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Global Change Biology > Plants In A Changing Atmopshere > Flashcards

Plants In A Changing Atmopshere Flashcards

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1
Q

What are the 3 things plants respond to

A

Elevated co2
The impact of ozone depletion and increaed Uv-B
Air pollutants

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2
Q

What is the perturbed carbon cycle

A

Humans can release the locked carbon from carbon bearing rocks, shales and gases

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3
Q

What does more co2 entering the atmosphere than coming out else to

A

Increaed co2 concentrations

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4
Q

What drives the agricultural demands

A

Large populations suffering from hunger

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5
Q

What is the predicted growth rate of population

A

The rate is increasing but slowing down

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6
Q

What2 ways can increaed co2 affect plants

A

Directly and indirectly

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7
Q

What has happened to photosynthesis form the mid 20th century to the mid 21st century

A

Increased co2 concentration gradient
Increaed co2 uptake
Increased co2 concentration in leaf
Increaed rate of photosynteheis as more co2 in air spaces

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8
Q

What is a c3 plant

A

Co2 being fixed in plant as sugars containing 3 carbons

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9
Q

How do most plants fix co2

A

Using ribulose bisphosphate carboxylase-oxygenase (RUBISCO)

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10
Q

Why is rubisco most abundant protein on globe

A

Bc it’s in all plants

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11
Q

What are the two properties of rubisco

A

Carboxylase or oxygenase

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12
Q

What happens during photosynthesis in rubisco

A

Carboxylase to phosphotlyceetate to sugars (used in Calvin cycle to fix carbon as sugar) good for plant

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13
Q

What happens during photo respiration in rubisco

A

Oxygenase to phosphoglycolate to co2 it uses oxygen and takes fixed carbon to spit it co2 in other side

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14
Q

What is photorespiration classed as

A

An energetically wasteful process

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15
Q

Why is photorespiration not a useful process

A

Uses lots of energy and ATP as it does so not useful. Affects co2 gradient within leaf as it increases co2 in leaf.

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16
Q

What are the results of photorespiration

A

Increased co2 concentration in leaf
Decreased co2 concentration gradient
Decrease co2 uptake
Decreased rate of photosynthesis

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17
Q

What happens if there’s an increase in co2 concatenation in the Calvin cycle

A

Increase carboxylase activity - increases photosynthesis
Inhibits oxygenase activity - reduces photorespiration
Increased carbon fixed as C3 sugars

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18
Q

In C3 plants how does elevated atmospheric co2 concentration increase photosynthesis

A

By increasing the gradient for co2 and by increasing the efficiency of rubisco (decreasing photorespiration)

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19
Q

How does C4 plants photosynthesis

A

It is initially fixed as acid. These are then transported into bundle sheath cells and broke down into c3 acid and co2. In breaking them down the co2 allows the rubisco in the sheath cell to always be in a high co2 environment. Rubisco then fixes carbon dioxide in the Calvin cycle.. co2 has different effect therefore.

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20
Q

What happens in the mesophyll of a c4 plant during photosynthesis

A

Co2 fixed by PEP carboxylase as C4 acids (Malate/aspartate6

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21
Q

What happens in the bundle sheath of a c4 plant during photosynthesis

A

C4 acid broken down to co2 and fixed by rubisco

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22
Q

In C4 plants what does high co2 do

A

Surpressed rubisco oxygenase activity

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23
Q

In C4 plants how does elevated atmospheric co2 concentration increase photosynteheis

A

By increasing the gradient for co2 uptake

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24
Q

Why does increasing the co2 gradient in C4 plants have no effect in rubisco

A

They already have highco2 environment in the bundle shealth even under ambient atmospheric conditions

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25
Q

Example of C4 plant

A

Sugar cane

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26
Q

What does increasing co2 concentration result in C4 plants compared to c3 plants

A

Smaller increase in rate of photosynthesis

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27
Q

How does increaed co2 indirectly effect photosynteheis

A

Increasing temperatures lead to increasing photosynteheis

Temperature related increase in photosynthesis are far greater in C4 plants than C3

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28
Q

Why does increaed temp mean higher increase in C4 plants than C3 ones

A

Increase in oxygen means wasteful photorespiration but for C4 it’s always suppressed so no change

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29
Q

What happens to the rubisco cycle if we increase temperature

A

Increase oxygenase activity wnd increases photorespiration
Relatively small increase in carboxylase activity
Increased loss of fixed carbon

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30
Q

What effects does high temperature have on C4 plants

A

Minimal

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31
Q

What effect can increase in photorespiration with temperature have

A

A marked effect on crop photosynthesis and productivity

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32
Q

In which plant is the direct effect of infrwsed co2 on photosynteheis greater

A

C3

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33
Q

In which plant is indirect effect of increased co2 in photosynteheis via higher temperature greater

A

C4

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34
Q

What does overall effect on c3 and C4 species depend on

A

Region and climate : tempetehee and drought

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35
Q

What is the effect of increaed co2 in stomata

A 
Results in stomata closure:
No increase in photosynwthsis
Decrease water loss via transpiration
Decreased water loss while maintains photosynteheis 
Increased water use efficiency
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36
Q

What is WUE measured by

A

Yield per unit of crop water used

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37
Q

What is a way to measure stomata aperture

A

Thermal imaging. Take a field or a Forest and put a ring of gas releasing tubes and you make within the ring elevated co2 concentration to look at physiology or stomata apeture.

