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ecology exam 2 and 3 > chapter 6 plant adaptations > Flashcards

chapter 6 plant adaptations Flashcards

1
Q

Sunlight

A

Primary Energy Source
Exception in Deep Sea Hydrothermal Vents
Energy from Oxidation of Hydrogen Sulfide

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2
Q

PAR

range of

A

photosynthetic active radiation

-range of visible spectrum of light

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3
Q

Spectrum of Light

A

Energy Varies on Wavelength
Ultraviolet (< 400 nm)
Visible Spectrum (400 – 700 nm) range of PAR for plants for photosynthesis
Infrared (>700 nm)

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4
Q

Pigments Absorb Energy

A

Chlorophyll-reflect green, absorb Red and blue
Carotenoids-absorb green, reflect red, yellow, autumn leaves
Phycobilins-bacteria, absorbs wider range, blue green color

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5
Q

Water & Light

  • long vs. short
  • what light at depth
  • what light at surface
A 
Water Limits Energy from Light
Absorbs Light quickly
-----Longer Wavelengths – Infrared Light 
Scatters Light
------Short Wavelengths Most
Green Light Predominates at Depths
white light  at surface
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6
Q

Adaptations to Light In Water

A

Deeper Plants must Harness Different Range of Light
Ulva absorbs Red & Blue-mirror chlorophyll
—–Shallow
—-Green Alga
—-Similar to Terrestrial
Porphyra absorbs green-mirrors carotenoids
——deep
——Red Alga

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7
Q

Photosynthesis

A

6 CO2 + 6 H2O → (CH2O)6 + 6O2

-uses sun, carbon, water-> produces sugar and oxygen

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8
Q

Respiration

A

(CH2O)6 + 6O2 → 6 CO2 + 6 H2O
uses sugar and oxygen-> to produce carbon and water
Gives off Heat
Converts ADP to ATP

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9
Q

Light Dependent

A

Uses light energy to Chemical Bond energy (ATP)

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10
Q

Light Independent

A

Uses ATP to convert CO2 into simple sugars
Does not require sunlight, BUT
Limited by ATP availability from Light Reactions

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11
Q

C3 Photosynthesis
catalyzed by
Net Photosynthesis=

A

CO2 + ribulose bisphosphate (5 carbon sugar)
Produces phosphoglyceric acid (3 carbon acid)
Catalyzed by Rubisco
Net photosynthesis
Photosynthesis − Respiration
Usually measured in moles CO2 per leaf area (or mass) per unit time

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12
Q

C3 pathway has one major drawback
rubisco is also an
and results in
reduces what

A

Rubisco is also an oxygenase
Can catalyze reaction between O2 and RuBP
Results in photorespiration – the release of CO2
Occurs when Internal CO2 levels low
Reduces the efficiency of C3 photosynthesis by as much as 25%

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13
Q

Photosynthesis related to light availability

A

Rate increases quickly at low light
Slows as intensity increases
-as light increases photosynthesis increase, continues to increase, photosynthesis decreases

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14
Q

Light compensation point (LCP)

A 
Light level (PAR) at which:
Net photosynthesis = 0
CO2 uptake = CO2 loss 
photosynthesis = respiration
-all equal all balanced out
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15
Q

Light saturation point

A

value of PAR above which photosynthesis does not increase

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16
Q

Photoinhibition

A

Rate of photosynthesis declines as PAR exceeds saturation point
Seen in some shade-adapted plants

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17
Q

Reactions of photosynthesis take place in

A

mesophyll cells

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18
Q

Stomata
driven by
determined by

A 
Openings on the leaf surface 
Allow CO2 to enter
-Driven by Diffusion/Gradients
-determined by
------stomatal density
number per unit leaf surface area
------Aperture
size of stomatal openings
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19
Q

Stomatal Aperture

  • open when
  • close when
A 
Controlled by Plant
Open when:
CO2 concentration outside > inside leaf 
Closed when:
Photosynthesis reduced
Demand for CO2 reduced
Often based on Water Availability
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20
Q

Wip= Wr + Wa - Wt - Ws

A 
Wip= Plant’s internal water
Wr = Roots
Wa = Air
Wt = Transpiration
Ws = Secretions
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21
Q

plants must move water, movement against, and ____size

A

from soil to roots-from soil to roots, from roots to uppermost parts-friction

and limits size

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22
Q

Extent of plant root development
Reflects differences in:
deeper roots help plants that live in

A

Evolutionary History
Water availability.
Deeper roots
Help plants in dry environments extract water from deep within the soil profile.

