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Molecular Weight and 14 C Distribution of Fructosan in Timothy Stem Bases at Three Stages of Development 1
Author(s) -
Kühbauch W.,
Soberalske R. M.
Publication year - 1977
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1977.0011183x001700020003xa
Subject(s) - elongation , anthesis , biology , phleum , botany , materials science , cultivar , metallurgy , ultimate tensile strength
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 14 CO 2 was investigated. Molecular weight distribution of 14 C‐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, M̄ a = 18,000 to M̄ n = 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, 14 C‐labeled fructosan appeared as early as 1 hour after exposure to 14 CO 2 with label distributed throughout the molecular weight range. High 14 C 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 14 C activity may explain the above observation.