Developmental control of apiogalacturonan biosynthesis and UDP-apiose production in a duckweed. [Spirodela polyrrhiza]
- Univ. of Edinburgh (England)
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-({sup 3}H)glucuronic acid for 30 minutes, the accumulated UDP-({sup 3}H)apiose pool accounted for about 27% of the total phosphorylated ({sup 3}H)pentose derivatives; in turions, the UDP({sup 3}H)apiose pool accounted for only about 4% of the total phosphorylated ({sup 3}H)pentose derivatives. They 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.
- OSTI ID:
- 7151028
- Journal Information:
- Plant Physiology; (USA), Vol. 90:3; ISSN 0032-0889
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
WEEDS
PHYSIOLOGY
AQUATIC ORGANISMS
CARBON 14 COMPOUNDS
CELL WALL
CHEMICAL COMPOSITION
ENZYME ACTIVITY
POLYSACCHARIDES
TRACER TECHNIQUES
TRITIUM COMPOUNDS
CARBOHYDRATES
CELL CONSTITUENTS
HYDROGEN COMPOUNDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
ORGANIC COMPOUNDS
SACCHARIDES
551001* - Physiological Systems- Tracer Techniques