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Comparative kinetic analysis of ammonium and nitrate acquisition by tropical lowland rice: implications for rice cultivation and yield potential
Author(s) -
KRONZUCKER H. J.,
GLASS A. D. M.,
SIDDIQI M. Y.,
KIRK G. J. D.
Publication year - 2000
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1046/j.1469-8137.2000.00606.x
Subject(s) - nitrate , oryza sativa , ammonium , agronomy , yield (engineering) , ammonium nitrate , biology , nitrogen , crop , environmental science , chemistry , ecology , materials science , biochemistry , organic chemistry , metallurgy , gene
Nitrogen limitation compromises the realization of yield potential in cereals more than any other single factor. In rice, the world's most important crop species, the assumption has long been that only ammonium‐N is efficiently utilized. Consequently, nitrate utilization has been largely ignored, although fragmentary data have suggested that growth could be substantial on nitrate. Using the short‐lived radiotracer 13 N, we here provide direct comparisons of root transmembrane fluxes and cytoplasmic pool sizes for nitrate‐ and ammonium‐N in a major variety of Indica rice ( Oryza sativa ), and show that nitrate acquisition is not only of high capacity and efficiency but is superior to that of ammonium. We believe our results have implications for rice breeding and molecular genetics as well as the design of water‐management and fertilization regimes. Potential strategies to harness this hitherto unexplored N‐utilization potential are proposed.