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23
Q

Turgor pressure

plants function best when

A

Force exerted outward on a cell wall by the water inside the cell
plants function best when their cells are fully hydrated (at maximum turgor)

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24
Q

Vascular Plants

A 
Plants with internal structure for fluid movement
Xylem
Water Movement
Tracheids 
-------Structural & Movement
Vessel Elements
-------Mainly Movement
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25
Q

Water Transport occurs because of

A

Transpiration

Cohesive Properties of Water

26
Q

Transpiration
water moves to
Transpirational Pull
acts as

A 
Transpiration
Water Vapor Lost from Leaves
Water moves to Equalize Osmotic Pressure
Transpirational Pull
Force or tension in leaves due to transpiration
Affects Water Column in Xylem
Acts as Lower Atmospheric Pressure
27
Q

Cohesive Properties of Water

as it gets smaller=

A

Cohesion of Water

Capillary Action-as it gets smaller, more capillary action

28
Q 
Water Movement Between Soils and Plants
flows down a 
water potential symbol is
pure water has a water potential of 
water potential in nature generally
A 
Water moving between soil and plants flows down a water potential gradient.
Water potential (ψ) 
The capacity to perform work.
Dependent on free energy content.
Pure Water ψ = 0.
ψ in nature generally negative.
29
Q

ψ plant = ψ π + ψ m + ψ p

as long as what, water flows from soil to plant

A

ψ π
Reduction in ψ due to dissolved substances.
ψ m
Reduction in ψ due to Matric Forces
Tendency to adhere to container walls
ψ p
Reduction in ψ due to negative pressure created by Transpiration & changes in Turgor pressure
As long as ψ plant < ψ soil, water flows from the soil to the plant.

30
Q

water movements in plants
go from areas of ____ water potential to ____ water potential
As water moves from soil to root to leaf to atmosphere:
Stomata close at night and ψleaf becomes

A

Movement goes from areas of higher water potential to lower potential
Depends on increasingly negative water potential
As water moves from soil to root to leaf to atmosphere:
ψatm < ψleaf < ψroot < ψsoil
There is daily variation in ψleaf and ψroot
Stomata close at night and ψleaf
Less negative because water is not being lost

31
Q

Water loss through transpiration will continue as long as:

roots are able to maintain more ____ water potential than soil

A

light energy striking the leaf supplies enough heat for evaporation
moisture is available in the soil
Roots are able to maintain more negative water potential than soil

32
Q

at field capacity
water is
water potential of soils is close or at

clay soils have a more ____ water potential than sandy soils

A 
At field capacity
water is freely available
ψsoil is at or close to zero
As water is taken from the soil
ψsoil becomes more negative
water holds more tightly to the soil
ψm becomes more negative
Strongly affected by soil type
clays soils have a higher surface area so have more negativeψm than sandy soils
33
Q

soil and water
-wilting coefficient
less water= ____ hold by soil particles

A 
Availability of Water to Plants:
Amount of water present
Ability of Soils to Hold water
Wilting Coefficient 
Minimum water content of uptake
Less Water-> Tight hold by soil particles
34
Q

Water & Wilting
water uptake dependent on
-modify ____ concentration
-ability of plants to survive depend on ______

A

Water Uptake Dependent on Osmotic Pressure
Modify Solute Concentration
Ability of Plants to Survive Depend on Evolution
Desert Plants
Changing Environments

35
Q

Water & Photosynthesis
-as soil dries water potential of root and leaf must also
become more ____ in order to maintain water potential gradient
when gradient is lost
stomatas
photosynthesis

A 
As soil dries:
ψroot and ψleaf must also become more negative to maintain the water potential gradient
When Gradient is lost
Stomatas must close
Photosynthesis Ceases
Varies among plants
36
Q

