Transport and use of CO sub 2 in the xylem sap of Populus deltoides

Conference · Tue May 01 04:00:00 EDT 1990 · Plant Physiology, Supplement; (USA)

OSTI ID:5841488

Stringer, J W; Kimmerer, T W ^[1]

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1. Univ. of Kentucky, Lexington (USA)

Results of recent experiments indicate an internal cycling of respiratory CO{sub 2} in woody plants. The CO{sub 2} concentration of xylem sap expressed from the twigs of field grown Populus deltoides ranged from .14 to .50 mM. The pH of the xylem sap was 5.7 to 6.7, providing a significant bicarbonate concentration in many samples. Total dissolved inorganic carbon (DIC = CO{sub 2} + H{sub 2}CO{sub 3} + HCO{sub 3}{sup {minus}}) was 0.5 mM to 1.3 mM. Results from the analysis of xylem sap of 10 other species of woody plants were similar. To determine the fate of DIC delivered to the leaves of Populus deltoides, excised leaves were fed 1mM NaHCO{sub 3} (2 {mu}Ci NaH{sup 14}CO{sub 3} ml{sup {minus}1}). Less than 0.4% of the label escaped from the leaves, and {ge}93% was fixed. Of the carbon fixed 56% of the {sup 14}C was found in the petiole and midrib, and 14% was in the major veins, with the remaining 30% in the minor veins and lamina. Shading of the peptiole and midrib of leaves decreased the amount of fixed carbon in these tissues to 38% and increased the amount in the lamina to 55%.

• OSTI ID: 5841488
• Report Number(s): CONF-9007196--
• Conference Information: Journal Name: Plant Physiology, Supplement; (USA) Journal Volume: 93:1
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
CARBON 14 COMPOUNDS
CARBON COMPOUNDS
CARBON CYCLE
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAGNOLIOPHYTA
MAGNOLIOPSIDA
OXIDES
OXYGEN COMPOUNDS
PLANTS
POPLARS
TRACER TECHNIQUES
TREES