Computer-Assisted Image Analysis of Tissues of Ethrel-Treated Pinus taeda Seedlings.

A microcomputer based video image analyzer is described and demonstrated in the analysis and comparison of tissue types of 6-month-old Ethrel-treated and control seedlings of loblolly pine (Pinus taeda L.). Two different programs were employed. ;Topographer I' sought, identified, and measured cell or resin canal lumen areas, and ;Area' measured tracheid length and silhouette areas. Ethrel treatment induced an increase in radial growth and a decrease in shoot elongation and needle growth. Bark production was stimulated by the same treatment. The tracheid lumens of Ethrel-treated plants were shorter and had a smaller cross-sectional area, whereas the tracheid cell walls increased in thickness. The treatment also increased resin canal formation in the xylem.