Redistribution of boron in leaves reduces boron toxicity
Redistribution of boron in leaves reduces boron toxicity
复制标题
硼在叶子中的重新分布降低了硼的毒性
DOI：
10.4161/psb.4.11.9798
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发表时间：
2009
影响因子：
2.9
通讯作者：
Kate L. Fitzpatrick
中科院分区：
文献类型：
--
作者：
R. Reid;Kate L. Fitzpatrick
土壤硼(B)浓度高导致B在叶片中积累，导致叶尖和叶缘坏死区发育，并沿叶片逐渐向后延伸。植物对B毒性的耐受性差异很大，最近发现其中一种耐受性机制涉及从根中挤出B。一种编码根B外排转运蛋白的基因在耐受性品种中的表达量要高得多。在我们目前的研究中，我们已经表明，同样的基因在叶子中也被上调。然而，与根部不同的是，叶片中B外排转运体活性的增加并不能降低组织B浓度。相反，我们已经证明，在耐受性品种中，这些转运体将B从细胞内毒性阶段重新分配到对B不太敏感的外质体中。这些结果解释了为什么具有相同叶片B浓度的不同品种会表现出明显不同的毒性症状。我们还表明，雨水可以去除叶片B的很大一部分，导致叶片和根的生长都有显着改善。
High soil boron (B) concentrations lead to the accumulation of B in leaves, causing the development of necrotic regions in leaf tips and margins, gradually extending back along the leaf. Plants vary considerably in their tolerance to B toxicity, and it was recently discovered that one of the tolerance mechanisms involved extrusion of B from the root. Expression of a gene encoding a root B efflux transporter was shown to be much higher in tolerant cultivars. In our current research we have shown that the same gene is also upregulated in leaves. However, unlike in the root, the increased activity of the B efflux transporter in the leaves cannot reduce the tissue B concentration. Instead, we have shown that in tolerant cultivars, these transporters redistribute B from the intracellular phase where it is toxic, into the apoplast which is much less sensitive to B. These results provide an explanation of why different cultivars with the same leaf B concentrations can show markedly different toxicity symptoms. We have also shown that rain can remove a large proportion of leaf B, leading to significant improvements of growth of both leaves and roots.