作者： WEI WANG1,2, XUE QIANG ZHAO1, RONG FU CHEN1, XIAO YING DONG1, PING LAN1, JIAN FENG MA1,3 andREN FANG SHEN1

1State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China

2University of Chinese Academy of Sciences, Beijing, China

3Institute of Plant Science and Resources, Okayama University, Kurashiki, Japan

 

摘要：The phytotoxicity of aluminium (Al) ions can be alleviated by ammonium (NH4+) in rice and this effect has been attributed to the decreased Al accumulation in the roots. Here, the effects of different nitrogen forms on cell wall properties were compared in two rice c*rs differing in Al tolerance. An in vitro?Al-binding assay revealed that neither NH4+ nor NO3− altered the Al-binding capacity of cell walls, which were extracted from plants not previously exposed to N sources. However, cell walls extracted from NH4+-supplied roots displayed lower Al-binding capacity than those from NO3−-supplied roots when grown in non-buffered solutions. Fourier-transform infrared microspectroscopy analysis revealed that, compared with NO3−-supplied roots, NH4+-supplied roots possessed fewer Al-binding groups (-OH and COO-) and lower contents of pectin and hemicellulose. However, when grown in pH-buffered solutions, these differences in the cell wall properties were not observed. Further analysis showed that the Al-binding capacity and properties of cell walls were also altered by pHs alone. Taken together, our results indicate that the NH4+-reduced Al accumulation was attributed to the altered cell wall properties triggered by pH decrease due to NH4+ uptake rather than direct competition for the cell wall binding sites between Al3+ and NH4+.

 

關(guān)鍵詞：Al-binding capacity;nitrate;pH