Display options
Share it on

Plant Physiol. 1979 Jul;64(1):94-8. doi: 10.1104/pp.64.1.94.

Partitioning of C-photosynthate, and long distance translocation of amino acids in preflowering and flowering, nodulated and nonnodulated soybeans.

Plant physiology

T L Housley, L E Schrader, M Miller, T L Setter

Affiliations

  1. Department of Agronomy, University of Wisconsin, Madison, Wisconsin 53706.

PMID: 16660923 PMCID: PMC543031 DOI: 10.1104/pp.64.1.94

Abstract

The influence of stage of development (preflowering versus flowering) in nodulated and nonnodulated soybeans (Glycine max [L.] Merr. cv. Wells) on partitioning of (14)C into assimilates following exposure of a soybean leaf to (14)CO(2) by both steady-state and pulse-labeling techniques was studied. Blades on the second fully expanded leaf from the stem apex were exposed to (14)CO(2). Radioactive assimilates were extracted from source leaf blades, petioles, and stems (both the path up and path down from source leaf), were separated into neutral (sugars), basic (amino acids), and acidic (organic acids, sugar phosphates) fractions by ion exchange chromatography. The basic fraction was further resolved using thin layer chromatography and the percentage of radioactivity recovered in each amino acid was determined.The distribution of radioactivity in the neutral, basic, and acidic fractions of the source leaf blades was significantly different from that of the transport path (petiole and stems). About 70% of the radioactivity in source leaf blades was recovered in the neutral fraction, whereas about 90% of the recovered radioactivity in the path was in the neutral fraction. (14)C-Aminoacids constituted 8 to 17% and 2 to 7% of the recovered radioactivity in source leaves and paths, respectively. Recovered (14)C in organic acids ranged from 13 to 20% and 2 to 7% in source leaves and paths, respectively. Partitioning of (14)C-assimilates among the neutral, basic, and acidic fractions was not affected by the presence of nodules or flowers. However, when steady-state labeling was compared to pulse labeling, a significantly lower percentage of (14)C was recovered in the neutral fraction with a concomitant increase in the basic fraction. Asparagine-arginine, serine, glutamate, gamma-aminobutyrate-alanine, and aspartate accounted for 69 to 85% of the recovered radioactivity in the basic fraction from the various treatments. [(14)C]Serine was significantly higher in pulse-labeling experiments, whereas glutamtate and proline were higher with steady-state labeling. [(14)C]Serine was significantly higher in nonnodulated plants than in nodulated plants, whereas gamma-aminobutyrate-alanine was significantly higher in preflowering plants as compared to flowering plants.

References

  1. Plant Physiol. 1964 Mar;39(2):269-73 - PubMed
  2. Arch Biochem Biophys. 1973 Aug;157(2):613-24 - PubMed
  3. Plant Physiol. 1977 Feb;59(2):217-20 - PubMed
  4. Plant Physiol. 1978 Nov;62(5):812-4 - PubMed
  5. Plant Physiol. 1970 Feb;45(2):114-8 - PubMed
  6. Plant Physiol. 1975 Dec;56(6):807-12 - PubMed
  7. Arch Biochem. 1950 Nov;29(1):179-86 - PubMed
  8. Plant Physiol. 1977 Mar;59(3):506-10 - PubMed
  9. Plant Physiol. 1970 Feb;45(2):107-13 - PubMed
  10. Plant Physiol. 1972 Jun;49(6):919-23 - PubMed
  11. Plant Physiol. 1956 Sep;31(5):323-9 - PubMed
  12. Plant Physiol. 1972 Feb;49(2):146-54 - PubMed

Publication Types