Developmental changes in carbohydrate partitioning and translocation in celery (Apium graveolens L. )

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1987

OSTI ID:6079281

Davis, J M

The major photoassimilates and translocated carbohydrates in celery (Apium graveolens L.) are sucrose and mannitol. /sup 14/CO/sub 2/ pulse-chase labeling studies were conducted to determine if carbon partitioning between and translocation of mannitol and sucrose change with leaf development. After a 10 min pulse and 10 min chase the proportion of /sup 14/C fixed into mannitol increased with leaf maturation whereas that in sucrose remained fairly constant. In contrast, mannitol content was high in all leaves but sucrose content rose as leaves developed. Activities of various enzymes important in sucrose and mannitol metabolism also increased with leaf maturity. After a 1 or 2 h chase, export of /sup 14/C-mannitol, relative to /sup 14/C-sucrose, was also lower in expanding leaves than older leaves, but there was more label in sucrose than mannitol in all petioles. Labeling patterns were different in the light and dark, which was investigated further by following the disappearance of soluble /sup 14/C-carbohydrates from mature leaves during an extended chase in the light or dark. Efflux curves for /sup 14/C-sucrose and /sup 14/C-mannitol from leaf discs that had been incubated with the /sup 14/C-sugars provided further evidence for both of these claims. A diurnal study revealed that mannitol and sucrose remained fairly constant in young and old leaves, but in mature leaves both exhibited diurnal fluctuations; sucrose more so than mannitol.

• Research Organization: Washington State Univ., Pullman (USA)
• OSTI ID: 6079281
• Country of Publication: United States
• Language: English

Related Subjects

550501* -- Metabolism-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AGE DEPENDENCE
CARBOHYDRATES
CARBON 14 COMPOUNDS
CELL DIFFERENTIATION
DAILY VARIATIONS
DISACCHARIDES
ELECTROMAGNETIC RADIATION
ENZYME ACTIVITY
FOOD
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LEAVES
MEMBRANE TRANSPORT
METABOLISM
OLIGOSACCHARIDES
ORGANIC COMPOUNDS
PLANTS
RADIATIONS
SACCHARIDES
SACCHAROSE
TRACER TECHNIQUES
VARIATIONS
VEGETABLES
VISIBLE RADIATION