Plant tissues

Made by: Kotánné Baló Krisztina

Plant tissues

Tissues are groups of cells of

» similar shape,

» similar structure,

» and similar origin - specialized for a particular function

» In plants tissues are grouped into two major categories:

» meristematic and

» permanent (consolidated) tissues

Meristems

• Where?

-at the tip of the stem

-at the tip of the root

-BETWEEN VASCULAR BUNDLES

RESULT: GROWTH IN LENGTH

RESULT : GROWTH IN THICKNESS

MERISTEMS

What are the characteristics of meristems?

Small cells

with large nucleus and

thin cell walls.

The cells are tightly packed

Because of their proliferative capacityparenchyma cellsalso serve as stem cells for wound healing and regeneration!

Permanent tissues

• Dermal tissues

• Ground tissues

• Vascular tissues

Dermal tissue

• Covers the outer surface

of herbaceous plants• Features:

-Its cells are closely packed

-Its cells are transparent because they don’t contain chloroplasts(With one exception: guard cells)

Epidermis-Covered by waxy cuticle layer against water loss, infections or damages

‘waxy bloom’

Epidermis

for dispersion by wind

for protectionagainst beingeaten

for reducing water loss

for protection againstintense sunlight

- can have hairsfor protecion against cold

Edelweiss

Easter flower

Dandelion

Cotton

Stinging nettle

MulleinsSaintpaulia

Pelargonium

Silver Lime/Linden

glandular hairssecrete perfume

Rhizodermis

No stomata

Hairs for absorption

No cuticle, no wax

Characteristics:

Functions of the dermal tissues

• Protection

• Evaporation

• Gas exchange

• Absorption

Ground tissues

• 1.Chlorenchyma: with many

chloroplasts

Ground tissues

• 2. Storage parenchyma: with starch grains

„Hot potato”

Ground tissues• 3.Aerenchyma: air filled cavities

and channels

Ground tissues

• 4.Water-storage parenchyma:

mucilage bearing cells

Ground tissues

• 5.Storing and secreting parenchyma: latex,

inclusions,

anthocyanin,

volatile oilsOnion scale (skin)Tomato

Red cabbageColours scale (depending on the pH)

Ground tissues• 6.Collenchyma (alive)

• and sclerenchyma(dead): for supporting

Fibers Stone cells ‘Gritty texture’

Vascular tissues

• Complex, because contain a lot of cell types• are arranged in long, discrete strands called

vascular bundles.

-A bundle can be simple if it contains only xylem or only phloem. (Usually in roots)

-A bundle can be complex if it contains both xylem and phloem with cambium between them

Vascular tissues

• 1.Xylem: dead cells and vessels

conducts water

from the root upward to the leaves

Its fibers are used in paper and furniture industry

Two parts:

Vascular tissues

• 2.Phloem: -living tissue,

-carries organic nutrients(known as photosynthate), in particular, sucrose,

-to all parts of the plant where needed

Its fibers are used in textile industry

Vascular tissues

• Mixed vascular bundles in a dicot stem form a ring

Mixed vascular bundles in a monocot stem have a typically scattered arrengement

SummaryPlant tissues

meristematic permanent

Dermal tissues vascularground

rhizodermis epidermis chlorenchyma

Parenchyma For starch storage

Parenchyma For water storage

aerenchyma

Storing and secretingparenchyma

Collenchyma andsclerenchyma

xylem phloem

Apical meristems cambium