Chloroplasts

Cell walls

NonvascularGametangia, need water to reproduce

Seedless, but vascularMonocots &dicots

Adaptations to Terrestrial Life• Stomata(gas exchange)

• Cuticle(prevention water loss)

• Lignin(support)

• Gametangia & seeds (reproduction)

• Pollen(reproduction)

• Vascular tissue(support & transport)-xylem & phloem

• Roots(water acquisition, support)

• Seed dispersal mechanisms

General Structure

Plants-General Characteristics• Terrestrial• Photosynthetic• Alternation of generations

charophyte

bryophytes

pteridophytes

gymnosperms

angiosperms

Plant Morphology

Organs tissues cellsLeaves dermal parenchyma

Stems vascular collenchyma

Roots groundsclerenchyma

meristematic

Tissues1. Dermal

• Outer covering

• Protective

• Epidermal cells (cuticle)

• Guard cells

• Root hairs

2. Vascular• Transport & support

• Xylem & phloem

3. Ground• Bulk of plant

• Photosynthesis, storage,

support

4. Meristematic– Embryonic tissue-

grows throughout life of plant

– Roots, shoots, stem(lateral)

Cell Types

Found in all 3 tissue types

phloem

Found in vascualr bundlesThicker cell walls

Heavy ligninInclude Fibers-bundles, supportScleroids-nut shells, seedsTracheids & vessels ofxylem

parenchyma

collenchyma sclerenchyma

Stems

Functions• Transport between

roots & leaves• Storage• support

Stems-basic structure

• Epidermis– Cuticle, stoma,

photosynthetic• Body mostly parenchyma• Support tissues-collenchyma

& sclerenchyma• Vascular tissues in bundles

• Scattered (monocots) or in rings (dicots)

• Can grow up or out

Monocot stems

scattered

Epidermis______

Dicot Stems

In ring, around pith

Secondary growth-woody dicots onlyProduce a new layer of xylem & phloem each year

Vascular cambium divides & differentiates

Epidermis becomes cork cells, part of bark, along w/ phloem

•Vascular cambium-undifferentiated cells•Pith & cortexparenchyma for storage•Phloem & xylem raysTransport H2O & nutrientsLaterally•Primary xylem & phloemNon-functioning•Cork cambiumProduces cork cells which replace epidermis-secrete suberin & die•BarkPhloem(living & dead), cork cambium & cork•Periderm•Cork cambium & cork

Xylem = oldest

Dead cells & suberin

How does secondary growth happen?

c=vascular cambium cellD=undifferentiated product of mitosisX=xylemP=phloem

Roots

Protection/lubrication1st stage of

differentiation

Responsible for lengthening of root

Differentiationcomplete

Root Functions

• Anchoring• Take up water &

minerals• 1st part to develop• 2 types

– Taproot(dicot)

– Fibrous(monocot)

•

Basic Structure• Epidermis(dermal)-covers

entire surface, including hairs– Absorption, protection

– No cuticle

• Cortex-mainly parenchyma– No chloroplast, but has storage

plastids

• Stele/vascular cylinder– Surrounded by endodermis-cells

are highly selective

– Xylem & phloem inside

– Casparian strip

– Pericycle

– Pith(monocots) Thru cytoplasm

Thru cell walls

Lateral branch from pericycle

Differences between monocots &dicots

Monocots

__________endodermis

____________pericycle

Dicots________ epidermis

__________________ cortex

VascularCylinder___

________________xylem

________________phloem

Endodermis___________

Pericycle________________

LeavesFunctions• Photosynthesis• Maximize sunlight

exposure• Gas exchange• Water conservation

Special Leaf Adaptations

• Specialized photosynthetic cells

• Shape-most are broad & flat

• Stomata

• Pointed-water run off

• Needle-shaped-cold & wind

• Succulents-water storage

•

General StructureOuter leaf1. Cuticle(cutin)2. Epidermis(upper &

lower)3. Stomata & guard cellsInner leaf1. Mesophyll

• Palisade parenchyma• Densely packed,

columnar, upper surface only

• Spongy parenchyma• Irregular shapes, large

spaces for gas diffusion• Bundle-sheath cells(C4

plants)

2. Vascular bundles/veins

Monocots vs Dicots• Monocots

– Parallel veins

– No palisade layer

– Vascular bundles appear scattered under ‘scope

• Dicots– One large central vein,

smaller veins branching off (perpendicular)

– Palisade layer distinct

monocot

dicot

monocot

Main vein________

Palisade layer_______

_________spongylayer

Leaf epidermis

General Structure cont…

fibers