Secondary Growth Flashcards
What is secondary growth?
Increase in girth.
Only dicots can undergo true secondary growth.
What are tree rings?
Rings that form from seasonal changes where the xylem is larger in warm water weather and smaller in cold dry weather.
What is late wood?
Smaller tighter cells, usually older
What is early wood?
Larger cells that move water
What is cavitation?
Where the cell can no longer conduct water and collapses in on itself
What is the vascular cambium?
Produces secondary phloem to the outside and secondary xylem to the inside
What are fusiform initials?
Gives rise to cells that transport vertically (xylem and phloem)
What are ray initials?
Gives rise to rays that transport horizontally.
What is the periclinal division of the vascular cambium?
It produces the xylem and phloem cells
What is the anticlinal division of the vascular cambium?
It produces meristematic cells
What is wood?
Is it secondary xylem
What is Heartwood?
Old xylem cells that no longer conduct water
What is sapwood?
Xylem cells that still conduct water
What is the cork cambium?
Produces cork to the outside and phelloderm to the inside. When enough cork/phelloderm forms the epidermis will rupture.
What are lenticels?
Spongy structures on the epidermis that are used in gas exchange
What is outer bark?
Cork and phelloderm produced by the cork cambium
What is inner bark?
Secondary phloem produced by the vascular cambium.
Why do monocots not have secondary growth?
They don’t have a vascular cambium and they don’t produce true wood.
