Root System Shoot System: Stem Shoot System: Leaf Plant Processes

The Root System Subterranean portion of the plant Arises from the RADICLE. Roots which aroused from stems or leaves are called

ADVENTITIOUS ROOTS. Primary functions: 1. absorption 2. anchorage Have fine hair like extensions called ROOT HAIRS which arises from specialized cells called TRICHOBLASTS. This increases the area of absorption. All primary tissues aroused from the APICAL MERISTEM

Monocot Root Fibrous Root System Zea mays Panicum maximum Without a distinguished

primary/lateral root With secondary roots of roughly the same size Provides plants with stronger anchorage

Dicot Root Tap root system With a distinguished primary root With secondary or tertiary roots

Anatomy: Monocot Root Stele: Siphonostele

(presence of a pith) No. of Xylem ridges: many Narrow cortex

Anatomy: Dicot Root Stele: Protostele

(absence of pith) Xylem maturation: Exarch (protoxylem sa labas; meta sa gitna) No. of xylem ridges: 4 Wide cortex

Anatomy: Root Tip 3 regions: Region of active cell division-with meristematic cells Region of elongationwith cells undergoing differentiation Region of maturationwith differentiated/mature cells.

Roots with specialized functions.

Enlarged primary root For storage Chloraphytum elatum Ipomoea batatas Pacchyrizus erosus Daucus carota Manihot esculenta Raphinus sativus

Prop roots For additional support Ficus benjamina

Green roots For photosynthesis Dendrobium

Pneumatophores For gas exchange Mangrove species

The Stem

The Shoot System Occurs above the ground Originates from the PLUMULE. 2 Divisions: Branched or unbranched aerial stem Appendages (leaf,bud,fruit,flower)

Stem Longitudinal aerial axis with a tip as a growing point

where all tissues are derived Functions: Production and support of appendages Conduction of water and solutes

Primary Meristem Responsible for increase in plant height or length Found in the Apical meristem (apex of the stem) Promeristem form primary meristem Procambium Protoderm Ground meristem

Secondary/Lateral Meristem Responsible in plants increase in width or girth Secondary/Lateral Meristem Cork cambium or phellogen Vascular cambium

Secondary xylem Secondary phloem

Woody Stem Hard, thick, long-lived, with secondary growth

Herbaceous Stem Green, soft, short-lived, without or little secondary growth

Dicot StemGliricidia sepium Lenticelsfunctions for gas exchange

Node-part of the stem where the leaf arises

Monocot stem

Leaf Sheath hides the node; characteristic of monocot stem Intercalary Meristem portion of the node just above the internode; responsible for increase in length of monocot stem.

Shoot ApexTunica-several peripheral cell layers;divides anticlinally(perpendicular) Corpus-forms the core of the shoot apex; single cell layer; divides anticlinally and periclinally; causes secondary growth Coleus

Dicot Stem Stele: Eustele (vascular

bundles enclose the pith) Xylem maturation: Endarch (labas yung meta; loob yung proto)

Dicot Stem

Casparian strips compactly arranged cells of the endodermis (perpendicular to cell surface); composed of fatty substance suberin; prevents the back flow of water Fascicular cambium

Monocot Stem Stele: atactostele (no

distinct pith and cortex) Vascular bundles are scattered and embedded in the ground tissue pith + cortex

Monocot StemClosed Vascular Bundle enclosed by a metaxylem protoxylem bundle sheath lacuna phloem

Old dicot wood

Periderm Phellem- consists of suberized cork cells Phellogen or cork cambium flattened dividing cells Phelloderm parenchymatous single layer of cells

bark

wood

Stems with specialized functions.

Additional Support Tendrils Antigonon leptopus

Storage and Asexual Reproduction Tuber Solanum tuberosum Corm Colocasia esculenta Rhizome Zingiber officinale

Storage Flattened dics Allium cepa

Asexual Reproduction Runner/stolon Cynodon dactylon Offset Eichhornia crassipes

Photosynthesis Cladophyll Opuntia

Protection Thorns Bougainvillea

The Leaf

Leaf Part of the plant which is green and flattened. Functions: Photosynthesis Transpiration

Parts of the Leaf1. Blade/Lamina flattened portion of the leaf 2. Midrib expanded portion; centrally located; vascular bundles 3. Veins (veinlet) extensions in the midrib 4. Petiole stem like structure supporting the leaf. 5. Stipule leaf like structure in the petiole.

Venation Pattern Parallel (Monocot) Netted (Dicot)

+/- of petiole Petiolate with petiole Sessile without petiole

+/- of stipule Stipulate with stipule Exstipulate without

stupules

Overall Shape

Shape of Margin/edge

Shape of Apex

Shape of Base

Composition

Phyllotaxy arrangement of leaves in stem

Monocot vs. Dicot

Monocot Leaf

Bulliform cells specialized cells that roll/fold when it becomes flaccid. Simple upper epidermis cutinized by waxy substance cutin to avoid drying out and to protect plants from injury Vascular bundle Isolateral mesophyll differentiation

Simple lower epidermis

Monocot Leaf

Dicot Leaf

Dicot Leaf with Xeromorphic Features Nerium Oleander(multiple)

Trichome traps the water vapor that escapes from the stomata

Leaves with specialized functions.

Fleshy leaves For asexual reproduction Kalachoe pinnata

Bud scales To protect or cover buds Ficus elastica

Bulb scales Storage of water Allium cepa

Bracts/Semaphyll To attract insects

(pollinators) Mussaenda Bougainvillea

Pitcher shaped leaves Fumes out an odor which

attracts insects Has slippery mouth Has digestive enzymes that digests the insects Supply of inorganic materials Nephentes alata

Psuedostem For support Musa sapientum

Enlarged Petiole For buoyancy/floatation Eichhornia crassipes

Tendrils Additional support Coccinea grandis

Spines Protection Livistonia rotundifolia

Transpiration Loss of water vapor through the stomata A way of thermoregulation (cohesion tension

transpiration theory)

Xylem Transport Transport of water from the xylem of the roots to the

xylem of the leaves to be used for photosynthesis. Cohesion tension transpiration theory

Stomata Entry point of carbon dioxide for photosynthesis Passageway of water vapor in transpiration

Stomatal Apparatus