NMT历史上的今天丨Front Plant Sci：高铵抑制小麦根部钾吸收

2014年12月16日，山东省农科院孔令安用NMT在Frontiers in Plant Science上发表了标题为Effects of high NH4+ on K+ uptake, culm mechanical strength and grain filling in wheat的研究成果。

期刊：Frontiers in Plant Science

主题：高铵抑制小麦根部钾吸收

标题：Effects of high NH4+on K+ uptake, culm mechanical strength and grain filling in wheat

影响因子：4.495

检测指标：K+流速

作者：山东省农科院孔令安

英文摘要

It is well established that a high external  NH4+ concentration depresses many processes in plant development, but  the underlying mechanisms are still not well understood. To determine  whether the negative effects of high levels of NH4+ are related to  competitive cation uptake, wheat was grown in a field with moderate (18 g  N m−2) and high (30 g N m−2) supplies ofNH4+ in the presence or absence  of additional K+ (6 g K2O m−2) to examine culm mechanical strength, the  main components of the vascular bundle, nitrogen (N) remobilization and  the grain-filling rate.

The results indicated that an excessive  supply of NH4+ significantly decreased culm mechanical strength, the  cellulose and lignin contents of vascular bundles, the N remobilization  efficiency (NRE) and the grain-filling rate compared with a moderate  level of NH4+. The additional provision of K+ considerably alleviated  these negative effects of high NH4+, resulting in a 19.41–26.95%  increase in culm mechanical strength during grain filling and a 34.59%  increase in the NRE. An assay using the scanning ion-selective electrode  technique (SIET) showed that the net rate of transmembrane K+ influx  decreased by 84.62%, and measurements using flame photometry  demonstrated that the K+ content decreased by 36.13% in wheat plants  subjected to high NH4+.

This study indicates that the effects of  high NH4+ on culm mechanical strength, cellulose and lignin contents,  the NRE and the grain-filling rate are probably associated with  inhibition of K+ uptake in wheat.

中文摘要（谷歌机翻）

众所周知，外部NH4+  的高浓度会抑制植物发育中的许多过程，但其潜在机理仍未得到很好的理解。为了确定高水平的NH4+的负面影响是否与竞争性阳离子摄入相关，将小麦种植在提供适量（18  g N m-2）和大量（30 g N m-2）NH4+的田地上在存在或不存在额外的K+（6 g K2O  m-2）的情况下进行图4的测试，以检查茎秆机械强度，维管束的主要成分，氮（N）迁移和谷粒填充率。

结果表明，与中等水平的NH4+相比，过量供应NH4+会显着降低茎秆机械强度，维管束中纤维素和木质素的含量，氮的固定效率（NRE）和籽粒填充率。额外提供的K+大大减轻了高NH4+的这些负面影响，导致籽粒灌浆期间茎秆机械强度提高了19.41–26.95％，NRE增加了34.59％。使用扫描离子选择电极技术（SIET）进行的分析表明，跨膜K  +流入的净速率降低了84.62％，而使用火焰光度法的测量结果表明，在高NH4+的小麦植株中，K+含量降低了36.13％。。

这项研究表明，高NH4+对小麦茎秆机械强度，纤维素和木质素含量，NRE和籽粒充实率的影响可能与抑制小麦吸收K+有关。

(B) The effects of 10 mM NH4+ on the kinetics of the net K+ fluxes in  wheat root epidermal cells; each point is the mean from six individual  plants. (C) Each column presents
the mean values of the K+ fluxes  measured in the root epidermal cells over a recording period of 30 min.  Nm: moderate NH4+,Nh:10mM NH4+ treatment. The bars represent the  standard deviation for six individual plants. The different letters  indicated above each column refer to significant differences at the P  < 0.05 level.