Nutrients are taken up by the fungus but rarely transported and transferred to the host in exactly the same form. Nitrogen is an example. NO3- can be transported directly but it is also moved via mass flow so that direct transport is generally less important in many agricultural ecosystems. On the other hand, NH4+ is an important resource provided by mycorrhizal fungi but cannot be transported as NH4+ within the fungal tissue because it is toxic. For that reason, NH4+ must be converted to glutamine (NH4+ plus glutamate) to be translocated through the fungal tissue and transfer to the plant. This is from my M.Sc thesis, the attached file.
A useful relatively recent and very relevant review of this is by Hu et al (2012) - link attached, sorry it's such a long URL - also identifies amino acid forms (glutamate, glutamine, asparagine, aspartate, alanine and arginine) as transfer forms within the AM fungi. Nitrate is very mobile but it is thought now that it is reduced and assimilated within the AM fungi rather than actually transferred to the plant (as previously thought).
http://download.springer.com/static/pdf/953/art%253A10.1007%252Fs11427-012-4330-y.pdf?originUrl=http%3A%2F%2Flink.springer.com%2Farticle%2F10.1007%2Fs11427-012-4330-y&token2=exp=1440191579~acl=%2Fstatic%2Fpdf%2F953%2Fart%25253A10.1007%25252Fs11427-012-4330-y.pdf%3ForiginUrl%3Dhttp%253A%252F%252Flink.springer.com%252Farticle%252F10.1007%252Fs11427-012-4330-y*~hmac=421cb701336306e56944c73f97df9b48d813894d42625eb559bd26d98f72a5db
- Badges
- Science topic
- Similar topics
- Medicine
- Disease
- Infectious Diseases
- Immunization
- Vaccination