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38
Q

What does stomata closure in thermal imaging mean

A

The plant got hot as the pink is higher temperature and darker ones on outside are lower temps. Plants are warmer meaning less water is escaping through stomata

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39
Q

What does stomata closure show

A

Elevated co2 affects transpiration as well

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40
Q

How does elevated co2 increase water efficiency

A

You use more water more efficiently and you need less water to produce the crop making it more important in being drought resistant

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41
Q

What is the water use efficiency typically under elevated co2

A

20-25% higher

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42
Q

What can plants grown at elevated co2 have

A

An increased ability to cope with drought

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43
Q

What is the triangle for direct effects of elevated co2

A

Can effect temperature which has effects on drought. Interplay between all three.

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44
Q

Where is good ozone

A

Stratosphere

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45
Q

Where is bad ozone

A

Troposphere

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46
Q

Where is the upper part of the atmosphere

A

20km upwards

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47
Q

What is reducifon of ozone proportionate to

A

Useage of CFCs

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48
Q

Can ozone have localised effects

A

Yes w.g spring ozone depletion in Manchester

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49
Q

For each 1% decrease in stratospheric ozone what happens to uv-b radiation reaching the biosphere

A

There is a 2% increase

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50
Q

What is the wavelength of visible light

A

400-700nm

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51
Q

What is the name of visible light

A

Photosynthetically Active Radiation (PAR)

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52
Q

What is the wavelength of ultraviolet radiation

A

200-400nm

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53
Q

What percentage of environment UV is uv-b

A

5%

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54
Q

Why does uv-b has protential to be absorbed by biomolecules and causes significant damage

A

Short wavelength so highly energetic

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55
Q

Which uv light is affected by stratospheric ozone detention

A

Uv-b

56
Q

In humans what can uv-b lead to

A

Skin damage and ultimately cancers. Unable to repair dna damage

57
Q

Why does skin cancer develop

A

Damage caused by uv-b to dna that can not be repaired

58
Q

What can the absorption of uv-b in nuclei acids lead to

A

Cancer in high prevalence incidences

59
Q

What 4 things is uv-b radiation strongly absorbed by

A

Nucleic acids
Amino acids
Proteins
Plant hormones

60
Q

Examples of nucleic acids

A

DNA

RNA

61
Q

Examples of amino acids

A

Phenylalanine

Tyrosine

62
Q

Examples of proteins

A

photosynthetic ones

63
Q

Examples of plant hormones

A

IAA

GIbberellins might be influences so growth is reduced despite lack of change in photosynteheis

64
Q

How does uv-b damage affect plants

A

DNA damage does occur but it is repaired very quickly

Not much evidence that uv-b induced dna damage in plants is an issue in terms of ozone depletion

65
Q

How long does it take for plants to repair after exposure to uv-b

A

6 hours

66
Q

How does uv-b affect photosynthesis

A

Nothing dramatic in field. However reduced leaf area but not reduced photosynthesis

67
Q

Why do we have to be careful doing experiments on increased uv-b and photosynthesis

A

Quite often light level in field is less

68
Q

What may happen to plant growth due to increased uv-b

A

Reduce it with potential impacts of crops and natural ecosystems. Has ability to change ecosystem composition.
Not caused by damage to photosynthesis however.

69
Q

Why are changes in growth due to ozone dpwelerion likely to be small

A

Due to the implementation of the Montreal protocol (on substances that deplete the ozone layer)

70
Q

How does changes in uv-b raidqiron alrer the plant

A

Changes in primary metabolism, growth and morphology.

71
Q

What can we assume when we look at ecosystems rather than looking at individuals in isolation

A

We can expect to see different species responding differently to uv-b effects, changes in competitive ability in species and changes in composition of ecosystems

72
Q

How do plants acclimate to increaed uv-b

A

Accumulating uv absorbing pigments. This accumulation involves increased synthetic of phenolic compounds. These compounds are vital for defence against pests and disease.

73
Q

How is uv-b making plants more tolerant to uv-b and pedts and pathogens and decomposers

A

accumulation of uv absorbing pigments involves increased synthetic of phenolic compounds. These compounds are vital for defence against pests and disease.

