27: Secondary Growth

suberin

hydrophobic

impermeable

elastic

fire resistant

biopolymer found in plant cell walls that helps protect against damage and water loss.

soft wood

wood derived from trees that have only tracheids for water conduction, typically lighter and less dense than hardwoods.

-only tracheids

-small amt parenchyma

-no fiber-tracheids specialized bordered pits

-resin canal

UNIFORM texture

softwood ex:

coniferssuch as pine, spruce, and fir.

hardwood

heterogenous cell types

have vessels, tracheids, parenchyma

more variation in wood structure

fiber-tracheid

sand other specialized cells, making it denser and generally stronger than softwoods. Common examples include oak, maple, and cherry.

hardwood ex

angiosperm

secondary xylem 4 types

soft wood

hardwood

sapwood

heart wood

heart wood

dark colour

no actively conducting

sap wood

actively conducting part of wood

lighter in colour

hard wood

variable texture

colour variations

dicots

tracheid

vessel element

soft wood

unifrom texture

conifer

monocots , ferns - have secondary growth?

no

bark made of?

secondary phloem

layers of periderm

early wood formed in

spring

has thin cell walls to maximize water delivery

late wood fromed in

late summer

thickened cell walls

contribute to stem support

dendrochronology

the study of tree rings to determine age and climate history.

earlywood vs latewood size

earlywood bigger holes

latewood smallholes due to thicker cell walls.