Rate of transpiration 

varies depending on what factors
controlling the stomata is the plants most important way to regulate what

water use efficiency
higher ratio=
lower ratio=

A

Varies daily depending on:
Environmental conditions
Characteristics of an individual plant
Controlling the stomata
Plant’s most important way to regulate water loss
leads to a trade-off
Taking in CO2 for photosynthesis
Losing water that it requires to live
Water use efficiency
Ratio of carbon fixed per unit of water lost
higher ratio=arid climate lower ratio= moist climate

37
Q 
Aquatic Autotrophs
CO2 diffuse water across
no 
uses enzyme 
what layer is important it is an area of
A 
no cell wall
CO2 diffuses water across cell membrane
Some can use bicarbonate as a carbon source
convert HCO3− to CO2 
Using the enzyme carbonic anhydrase
Boundary Layer Important
Area of unstirred water 
May become deprived of CO2
38
Q

temp in photosynthesis vs respiration

A

Temperature important Both for respiration & photosynthesis
Maximum temperature for reactions
*Photosynthesis lower than cellular respiration

39
Q

Most solar radiation not used for photosynthesis

what is the main avenue for heat loss

A

Most solar radiation not used for photosynthesis
Potential for heating (or overheating) plants
Evaporation
Main avenue for heat loss in terrestrial plants
Part of Transpiration

40
Q

Balancing Heat Gain Against Heat Loss

A

HS = Hm ± Hcd ± Hcv ± Hr - He

HS = Total heat stored in an organism
Hm = Gained via metabolism
Hcd = Gained / lost via conduction
Hcv = Gained / lost via convection
Hr = Gained / lost via electromag. radiation
He = Lost via evaporation
41
Q

Temperature Regulation by Desert Plants

A 
Desert Plants: Must reduce heat storage.
Hs = Hcd + Hcv + Hr
To avoid heating, plants have (3) options:
Decrease heating via conduction (Hcd).
Increase convective cooling (Hcv).
Reduce radiative heating (Hr).
Missing Hm + He ?
42
Q

Temperature Regulation by Arctic Plants

A

Arctic and Alpine Plants
Two main options to stay warm:
Increase radiative heating (Hr).
Decrease Convective Cooling (Hcv).

43
Q

Plants Adapt to Their Environments

allocate carbon more to

A

Conditions can lead to trade-offs
adaptations for one may not be as effective in a different environment
Results in differing suitability
Carbon Distribution
Allocating more to leaves & stems
increases access to light & CO2
Reduces carbon available to produce roots
Decreases access to water & soil nutrients

44
Q

Shade intolerant plants

A

adapted to high-light environments

45
Q

Shade tolerant plants
adapted to
limited to

A 
adapted to low-light environments
Produce less rubisco
Require less energy 
Leaf respiration lower
light saturation point is lower
Limited in High Light Environments
46
Q

shade tolerant and intolerant
leaf size and thiness
Surface leaf area

A

Shade-tolerant and shade-intolerant species also show differences in leaf morphology
Specific Leaf Area (SLA)
ratio of surface area weight (cm2 : g)
Surface area of leaf produced per gram of biomass allocated to leaf production

shade tolerant- leaves thinner, greater SLA, larger leaves
Shade intolerant-leaves thicker, smaller SLA, smaller leaves

47
Q

C3 Photosynthesis

A

Used by most plants and algae.
CO2 + ribulose bisphosphate (5 carbon sugar) = phosphoglyceric acid (3 carbon acid)
To fix carbon, plants must open stomata to let in CO2 .
Water gradient may allow water to escape.
Photorespiration can become a problem

48
Q 
C4 Photosynthesis
need fewer what 
reduce what 
increase rate of what 
diffuse to specialized cells surrounding
A 
Reduce internal CO2 concentrations.
Increases rate of CO2 diffusion inward.
Need fewer stomata open.
Conserving water
Acids produced during carbon fixation diffuse to specialized cells surrounding bundle sheath.
49
Q

CAM Photosynthesis
____ rates of photosynthesis
_____rates of water use efficiency

A

(Crassulacean Acid Metabolism)
Limited to succulent plants in arid and semi-arid environments.
Carbon fixation takes place at night.
Reduced water loss.
Low rates of photosynthesis.
Extremely high rates of water use efficiency.

