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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
RESULT: GROWTH IN LENGTH
-at the tip of the root
RESULT : GROWTH IN THICKNESS
-BETWEEN VASCULAR BUNDLES
MERISTEMS
Small cells
with large nucleus and
What are the characteristics of meristems?
thin cell walls.
The cells are tightly packed
Because of their
proliferative capacity
parenchyma cells
also 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’
Cotton
Dandelion
Easter flower
Epidermis
Silver Lime/Linden
for dispersion
by wind
Edelweiss
- can have hairs
for protecion against cold
glandular
hairs
secrete
perfume
for protection
against being
eaten
Pelargonium
Stinging nettle
for reducing water loss
for protection against
intense sunlight
Mulleins
Saintpaulia
Rhizodermis
No stomata
Hairs for absorption
Characteristics:
No cuticle, no wax
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,
Tomato
volatile oils
Onion scale (skin)
Red cabbage
Colours 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
Two parts:
• 1.Xylem: dead cells and vessels
conducts water
from the root upward to the leaves
Its fibers are used in paper and furniture industry
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
Summary
Plant tissues
meristematic
Apical meristems
cambium
permanent
Dermal tissues
rhizodermis
epidermis
ground
vascular
chlorenchyma
Parenchyma
For starch storage
Parenchyma
For water storage
aerenchyma
Storing and secreting
parenchyma
Collenchyma and
sclerenchyma
xylem
phloem