VASCULAR PLANT ORGANS JJA OBICO Instructor, Dept. of Biology CAS UP M il CAS, UP Manila
VASCULAR PLANT ORGANSJJA OBICOInstructor, Dept. of BiologyCAS UP M ilCAS, UP Manila
MERISTEMS
Apical Meristemp
• Shoot Apical MeristemRoot Apical Meristem• Root Apical Meristem
Primary Growthy
• Increase in length of roots and shootsCaused by APICAL MERISTEMS• Caused by APICAL MERISTEMS
• Outcome: PRIMARY PLANT BODY
APICAL MERISTEMS• Give rise to primary meristems• Give rise to primary meristems
Primary meristemsy
• Produces tissues of the primary plant bodyConsists of: Consists of: 1. Protoderm
Primary dermal tissue/ epidermisPrimary dermal tissue/ epidermis2. Procambium
Primary vascular tissuePrimary vascular tissue3. Ground meristem
Ground tissue
Primary meristems Primary tissuesPrimary meristems Primary tissues
ProtodermDermal Tissue
(Epidermis)
Apical Meristem Ground meristem
Ground Tissue
(parenchyma, ll h collenchyma,
sclerenchyma)
Vascular Tissue Procambium
Vascular Tissue
(Primary Xylem and Phloem)
Lateral Meristems
• aka secondary meristemsCauses thickening of the stems and roots • Causes thickening of the stems and roots ▫ SECONDARY GROWTH
Common in eudicots and gymnospermsCommon in eudicots and gymnospermsRare in monocots
• Single-cell layers of meristematic cells that usually form cylinders running lengthwise along
t ta stem or root
L l iLateral meristem• Vascular cambium
C k bi• Cork cambium
- Primary Growth
leafleaf
bladebladeaxillary budaxillary bud
shoot apical meristemshoot apical meristemterminal budterminal bud
Sh t Sh t
bladebladepetiolepetiole
nodenode
vascular tissuevascular tissue
Shoot Shoot systemsystem
vascular tissuevascular tissueinternodeinternode
vascular tissuevascular tissue
root hairroot hairRootRootsystemsystem
dermal tissuedermal tissue
root tiproot tiproot caproot cap
root apical meristemroot apical meristemdermal tissuedermal tissueground tissueground tissuevascular tissuevascular tissue
ROOT• Anchors the plant• Absorbs water and • Absorbs water and
minerals• Root hairs
Patterns of root growthg
• Taproot system▫ Most eudicots gymnosperms▫ Most eudicots, gymnosperms
• Fibrous root systemFibrous root system▫ Seedless vascular plants, monocots▫ Adventitious roots▫ More shallow and horizontal ▫ Common in dry regions
• Zone of cell division▫ Root apical meristem and primary meristemsRoot apical meristem and primary meristems
• Zone of elongation▫ Derivatives stop dividing and begin to grow in
length• Zone of maturation▫ Cells begin specializing in structure and function ▫ Cells begin specializing in structure and function
into different cells types, epidermal cells and conducting cellsR h i▫ Root hairs
External Structures
• Root cap▫ Protects the apical meristem▫ Protects the apical meristem▫ Helps the root penetrate the soil▫ Secretes mucigel- slimy polysaccharide for Secretes mucigel slimy polysaccharide for
lubrication• Root hairs▫ Zone of maturation▫ Where most of absorption of water and mineral
occurs
Tissues of the root
• EpidermisCortex• Cortex
• Endodermis• Stele• Stele▫ Pericycle▫ Vascular TissuesVascular Tissues▫ Pith*
uncutinized epidermis
Root hair
Lateral root
phloemp o
pericycle
Endodermis- with Casparian strip
pericycle
xylem
Cortex- parenchymap y
Casparian stripComposed of suberin-Composed of suberin
Thick cortexExarch- protoxylem devpt.Tetrarch Protostele
• Aerial roots – epiphytesButtress roots flared roots extending from tree • Buttress roots – flared roots extending from tree trunks
• Contractile roots • Contractile roots • Suckers- asexual reproduction• PneumatophoresPneumatophores• Mycorrhiza- absorption of P▫ Endomycorrhizay▫ Ectomycorrhiza
axilTerminal bud
STEMnode
Axillary bud
• Supports leaves or reproductive structures
internode
reproductive structures• Conduct water, minerals
and organic molecules
Protoderm
Ground meristem
Procambium
