Wood and Bark and Leaves Flashcards
Wood
Secondary xylem
- Conducts water
- Stores water and carbs
- Support
- Accumulates
Vascular cambium
adds secondary phloem and xylem
Phellogen
yields the periderm
Fusiform Initials
Produce axial system
Ray Initials
Give rise to rays in xylem and phloem
Axial System
Cells w/ vertical axes
- Comes from fusiform initials
- Includes bulk of wood, vessel elements, tracheids, fibers, parenchyma
Radial System
- Consists of rays
- Made of ray parenchyma cells w/ horizontal axes
- Comes from ray initials
- Allows for horizontal movement of food and water
Gymnosperm Wood
Conifers, pine trees, fir trees, etc
-Simple axial system (tracheids w/ large bordered pits and resin ducts)
Angiosperm Wood
Flowering plant and trees and shrubs
-Complex axial system (tracheids, vessel elements, fibers, axial parenchyma)
Spring (early) wood
Water abundant so vessels are numerous and wide in diameter
Summer (late) Wood
Less water so fewer vessels and narrower
Sap Wood
- Secondary xylem accumulates but only 2-3 years are functional
- Functional xylem conducts water but non-conducting can cause infection
Heartwood
Non-functional wood that no longer conducts water and needs to be sealed off
-may store wastes and change color
Tyloses
Parenchyma cells next to vessel elements
-Grow through pit and block off old vessel elements
Gummosis
Parenchyma cells next to vessel elements
-Secrete gum into vessel elements
