Comparative study of N uptake and distribution in three lines of common bean (Phaseolus vulgaris L.) at early pod filling stage

• Published in: Plant and soil 1986-02, Vol.93 (1), p.79-86
• Main Authors: DUBOIS, J.D., BURRIS, R.H.
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Atoms; Beans; Biological and medical sciences; Economic plant physiology; Fructification, ripening. Postharvest physiology; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Growth and development; Mineral nutrition; Nitrogen; Nitrogen fixation; Nodules; Nutrition. Photosynthesis. Respiration. Metabolism; Plant roots; Plants; Seeds; Soil-plant relationships. Soil fertility. Fertilization. Amendments; Soybeans; Stems
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/bf02377147

The uptake and distribution of ¹⁵NH⁺₄, ¹⁵NO⁻₃ and ¹⁵N₂ was studied in greenhousegrown beans (Phaseolus vulgaris L.)⁻with a commercial cultivar and 2 recombinant inbred backcross lines; ¹⁵N was supplied in the nutrient solution at the R3 (50% bloom) stage. Plants were harvested 1, 5 and 10 days after treatment, and were separated into nodules, roots, stems, mature leaflets, immature leaflets, and flowers/fruits. All 3 lines showed rapid increases in the N content of flowers/fruits after the R3 stage. However, the percentage N in these tissues decreased after the R3 stage. One of the recombinant lines showed a greater uptake of NH⁺₄ than the other 2 lines. Rates of ¹⁵N₂ fixation and NO⁻₃ uptake were similar for all 3 lines. N₂ fixation estimated from total N content showed the 2 recombinant lines with 24 and 34 percent greater activity than the commercial cultivar. Distribution of ¹⁵N at the whole plant level was similar for all 3 lines for a similar N source. ¹⁵NO⁻₃ was transported first to leaflets and the label then moved into flowers/fruits. Transport of fixed N₂ was from the nodules to roots, stems and into flowers/fruits; usually less than 10 percent entered the leaflets. This indicates that N₂ fixation furnishes N directly to flowers/fruits with over 50 percent of the fixed N being deposited into flowers/fruits within 5 days after treatment.