What are Tyloses?
Tyloses (singular – tylosis) are the balloon like outgrowth of parenchymatous cells to the lumen of tracheids or vessels of the secondary xylem.
The axial and ray parenchyma of the xylem develops protrusion and these protrusions enter or invade into the lumen of tracheids or vessels through pits. This invasion of parenchyma occurs when tracheids or vessels become inactive or damaged.
Who discovered Tyloses?
Malpighi (1686) for the first time reported the ‘balloon-shaped sacs’ in the lumen of vessels of heartwood and he named it as tyloses based on the Greek word ‘Thyllen’ meaning ‘bag’ or ‘container’.