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Wang, Wei-Hong; Liu, Guo-Wei; Liu, Lai-Hua等. Inadequate root uptake may represent a major component limiting rice to use urea as sole nitrogen source for growth
发布日期:2013-03-26浏览次数: 字号:[ ]

标题:Inadequate root uptake may represent a major component limiting rice to use urea as sole nitrogen source for growth

作者:Wang, Wei-Hong; Liu, Guo-Wei; Liu, Lai-Hua等

出版物:Plant and soil (2013) 363: 191-200

摘要:

Background and aims: Urea represents over 50 % of nitrogen fertilizers applied worldwide to crop production, however one-third of nitrogen fertilized could be recovered by crops. Previous studies have provided useful knowledge of urea-related plant nitrogen nutrition, whereas information about crop growth response to urea without its external degradation seems limiting. We thus assess the ability of rice seedlings to use urea at a physiological level.

Methods: Rice growth on urea versus other nitrogen regimes was tested under aseptic conditions. Activity of urease and GS was analyzed; urea, ammonium, total nitrogen and expression of a nitrogen limitation responsive gene OsDUR3 were examined.

Results: Growth phenotyping revealed urea-dose-dependent growth improvement but significant growth reduction associated with nitrogen-deficiency of plants compared to those on other nitrogen-sources, indicating a physiological impediment of effective urea utilization by rice. Enzymatic assay showed that activities of urease and GS were well expressed in plants supplied with urea. Low concentrations of urea and ammonium were detected in rice (particularly in roots) on 1 mM urea or other nitrogen-forms, and a less nitrogen-content was determined in urea-fed plants. Additionally, the strongest OsDUR3-expression occurred in seedlings on no nitrogen or 1 mM urea.

Conclusions: We suggest that insufficient urea absorption but not assimilation represents likely a factor constraining rice to use urea as sole nitrogen-source.

 

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