Send to

Choose Destination
See comment in PubMed Commons below
Plant Physiol. 1970 Mar;45(3):284-8.

Mobilization and Incorporation of Photoassimilated C by Growing Vegetative and Reproductive Tissues of Adult Pinus resinosa Ait. Trees.

Author information

  • 1Department of Forestry, University of Wisconsin, Madison, Wisconsin 53706.


Variations in translocation and incorporation of (14)C-labeled photosynthate in actively growing vegetative and reproductive tissues of 20-year-old Pinus resinosa trees with time were investigated. Five hours after exposure of 1-year-old needles on second order branches to (14)CO(2), 90% of the recoverable activity was still in the needles. The 1-year-old bark showed a small amount of activity, but terminal sinks had accumulated little (14)C. After 24 hours, activity in the 1-year-old needles decreased to 59% while actively growing terminal and lateral shoots and 2nd year cones had accumulated considerable tracer. Whereas activity in the 1-year-old bark increased, recovery from the 1-year-old wood was only 1.8%. After 1 week, relative activity in the 1-year-old needles had declined to 27%. Recovery of (14)C from various sinks was high and in the following order: 2nd year cones > terminal needles > lateral needles > terminal internode > lateral internodes > 1-year-old wood. Ninety per cent of the (14)C recovered after 5 hours was in the ethanol-soluble form, but by the end of 1 week only half was in the soluble fraction. Incorporation of tracer into insoluble compounds was high in expanding internodes and in 1-year-old xylem, and low in 2nd year cones. Total activity in the terminal internode generally declined toward the distal end while specific radioactivity increased. Only 5% of the (14)C recovered from cones was localized in developing seeds, but specific radioactivity of seeds was higher than in the cone scales and axis.

PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk