1. Effects of supplemental nitrogen on nitrogen‐assimilation enzymes, free amino nitrogen, soluble sugars, and crude protein of rice
- Author
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J. R. Magalhães, Manlio Silvestre Fernandes, Sônia Regina de Souza, and Elvia Mariam Lis Martinez Stark
- Subjects
Nitrogen assimilation ,food and beverages ,Soil Science ,chemistry.chemical_element ,Free amino nitrogen ,engineering.material ,Nitrate reductase ,Nitrogen ,chemistry.chemical_compound ,Horticulture ,chemistry ,Agronomy ,engineering ,Urea ,Ammonium ,Fertilizer ,Sugar ,Agronomy and Crop Science - Abstract
An upland rice variety IAC‐47 was grown in a greenhouse to determine the effect of foliar nitrogen (N) supplementation during grain development on the activity of the N assimilation enzymes, nitrate reductase (NR) and glutamine synthetase (GS), on free amino‐N content and leaf soluble sugars, and on grain crude protein content. At 10 and 20 days after anthesis (DAA), the leaves were fertilized with a liquid fertilizer containing 32% N as 12.8% urea, 9.6% ammonium (NH4), and 9.6% nitrate (NO3) in increasing rates corresponding to 0,20+20, 40+40, and 60+60 kg N ha‐1. Leaves were collected twice (at 12 DAA and 14 DAA for GS activity, sugar and amino‐N content, and at 11 and 13 DAA for NRA) after each application of leaf N. The late foliar application of N increased significantly grain crude protein without a corresponding decrease in grain weight. The NR activity (NRA) increased after the foliar application of N. In the flag leaf, 60+60 kg N ha‐1 (21 DAA) resulted in higher NRA (20x over the control...
- Published
- 1999
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