Download Ground Tissue

Date: _______________________________
Plant Cells and Tissues (13.2)
Organization Within Plants
Fill in using the words: companion cells, dermal tissue, fibres, ground tissue, phloem, root, sclereids, shoot, sieve tubes, tracheids,
vascular tissue, vessels, xylem
Plant Body
is divided into...
SHOOT system
ROOT system
made up of one or more
roots
made up of stem, leaves,
flowers, and fruit
...which are both composed of....
DERMAL TISSUE
VASCULAR TISSUE
GROUND TISSUE
the outer covering
the transport system
all other types of tissue
...that contain the cell types:
XYLEM
PHLOEM
transports water
transports sugars, ions, minerals
parenchyma
VESSEL
ELEMENTS
sclerenchyma
...which can be classified as....
...which is composed of....
TRACHEID
S
collenchyma
SIEVE
TUBES
COMPANIO
N CELLS
FIBRES
SCLEREIDS
Meristematic Tissue
Meristematic tissue is undifferentiated – it has the potential to become any of the three other types of tissue.
You can think of these as being the plant equivalent to animal stem cells.
Meristem is only found in certain parts of the plant body, but it is responsible for
all of the growth and division that occurs in the plant. It can be found only at the
tips of shoots and roots, and at nodes along the shoots.
Type of
growth
Primary
Secondary
Description of
growth
Primary growth
increases the plant’s
HEIGHT.
Secondary growth
increases the plant’s
WIDTH
Occurs in all
plants? (Y/N)
yes
Type of meristem
responsible
Apical
Intercalary
no
lateral
Classification of Meristem Type
Based on Position
Label: apical, intercalary, lateral
Dermal Tissue
Dermal tissue makes up the outer covering of all parts of a plant. There are two different types of dermal tissue:
1. Epidermis: green fleshy (herbaceous) stems
2. Periderm: woody stems
Ground Tissue
Function
Cell types
Examples



Parenchyma tissue
photosynthesis
food storage
healing and tissue
regeneration


Collenchyma tissue
support in young stems,
roots, and petioles
healing and tissue
regeneration
parenchyma cells
collenchyma cells
mesophyll in leaves
strings of a celery stalk
Sclerenchyma tissue
rigid support in older
parts of plant
 protection

sclereid cells (“stone cells”),
fibre cells
nutshells, apple cores,
hemp and jute fibres
Picture
a – lengthwise
b – cross section
Vascular Tissue
The transport system of the plant. Two major types of vascular tissue:
1. Xylem: transports water and minerals
2. Phloem: transports nutrients
The conducting parts of both the xylem and phloem are made up of two types of cells:
Xylem
All types of xylem tubes are dead at maturity. This means that they have no cytoplasm or organelles,
but their cell walls remain, fortified by supportive ground tissue.
Type of cell
Tracheids
Diameter
wide
Shape
tapered
Arrangement
overlapping
Vessel elements
narrow
cylindrical
end-to-end
Found in
gymnosperms
angiosperms
angiosperms
Both the gymnosperms and angiosperms have tracheids, but only the angiosperms have vessel elements.
Based on this observation, which evolved later – the tracheids, or the vessel elements? ___________________
Phloem
Though phloem cells are alive at maturity, some cells – the sieve tube elements - are
specialized so that they do not perform any essential life functions. Instead, these sieve tubes
have attached companion cells that do this.
Type of cell
Alive?
(Y/N)
Relative
size
Function
large
Has nucleus
& organelles?
(Y/N)
No
Sieve tube
elements
yes
Companion
cells
yes
Small
Yes
Perform life functions for itself &
sieve tube (includes pumping
sugars)
Conduct nutrients
Ground Tissue
The ground tissue system is important because it serves a variety of essential functions for plants. Each type of
ground tissue has its role, such as food creation and storage or support during and after growth. Filling all the
spaces that are not used by the dermal and vascular tissue systems, ground tissue can be found throughout the
plant. There are three types of ground tissue, and each one has a specific function or set of functions for the
plant.
A. Parenchyma is a very versatile type of ground tissue, and it is responsible for
photosynthesis and food storage. Parenchyma cells are also responsible for healing in
the plant - this tissue can go through cell division and regenerate when needed. You
are likely familiar with parenchyma cells, because this is what the pulp in fruit is
comprised of.
Parenchyma is suited for its function because:
 It has a thin cell walls that allow the water and other nutrients to pass through
Figure 1 Cross section
to another cell with ease
 A large vacuole is constantly filled with water allowing the soft tissue to remain of parenchyma cells
firm
 The air spaces allow gases like O2 and CO2 to pass through the plant efficiently
 A permeable cell wall allows gases to diffuse through it
B. Collenchyma is ground tissue that provides structural support to growing parts of
the plant. Like parenchyma cells, collenchyma cells also go through cell division and
therefore elongate parts of the plant such as stems and leaves. Collenchyma cells
are long and thin, have very thick cell walls, and are grouped in strands. This
structure makes them very well suited to support the parts of the plants that are
growing and have not become established yet. The thick, rigid structure of celery is
due to collenchyma tissue.
Figure 2 Cross section of
collenchyma cells
How is Collenchyma suited for its function?:
 Strong cell wall allows for the plant's structure to be supported but also flexible
enough to bend
 The weaker parts of the wall allow nutrients to pass through
 The air spaces allow gases to pass freely through the cell
C. Sclerenchyma is the ground tissue that provides structural support to the parts of the
plant that are no longer growing. There are two types of sclerenchyma cells: fibres and
sclereids. Fibres are long and thin and are responsible for many materials you use on a
daily basis, such as clothing fabrics and rope. Sclereids are compact and dense, and
they are what makes up that tough texture in apple cores.
Figure 3 Cross section of
parenchyma cells
Sclerenchyma's suitability for its function:
 Evenly thickened cell walls help to support the plant's structure
 The lignified cell wall makes the plant rigid
 Parts of the sclerenchyma act as supports for the plant as they are tightly packed and do not contain
air spaces