Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan.
Cormorant Group K.K., Minato, Japan.
Plant Biol (Stuttg). 2021 Sep;23(5):874-877. doi: 10.1111/plb.13279. Epub 2021 Jun 9.
After the nuclear accident in Fukushima Prefecture, Japan, in 2011, Caesium (Cs) contaminated nearby agricultural regions. Studies in these rice fields found that low K and high N fertilizer application enhanced Cs uptake in rice shoots. However, the influence of root and soil physics on these findings, as well as precise nutrient levels, remain to be clarified. We sought to analyse these relationships utilizing hydroponically grown rice plants. The rice plants were subjected to various concentrations of K and N nutrient solutions. We measured Cs allocation within the plants and performed transcript analyses using root tissues. Under low-K conditions, low-N plants accumulated less Cs in shoots and more in roots when compared to control-N conditions, even though overall Cs uptake remained unchanged. Expression analyses of root mRNAs showed that low-N plants accumulated reduced levels of OsAKT1 mRNA, encoding a K transporter. We also found a negative relationship between shoot Cs and K status in control-N but not in low-N conditions. Our results suggest that the application of N shifts Cs from roots into the shoots and that OsAKT1 in root vascular tissues influences Cs allocation. In practice, fine tuning N/K application and targeted breeding of K transporters might mitigate Cs contamination in rice plants.
2011 年日本福岛县核事故后，铯（Cs）污染了附近的农业区。在这些稻田的研究中发现，低钾高氮施肥会促进水稻幼苗吸收 Cs。然而，根和土壤物理特性以及精确的养分水平对这些发现的影响仍需阐明。我们试图利用水培水稻植物来分析这些关系。将水稻植物置于不同浓度的 K 和 N 营养溶液中。我们测量了植物内 Cs 的分配，并使用根组织进行了转录分析。在低钾条件下，与对照-N 条件相比，低-N 植物在地上部分积累的 Cs 较少，而在根部分积累的 Cs 较多，尽管总 Cs 吸收量保持不变。根 mRNA 的表达分析表明，编码 K 转运体的 OsAKT1 mRNA 在低-N 植物中积累减少。我们还发现，在对照-N 条件下，地上部 Cs 与 K 状态呈负相关，但在低-N 条件下则没有。我们的结果表明，N 的施加将 Cs 从根部转移到地上部，而根维管束组织中的 OsAKT1 影响 Cs 的分配。在实践中，精细调整 N/K 的施加和 K 转运体的靶向培育可能会减轻水稻植株中的 Cs 污染。
