Secondary Growth Flashcards
What does secondary growth help with?
Increasing the diameter of the stem and root
What new meristem is needed in secondary growth?
Lateral meristem
-Derived from secondary tissue
-Adds thickness to woody plants
What are the two types of lateral meristem?
- Vascular Cambium
-adds secondary xylem and secondary phloem - Cork Cambium
-replaces the epidermis with periderm (the outer bark)
Where does secondary growth occur?
In the mature stems and roots of woody plants
Does it occur before or after elongation?
After
Does secondary growth occur in gymnosperms, eudicots, or monocots?
Gymnosperms and eudicots
NOT monocots
What do rays do?
Lateral transport
What arises after the vascular cambium?
Cork cambium
How many cell layers is vascular cambium and what is it responsible for the production of?
One cell layer thick
Production of secondary vascular tissue
-secondary xylem/phloem
What does vascular cambium develop from?
Undifferentiated parenchyma cells
Vascular cambium of a woody stem is located _____ the pith and primary xylem, and _____ of the primary phloem and cortex
Outside
Inside
Vascular cambium of a woody root forms _____ to the primary xylem and _____ to the primary phloem and pericycle
Exterior
Interior
____ is added to the inside, and ______ to the outside
Secondary xylem
Secondary phloem
What is most of the thickening of the wood from?
Secondary xylem
When is early wood formed?
The spring
Does early wood have thick or thin cell walls? Why?
Thin, to allow more water to enter
When is late wood formed?
Late summer
Does late wood have thick or thin cell walls? Why?
Thick, to contribute to stem support
_______ are visible where late and early wood meet and can be used to estimate a tree’s age
Tree rings
What type of wood has uniform texture?
Soft wood
What type of wood has variable texture and colour variation in dicots?
Hard wood
What type of wood is the actively conducting part of the wood and light in colour?
Sap wood
What type of wood is no longer actively conducting and is darker in colour?
Heart wood
