Plant Structure And Growth The Plant Body is Composed of Cells and Tissues
Tissue systems
made up of tissues
made up of cells Plant Tissue Systems (Functions)
Ground Tissue System
storage
support
Vascular Tissue System
conduction
support
Dermal Tissue System
Covering Ground Tissue System
Different types of Ground Tissue
Parenchyma Tissue
Collenchyma Tissue
Sclerenchyma Tissue
Helpful hint: remember which ones are living or dead at maturity and which have only a primary wall and which have a secondary wall) Parenchyma Tissue
Made up of Parenchyma Cells
Living Cells at maturity
Primary Walls
Functions
photosynthesis
storage Collenchyma Tissue
Made up of Collenchyma Cells
Living Cells at maturity
Primary Walls that are thickened
Function
Support Sclerenchyma Tissue
Made up of Sclerenchyma Cells
Usually Dead at maturity
Primary Walls and Secondary Walls which are thickened with lignin
There are two types
Fibers (seen in the top picture - red cells on top and bottom)
Sclerids (seen in the bottom picture)
Function
Support Vascular Tissue System
Xylem (two types of cells)
Tracheids
Vessel Elements
Phloem (two types of cells)
Sieve-tube Members
Companion Cells Xylem Tracheids
Dead at maturity
They have pits - water moves through pits from cell to cell
Vessel Elements
Dead at maturity
They have perforations - water moves directly from cell to cell Phloem
Sieve-tube Members
alive at maturity
lack nucleus at maturity
Sieve plates - on end to transport food
Companion Cells
alive at maturity
helps control sieve- tube member cell Dermal Tissue System
complex tissue
usually transparent
secretes cuticle
Periderm
replaces epidermis in woody plants
protection Root System
Tap Root
Lateral Roots
Shoot System
Stems
Nodes
Internodes
Leaves
blades
petioles
Buds
Terminal (apical)
Axillary Plant Systems Plant Growth
Meristematic Tissue
generates cells for new growth
apical meristems
lateral meristems Apical Meristems
increases length called primary growth
Protoderm - gives rise to dermal tissue
Ground Meristem - gives rise to ground tissue
Procambium - gives rise to vascular tissue Lateral Meristems
increases girth called secondary growth
Vascular Cambium - produces secondary xylem and secondary phloem
Cork Cambium - produces cork and phelloderm
The Root System
Functions
anchor plant
absorb minerals, water and nutrients
store food
Systems
taproots - one large root with smaller lateral roots (dicots)
fibrous roots - threadlike roots (monocots) Root Structure
Four Regions
Root Cap - protection
Region of Cell Division - new cells
Region of Elongation - cells get longer
Region of Maturation - cells begin to specialize Root Tissue
Protoderm - gives rise to the epidermis
Procambium - gives rise to the stele
xylem and phloem
may include pith
Ground Meristem
Cortex Monocot vs. Dicot Root
You will need to be able to recognize the difference between a monocot root and a dicot root Monocot Root (inside to outside)
Pith Endodermis
Xylem Casparian Strip made
transport of suberin to regulate water water and minerals
Phloem Passage Cells to allow
transport water to pass through food Cortex Pericycle storage dividing cells Epidermis protection Monocot Root
You will need to be able to recognize parts
Epidermis
Cortex
Endodermis (red circle)
Pericycle (one layer inside the red circle)
Pith
Xylem (red)
Phloem (green) Dicot Root (inside to outside)
Xylem Endodermis
transport Casparian Strip made water of suberin to regulate water and minerals Phloem Passage Cells to allow transport food water to pass through Cortex Pericycle storage dividing cells Epidermis
protection Dicot Root
You will need to be able to recognize parts
Epidermis
Cortex
Endodermis (red circle)
Pericycle (one layer inside the red circle)
Xylem (red)
Phloem (green)
No pith Modified Roots
Food Storage
carrots, sweet potatoes, yams Modified Roots
Water Storage
manroot, pumpkin family Modified Roots
Propagative Roots which produce adventious buds
cherries, pears Modified Roots
Pnematophores
Prop Roots
mangroves Modified Roots
Aerial Roots
orchids, ivies Modified Roots
Buttress Roots
tropical trees Modified Roots
Haustoria
dodder Shoot System The Shoot System
Made up of Stems, Leaves, Flowers, Fruits
Stems - support, conduction, growth
Leaves - photosynthesis
Flowers - pollination
Fruits - seed protection, dispersal Stems (Primary Growth)
Protoderm - gives rise to the epidermis
Procambium - gives rise to the stele
xylem and phloem in vascular bundles
dicots - found in ring
monocots - scattered throughout
includes pith in dicots
Ground Meristem
Cortex Vascular Bundle
Parts
Fibers
Phloem
Xylem Monocot vs. Dicot Stem You will need to be able to recognize the difference between a monocot stem and a dicot stem Monocot Stem (Inside to Outside)
Ground Tissue
Vascular Bundles
Xylem
Phloem
Fibers
Cortex
Epidermis Monocot Stem
You will need to be able to recognize parts
Epidermis
Cortex (very small)
Ground Tissue
Vascular Bundle
Xylem (red)
Phloem (green)
Fiber (red) Dicot Stem (Inside to Outside)
Pith
Vascular Bundles
Xylem
Phloem
Fibers
Cortex
Epidermis Dicot Stem
You will need to be able to recognize parts
Epidermis
Cortex
Pith
Vascular Bundle
Xylem (red)
Phloem (green)
Fiber (red) Roots vs Stems Roots have Endodermis / Stems Vascular Bundles
Monocot Dicot
Roots – has pith Roots – no pith
Stems – No pith Stem – pith
Vascular bundles in a ring Vascular bundles are scattered Stems (Secondary Growth)
Occurs to increase girth (thickness)
Vascular Cambium
produces secondary xylem and phloem
Cork Cambium
produces cork and phelloderm
together these structures are called periderm Secondary Growth Secondary Growth
C – Vascular Cambian The vascular cambian goes through mitosis and D – Differentiated cell creates a cell (D) which on (will turn into another the inside of the plant type of cell) becomes a xylem cell.
X – Xylem The next mitotic division produces another cell (D) P - Phloem which is on the outside and becomes a phloem cell
Secondary Growth of a Stem
You will need to know the parts Secondary Growth of a Stem Secondary Growth of a Stem (Inside to Outside)
Pith Secondary
Primary Phloem Xylem Primary Phloem
Secondary Cortex
Xylem Phelloderm (wood) Cork Cambium Vascular Cork Cambium Secondary Growth
Periderm is cork cambium and cork
Bark is everything outside the vascular cambium
Wood (to a botanist) is secondary xylem
Sap wood – still moves water
Heart wood – no longer moves water, hardened now used for support Modified Stems
Stolons - horizontal stems above the ground Modified Stems
Rhizomes - horizontal stems below the ground Modified Stems
Tubers - swollen areas of rhizomes Modified Stems
Bulbs & Corms - vertical shoots under the ground Modified Stems
Cladophylls - cactus pads Leaf Structure
Simple leaf – one blade after axillary bud
Compound leaf – multiple blades called leaflets
Double Compound leaf – leaflets broken up into smaller leaflets Leaf Structure Leaves
Epidermis
Stomata - openings on underside of leaf
Guard Cells - surround stomata
Cuticle - waxy coating excreted by epidermis
Mesophyll - middle of leaf
Palisade layer - photosynthesis
Spongy layer - gas exchange Modified Leaves
Needles - reduce water loss Modified Leaves
Tendrils - long thin leaves for clinging Modified Leaves
Spines - protection Modified Leaves
Succulents – water storage