Chapter 8: Structure of Woody Plants

Initiation

Provascular Tissue

Fascicular

Vascular Cambium

Secondary Xylem

Outer Bark

Types of Wood Cells

Growth Rings

Heartwood & Sapwood

Reaction Wood

Secondary Phloem #

Cork and the Cork Cambium

Lenticels and Oxygen Diffusion

Initiation

Secondary Growth in Roots

Anomalous Forms of Growth

Anomalous Secondary

Roots of Sweet Potatoes

Included Phloem

Unequal Activity of the Vascular Cambium

Secondary growth in Monocots

Unusual Primary Growth

produces secondary plant body

Cells

Arrangement of Cambial Cells

Ray initials

Pith

Fusiform Initials

Interfascicular

axial xylem

axial phloem

make cork cambium # # #

Phloem Rays

Xylem Rays

long, tapered cells

short and cuboidal

fusiform

regular horizontal rows

ray

short vertical rows

storied

irregular no pattern

nonstoried

periclinal wall

anticlinal wall

parallel

perpendicular

wood

made from fusiform and ray # #

axial system

radial system

fusiform

ray

tracheary elements

longitudinal conduction

parenchyma

hardwoods

fibers-stronger

softwoods

less fibers-softer

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ray cells

upright

procumbent

ray tracheids

horizontal rectangular cells

secondary walls

circular bordered pits

quiescence

stress, winter, drought

no cell division

annual ring-1 year growth

early wood

late wood

spring wood

summer wood

high vessel count

less vessels

first wood

diffuse porous

ring porous

vessels form constantly

vessels restricted to early wood

indistinct

Heartwood

Sapwood

center

dark, dry

outer

lighter, moister

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new layer formed by vascular cambium every year

one annual ring converted to heartwood each year

become indistinguishable and join together to make vascular cambium

tension wood

angiosperms

upper side of branch=wider

gravity

eccentric

compression wood

conifers

rich in cellulose

little lignin

underside =wider

less cellulose

more lignin

formed from vascular cambium

axial and radial system

no arrangement

only innermost layer of phloem capable of conduction

phellogen

cells =cuboidal

cell division

inner cell =remains cork cambium

outer cell =cork cell

periderm

maturation

protection

short lived

new cork

tissues outside inner cork cambium

inner bark

all secondary phloem between vascular cambium and innermost cork cambium

keeps out pathogens

maintain water

Blocks absorption of oxygen