Department of Agricultural Chemistry and Food Science, Universidad Autónoma de Madrid, Av. Francisco Tomás y Valiente 7, 28049 Madrid, Spain.
Department of Physical and Analytical Chemistry, Facultad de Química, Universidad de Oviedo, Julian Clavería, 8, E-33006 Oviedo, Spain.
Plant Physiol Biochem. 2018 Apr;125:153-163. doi: 10.1016/j.plaphy.2018.01.033. Epub 2018 Feb 1.
A protective effect by silicon in the amelioration of iron chlorosis has recently been proved for Strategy 1 species, at acidic pH. However in calcareous conditions, the Si effect on Fe acquisition and distribution is still unknown. In this work, the effect of Si on Fe, Mn, Cu and Zn distribution was studied in rice (Strategy 2 species) under Fe sufficiency and deficiency. Plants (+Si or-Si) were grown initially with Fe, and then Fe was removed from the nutrient solution. The plants were then analysed using a combined approach including LA-ICP-MS images for each element of interest, the analysis of the Fe and Si concentration at different cell layers of root and leaf cross sections by SEM-EDX, and determining the apoplastic Fe, total micronutrient concentration and oxidative stress indexes. A different Si effect was observed depending on plant Fe status. Under Fe sufficiency, Si supply increased Fe root plaque formation, decreasing Fe concentration inside the root and increasing the oxidative stress in the plants. Therefore, Fe acquisition strategies were activated, and Fe translocation rate to the aerial parts was increased, even under an optimal Fe supply. Under Fe deficiency, +Si plants absorbed Fe from the plaque more rapidly than -Si plants, due to the previous activation of Fe deficiency strategies during the growing period (+Fe + Si). Higher Fe plaque formation due to Si supply during the growing period reduced Fe uptake and could activate Fe deficiency strategies in rice, making it more efficient against Fe chlorosis alterations. Silicon influenced Mn and Cu distribution in root.
硅在改善缺铁症方面的保护作用最近已被证明对策略 1 物种在酸性 pH 值下有效。然而，在石灰性条件下，硅对铁吸收和分布的影响仍不清楚。在这项工作中，研究了硅对铁、锰、铜和锌在水稻（策略 2 物种）中的分布的影响，这些水稻处于铁充足和缺铁两种状态下。最初向植物（+Si 或-Si）中添加铁，然后从营养液中去除铁。然后使用包括 LA-ICP-MS 图像在内的综合方法对植物进行分析，该方法对每个感兴趣的元素进行成像，通过 SEM-EDX 对根和叶横截面上不同细胞层的铁和硅浓度进行分析，并测定质外体铁、总微量元素浓度和氧化应激指标。观察到的硅效应因植物铁状态而异。在铁充足的情况下，硅供应增加了铁根斑的形成，降低了根内的铁浓度，并增加了植物的氧化应激。因此，铁获取策略被激活，铁向地上部分的转运率增加，即使在最佳铁供应下也是如此。在缺铁的情况下，与-Si 植物相比，+Si 植物从斑块中更快地吸收铁，这是由于在生长期间（+Fe+Si）激活了缺铁策略。生长期间硅供应导致的更高铁斑形成减少了铁的吸收，并可能在水稻中激活缺铁策略，使其更有效地应对铁失绿症的改变。硅影响了根中的锰和铜分布。
