Transcript Plant Form and Function

Plant Form and Function
Learning Goal:
How are plants structurally adapted for survival?
Concept 3: Analyzing how plants detect and defend themselves
against herbivores and environmental stresses (Ch 39)
Refer to
pg 219-222 in Holtzclaw
Ch 39 in Campbell
Media resources
Checkpoint Next Class:

Concept 1: Analyzing the structure, growth,
development and nutrition of plants (Ch 35, 37)

Concept 2: Analyzing the reproduction of
angiosperms and modifications through biotechnology
(Ch 38)

Concept 3: Analyzing how plants detect and
defend themselves against herbivores and
environmental stresses (Ch 39)
Try This!
Which of the following constitute plant
macronutrients?
A.
B.
C.
D.
E.
Potassium, oxygen, hydrogen and zinc
Carbon, oxygen, nitrogen and copper
Carbon, oxygen, nitrogen, and hydrogen
Carbon, boron, nitrogen, and chlorine
Phosphorus, oxygen, nitrogen and iron
Try This!
Which of the following constitute plant
macronutrients?
A. Potassium, oxygen, hydrogen and zinc
B. Carbon, oxygen, nitrogen and copper
C. Carbon, oxygen, nitrogen, and
hydrogen
D. Carbon, boron, nitrogen, and chlorine
E. Phosphorus, oxygen, nitrogen and iron
CHNOPS!!
Try This!
In double fertilization, how is the
endosperm formed?
A.
B.
C.
D.
E.
The fusing of two sperm and an egg
From the epidermis
From the fertilization of the egg
From the zygote during development
From the fusing of a sperm with two polar
bodies
Try This!
In double fertilization, how is the
endosperm formed?
A.
B.
C.
D.
E.
The fusing of two sperm and an egg
From the epidermis
From the fertilization of the egg
From the zygote during development
From the fusing of a sperm with two
polar bodies
From Last Class… Free Response

Page 820 in Campbell – Assess next class
◦ # 12 Evolution Connection
With respect to sexual reproduction, some plant
species are fully self-fertile, others are fully selfincompatible, and some exhibit a “mixed strategy”
with partial self-incompatibility. These reproductive
strategies differ in their implications for evolutionary
potential. How, for example, might a self-incompatible
species fare as a small founder population or remnant
population in a severe population bottleneck
(see Ch 23), as compared with a self-fertile species?
From Last Class… Free Response

Free Response – Evolution Connection
Small populations of self-incompatible species, whether due
to being founding populations or to bottleneck, would be
at a disadvantage relative to self-fertile species. Small
populations already have significant challenges in avoiding
extinction. Adding the fact that they cannot perform sexual
reproduction independently of other organisms merely
adds to the list of challenges.
Beginning
Does not
demonstrate a
basic
understanding of
concept.
Substantial errors
throughout.
Developing
Basic
understanding of
concepts. Errors
and inconsistency
reveal some
missing elements.
Accomplished
Solid
understanding of
concepts. Most
answers are
correct. Few
errors.
Exemplary
Complete and in
depth
understanding of
concepts.
Answers are
correct, with
elegant
connections.
Concept 3: Analyzing how plants detect and
defend themselves against herbivores and
environmental stresses (Ch 39)
Concept 3: Analyzing how plants detect and
defend themselves against herbivores and
environmental stresses (Ch 39)
You must know:
The three steps to a signal transduction pathway
 The role of auxins in plants
 The survival benefits of phototropism and
gravitropism
 How photoperiodism determines when flowering
occurs

Try This!
Both plants and animals respond to environmental stimuli.
Which of the following statements are true and which
ones are false?
A.
The processes by which plants and animals perceive
environmental changes are equally complex.
B.
The processes by which plants and animals perceive
environmental changes are often homologous.
C.
Unlike animal hormones, plant hormones act only locally.
D.
Both plants and animals have physiological cycles called
circadian rhythms.
Try This!
Both plants and animals respond to environmental stimuli.
Which of the following statements are true and which
ones are false?
The processes by which plants and animals perceive
environmental changes are equally complex.
TRUE
B. The processes by which plants and animals perceive
environmental changes are often homologous.
TRUE
C. Unlike animal hormones, plant hormones act only locally.
FLASE
D. Both plants and animals have physiological cycles called
circadian rhythms.
TRUE
A.
Try This!

