Transcript No Slide Title

Plant Structure and
Growth
Why should we care about plants?
Four questions from Dr. Hutchens
• Do you enjoy breathing?
• Hungry?
• What are you writing on?
• Don’t feel well?
Outline
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What’s a plant? What’s a flowering plant?
Why flowering plants?
Monocots and dicots
Common features of plants - organs
Leaves, stems, roots, flowers
Tissues, cells and tissue systems
Plant growth
Plant or not plant?
Ferns (First
Vascular Plants)
11000 species
Mosses
(first land
plants)
Green algae
(ancestral
plant)
Gymnosperms
(including conifers)
First seed plants
>1000 species
Angiosperms
(flowering plants)
235000 species
So, why do we
focus on flowering
plants?
Monocot, Dicot
Common Plant Structures
• Two major systems
– Their roles?
• Three major organs
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Fig. 35.2
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Leaves
• Leaves as solar energy collectors
• Leaf anatomy
• Leaf shape
Leaf Structure - the
sandwich
Gas Exchange in Leaves
• Spongy Mesophyll, Stomata, and
Guard Cells
Transpiration
• Water loss from leavestranspiration
• Not simply wasted water
– Transpiration brings water up from
roots
– Which brings up minerals
– And provides evaporative cooling
• Control of stomata
• Wilting
• Special adaptations
Modified leaves
serve many functions
Stems
• Stems give rise to buds
• Stem Functions
• Anatomy of a stem
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Node
Internode
Axillary buds
Terminal bud
Leaf scar
Bud scale
Modified Stems
• Stolons
• Rhizomes
• tubers
ROOTS
The root system
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Fibrous roots—role?
Tap roots—role?
Root hairs—role?
Adventitious roots—
role?
Roots
• Fibrous root systems vs. taproot
systems
• Root spread
• Root functions
The 3 major types of plant cells
Parenchyma & collenchyma cells and their roles
Fig. 35.10
The 3 major types of plant cells
Sclerenchyma cells…and their roles
Fig. 35.10
Tissues and Tissue Systems
3 tissue systems, 7 tissues
• Ground Tissues - their roles?
– Parenchyma
– Collenchyma
– Sclerenchyma
• Vascular Tissues - their roles?
– Xylem
– Phloem
• Dermal Tissues - their roles?
– Epidermis
– Periderm
Tissue systems
• Leaves, stems, and
roots have three
tissue systems each
Fig. 35.8
Ground Tissues
• It’s all about the texture…
Vascular Tissues and Cell Types
Xylem
-Vessel elements
-Tracheids
Both are sclerenchyma cells
Phloem
Vascular Tissues
Xylem
Phloem
Sieve tubes
Companion cells
Dermal Tissues
– Epidermis
• Cuticle
• Modifications of epidermal cells
– Periderm
Dermal tissue (1)
• Epidermis
– Root hairs
– Cuticle
• Periderm
Announcement
• In Chapter 35, just skim “Plant
morphogenesis and differentiation”
from p 755 to the end of the
chapter. I will hold you responsible
for everything before that, but not
for the details of that section.
Root Tissues in dicot
• Epidermis
• Cortex
– Ground tissue
– Storage
– Endodermis
• Stele
– Vascular
– in center
Note X of xylem
in dicots
Root Cross section of Ranunculus - a dicot
Root Tissues (monocot)
• Epidermis
• Cortex
• Stele
Note ring of xylem
in monocots
Root Cross section of Zea - a moncot
Interactions between roots
Basics of Plant Growth
Up and Out
Plant Growth occurs only at
meristems
• Apical meristems are found at
growing tips and give rise to primary
growth (lengthening)
• Woody plants have secondary growth
(thickening), which occurs at
cylindrical meristems called cambium
Meristems
• Shoot apical
meristems
• Lateral meristem
• Root apical meristem
Primary Growth in Shoots
Primary Growth in
Roots
• Root cap
• Root apical meristem
– Zone of matuiration
– Zone of elongation
– Zone of division
Secondary Growth
• Vascular cambium adds xylem and
phloem to woody branches and trunks
Growth Rings in Secondary
Xylem
• Cork cambium, outside the vascular
cambium, adds to the periderm (outer
bark)
• Cork cambium, outside the vascular
cambium, adds periderm
• Can you define “plants”?
• Why do we focus on flowering plants?
• What are monocots and dicots?
• List the Tissue systems, tissues and cell types
• What are common features of plants
• Plant organs – definitions and functions: Leaves, stems,
roots, flowers
• How do plants grow?
• How do we define a plant?
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A multicellular, eukaryotic, photosynthetic autotroph
• Why are we studying flowering plants?
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Most plants fall in that category
• What are monocots and dicots?
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The two common body plans for flowering plants
• Know the tissue systems, tissues [and cell types]
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Ground system (parenchyma, collenchyma, sclerenchyma)
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Vascular system (xylem, phloem)
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Dermal system
• What are common features of plants?
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All plants are made up of shoots and roots; the same types of
tissue systems and tissues and cells occur widely
• Plant organs – be able to define and describe the structure
and function of leaves, stems, roots, and flowers
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Themes and variations
• How do plants grow?
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Localized growth at two types of meristems