Opportunities for increased nitrogen-use efficiency from improved lowland rice germplasm uri icon

abstract

  • Understanding of the mechanisms governing the efficient use of N by rice plants-both its acquisition and internal use-is reviewed. Acquisition efficiency is considered in terms of root properties influencing the absorption and assimilation of NH4+ and other N species, and their regulation; root-induced changes in the rhizosphere affecting N mineralization, transformation and transport; and root-associated biological N-2 fixation. Efficiency of internal use is considered in terms of the translocation, distribution and remobilization of absorbed N in different plant organs, flag leaf N import/export and leaf senescence patterns, and the efficiency with which N is used in CO2 fixation. Evidence for genetic variation in both acquisition efficiency and internal-use efficiency is given for plants under N-sufficient and N-limited conditions. The possibility of incorporating in rice the machinery for N-2 fixation is discussed. (C) 1998 Elsevier Science B.V.

publication date

  • 1998
  • 1998