Abstract：
An urgent challenge within crop production is to maintain productivity in a world plagued by climate change and its associated plant stresses, such as heat, drought and salinity. A key factor in this endeavor is to understand the dynamics of root suberization, and its role in plant-water relations and nutrient transport. This study focuses on the hypothesis that endodermal suberin, acts as a physical barrier preventing radial potassium (K) movement out of the vascular tissues during translocation. Previous attempts to experimentally support this idea have produced inconsistent results. We developed a Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) method, allowing us to visualize the distribution of mineral elements and track K movement. Cesium (Cs), dosed in optimized concentrations, was found to be an ideal tracer for K, due to its low background and similar chemical/biological properties. In suberin mutants of Arabidopsis thaliana, we observed a positive correlation between suberin levels and K translocation efficiency, indicating that suberin enhances the plant\'s ability to retain K within the vascular tissues during translocation from root to shoot. In barley (Hordeum vulgare), fully suberized seminal roots maintained higher K concentrations in the stele compared to younger, less suberized root zones. This suggests that suberization increases with root maturity, enhancing the barrier against K leakage. In nodal roots, suberin was scattered towards the phloem in mature root zones. Despite this incomplete suberization, nodal roots still restrict outward K movement, demonstrating that even partial suberin barriers can significantly reduce K loss. Our findings provide evidence that suberin is a barrier to K leakage during root-to-shoot translocation. This understanding is crucial to maintain crop productivity in the face of climate change.
摘要：
作物生产中的一个紧迫挑战是在受气候变化及其相关植物胁迫困扰的世界中保持生产力。比如热，干旱和盐度。这项工作的一个关键因素是了解根茎化的动态，及其在植物-水关系和养分运输中的作用。这项研究的重点是内胚层亚蛋白，充当物理屏障，防止在易位过程中放射状钾（K）移出血管组织。以前在实验上支持这一想法的尝试产生了不一致的结果。我们开发了激光烧蚀-电感耦合等离子体质谱（LA-ICP-MS）方法，使我们能够可视化矿物元素的分布并跟踪K的运动。铯（Cs），以优化的浓度给药，被发现是K的理想示踪剂，由于其低背景和相似的化学/生物学特性。在拟南芥的suberin突变体中，我们观察到suberin水平与K易位效率之间呈正相关，表明suberin在从根到芽的易位过程中增强了植物在维管组织中保留K的能力。在大麦（大麦）中，与年轻相比，完全深化的精根在石碑中保持较高的K浓度，根区较少。这表明随着根成熟度的增加，增强防止K泄漏的屏障。在节点根中，suberin散布在成熟根区的韧皮部。尽管这种不完全的suberization,节根仍然限制了向外的K运动，证明即使是部分地下屏障也可以显着降低K损失。我们的发现提供了证据，表明suberin是根到茎易位过程中K泄漏的障碍。这种理解对于面对气候变化保持作物生产力至关重要。
