Role of Free Space in Translocation in Sugar Beet
Document Type
Article
Publication Date
12-1-1974
Publication Source
Plant Physiology
Abstract
The involvement of the free space in phloem loading of sucrose was studied in sugar beet source leaves (Beta vulgaris, L.). Sucrose, supplied exogenously to the abraded upper surface of leaves at a concentration of 20 mM, was available for translocation at rates similar to those obtained with photosynthesis. The exogenous sucrose substituted as a source of translocate for assimilate derived from photosynthesis when the latter process was disrupted by plasmolysis of the leaf with 0.8 M mannitol. The mesophyll symplast was not completely disrupted by this treatment, however. Data from the sugar uptake experiments indicate that phloem loading can occur from the free space. Isotope trapping of labeled sugars derived from 14CO2 was used to intercept and identify sugars passing through the free space prior to phloem loading. Increased translocation rates induced by 4 mM ATP or increased light intensity were accompanied by increased trapping of sucrose but not of glucose. The data support the view that sucrose passes into the free space prior to phloem loading.
Inclusive pages
892-898
ISBN/ISSN
0032-0889
Publisher
American Society of Plant Biologists
Volume
54
Peer Reviewed
yes
eCommons Citation
Geiger, Donald R.; Sovonick, Susan A.; Shock, Terri L.; and Fellows, Robert J., "Role of Free Space in Translocation in Sugar Beet" (1974). Biology Faculty Publications. 59.
https://ecommons.udayton.edu/bio_fac_pub/59
