Developmental control of apiogalacturonan biosynthesis and UDP-apiose production in a duckweed

Stephen C. Fry*, Anthony J. Trewavas

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Vegetative fronds of Spirodela polyrrhiza were induced to form dormant turions by the addition of 1 micromolar abscisic acid or by shading. The cell wall polymers of fronds contained a high proportion of the branched-chain pentose,D-apiose (about 20% of total noncellulosic wall sugar residues), whereas turion cell walls contained only trace amounts (about 0.2%). When the fronds were fed D-[3H]glucuronic acid for 30 minutes, the accumulated UDP-[3H]apiose pool accounted for about 27% of the total phosphorylated [3H]pentose derivatives; in turions, the UDP-[3H]apiose pool accounted for only about 4% of the total phosphorylated [3H]pentose derivatives. We conclude that the developmentally regulated decrease in the biosynthesis of a wall polysaccharide during turion formation involves a reduction in the supply of the relevant sugar nucleotide. One controlling enzyme activity is suggested to be UDP-apiose/UDP-xylose synthase. However, since there was a 100-fold decrease in the rate of polysaccharide synthesis and only a 9-fold decrease in UDP-apiose accumulation, there is probably also control of the activity of the relevant polysaccharide synthase.

Original languageEnglish
Pages (from-to)972-976
Number of pages5
JournalPlant physiology
Issue number3
Publication statusPublished - Jul 1989


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