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Biology, Seventh Edition
Solomon • Berg • Martin
Unit seven
Plant tissues
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 31 Plant Structure, Growth, and Differentiation
Plants
• Herbaceous
– Aerial parts (stems and leaves) die at the
end of the growing season.
– Nonwoody.
– Annuals, biennials, perennials
• Woody
Wolffia
Tulip
– Aerial parts persist
– Produce hard, lignified secondary tissues
– Perennials
Gum trees
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 31 Plant Structure, Growth, and Differentiation
Plant cells and tissues
• A tissue is a group of cells organized to form a functional
unit or a structural unit.
• Plant body is made of tow tissue systems:
1. Meristematic tissues.
2. Permanent tissues:
A. Simple permanent tissues: which is made only of one type of cells such
as :
– Ground tissue system (photosynthesis, storage, and support).
• Parenchyma , Collenchyma, Sclerenchyma
– Dermal tissue system (covering the plant body).
• Epidermis , Cork , Endodermis
B. Compound permanent tissues: which is made of more than one type of
cells such as:
– Vascular tissue system (conduction of water, dissolved minerals and
food).
• Xylem , Phloem
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 31 Plant Structure, Growth, and Differentiation
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.
• Meristems give rise to permanent tissues
• They have the following characteristics:
•
•
•
•
•
The cells are small,
The cells walls are thin,
Cells have large nuclei,
Vacuoles are absent or very small, and
There are no intercellular spaces.
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 31 Plant Structure, Growth, and Differentiation
Meristematic tissues is found in
the following locations:
1.
Shoot tip (apical meristem)
2.
Root tip (root meristem)
3.
Between vascular tissues
(vascular cambium)
1.
Periderm (cork cambium)
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 31 Plant Structure, Growth, and Differentiation
Shoot tip and Root tip
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 31 Plant Structure, Growth, and Differentiation
Vascular cambium and cork cambium
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 31 Plant Structure, Growth, and Differentiation
Permanent tissues
A.Simple permanent tissues: which is made only of
one type of cells such as :
– Ground tissue system (photosynthesis, storage,
and support).
• Parenchyma , Collenchyma, Sclerenchyma
– Dermal tissue system (covering the plant body).
• Epidermis , Cork , Endodermis
B.Compound permanent tissues: which is made of
more than one type of cells such as:
– Vascular tissue system (conduction of water,
dissolved minerals and food).
• Xylem , Phloem
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
Ground tissue system
CHAPTER 31 Plant Structure, Growth, and Differentiation
(Simple Tissues: consist of one kind of cell)
• Parenchyma
• Collenchyma
• Sclerenchyma
• These tissues can be
distinguished by their cell
wall structure.
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 31 Plant Structure, Growth, and Differentiation
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 31 Plant Structure, Growth, and Differentiation
Cell wall
• Primary Cell Wall
– Formed while the cell is growing.
– Stretches and expands as the cell increases in size.
– Generally thin, flexible and extensible.
• Secondary Cell Wall
– Forms after the cell stops growing.
– Thick and strong.
– Deposited between the primary cell wall and the plasma
membrane.
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
Parenchyma cells
CHAPTER 31 Plant Structure, Growth, and Differentiation
• Living cells with thin primary cell walls.
• The soft parts of a plant (edible parts).
• Spherical in shape (various shapes and
sizes).
• They tend to have large vacuoles
• More often they have spaces between
them
• Functions
• Photosynthesis
• Storage
• Secretion
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Biology, Seventh Edition
Collenchyma cell
•
•
•
•
CHAPTER 31 Plant Structure, Growth, and Differentiation
They have unevenly thickened primary walls.
Thick in the corners (extra primary wall).
They often occur just beneath the epidermis.
Function is to provide flexible structural support.
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
Sclerenchyma tissue
CHAPTER 31 Plant Structure, Growth, and Differentiation
• Have primary cell wall and thick
secondary walls
• Extreme thickness.
• Unable to stretch or elongate.
• Hard structural support
• Are often dead at maturity
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Biology, Seventh Edition
Dermal Tissue System
CHAPTER 31 Plant Structure, Growth, and Differentiation
• Outer protective covering of the plant body
• Epidermis
• Periderm
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Biology, Seventh Edition
CHAPTER 31 Plant Structure, Growth, and Differentiation
Epidermis
• Outermost tissue layer, usually one cell thick, multiple-layered
epidermis also occurs.
• Covers the primary plant body (leaves, stems and roots).
• Covers stem, root, and leaves
• Have pores ( stomata)
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Biology, Seventh Edition
CHAPTER 31 Plant Structure, Growth, and Differentiation
Stomata
permit gas exchange surrounded by guard cells
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Biology, Seventh Edition
CHAPTER 31 Plant Structure, Growth, and Differentiation
Endodermis
1. Single internal layer in roots
2. Controls the enter of water
into the xylem.
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Biology, Seventh Edition
CHAPTER 31 Plant Structure, Growth, and Differentiation
Periderm
• Outermost layer of cells covering a woody stem
or root.
• The outer bark that replaces epidermis when it
is destroyed during secondary growth.
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 31 Plant Structure, Growth, and Differentiation
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 31 Plant Structure, Growth, and Differentiation
Secretory tissue
In pine leaves
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 31 Plant Structure, Growth, and Differentiation
Permanent tissues
A.Simple permanent tissues: which is made only of
one type of cells such as :
– Ground tissue system (photosynthesis, storage,
and support).
• Parenchyma , Collenchyma, Sclerenchyma
– Dermal tissue system (covering the plant body).
• Epidermis , Cork , Endodermis
B.Compound permanent tissues: which is made of
more than one type of cells such as:
– Vascular tissue system (conduction of water,
dissolved minerals and food).
• Xylem , Phloem
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 31 Plant Structure, Growth, and Differentiation
Vascular tissue system
•
•
•
•
Composed of two or more kinds of cells.
Transport materials throughout plant body (water, dissolved minerals and food).
Provides strength and support.
Consists of:
– Xylem
– Phloem
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 31 Plant Structure, Growth, and Differentiation
Xylem
• Conducts water and dissolved minerals from the
roots to the stems and leaves.
• Xylem composed of four cell types:
– Tracheids
– Vessel elements
– Xylem parenchyma cells
– Fibers
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 31 Plant Structure, Growth, and Differentiation
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 31 Plant Structure, Growth, and Differentiation
Phloem
• Complex tissue conducting sugar in solution.
• Provides structural support.
• Phloem tissue composed of four cell types
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•
•
•
Sieve tube elements
Companion cells
Fibers
Phloem parenchyma cells
• Conducting cells are sieve tube elements;
they are assisted by companion cells
Copyright © 2005 Brooks/Cole — Thomson Learning