Plant Cell Types

MULTICELLULAR
PLANT BODY

Plant Cell Types
Plant Tissues: Ground, Dermal, Vascular
Meristems

LEARNING
TARGETS

At the end of this lesson, I can:

• Identify the different Plant Cell Types.

• Describe the different Plant Tissues.

• Differentiate Meristematic and Non-meristematic Tissues

• Explain how different plant tissues aid in growth and development of

the plant.

PLANT CELL TYPES

GROUND TISSUE CELLS

•Ground tissue

•Makes up the majority of an herbaceous plant
•Consists of:

Parenchyma

Collenchyma

Sclerenchyma

PARENCHYMA

• Most abundant

• Alive at maturity

• Thin primary cell walls

• Has the ability to divide

• Response to injury or changing environment

• Functions: photosynthesis, respiration, gas exchange,

storage of starch and other materials

COLLENCHYMA

•Elongated living cells

•Unevenly thickened primary cell walls

•Function: elastic support

SCLERENCHYMA

•Inelastic support to non-growing plant parts

•Dead at maturity

•Thick, rigid secondary cell walls

•Lignin – tough, complex molecule that adds
strength to cell walls

Multiple Choice

Which of the following is not a ground tissue?

• Parenchyma

• Collenchyma

• Sclerenchyma

• Xylem and Phloem

Multiple Choice

What ground tissue is the most abundant?

• Parenchyma

• Collenchyma

• Sclerenchyma

• Xylem and Phloem

Multiple Choice

What complex molecule adds
strength to cell walls?

• Cuticle

• Lignin

• Starch

• Cellulose

Conducting Cells in
Xylem and Phloem

Vascular Tissue Cells

•Vascular tissues

•Transport water,
minerals, carbohydrates,
and other dissolved
compounds throughout
the plant

Xylem

Tracheids

Vessel elements

Phloem

Sieve tube elements

Companion cells

Tracheids

•Long, narrow cells that overlap at their
tapered ends
•Water moves from tracheid to tracheid
through pits
•Pits – thin areas of the cell wall

Vessel Elements

• Short, wide, barrel-shaped
• Stack end-to-end, forming long, continuous tubes
• Side walls – have pits
• End walls- perforated or absent
• Water movement is faster than tracheids

Tracheid

vs

Vessel Element

Sieve Tube Elements

•Main conducting cells of phloem

•Align end-to-end to form sieve tube

•Alive but no nucleus and little
cytoplasm

Companion Cell

• Adjacent to sieve tube element

• Specialized parenchyma cell

• Transfer carbohydrates into and out of the sieve tube

elements

• Provide energy and proteins to the conducting cells

Multiple Choice

What is the main conducting cells of phloem?

• companion cells

• sieve tube elements

• tracheid

• vessel element

MULTICELLULAR
PLANT BODY

Plant Cell Types
Plant Tissues: Ground, Dermal, Vascular
Meristems

LEARNING
TARGETS

At the end of this lesson, I can:

• Identify the different Plant Cell Types.

• Describe the different Plant Tissues.

• Differentiate Meristematic and Non-meristematic Tissues

• Explain how different plant tissues aid in growth and development of

the plant.

Determinate vs
Indeterminate Growth

• Determinate growth

• Plants that stop growing after they reach their mature size
• Ex: bush types

• Indeterminate growth

• Plants that continue to grow as long as environmental conditions allow it

• Ex: majority of tomato varieties

Meristems

• Regions that undergo active mitotic cell division

• Patches of “immortality” that allow a plant to grow, replace damaged parts, and respond to environmental change

• Types:

• Apical – small patches of actively dividing cells near the tip of roots and shoots

• Lateral – produce cells that thicken a stem or root

Shoot Apical
Meristem

• Primary growth

• Lengthens the shoot or root tip by adding cells
• New cells originate at the apical meristems

• Daughter cells give rise to ground tissue, epidermis, and vascular tissue

• Stem elongates as the vacuoles of the new cells absorb water, pushing the
apical meristem upward

• New leaves originate on the flanks of the meristem

Shoot Apical
Meristem

• Remnants remain in the axillary buds that form at stem

nodes

• Buds may either remain dormant or “awaken” to form wider branches

• When a shoot loses its terminal bud, cells in one or more dormant axillary buds begin to divide

Root Apical
Meristem

• Some of the cells produced at this meristem differentiate

into the root cap

• Other cells elongate by absorbing water

• Cells enlargement → root grows farther in the soil

• Zone of maturation – cells complete their differentiation and mature into the functional ground, dermal and
vascular tissues

Multiple Choice

Plants that stop growing after they reach their mature is known to have determinate growth. True or False?

