Anatomy

of flowering plants

Anatomy

• Cells- tissues- organs-• Different internal structure – Monocot Dicot• Anatomy definition• Tissue definition

Plant tissue classification

Meristematic tissue• Meristos – meaning• Thin walled, active dense protoplasm, Prominent Nucleus• Active, dividing• Definition• Types – Apical• Intercalary• Lateral

Types of meristem

Meristem

Primary

Apical Intercalary

Secondary

Lateral

Apical meristem

• Root shoot apex (tip)• Elongation of stem , leaves formation, stem

apical cells left behind --- axillary bud – form branch or flower

• Forms Dermal tissues, Ground tissues and vascular tissues

Intercalary

• Mature roots and shoots – woody axis• Later than primary meristem • Cylindrical • Forms secondary tissues

Simple Permanent

Parenchyma

• Isodiametric (roughly spherical / polyhedral)

• Spherical,oval,round—• Thin wall- cellulose• Compact packed• Less intercellular spaces• Photosynthesis, storage,

secretion

Collenchyma ( Kollas- glue)• Oval, spherical, polyhedral• Thickened corners• Living• Cell wall – cellulose,

hemicellulose, pectin• No intercellular spaces• Contain chloroplast• Assimilation of food• Mechanical support – young

stem petiole ( green plants)

Sclerenchyma

• Long, narrow cells• Cell wall lignified – few or many pitts• Dead , lumen presence• Fibres – Thick walled elongated pointed cells• Sclerides – Pherical, oval, cylindrical- narrow lumen ( fruit

walls of nuts, seed coats of guava, pear, papapya)• Mechanical support

Complex permanent tissue

Xylem

• Function• Xylem Tracheids• Xylem Vessels ( absent in Gymnosperms but

in Angiosperms main water transporting system)

• Xylem Fibres• Xylem Parenchyma - living

Tracheids

• Elongated tube like• Thick lignified walls tapering ends• Dead No protoplasm• Inner cell wall vary in thickenings• Vessels interconnected through perforations

in common walls.

Xylem Fibres

• Thickened wall, large central cavity• Septapte or aseptate

Xylem Parenchyma

• Living , thin cell wall cellulosic• Fodd starage – starch, fat, or tannins• Radial conduction of water - ray

parenchymatous cells

Vessel

• Long cylindrical tube like structure – many cells ( vessel members)

• Lignified walls, large central cavity• Dead cells

Protoxylem, Metaxylem

EndarchProtoxylem twds pith/centre, Metaxylem twds peripheryIn stem

ExarchProtoxylem twds peripheryMetaxylem twds centreIn roots

Phloem

Tissue System

• Structure and function on location• Types1. Epidermal tissue2. Ground tissue3. Vascular Tissue

Epidermal tissues

• Outer most covering whole plant body• Elongated, compactly arranged, usually single

layered• Parenchymatous, small amt of cytoplasm,

large vacuole• Covered by waxy layer- cuticle ( absent in

roots ) - loss of water is prevented

Modification

• Stomata• Root hairs• Trichomes

Stomatal apparatus

Stomatal aperture , guard cells , subsidiary cells

Root hair

Elongations of epidermal cells, help to absorb water and minerals.

Trichomes

Shoot system, multicellular.Branched / unbranchedSoft / stiffPrevent water loss due to transpirationMay be secretory

Terminology

The ground tissue system

• Parenchyma( cortex, pericycle, pith, medullary rays) collenchyma sclerenchyma

• Leaf ground tissue – with chlorophyll - mesophyll

Vascular tissue system – open vascular bundle

Open& Closed Vascular bundles

Open Vascular Bundle Closed Vascular Bundle

Contains an interfascicular cambium in between phloem and xylem.

Interfascicular cambium is absent.

Phloem and xylem are not in direct contact with each other.

There is direct contact between phloem and xylem.

Secondary phloem and xylem are formed in between the primary phloem and xylem.

Such activity is absent.

These are present in dicot and gymnosperm stems.

Present in leaves and monocot stems.

These are either collateral or bicollateral. These can be collateral or concentric.

Radial & Conjoint

• In roots• Xylem Phloem are

arranged in an alternate manner on different radii

• In leaf, Stem• Xylem Phloem are

arranged in an alternate manner on same radii

http://www.youtube.com/watch?v=4KLFlz0SdIQ