plant kindom

Plant Body Systems The plant body is organized into a root system and a shoot system:  Root system is generally below ground.. The Root System Although we do not see much of root

Plant Morphology

& Anatomy

Plant Organs

Types of Plant Organs

Plant Body Systems

 The plant body is

organized into a root

system and a shoot

system:

 Root system is generally

below ground.

 Shoot system consists of

vertical stems, leaves,

flowers, & fruit s that

contain seeds.

Root System

“absorbtion” and

“anchorage” …

The Root System

 Although we do not see

much of roots, they are

equally important to

plant growth as stems

and leaves …

growth as long as the

plant can get enough

water and nutrients from

its roots!

Types of Root Systems

 A true root system

consists of both

primary & secondary

roots (lateral roots)

 Primary root system:

Primary Root System

 The 1st root to emerge

from a seed is the

radicle (primary

root), which emerges

to form a taproot that

persists throughout

the life of the plant.

 Many progressively

smaller branch roots

(lateral roots) grow

from the taproot.

Taproot System

 Definition: the root system

consisting of a thick,

central primary root,

which forms many smaller

lateral roots

 Common in dicots and

conifers.

 In some plants such as

carrots and beets, fleshy

taproots are the plant’s

“food pantry”

 In other plants the long

taproots are modified for

reaching water deep in

the ground

Fibrous Root System

 Definition: root system

that consists of several to

many roots of the same

size that develop from

the end of the stem with

smaller, lateral roots

branching off of them

 Typically slender, small

roots

 Found in monocots like

onion, sweet potatoes,

etc…

 Form in plants in which the

embryonic root is

short-lived.

Fibrous Root System

 Most fibrous roots

are very extensive

and cling to soil

Adventitious Roots

 Definition: roots that

arise on organs other

than roots

 Usually begin growing

after the seed germinates

 They form in all sorts of

places on plants

including leaves, petioles,

and stems

Adventitious Roots

Why Different Root Types?

 Help plants compete for water

Root Functions

Primary & Specialized

Primary Root Functions

 Roots perform 4 main

 Production of hormones (e.g.,

gibberellins) & secondary plant

compounds (e.g., nicotine in

tobacco plants)

 Some specialized roots are

modified for other functions …

the soil and

support the tree

Strangling

Roots

 Help the plants to

“climb” up another tree to get to

Contractile Roots

 Pull the plant shoot

closer to the

ground or deeper

into the soil where

the soil is relatively

Parasitic Roots (Haustoria)

 Penetrate the stems &

roots of host plant to

obtain water, minerals,

and organic molecules

Pneumatophores (air roots)

Root Structure

Intimately related to root

function …

Primary Structure of a Root

Monocot vs Dicot Root

External Root Structure

 Branch roots

 Root hairs

 Root tip (root

cap and apical

meristem)

Branch Roots

 Also known as lateral

roots or feeder roots

when they are young

 Decrease in age from the

soil surface to the root tip

the root tip

 Soil texture influences

root branching:

through hard, dry soil have

fewer branch roots than those

in moist, loose soil.

Root hairs

 Definition:

short-lived, single-celled

extensions of

epidermal cells near

the growing root tip

 Form in the region of

maturation

 Short, but numerous

 Function: raise

absorptive capacity of

the root by increasing

surface area of the

root that is in contact

Root cap

 Definition: a protective

thimble-like layer many

cells thick that covers

the delicate root apical

meristem

 As the root grows and

pushes its way through

the soil, parenchyma

cells of the root cap

slough off and are

replaced by new cells

Vascula r

cylinder

Cortex Epidermis

Root hair

Cellulose fibers

Apical meristem region

Root cap

Root apical Meristem

polysaccharide containing

sugars, organic acids,

vitamins, enzymes, and

amino acids

roots

as they move through the

ground

maintain the connection

between roots and water for a

continuous flow

take in nutrients through

intake of water

Roots Have Cooperative Relationships with Others …

absorption of minerals and don’t need to produce as many root hairs; also fungi may protect against disease- causing fungi & worms

(Fungus gets “food”.)

Roots Have Cooperative Relationships with Others …

Bacteria: Bacteria can convert nitrogen gas from the air into

ammonium, which is incorporated into

various organic molecules, which plants can take up.

get “useable” nitrogen.

pictures to the right) are the “homes” of

The End

to gravity to the lower

side of the cell.

– This is how plant roots

perceive gravity.

Peripheral cells

• Columella cells differentiate

into peripheral cells within

2-3 days, which surround

the columella cells.

– Thousands of these cells are

shed from the cap as the

plant pushes through the soil.

• Peripheral cells secrete

large amounts of mucigel

—a slimy substance with

many functions …