1. Home
    2. Journals
    3. Journal of Biosciences
    4. Volume 31
    5. Issue 5

    • Fulltext

       

        Click here to view fulltext PDF


      Permanent link:
      https://www.ias.ac.in/article/fulltext/jbsc/031/05/0639-0643

    • Keywords

       

      Lichen; nitrogen fixation; rock weathering

    • Abstract

       

      It is known that cyanobacteria in cyanolichens fix nitrogen for their nutrition. However, specific uses of the fixed nitrogen have not been examined. The present study shows experimentally that a mutualistic interaction between a heterotrophic N2 fixer and lichen fungi in the presence of a carbon source can contribute to enhanced release of organic acids, leading to improved solubilization of the mineral substrate. Three lichen fungi were isolated fromXanthoparmelia mexicana, a foliose lichen, and they were cultured separately or with a heterotrophic N2 fixer in nutrient broth media in the presence of a mineral substrate. Cells of the N2-fixing bacteria attached to the mycelial mats of all fungi, forming biofilms. All biofilms showed higher solubilizations of the substrate than cultures of their fungi alone. This finding has bearing on the significance of the origin and existence of N2-fixing activity in the evolution of lichen symbiosis. Further, our results may explain why there are N2-fixing photobionts even in the presence of non-fixing photobionts (green algae) in some remarkable lichens such asPlacopsis gelida. Our study sheds doubt on the idea that the establishment of terrestrial eukaryotes was possible only through the association between a fungus and a phototroph.

    • Author Affiliations

       

      Gamini Seneviratne1 I K Indrasena1

      1. Biological Nitrogen Fixation Project, Institute of Fundamental Studies, Hantana Road, Kandy, Sri Lanka

    • Dates

       
      Published
      December 2006
      Manuscript revised
      30 May 2006
      Accepted
      11 November 2006

  • Journal of Biosciences | News

      Forthcoming Special issue.


    • To trigger further research on plant mitochondria, the Journal of Biosciences is bringing out a special issue titled "Plant Mitochondria: Properties and Interactions with Other Organelles".


      Plant mitochondria are quite distinct and have unique features, such as a cyanide-insensitive alternate pathway. They also interact with chloroplasts to optimize photosynthetic carbon assimilation.


      Submissions are welcome until 30 July 2023. The contributions can be original articles, short communications, reviews, or mini-reviews on any topic related to plant mitochondria.


      Authors can submit their articles online at https://www.editorialmanager.com/jbsc/default2.aspx

      Posted on April 12, 2023
      <

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

© 2022-2023 Indian Academy of Sciences, Bengaluru.

Contact | Site index