RESTRICTED LATERAL GAS MOVEMENT IN PINUS-STROBUS BRANCHES

Argon gas was incorporated into the sap flowing through xylem of cut b ranches, or added to the air in a sealed cuvette surrounding a needle- free portion of the branch to investigate lateral movement of gases in Pinus strobus, Microdialysis was used to sample air in the xylem and evacuated vials were used to collect samples of air from cuvettes atta ched to branches. Argon concentrations of samples of air were measured by GC-MS. When argon was added through the sap, concentrations of arg on in the xylem and in air of chambers enclosing needle stumps was gre ater than that of controls, but argon concentrations of air in cuvette s enclosing a needle-free portion of the branch were not greater than controls. When argon was added to cuvettes enclosing a needle-free por tion of the branch, the argon did not enter the xylem and it was not e mitted by needle stumps.