1 / 26

Plant Nitrogen Assimilation and Use Efficiency

Plant Nitrogen Assimilation and Use Efficiency. 03/21/2012. relative amount of nitrate. Nonlegume plants: 20–50 g of N 1 kg of dry biomass 44 million tons for 9 billion people by 2050. ( Dechorgnat J, et al., 2011) . Pathway of nitrogen from rhizosphere to seeds. N efflux and

hasad
Download Presentation

Plant Nitrogen Assimilation and Use Efficiency

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Plant Nitrogen Assimilationand Use Efficiency 03/21/2012

  2. relative amount of nitrate • Nonlegume plants: 20–50 g of N 1 kg of dry biomass • 44 million tons for 9 billion people by 2050 (Dechorgnat J, et al., 2011)

  3. Pathway of nitrogen fromrhizosphere to seeds • N efflux and • N transportation and remobilization • N assimilation • N acquisition • Rhizosphere

  4. N forms and concentration changes in Rhizosphere • aerobic soils nitrate • flooded/acidic soils ammonium (Kirk GJD, Kronzucker HJ. 2005)

  5. Nitrogen acquisition low external concentrations (1 μM to 1 mM) • transport system : • high affinity transport system (HATS) • constitutive system (cHATS) • inducible system (iHATS) • low affinity transport system (LATS)

  6. Nitrogen assimilation (Masclaux-Daubresse C, et al., 2010)

  7. Nitrogen remobilization • 95% of seed protein is derived from amino acids

  8. Nitrogen transportation • NTR1s: nitrate transporter (Kirk GJD, Kronzucker HJ. 2005)

  9. Nitrogen efflux • ATP-dependant H+-pumping activity • low-affinity (Kirk GJD, Kronzucker HJ. 2005)

  10. Volatile nitrogen losses • imbalance between N accumulation and N assimilation • gaseous N losses: 40 kg of N/ha (soybean and maize)

  11. outline • GENETICALLY CONTROLLED DIFFERENCES IN NITROGEN USE EFFICIENCY • AGRONOMY EFFICIENCY OF SOIL NITROGEN AND FERTILIZER NITROGEN

  12. Natural Variation in DifferentGenotypes of the Same Plant Species • Genetic variation • total N uptake • postanthesisN uptake • N translocation • N assimilation • Accurate fertilizer Nfor different cultivars • developmental stages • harveststage Ex: tillers, HI↑ NpUE↑

  13. Favorable alleles for breeding • N uptake & remobilization genes are independently inherited traits • Modulating the activities of enzymes which related to high NUE • Ex:GS1&GS2in wheat

  14. Variation of Nitrogen Use Efficiency at Limited and Sufficient Nitrogen Conditions • genotype & genotype N fertilization level

  15. Strategy of breeding high-NUE cultivars • high-yield breeding in Chinese maize Root growth was improved only under N-sufficient conditions • root growth traits have been inadvertently selected to adapt to the increasing N supply in the environment • Genetical materials of Arabidopsis was unaffected by N supply levels at the vegetative stage • breeding high-NUE cultivars should occur under conditions of moderate N supply

  16. AGRONOMY EFFICIENCY OF SOIL NITROGEN AND FERTILIZER NITROGEN • Soil and Fertilizer Nitrogen Use Efficiency • Integrated Nutrient Management in Intensive Agriculture

  17. Soil and Fertilizer Nitrogen Use Efficiency • Mismatching of N availability with crop needs is probably the single greatest contributor to excess N losses Soil surface • Leaching • Ground water • Denitrification to N2 • Soil erosion Fluxes to atomosphere Volatilization

  18. fertilizer application • Base on leaf chlorophyll level & N concentration deep placement, controlled release materials multiple-split applications • biological sources of supplement fertilizer N Azollaand legumes

  19. Integrated Nutrient Management in Intensive Agriculture • management tools Rotations Intercropping perennial crops • site-specific conditions to decrease N losses and optimize crop performance • remote sensing of the visible light reflected

  20. Root & NUE In previous review • a root system that is more efficient at taking up N • maintaining root activity enhance NUpE Nitrate and ammonium transporter (NRT, AMT) (Werner, 2010)

  21. Cytosolic pH Balance Rice prefer ammonium than nitrate • alkalinization in the cytoplasm • influences pH homeostasis • ammonium and nitrate uptake

  22. A tonoplastdicarboxylate (malate and fumarate) transporter (AttDT) • C-N metabolism • pH balance, N & organic acid metabolism

  23. Increasing Yield and Nitrogen Harvest Index • NUpEN losses from soil • NUtEand NpUEN concentration • Target : improve the grain yield per unit of N application • A low seed N concentration • HI and NHI are highly correlated

  24. Gln1-3 : specific to grain production (Martin, 2006) • Gpc-B1 :enhancing N remobilization from source leaves to the seeds (Uauy, 2006) • Asnsynthetase 1 : enhancing HI and N remobilization from vegetative tissues to the seeds (Masclaux-Daubresse, 2010)

More Related