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
 Crops Pathology and Genetics Research: Davis, CA
 close



    Research

                    Research Projects
                                    Publications
                                    Collaborations
                                    News
                People

                    Staff Listing
                                    Careers


        


                    Outreach Events
                        UC Davis Picnic Day
                                    Kinders go to College
                                    STEM Girls
                                    Future Scientist Program
                                    Agriculture Future of America
                                    Wallace-Carver Fellowship
                                    Young Scholars Program
                                    Annual Awards Banquet
                    About Us
                        About Us
                                    Our Mission
                                    Principal InvestigatorsSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Pacific West Area Davis, California Crops Pathology and Genetics 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
- Etiology and Biology of Tree Crop Diseases
- Rice Genetics
- Sustainable Floriculture
- Sustainable Viticulture

Title:   Author  item
                                            CHENG, XIAOMEI - UCD PLANT PATHOLOGYitem
                                            Baumgartner, Kendra
  Submitted to: Soil Biology and Biochemistry
                                    Publication Type: Peer Reviewed Journal
                                    Publication Acceptance Date: 3/14/2006
                                    Publication  Date: 5/11/2006
                                    Citation: Cheng, X., Baumgartner, K. 2006. Effects of mycorrhizal roots and extraradical hyphae on 15N uptake from vineyard cover crop litter and the soil microbial community. Soil Biology and Biochemistry. 38:2665-2675.Interpretive Summary: The goal of our study was to investigate the roles of arbuscular mycorrhizal (AM) fungi in absorption of nutrients by grapevines, which are known to be dependent on AM fungi for adequate nutrition. To this end, we compared the relative contributions of mycorrhizal roots (the mycorrhizosphere) and extraradical hyphae (the hyphosphere) to nutrient uptake from cover crop litter labeled with a stable isotope of nitrogen, 15N, in specially-designed containers in the greenhouse. In addition, we examined the response of the soil microbial community to the cover crop litter under the influence of the mycorrhizosphere and the hyphosphere, using phospholipid fatty acid (PLFA) analyses. Collectively, both of the methods provided evidence of the important roles of AM fungi in utilizing nutrients from cover crops. AM fungi significantly increased the uptake of 15N in grapevines, relative to our bulk soil treatment, in which neither roots nor hyphae had direct access to the cover crop litter. We also found that the AM fungi supported a soil microbial community that responded similarly to addition of the cover crop litter, as did the soil microbial community supported by the mycorrhizal roots. Our findings demonstrate the significance of AM fungi in supporting other soil microbes, a topic that is of interest to researchers who study mycorrhizal fungi, but of which there is little substantive evidence.
                                Technical Abstract: The objectives were to quantify the contribution of arbuscular mycorrhizal (AM) fungal hyphae to 15N uptake from vineyard cover crop litter, and to examine the soil microbial community under the influence of the mycorrhizosphere and the hyphosphere.  Mycorrhizal grapevines were grown in containers, within which mesh cores were vertically inserted.  The mesh allowed mycorrhizal roots (mycorrhizosphere treatment), extraradical hyphae (hyphosphere treatment), or neither (bulk soil treatment) to access 15N-labeled cover crop litter placed inside the cores.  Grapevines and soil were harvested 0, 7, 14, and 28 days after addition of the litter.
Extraradical hyphae increased 15N uptake from the cover crop litter, but their contribution relative to that of the mycorrhizal roots was small.  We detected similar peaks in soil microbial biomass in the hyphosphere and mycorrhizosphere treatments after addition of the cover crop litter, despite significantly lower microbial biomass in the hyphosphere treatment initially.
Our results suggest that although grapevine roots play a dominant role in the direct uptake of nutrients from a decomposing cover crop, AM hyphae may have a more important role in maintaining soil microbial communities associated with nutrient cycling.


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