Tylosis Formation in Pinus Tracheids

Abundant tyloses were discovered in the stem xylem of Pinus elliottii Engelm. and P. palustris Mill. following a combination of mechanical wounding and chemical treatment. Tyloses started from ray parenchyma and continued growing in vesicles of cells in tracheid lumens. Chemical stimulation, tracheid length, size and structure of bordered pits, and oleoresin saturation were restricting factors in tylosis development.