50
Q 
C3 Photosynthesis
adaptations
assimilate in \_\_\_ biochemical process
mostly \_\_\_\_ environment
requires opening of \_\_\_
lead to \_\_\_\_
A

Assimilate Carbon in single biochemical process
Calvin-Benson Cycle
Mostly Mesic Environments
CO2 availability Limiting Factor for photosynthesis
Requires Opening of Stomata
Leads to Water Loss

51
Q 
C4 Photosynthesis adaptations
\_\_\_\_ separates
initial c assimilation where
Calvin benson cycle where
what kind of environments what kind of plants
A

Assimilate Carbon in 2 biochemical processes
Spatially Separates:
Initial C assimilation (4-carbon acid) – Mesophyll
Calvin-Benson Cycle (C3 Process) – Bundle Sheath
CO2 availability Limiting
Not as much as C3
Can Concentrate in Bundle Sheath Cells
Increases Stomatal Resistance
Reduces Water Loss
Mostly Xeric Environments
Grasses

52
Q 
CAM adaptations
\_\_\_\_\_\_ separates
initial assimilation-
Calvin benson cycle
open stomata during 
\_\_\_ environments
A 
CAM Photosynthesis
Crassulacean acid metabolism
Assimilate Carbon in 2 biochemical processes
Temporally Separates:
Initial assimilation (night)
Calvin-Benson Cycle Temporally (Day)
Only open stomata during night
Mostly xeric Environments
Desert Succulents
53
Q

tradeoffs of diff photosynthesis c3 c4
photosynthesis at what temperatures
which is more efficient high levels of CO2

A

c3 high photo at low temps-loose photosynthesis at not that nigh temps compared to c4
c4 high photo at high temps

c3 efficient at high levels of co2

54
Q

C3, C4, CAM plants

which one will predominate

A 
Tell story of Historic Temperature Changes
C3 more adapted to cool environments
C4  more adapted to warm environments
Presently
Increasing Temperatures
Increasing CO2
Which One will Predominate?
C3
55
Q

Photosynthesis & Climate Change

A 
Greenhouse Gasses Trap Heat
Maintain Physiological Temperature
Human Activities Increase Effect
Effects Distribution of C3 & C4 plants
Increase Efficiency of C3 
C4 plants expanded during low CO2
Question: How Does Temperature Play?
56
Q

Aquatic Plants utilize what kind of photosynthesis

A

Many Utilize C4 & CAM mechanisms
Balance CO2 an O2 levels
Time Photosynthesis to Coincide with Availability of C02

57
Q 
Water, Temperature & Plants
for dry environments
fewer smaller 
increases \_\_\_\_ efficiency 
greater allocation to
A 
Water & Temperature are central to plant Adaptations
Often a trade-off is required.
Dry Environments
Fewer, smaller stomatas
Increased water-use efficiency
Decreased photosynthic rates
Greater Allocation to roots
58
Q

Water, Temperature & Plants adaptations to seasonal variations, dry environments
drought deciduous

A

Adaptations to Seasonal Variations
Drought Deciduous
Grow new leaves before rainy season
May drop leaves during hot, dry times

59
Q

Adaptations to Seasonal Variations
cold tolerant plant
-frost Harding
winter deciduous

A 
Cold-tolerant plants
Frost hardening 
Genetic ability to tolerate extreme cold
variable within and among species
Produce compounds allowing leaves to survive freezing temperatures
needle leaf evergreens – pine and spruce
Winter deciduous 
Shed leaves before beginning of the cold season
60
Q

Macronutrients

needed in

A

Needed in large amounts
carbon, hydrogen, oxygen
derived from CO2 and H2O
nitrogen, phosphorus, potassium, calcium, magnesium, sulfur
terrestrial plants acquire from the soil
aquatic autotrophs acquire from the substrate or water

61
Q

Micronutrients (trace elements)

A

Needed in smaller amounts

62
Q 
plants and nutrients
in low nutrient environment 
-absorb \_\_\_ nutrients in fertile soils \_\_\_\_ levels when nutrients are limited
\_\_\_\_ root to shoot ratio
\_\_\_\_\_\_ leaf longevity
A 
Plants in low-nutrient environments 
Possess a number of adaptations
Low absorption rate 
Absorb fewer nutrients in fertile soils, but 
Higher levels when nutrients are limited
Higher ratio of roots to shoots
Lower growth rate
Increased leaf longevity

ecology exam 2 and 3 (10 decks)

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