Meristematic regionMeristematic region
Enlargement regionEnlargement region
ProtodermProtoderm epidermisepidermis
cortexcortex
Ground meristemGround meristemcortexcortex
pithpith
ProcambiumProcambium
phloemphloem
vascular cambiumvascular cambiumProcambiumProcambiumxylemxylem
Tissues of the stem
• Epidermis▫ Cuticle▫ Cuticle▫ Trichomes
• CortexCortex• Vascular Tissues• Pith*Pith
epidermisepidermiscortexcortex
pith raypith ray
pithpithprimary phloemprimary phloem
fascicular fascicular cambiumcambium
i li lprimary xylemprimary xylem
Vascular bundleVascular bundle
SIPHONOSTELE
M t d E di t tMonocot and Eudicot stem
bundle sheathbundle sheath
phloemphloemcompanion cellcompanion cell
sieve tubesieve tube
pitted vesselpitted vessel
Cross section of a monocot stCross section of a monocot stxylemxylem
pitted vesselpitted vessel
annular vesselannular vessel
air spaceair space
vascular bundlvascular bundl
epidermis
tcortex
vascular bundle
pith
Young herbaceous dicot stemYoung herbaceous dicot stemYoung herbaceous dicot stemYoung herbaceous dicot stem
d hd hd hd hendarchendarchendarchendarch
Vascular bundle of a dicot stemVascular bundle of a dicot stem
phloemphloemphloemphloem
Vascular bundle of a dicot stemVascular bundle of a dicot stem
vascular cambiumvascular cambium
phloemphloemphloemphloem
interfascicular cambiuminterfascicular cambiuminterfascicular cambiuminterfascicular cambium
fascicular cambiumfascicular cambium
xylemxylem
Comparison between ROOT and Stem
ROOT STEM
• Protostele • Siphonostele• Protostele• Wider cortex• Uncutinized epidermis
Lack nodes
• Siphonostele• Thinner Cortex• Cutinized epidermis
With nodes• Lack nodes • With nodes
cladode
ModifiedModifiedModifiedModifiedstemsstems
Modified stems: vegetative reproductionModified stems: vegetative reproduction
stoloniferousstoloniferous rhizomatousrhizomatous
CormsBulbs Tubers
Rhizomes Stolon/Runners
LEAF• Main photosynthetic
organ of the plantorgan of the plant• Flat• Transpiration
Leaf buttress
reticulate venation
V PV PVenation PatternsVenation Patternsparallel venation
Phyllotaxy
Leaf shape Leaf shape and and and and
arrangements arrangements have have
Leaf Type
have have environmental environmental significancesignificancesignificancesignificance
Tissues of the leafTissues of the leaf• Epidermis▫ Two surfacesTwo surfaces
Upper- AdaxialLower- Abaxial
▫ With cuticleW t cut c e▫ Stomata▫ Trichomes
• Mesophyll▫ Ground tissue
PalisadePalisadeSpongy
▫ Vascular TissueVein
epidermis
In most plants the epidermis is single layered.In most plants the epidermis is single layered.
epidermisepidermis
Others, as in rubber tree plant, have multiple layers Others, as in rubber tree plant, have multiple layers allowing them to occupy varied selective habitatsallowing them to occupy varied selective habitats
subsidiary cellssubsidiary cells grass-typestoma
dumbell shape
guardguard cellscellsK+K+K+K+KK++ K+K+
HH22OOHH22OOHH22OO HH22OO
CC ti th h th idti th h th idCrossCross--section through the midsection through the mid
upper epidermisupper epidermis xylemxylem
collenchymacollenchyma
phloemphloem
lower epidermislower epidermis
phloemphloem
hhcollenchymacollenchyma
parenchymaparenchyma
Cross section of a leafCross section of a leafcutting through a veincutting through a vein
cuticlestoma
adaxial epidermis
palisade mesophyllp p y
spongy mesophyllveinp gy p y
abaxial epidermisair spacesabaxial epidermis
stoma
L L Leaf modificationLeaf modificationinsectivorous plainsectivorous pla
Venus flytrapVenus flytrap
Nepenthes sp.Nepenthes sp. SarraceniaSarracenia sp.sp.
BRACTBRACT
Succulent
Leaves as homes Leaves as homes for antsfor ants
leaf tendril forleaf tendril forsupportsupport
leaf tendrilfor climbing
leaf tipsleaf tipsfor protectionfor protectionf pf p
The largest leaf is observed in the genus VictoriaVictoriain the genus VictoriaVictoria