Department of Crop Sciences, Division Quality of Plant Products, Carl-Sprengel-Weg 1, 37075 Göttingen, University of Göttingen, Göttingen, Germany.
Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences, Crop Science, Albrecht-Thaer-Weg 5, Humboldt-University of Berlin, Berlin, Germany.
Sci Rep. 2020 May 29;10(1):8796. doi: 10.1038/s41598-020-65896-z.
This study depicts relations between magnesium (Mg) transport and re-translocation, photoassimilate partitioning, cation and ion concentrations, and finally root growth of potato under different Mg supplies. Potato plants were grown in a hydroponic culture system under different Mg regimes while investigating Mg concentrations, the expression of various Mg transporters, soluble sugars, and cations and anions in source and sink organs at different growth stages. Reports from literature about the impact of Mg deficiency on root growth are inconsistent. As Mg is known to be a phloem mobile nutrient, it is expected to be re-translocated under restricted availability of Mg from source to sink organs. Thus, we assume that plants can tolerate a slight Mg restriction without severe root growth reduction. However, under severe Mg deficiency, the process of Mg re-translocation is hampered, resulting in an impaired photoassimilate partitioning, and finally root growth. This might also explain the findings of studies claiming that Mg deficiency does not impair root growth as plants of these studies likely only suffered a slight Mg restriction. Finally, this study gives indications that an interruption of the process of Mg-re-translocation in early plant growth could be an indicator for growth reductions of the plant at a later growth stage.
本研究描绘了镁（Mg）运输和再转运、光合产物分配、阳离子和离子浓度之间的关系，以及不同 Mg 供应下马铃薯根系生长的关系。在不同的 Mg 处理下，马铃薯植株在水培培养系统中生长，同时调查不同生长阶段源库器官中 Mg 浓度、各种 Mg 转运蛋白的表达、可溶性糖以及阳离子和阴离子。关于 Mg 缺乏对根生长影响的文献报道不一致。由于 Mg 被认为是韧皮部可移动的养分，因此预计在 Mg 供应受限的情况下，它会从源器官再转运到库器官。因此，我们假设植物可以在轻微的 Mg 限制下耐受，而不会严重减少根生长。然而，在严重的 Mg 缺乏下，Mg 再转运的过程受到阻碍，导致光合产物分配受损，最终导致根生长受损。这也可能解释了那些声称 Mg 缺乏不会损害根生长的研究结果，因为这些研究中的植物可能只受到轻微的 Mg 限制。最后，本研究表明，早期植物生长中 Mg 再转运过程的中断可能是植物在后期生长阶段生长减少的一个指标。
