Molecular Weight and 14C Distribution of Fructosan in Timothy Stem Bases at Three Stages of Development1
- W. Kühbauch and
- R. M. Soberalske2
Variation in fructosan concentration in the stem base of timothy (Phleum pratense L.) at three stages of growth (initiation of stem elongation, ear emergence, and anthesis) from 1 to 168 hours after exposure to 14CO2 was investigated. Molecular weight distribution of 14C-labeled fructosan was determined. From initiation of stem elongation to anthesis, fructosan concentration increased from about 13 to almost 40%. In the first two growth stages, fructosan showed a broad molecular weight distribution, M̄a = 18,000 to M̄n = 2,000. There was a tendency by 168 hours after initiation of stem elongation for the plants to accumulate primarily higher molecular weight fructosan, while by ear emergence, there was a distinct accumulation of long-chain fructosan molecules. In all growth stages, 14C-labeled fructosan appeared as early as 1 hour after exposure to 14CO2 with label distributed throughout the molecular weight range. High 14C activity was found in long-chain fructosans by 168 hours after exposure at ear emergence and anthesis. Condensation of short-chain fructosans and synthesis of new fructosans using monosaccharides with high 14C activity may explain the above observation.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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