Download Structural Organization of Plants

4/15/2014
1
4/15/2014
1.
2.
1.
2.
3.
Meristematic tissues are cells or group of
cells that have the ability to divide. These
tissues in a plant consist of small, densely
packed cells that can keep dividing to
form new cells.
Permanent tissues do not have the ability
to divide. These cells are already
differentiated in different tissue types and
is now specialized to perform specific
functions.
Apical meristem
a. Shoot apical meristem
b. Root apical meristem
Lateral meristem
Intercalary meristem
2
4/15/2014
3
4/15/2014
Root tip showing apical meristem
Dermal tissue
a. Epidermis
2. Vascular tissue
a. Xylem
b. Phloem
3. Fundamental tissue
a. Parenchyma
b. Chlorenchyma
c. Collenchyma
d. Sclerenchyma
1.
4
4/15/2014


The epidermis is the outermost cellular layer
which covers the whole plant structure. It
covers roots, stem, leaves, flowers and fruit.
The outer walls, which are exposed to the
atmosphere and usually thickened, and may
be covered by a waxy, waterproof cuticle
which are made up of cutin.
5
4/15/2014


Stoma is an opening (pore) which is bounded
by two bean shaped cells called guard cells.
The thin-walled epidermal cells of roots give
rise to root hairs. Hair- like outgrowths may
also be found in the epidermis of leaves and
stems.
Onion cells
6
4/15/2014
Stoma with guard cells
Root hairs
7
4/15/2014





The epidermal cells protect the underlying
cells
The waxy cuticle prevents the loss of
moisture from the leaves and stems
The transparent epidermal cells allow
sunlight for photosynthesis
The stomata of leaves and stems allow
gaseous exchange
The root-hairs absorb water and dissolved
ions from the soil
8
4/15/2014
Vascular
bundle

Xylem tissues are hollow tubular cells
important for upward movement of water and
nutrients.
9
4/15/2014
Xylem tissues



Xylem is an important strengthening tissue
Xylem vessels and tracheids transport water
and mineral salts
Starch is sometimes stored in the xylem
fibers and xylem parenchyma
10
4/15/2014

Phloem tissues are vessel cells important for
transport of food and nutrients throughout
the whole plant.
Phloem tissues
11
4/15/2014



Sieve tubes transport organic compounds
The phloem fibers give the plant mechanical
strength
The phloem parenchyma stores compounds
such as starch
12
4/15/2014

Parenchyma is the most common plant tissue.
The thin-walled parenchyma cells have large
vacuoles and distinct intercellular spaces.
13
4/15/2014
Parenchymal and collenchymal tissues

The most important function of the
parenchyma cells of roots and stem is the
storage of food (starch) and water

The intercellular air spaces permit gaseous
exchange
14
4/15/2014

Chlorenchyma cells are actually parenchyma
cells but they contain chloroplasts like the
parenchyma cells of leaves and stems.
Chlorenchymal tissues
15
4/15/2014



The chlorenchyma are the main
photosynthetic cells of the plant and
manufacture carbohydrates during
photosynthesis
Collenchyma cells have thick cellulose cell
walls which thickened at the corners.
The cells contain living protoplasm and they
sometimes contain chloroplasts.
16
4/15/2014
Parenchymal and collenchymal tissues


The collenchyma serve as supporting and
strengthening tissue
In collenchyma, chloroplast is where
photosynthesis takes place
17
4/15/2014


Mature sclerenchyma cells are dead and have
secondary cell walls thickened with cellulose
and usually filled with lignin.
In contrast to collenchyma, which is pliable,
sclerenchyma is elastic.
Sclerenchymal tissues
18
4/15/2014


Sclerenchyma is an important supporting
tissue in plants
Fibres probably play a role in the transport of
water in the plant
19