U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 Plant Science Research: St. Paul, MN
 close



    Research

                    Research Projects
                                    Publications
                                    Collaborations
                                    News
                People

                    Staff Listing
                                    CareersSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Midwest Area St. Paul, Minnesota Plant Science Research Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications

Title:   Author  item
                                            Vance, Carrollitem
                                            Miller, Susanitem
                                            LIU, JUNQI - UNIVERSITY OF MINNESOTAitem
                                            GANTT, J - UNIVERSITY OF MINNESOTAitem
                                            Samac, Deborah

                                                         - *Debby*
  Submitted to: Meeting Abstract
                                    Publication Type: Abstract Only
                                    Publication Acceptance Date: 6/5/2005
                                    Publication  Date: 6/5/2005
                                    Citation: Vance, C.P., Miller, S.S., Liu, J., Gantt, J.S., Samac, D.A. 2005. Carbon and nitrogen metabolism in legume nodules. 2005 Model Legume Congress, June 5-9, 2005, Pacific Grove, California. Paper No. S32, p. 43.Interpretive Summary:
                                Technical Abstract: Nitrogen-fixing symbiotic root nodules of legumes are model factories for carbon (C) and nitrogen (N) metabolism. Although nodules generally comprise less than 3% of legume total biomass, they can catalyze the reduction of more than 100 kg N per hectare each year. Globally, some 60-90 Tg of N2 are fixed symbiotically each year, an amazing amount considering that only a few kgs of the microbial enzyme nitrogenase are involved in catalysis. Although root nodules comprise only a small proportion of plant weight, they consume 13-28% of legume total photosynthate. This striking use of C is because reduction of N2 to NH4+ requires a substantial energy input. Based upon the average of more than 30 studies, the legume plant expends some 6-7 grams of C per gram N reduced. The biological C cost of symbiotic N2 fixation is substantially higher than the theoretical C cost due to the intrinsic complexity of the symbiotic system including nodule growth and maintenance as well as plant N and C metabolism. It is, therefore, quite apparent that integration of N and C metabolism in root nodules plays a key role in legume plant N and C cycle as well as being critical for growth and development. Many genes involved in N and C metabolism show enhanced expression in nodules as compared to roots. These genes are involved in a multiplicity of processes occurring in infected and uninfected cells. They function in providing N and C for both plant and bacterial metabolism, nodule amino acid biosynthesis, adaptation to the low O2 environment of the nodule, and nodule osmotic adjustment. Modification of selected genes may be useful in enhancing N2 fixation and legume N metabolism.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov