Download Plant Tissues

Tissues
an integrated group of cells with a
common structure and function
Plant Tissues
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Four tissue systems in plants:
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Meristematic tissue: rapid cell division, lengthening of
shoots and roots
Dermal tissue: provides covering for the plant body.
Ground tissue: variety of functions including support,
photosynthesis, and storage
Vascular tissue: “plumbing system” throughout plants;
conducts water, food (CH2O), and dissolved minerals;
also strengthens and supports the plant.
Plants Exhibit
Localized Growth
at Meristems
Meristematic Tissue
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specific areas of plant growth composed of
cells that do not differentiate
cells retain the ability to divide, which other
plant cells lose
allow plants to grow their entire lives
Types:
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Apical – primary growth at root and shoot tips
Lateral – secondary growth in trees and shrubs
Intercalary – secondary growth in monocot stems
Region of cell
differentiation
/maturation
Apical meristem
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Region of cell
elongation
In shoot tips and
root tips
Allium cepa root tip
shown here
Parenchyma cells
Region of cell
division
Apical meristem
Root cap
Apical Meristems
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Stem buds have a dome-like apical
meristem in addition to leaf
primordia and bud primordia,
which protect the apical meristem.
Dermal Tissue
System
Dermal Tissues
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Single layer of cells called
the epidermis in
herbaceous plants
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Epidermis
Guard cells
Trichomes
Root hairs
Functions
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Absorption
Secretion of cuticle
Cuticle
Protection
Control of gas exchange
The Ground
Tissue System
Parenchyma cells
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Spherical-shaped cells; most
common type of tissue (most of
apples & potatoes); found throughout
plant
Have thin primary walls
Living, metabolizing tissue
Functions:
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Photosynthesis & respiration
Storage (starch, oil droplets, water,
and salts)
Wound healing & regeneration
Collenchyma
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Beneath the epidermis in young
stems and in large veins of
leaves (“strings” in celery)
Elongated cells that have
unevenly thickened cell walls
(especially in the corners)
Flexible support system (like our
skeletal system)
Found uniformly throughout the
plant
Alive at maturity
Sclerenchyma
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Specialized for structural
support; occurs in many
areas
Two types:
 Fibers – support in
wood, bark, leaves,
stems
 Sclereids – protection
in fruits, seeds, other
plant organs
Primary and secondary
cell walls.
Dead at functional maturity
The Vascular
Tissue System
Complex
Vascular Tissues
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Xylem
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Phloem
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Conducts water and dissolved
minerals from the roots
Conducts dissolved food
materials, carbohydrates,
in solution
Continuous throughout
plant
Support plant body
All 4 types of
tissues are present
in the root tip
Young dicot stem
Young monocot stem