the concentration of nutrient elements in wheat seedlings showed discrepancies between the low and high Cd treatments, indicating that Cd stress disrupts the ion network within wheat plants. Correlation and redundancy analyses reveal that under low Cd stress, Zn, P, and Mg are likely to be the critical nutrients influencing Cd uptake and translocation. Under high Cd stress, in addition to Zn, P, and Mg, elements such as S, Mn, Fe, and K also significantly contributed to wheat Cd uptake and translocation. These findings suggest that the types of key nutrients influencing Cd uptake and translocation in wheat are related to the degree of wheat Cd stress. Wheat seedlings adapt to Cd stress by physiologically and biochemically adjusting their internal element contents in response to the level of Cd exposure.

     

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