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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