@article{oai:nagoya.repo.nii.ac.jp:00007240, author = {OMATA, Tatsuo}, journal = {農学国際協力}, month = {Jul}, note = {Nitrogen is one of the major elements that limit plant growth and productivity in both natural environments and plowed fields. To increase the harvest yield, nitrogen fertilizers are widely used in agriculture. The form of nitrogen commonly used as fertilizer is ammonium (NH_4^+), but in temperate aerobic soils, ammonium is rapidly oxidized to nitrate (NO_3^-) by nitrification. The resulting nitrate hence serves as the major source of nitrogen for most cultivated plants. Nitrate is, however, known to cause environmental and health problems. This paper summarizes current knowledge about the critical steps that determine the nitrate flow in plants and discusses possible strategies for improving the nitrate use efficiency.}, pages = {59--60}, title = {Control of Nitrate Uptake/Assimilation and Plant Productivity}, volume = {4}, year = {2004} }