This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Rodaway, S. Articles by Marcus, A. Search for Related Content PubMed PubMed Citation Articles by Rodaway, S. Articles by Marcus, A. Agricola Articles by Rodaway, S. Articles by Marcus, A.

Articles

Germination of Soybean Embryonic Axes

Nucleotide Sugar Metabolism and Initiation of Growth ¹

^a The Institute for Cancer Research, The Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111

UDP-Sugars comprise the dominant class of nucleotide sugars in isolated soybean axes during early germination. While "dry" axes contain 1 nanomole per axis of UDP-sugars, further synthesis is initiated upon imbibition such that the concentration of total UDP-sugars reaches 8 nanomoles per axis or roughly 1 millimolar after 10 hours, when the axes begin to elongate. The GDP-sugars are essentially absent before imbibition, accumulate rapidly for 90 min to 173 picomoles per axis, then decrease somewhat, reattaining the earlier peak level shortly before growth begins. Meanwhile, the level of ADP-sugars is unchanged. These data indicate that the 10-hour lag period preceding axis growth does not result from a diminished ability to synthesize a major category of nucleotide sugars.

Relative rates of synthesis of individual UDP- and GDP-sugars were determined by incorporation of [³H]uridine or [³H]guanosine. The distribution of label in the different classes of UDP-sugars and in the single class of GDP-sugar was quantitatively similar when analyzed before, at the onset, or during early growth. It therefore seems unlikely that synthesis of a key nucleotide sugar controls the initiation of growth.

The possible relevance of nucleotide sugars to growth is discussed and new methods for enzymic analysis of picomole levels of nucleotide sugars are described.