ISSN:
1399-3054
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
In contrast to the light-promoted uptake by mesophyll cells, light slightly inhibited sucrose uptake by stripped leaf disks of Commelina benghalensis L. This phenomenon appeared to result from a light-promoted vein-associated release, as light stimulated photosynthate release from stripped disks and inhibited that from mesophyll cells. In the -presence of the resorption-blocker p-chloromercuriphenylsulfonic acid, (PCMBS) the release of preloaded [14C]-sugars (sucrose, glucose) and [14C]-amino acids (alanine, asparagine, proline, valine, α-aminoisobutyric acid) from stripped disks was doubled in the light. Illumination enhanced by 20 to 60% the release of endogenous leaf cell compounds (sucrose, H2PO-4, K+, Mg2+, Ca2+) from stripped disks in the presence of PCMBS. Light also increased the export of [14C]-assimilates from intact leaves by 20% after pulse-labelling with 14CO2. A model for loading is proposed, based on the differential light sensitivities of the plasma membranes in the mesophyll-to-sieve tube path.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1399-3054.1986.tb02448.x
Permalink