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

Frontiers in Plant Science

卷:5

Fahong eWang¹  Bo eFeng¹  Bin eZhang¹  Lingan eKong¹  Mingze eSun¹  Jia eLiu¹  Jisheng eSi¹  Shengdong eLi¹  Huawei eLi¹ 

[1] Crop Research Institute, Shandong Academy of Agricultural Sciences;

关键词: Ammonium (NH4+);    K+ flux;    N remobilization;    wheat (Triticum aestivum L.);    culm mechanical strength;   

DOI  :  10.3389/fpls.2014.00703

来源: DOAJ

【 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 of NH4+ 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.

【 授权许可】

Unknown