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Chapter 6 - Tissues and the Primary Growth of Stems - Coggle Diagram
Chapter 6 - Tissues and the Primary Growth of Stems
Concepts
Herbs: 3 parts
stems
roots
leaves
Early plants evolved to be taller
Evolution has made plants parts harder to recognize
Angiosperms - informal name for flowering plants. Formal name is Magnoliophyta
Largest plant kingdom division
Evolved into several groups
Eudicots - Broadleaf plants such as roses, asters, and maples
Monocots - grasses. Lilies, cattails, palms, bromeliads.
Basal angiosperms - waterlilies, magnolias, laurels.
2 types of plant bodies
Primary Plant Body - aka herbaceous body
Secondary Plant Body - aka a woody body
Basic Types of Cells and Tissues
Parenchyma - cells with only primary walls that remain thin.
Most common type of cell and tissue
Chlorenchyma - parenchyma cells involved in photosynthesis
Glandular cells are also a type of parenchyma cell
Transfer cells are parenchyma cells that facilitate short distance transport
Phloem - parenchyma cells that conduct nutrients over long distance
The cells live into maturity
Collenchyma - primary cell walls remain thin but thicken in certain places
These cells exhibit plasticity
Present in elongating shoot tips that must be long and flexible
Works with parenchyma to create structures that are rigid but still able to grow
Sclerenchyma - has both a primary wall and a thick secondary wall that is almost always lignified
cells are elastic
Develop from parenchyma cells
Conducting sclerenchyma transports water and is a type of vascular cell
External Organization of Stems
Stem is an axis
node is part of stem where leaf is attached
internode is the region between nodes
Area just above this is the leaf axil. Contains axillary bud
axillary bud - mini shoot with dormant apical meristem and several young leaves
Bud scales - covering of buds
phyllotaxy - arrangement of leaves on the stem
Rhizomes are fleshy horizontal stems that allow a plant to spread underground (bamboo)
Tubers are horizontal stems that grow briefly and store nutrients
Shoot is a stem plus any leaves
Bulbs are short shoots with thick leaves (onions, garlic, etc.)
Corms are vertical thick stems with thin leaves.
Internal Organization of Stems: Arrangement of Primary Tissues
Epidermis
Outermost surface of a herbaceous stem
barrier and shield
Cutin makes outer tangenital walls impermeable to water
Layer called cuticle
Stoma allows entry/exit
Some epirdermal cells elongate into trichromes/hairs
help keep animals away
Cortex
layer interior to the epidermis
Vascular Tissues
Xylem - conducts water and minerals
tracheids
vessel elements
stack of vessel elements is vessel
tracheary element - either type of cell listed below
rings called annular thickenings
circular bordered pits
reticulate thickening
scalariform thickening
helical thickening
Phloem - distributes minerals and sugars
Sieve tube members
controlled by companion cells
Sieve cells
associated with albuminous cells
sieve pores
grouped in areas called sieve areas
sieve tube - large sieve areas aligned
sieve plates
Vascular bundles are how xylem and floem occur together
arranged surrounding the pith
are collateral
xylem in bundle called primary xylem
phloem in bundle called primary phloem
Stem Growth and Differentiation
apical meristem - the tip of a shoot where cells divide
Subapical meristem - region below apical meristem
protoxylem
metaxylem
protophloem and metaphloem occur in outer part of vascular bundle
protoderm is epidermal cells in early differentiation
young xylem and phloem called provascular tissues
primary tissues - those produced by apical meristems
Primary Growth - growth and tissue formation from apical meristem activity
