Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki 710-0046, Japan.
Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki 710-0046, Japan.
Trends Plant Sci. 2014 Sep;19(9):556-63. doi: 10.1016/j.tplants.2014.05.007. Epub 2014 Jun 19.
Mineral elements, including both essential and toxic elements, are delivered to different tissues after they are taken up from the roots, but the mechanism (or mechanisms) underlying the distribution remains poorly understood. In graminaceous plants, this distribution occurs in nodes, which have a complex, well-organized vascular system. A transfer of mineral elements between different vascular bundles is required, especially for preferential distribution to developing tissues that have low transpiration but high nutrient requirements. This intervascular transfer is mediated by various transporters localized at different cells in the node. In this opinion article, we propose four modes of distribution for different mineral elements: xylem-switch, phloem-tropic, phloem-kickback, and minimum-shift, based on specific molecular transport processes identified in the nodes mainly of rice (Oryza sativa). We also discuss the prospects for future studies on mineral nutrient distribution in the nodes.
矿物质元素，包括必需元素和有毒元素，在从根部吸收后被输送到不同的组织中，但它们的分配机制仍不清楚。在禾本科植物中，这种分配发生在节点中，节点具有复杂、组织良好的脉管系统。不同脉管束之间需要进行矿物质元素的转移，特别是对于优先分配到蒸腾作用低但营养需求高的发育组织。这种脉间转移是由定位在节点不同细胞中的各种转运蛋白介导的。在这篇观点文章中，我们根据在主要是水稻（Oryza sativa）节点中确定的特定分子运输过程，提出了四种不同矿物质元素的分配模式：木质部转换、韧皮部取向、韧皮部反冲和最小移位。我们还讨论了未来在节点中研究矿物质养分分配的前景。