What are the morphological differences
in dark-grown plants and light-grown
plants?
Try This!

What are the morphological differences
in dark-grown plants and light-grown
plants?
◦ Dark- grown have




long stems
underdeveloped roots
unexpanded leaves
shoots lack chlorophyll
How does this potato change its growth
when there is light?
How does this potato change its growth
when there is light?


Via the Signal Transduction Pathway!
How does this potato change its growth
when there is light?


Via the Signal Transduction Pathway!
◦ The signal (light) is transduced to a response (greening)
Signal Transduction - Review
Reception
 Transduction
 Response

Signal Transduction - Review

Reception: Receptors undergo changes in shape
due to an environmental stimulus
◦ Ex) phytochrome proteins changing in response to light
Signal Transduction - Review

Transduction: Amplification of signal through a
multistep pathway
◦ Allows small signal to produce large cellular response
 Uses protein kinases (phosphorylation cascade)
and second messengers (Ca2+ and cAMP)
Signal Transduction - Review
Response: Two ways response is accomplished:

1.
Transcriptional Modification:
•
2.
↑ or ↓ mRNA production (turning genes on/off)
Post-Translational Modification:
•
Activates existing enzyme molecules
Signal Transduction

For example, affected proteins for this
potato exposed to light include:
◦ Photosynthesis enzymes
◦ Plant growth hormones
 Auxin levels lower to slow stem growth
(focus on leaf growth)
So…. What was AUXIN?

A plant hormone…

Yes, plants have hormones too!
Examples of Plant Hormones

Auxins – stimulate elongation of cells within young
developing shoots

Cytokinins – stimulate cell division

Gibberellins – stimulate stem elongation, pollen,
fruit, seed development

Abscisic acid – promotes stomatal closure during
drought stress

Ethylene (gas!) – fruit ripening, leaf abscission
Plant Hormones

Hormones: chemical messengers that
coordinate the different parts of a
multicellular organism

Tropism: Plant growth response toward
or away from a stimulus
◦ Phototropism
◦ Gravitropism

How does this benefit survival?
Phototropism - Mechanism
Phototropism - Mechanism
Phototropism - Mechanism
Actions of hormones…

Photoperiodism – physiological
response to a photoperiod (relative
lengths of day and night)
◦ Example: Flowering
 Short day plants
 Long day plants
 Day-neutral plants

Circadian rhythms – physiological cycles that
have a frequency of about 24 hours
Responses to Mechanical Stimuli

Mimosa Plant
Herbivore Defense
Video Clip
Think:

Illustrate this statement with an example:
“A plant generally responds to
environmental cues by adjusting its
pattern of growth and development.”
How do plants detect and defend themselves
against herbivores and environmental stresses?
Do you know?
 The three steps to a signal transduction
pathway
 The role of auxins in plants
 The survival benefits of phototropism and
gravitropism
 How photoperiodism determines when
flowering occurs
Checkpoint Next Class:

Concept 1: Analyzing the structure, growth,
development and nutrition of plants (Ch 35, 37)
# 12, 13, 15, 16, 20, 21, 24 in Holtz

Concept 2: Analyzing the reproduction of
angiosperms and modifications through biotechnology
(Ch 38)
#5, 22, 23 in Holtz

Concept 3: Analyzing how plants detect and defend
themselves against herbivores and environmental
stresses (Ch 39)
# 1, 2, 7, 8, 9, 10, 11, 14, 25 in Holtz