Electron microprobe analysis of calcium solution penetration into milled pine bark particles

Abstract

Pine bark (Pinus taeda L. and P. elliottii Engelm.) pieces, 2.5 to 5.0 cm diameter, submerged in water became saturated more rapidly in a vacuum than at atmospheric pressure. A test was conducted to determine the extent of Ca solution penetration into smaller milled particles and the effect physical structure of particles has on this process. Particles 2.0–2.8 mm diameter were submerged in a solution of 1000 ppm Ca as Ca(OH)₂, placed in desiccators and evacuated to 150 mm Hg of tension. At intervals of 24, 48 and 96 hours samples were removed, freeze‐dried, and cut tangentially to expose the internal phloem. Electron microprobe x‐ray analysis initially showed different Ca concentration in peripheral and central zones and indicated that Ca solution had penetrated the particle and saturation was completed within 96 hours. The progression of Ca penetration was uniform from all edges and indicated that the varied structure of bark tissues did not impede water penetration.

Key words:

• Vacuum saturation
• wetting resistance

Notes

Graduate Student. Presently Assistant Professor, Plant and Soil Sciences Department, University of Massachusetts, Amherst, MA 01003.

Assistant Professor. Present Address: Department of Horticulture, University of Missouri, Columbia, MO 65211

Associate Professor.