Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and...

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Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education, Inc.

Transcript of Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and...

Page 1: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Plant Structure and Function

Professor Andrea Garrison

Biology 11

Illustrations ©2010 Pearson Education, Inc.

Page 2: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Plant Kingdom

• Traits of the kingdom

– Multicellular

– Cell walls of cellulose

– Pigments

• Chloroplasts w/ chl a & b

• Accessory pigments (ie, carotenoids)

– Primarily terrestrial

– Dominant P/S organisms on land

2 Plant Structure and Function

Page 3: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Adaptations required to live on land

• Shoot = portion above ground

– Leaves for P/S – increase surface area for light & CO2 absorption

– Flowers for reproduction

– Fruit for dispersal

3 Plant Structure and Function

Page 4: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Adaptations required to live on land

• Roots = portion below ground

– Root hairs increase surface area for absorption

– Anchor plant

– Absorb water

– Absorb minerals, nutrients, etc.

4 Plant Structure and Function

Page 5: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Adaptations required to live on land

• Adaptations to avoid dehydration

– Waxy cuticle covers stems & leaves

• Decreases evaporation

• Inhibits gas exchange

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Page 6: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Adaptations required to live on land

6 Plant Structure and Function

Page 7: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Adaptations required to live on land

• Adaptations to avoid dehydration

– Waxy cuticle covers stems & leaves

• Decreases evaporation

• Inhibits gas exchange

– Stomata on leaves

• Allow gas exchange

• Guard cells close over stoma to minimize water loss

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Page 8: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Adaptations required to live on land

8 Plant Structure and Function

Page 9: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Adaptations required to live on land

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Page 10: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Adaptations required to live on land

• Vascular system

– Provides transport • Water & P/S products

carried throughout plant

– Provides support • Holds leaves up for

sunlight

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Page 11: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Vascular Tissue • Xylem

– Carries water and minerals from roots to leaves

– Dead cells

– Hollow with pores or pits to allow water movement

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Page 12: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Xylem Function

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Transpiration pulls water out

Water molecules adhere to each other due to H-bonds

Roots actively pump minerals in, water follows via osmosis

Page 13: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Vascular Tissue • Phloem

– Carries P/S products from leaves to roots, etc.

– Living cells

– Plasmodesmata (=gap junctions)

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Page 14: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Phloem Function -- Translocation 1. High sugar in leaves is

actively pumped into phloem, water follows via osmosis from xylem

2. High pressure at source pushes sugar solution towards root

3. Sugar actively pumped into root, water leaves via osmosis into xylem

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Page 15: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Plant Growth

• Primary growth

– Growth in length or height

– Occurs at tips of branches and roots

• Secondary growth

– Growth in diameter

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Page 16: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Plant Growth

• Meristematic tissue

– Region of plant cell growth

– Undifferentiated, unspecialized

– Rapid rate of mitosis

– Area of cell division

• Cells will differentiate later

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Page 17: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Plant Growth

• Apical meristem

– Found at tips of stems and roots

– Produces primary growth

– Cells formed here are primary tissues • Will differentiate into

stems, leaves , flowers later

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Page 18: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Plant Growth

• Primary growth – Growth occurs at

tip

– One cell pushed forward, will wear off

– One cell pushed back, will elongate causing growth

– Will later differentiate

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Page 19: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Plant Growth

• Lateral meristem

– Occurs as a ring of cells inside stems and branches

– Vascular cambium

• Produces secondary growth

• Cells here differentiate as they are formed – Xylem is pushed inside the ring and dies

» Form tree rings

– Phloem is pushed outside the ring

» Living cells that eventually die (bark) and wear away

» not permanent, no rings

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Secondary Growth

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Secondary Growth

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Page 22: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Secondary Growth

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Page 23: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Secondary Growth

• Secondary growth gives rise to tree rings

– One ring = one year in temperate regions

• Count rings to tell age of tree

– Rings wider when season is wet

• More water uptake expands cells further

• Width of rings tells about climate that year

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Page 24: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Tree Rings

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Page 25: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Lost Colony of Roanoke

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Page 26: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Plant Hormones

• What is a hormone?

