Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If you need an accessible version of this item please contact JSTOR User Support

Carbohydrate Physiology of Mycorrhizal Roots of Beech. III. Movement of Sugars Between Host and Fungus

D. H. Lewis and J. L. Harley
The New Phytologist
Vol. 64, No. 2 (Jun., 1965), pp. 256-269
Published by: Wiley on behalf of the New Phytologist Trust
Stable URL: http://www.jstor.org/stable/2429913
Page Count: 14
  • Read Online (Free)
  • Subscribe ($19.50)
  • Cite this Item
If you need an accessible version of this item please contact JSTOR User Support
Carbohydrate Physiology of Mycorrhizal Roots of Beech. III. Movement of Sugars Between Host and Fungus
Preview not available

Abstract

In order to test the relevance of previous results of this series to conditions operative in the intact plant, a technique was devised to simulate translocation of sucrose to mycorrhizal roots and to determine its morphological and biochemical destinations by the use of [14C]sugar. It was shown that the fungus can absorb sugar from the host and that its chemical destination is essentially similar to that of exogenous sucrose, namely a synthesis of mannitol, trehalose and glycogen. In connection with the possibility of reciprocal flow from fungus to host, the ability of uninfected roots to utilize the soluble sugars of the fungus was tested. Whereas mycorrhizas readily absorb and metabolize mannitol and trehalose, uninfected roots have almost no ability to utilize mannitol and are restricted in their utilization of trehalose, throwing considerable doubt on the possibility of sugar absorption by host from fungus. The hypothesis is developed that the fungus absorbs carbohydrates from the host and transforms them into reserve substances peculiar to itself, so maintaining a concentration gradient with respect to the host carbohydrate. The mycorrhizal system has the added advantage to the fungus that its reserve sugars are not readily re-available to the host. As polyols are abundant in many angiosperm parasites, the physiology of polyols in general is reviewed with the conclusion that the role postulated for this class of compound in mycorrhizas may be applicable to host-parasite relations in general.

Page Thumbnails

  • Thumbnail: Page 
256
    256
  • Thumbnail: Page 
257
    257
  • Thumbnail: Page 
258
    258
  • Thumbnail: Page 
259
    259
  • Thumbnail: Page 
260
    260
  • Thumbnail: Page 
261
    261
  • Thumbnail: Page 
262
    262
  • Thumbnail: Page 
263
    263
  • Thumbnail: Page 
264
    264
  • Thumbnail: Page 
265
    265
  • Thumbnail: Page 
266
    266
  • Thumbnail: Page 
267
    267
  • Thumbnail: Page 
268
    268
  • Thumbnail: Page 
269
    269