Skip to main content
Plant Physiology logoLink to Plant Physiology
. 1972 Feb;49(2):198–202. doi: 10.1104/pp.49.2.198

Movement of 14C-Labeled Assimilates into Kernels of Zea mays L

I. Pattern and Rate of Sugar Movement 1

Jack C Shannon a,2
PMCID: PMC365928  PMID: 16657924

Abstract

Carbon-14, photosynthetically fixed in leaves of Zea mays L. and translocated to developing kernels, passed through specialized basal endosperm cells prior to movement into the starchy endosperm and embryo. Radioactivity migrated in the endosperm at a maximum rate of 2.7 millimeters per hour, and there was no difference in the rate of movement in kernels treated 14 to 30 days after pollination.

Sucrose contained over three-fourths of the radioactivity in the kernal base (fruit stalk) 1 to 6 hours after 14CO2 treatment of the plant. Conversely, in the basal endosperm three-fourths of the radioactivity was in glucose and fructose. A high proportion of the radioactivity was retained in the monosaccharides of the starchy endosperm the first 3 hours after the 14CO2 treatment. With additional time after treatment there was a decline in the percentage of radioactivity in the monosaccharides and an increase in sucrose-14C. From these data we suggest that translocated sucrose is cleaved to glucose and fructose during entry into the endosperm and that the monosaccharides diffuse throughout the endosperm. Once the sugars arrive in the cells active in starch synthesis, they are rapidly converted to sucrose which in turn is utilized in the synthesis of starch.

Full text

PDF
198

Images in this article

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Gunning B. E., Pate J. S., Briarty L. G. Specialized "transfer cells" in minor veins of leaves and their possible significance in phloem translocation. J Cell Biol. 1968 Jun;37(3):C7–12. doi: 10.1083/jcb.37.3.c7. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. PUTMAN E. W., HASSID W. Z. Sugar transformation in leaves of Canna indica. I. Synthesis and inversion of sucrose. J Biol Chem. 1954 Apr;207(2):885–902. [PubMed] [Google Scholar]
  3. Shannon J. C. Carbon-14 Distribution in Carbohydrates of Immature Zea mays. Kernels Following CO(2) Treatment of Intact Plants. Plant Physiol. 1968 Aug;43(8):1215–1220. doi: 10.1104/pp.43.8.1215. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Shannon J. C. Movement of C-Labeled Assimilates into Kernels of Zea mays L: II. Invertase Activity of the Pedicel and Placento-Chalazal Tissues. Plant Physiol. 1972 Feb;49(2):203–206. doi: 10.1104/pp.49.2.203. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Plant Physiology are provided here courtesy of Oxford University Press

RESOURCES