– Molecule that binds to receptor protein and triggers reaction inside cell

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Page 27: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Plant Hormones

• What is a hormone?

– Molecule that binds to receptor protein and triggers reaction inside cell

• Hormones have target cells

– Different target cells may respond differently to same hormone

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Plant Hormones

• Plants respond to hormones

– Start growing

– Stop growing

– Bends towards light

– Differentiation of specialized cell types

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Page 29: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Plant Hormones

• Auxins

– Group of growth hormones

– Indoleacetic acid (IAA) most common

– Produced at stem tips, root tips, embryos, young leaves, fruit

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Page 30: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Plant Hormones

• Auxins

– Shoot growth (primary growth)

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Page 31: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Plant Hormones

• Auxins

– Shoot growth (primary growth)

• Auxin produced in apical meristem and migrates to zone of elongation

• Causes cells behind apical meristem to elongate

• Cut off stem tip – no more auxin, no more primary growth

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Page 32: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Plant Hormones

• Auxins

– Secondary growth

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Page 33: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Plant Hormones

• Auxins

– Secondary growth

• Auxin produced in apical meristem eventually migrates to zone of differentiation

• Auxin stimulates differentiation of secondary xylem and phloem

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Page 34: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Plant Hormones

• Auxins

– Abscission

• Dropping of leaves & fruit

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Page 35: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Plant Hormones

• Auxins

– Abscission

• Dropping of leaves & fruit

• Older leaf and fruit stems ↓ auxin production – Cells at base of stem disintegrate

– Leaves or fruit fall off branch

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Page 36: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Plant Hormones

• Auxins

– Phototropism • Growing tips bend

towards light

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Page 37: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Plant Hormones

• Auxins

– Phototropism • Growing tips bend

towards light

• Auxin migrates away from light

– Causes elongation on “dark” side of stem

– Stem bends toward light

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Page 38: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Plant Hormones

• Auxins

– Apical dominance

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Page 39: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Plant Hormones

• Auxins

– Apical dominance

• Auxin from apical meristem inhibits side branches – Pinch off apical meristem to get bushy plants

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Page 40: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Plant Hormones

• Auxins

– Gravitropism

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Page 41: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Plant Hormones

• Auxins

– Gravitropism • Stems grow up

• Roots grow down

• Stems and roots respond differently to auxin

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Page 42: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Plant Hormones

• Gibberellins – Group of growth

hormones

– produced in stems, young leaves, seeds

– Cell division and elongation • Stem elongation

• ↑ gibberellins gives long, thin stems w/few leaves

– Enhances auxins • Fruit development

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Page 43: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Plant Hormones

• Ethylene

– Ripens fruit

– Leaf abscission

– Fading of chlorophyll

– Fading of flowers

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• What do you do with an avocado to ripen it more quickly?

Page 44: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Plant Hormones

• Ethylene

– Ripens fruit

– Leaf abscission

– Fading of chlorophyll

– Fading of flowers

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Page 45: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Photoperiod

• Light helps regulate plant life cycle

– Most plants respond to amount of light/dark

– Flowering often triggered by photoperiod

• Short-day plants (actually long-night plants) – Flower early spring or fall

• Long-day plants (actually short-night plants) – Flower in summer

• Day –neutral plants respond to something other than photoperiod

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Page 46: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Photoperiod

• Mechanism for flowering

– Actually respond to #dark hours

• Phytochrome is agent of flowering

– Two forms – Pfar-red and Pred

– Pred → Pfar-red in light

– Pfar-red → Pred slowly in dark

• Phytochrome far-red is active form

– Inhibits flowering in short day plants

– Stimulates flowering in long day plants

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Page 47: Plant Structure and Function - Bakersfield College€¦ ·  · 2015-10-09Plant Structure and Function Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education,

Photoperiod

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Pfar-red stimulates flowers Pfar-red inhibits flowers