• True

• False

Multiple Choice

Which type of growth lengthens the shoot or root tip by adding cells?

• Determinate

• Indeterminate

• Primary

• Secondary

Multiple Choice

Which among the following shows a shoot apical meristem?

Lateral
Meristems

•Secondary growth

•Increases the girth of
stems and roots in
woody plants

Lateral
Meristems

• Vascular cambium

• Internal cylinder of meristem tissue

• Produces thin layer between primary xylem
and phloem

Vascular Cambium

Vascular cambium

cell

Daughter cell

Remains a
meristem cell

Daughter cell

Matures inside –
secondary xylem

Matures outside –
secondary phloem

Cork Cambium

•Gives rise to parenchyma to the inside
and cork to the outside

•Cork – densely packed, waxy cells on
the surfaces of mature stems and roots
- dead at maturity and form waterproof, insulating layers

• Heartwood – innermost wood,

darker

• Gradually becomes unable to

conduct water through time

• Dark-colored chemicals

accumulate

• Sapwood – outer portion, lighter

• Transports water and dissolved

minerals

Multiple Choice

What type of growth increases the girth of
stems and roots in
woody plants?

• Primary

• Secondary

• Determinate

• Indeterminate

Multiple Choice

The sapwood is darker than the heartwood. True or False?

• true

• false

Multiple Choice

The vascular cambium gives rise to what tissue(s)?

• Xylem and Phloem

• Phloem only

• Xylem only

• None of the above

LEARNING
TARGETS

At the end of this lesson, I can:

• Identify the different Plant Cell Types.

• Describe the different Plant Tissues.

• Differentiate Meristematic and Non-meristematic Tissues

• Explain how different plant tissues aid in growth and development of

the plant.

Ground Tissue

• Fills the spaces between more specialized cell types inside roots, stems, leaves, fruits, and
seeds

• Cells that compose ground tissue are important sites of photosynthesis, respiration, and storage

PLANT TISSUES

Ground Tissue

Dermal Tissue

Vascular Tissue

Dermal Tissue

• Covers the plant

• Herbaceous plant

• Epidermis – single layer of packed, flat, transparent, parenchyma cells

• Woody plant

• Tough bark

Dermal Tissue

• Cuticle

• waxy layer that coats the epidermis of the leaves and

stem

• conserves water and protects the plant from predators and fungi

• Impermeable not only to water but also to CO2 and O2

Vascular Tissue

• Xylem

• Transport water and dissolved minerals from the roots to all parts of the plant

• Water conducting cells are elongated and have thick, lignin-rich secondary cell walls

• Phloem

• Transports dissolved organic compounds, primarily sugars

Dermal
Tissue

• Stomata

• Pores through which leaves and stems exchange gases with the
atmosphere

• Guard cells – surrounds stomata and controls its opening and
closing

Vascular
Tissue

• Vascular bundle

• Strand of tissue containing xylem and phloem, often
with collenchyma tissue
or sclerenchyma fibers

Vascular Tissue

•Xylem and phloem shuttle minerals and food throughout the plant’s body

•Other function:

•Support –lignin strengthens walls of xylem cells and sclerenchyma fibers

•Enables vascular plants to tower over their nonvascular counterparts – important for
competition

Multiple Choice

What type of tissue fills the spaces between more specialized cell types inside roots, stems, leaves, fruits, and seeds?

• ground

• vascula

• dermal

• all of the above

Multiple Choice

This is a waxy layer that coats the epidermis of the leaves and stem.

• leaves

• cuticle

• roots

• xylem

Multiple Choice

Xylem transports dissolved organic compounds while phloem transports water. True or False.

• True

• False