74
Q

What does understanding the impacts of ozone depletion on ecosystems require

A

An understand of the responses of a wide range of organisms, processes and interactions

75
Q

What is uv-bs direct effect in decompose fungi (aspergillosis)

A

When it’s ambient it’s a diffuse colony of fungus and when it’s elevated it’s even more diffused. Sees marker impact on growth

76
Q

What is the responses to fungi isolated from birch litter after 2 months under ambient or elevated uv-b at a sub-Arctic field site

A

In ambient one takes up about 50% but in elevated there’s a significant increase and significant loss and some new species

77
Q

Example of uv-b reducing plant disease

A

Leaf blotch disease in wheat.
Increased uv-b before inoculation had no effect.
Increaed uv-b after inoculation significantly reduced the infection. Doesn’t matter what happens before the fungus encounters plant.

78
Q

When does solar uv-b reducing herbivory occur

A

Within the ambient range not just when uv-b is underwear due to ozone depletion

79
Q

What does normal variations in uv-b do to ecosystems

A

Some parts of the community are exposed to ambient level while some is exposed to less due to natural shading of canopy

80
Q

Where are the effects of uv-b likely to be most pronounced

A

In high latitude ecosystems

81
Q

What is a pollutant

A

A chemical that is in the wrong place and the wrong concentration at the wrong time with the potential to cause damage

82
Q

What is an air pollutant

A

Chemicals that are emitted into the atmosphere which adversely affect physical and bipggical systems

83
Q

What are the two kinds of air pollutants

A

Particulate air pollutants

Gaseous pollutants

84
Q

What are primary pollutants

A

Chemicals that are emitted directly into the atmosphere

85
Q

Examples of primary pollutants

A

Nitrogen monoxide

Sulphur dioxide

86
Q

What are secondary pollutants

A

Chemicals that are formed by the reactions in the atsmlpehte between primary pollutants and other agents

87
Q

Examples of secondary pollutants

A

Nitrogen dioxide

Ozone

88
Q

How does nitrogen monoxide turn to nitrogen dioxide

A

Complex reactions in photochemical smog

89
Q

What is the general term of nitrogen’s in atmosphere

A

NOx

90
Q

What are the natural origins of gaseous pollutants

A

Volcanoes

Swamps

91
Q

What do volcanoes emitted

A

Sulphur dioxide so smells

92
Q

What do swamps emit

A

Methane and hydrogen sulphide

93
Q

What are anthropogenic sources of gasesous pollutants

A

Domestic sources

Industrial sources

94
Q

What did a report in America say about domestic sources of pollutants

A

If you cooked a Sunday roast you are raising particulate concentration in your house for an hour higher than the sixth most polluted city in the world

95
Q

Power and heat 74.9%

A

What is the main cause of sulphur dioxide in the atmosphere

96
Q

What is the main cause of oxides of nitrogen in atmosphere

A

Power and heat 53.2% and transport 41.7%

97
Q

Why is diesel not good

A

Produces less co2 but more nox

98
Q

Historically how did some poor countries real with pollutants

A

Dilute and dispersal - big chimney into atmosphere . This can move things globally

99
Q

How do air pollutants get deposited back

A

Dpeendns on if they encounter water and go into solution - wet deposition.
Dry deposition - once deposited go into solution in water coming into intercellular air spaces on surface cells.

100
Q

How does dry deposition of so2 effect photosynthesis

A

Disruption of H+ gradient across thylakoids membranes.

Activity of pH-sensitive Calvin cycle enzymes (RUBISCO - ph optima of 9)

101
Q

What are the 2 sets of reactions to be aware of photosynthesis

A

Light reactions and dark reactions

102
Q

What are light reactions

A

We have electron transport leading to photophospherer relations, produces ATP

103
Q

What is dark reCtions

A

Carbon benson where where we fix carbon into sugar. Have h optima and alkaline ph of 9.

104
Q

What happens if the gaseous airpollutants go into photosynthesis

A

Make everything acidic and move it away from the optima for rubisco, less activity, less co2 fixed and less sugars produced. Reducing availability of carbon for plants

105
Q

What percentage does so2 inhibit growth in plants

A

7.5-25%

106
Q

What percentage does NOx inhibit growth

A

Up t 55%

107
Q

What does inhibiting of growth depend on

A

Concentration
Exposure
Particular plant
Genotype of plant

108
Q

Why does gaseous pollutants affect plants

A

The stomata is open for co2 which let’s other gases in. Under high light the stomata is open more causing more pollution to be allowed in than low light conditions.

109
Q

What is protongradient under normal gradient dissipated by

A

ATP synthase (light reactions) generating ATP energy through photo phosperal relations

110
Q

How does the disruption of H+ gradient across thylakoids membrane work

A

Acidic gases put more protons into stomata do when election transport tries to generate proton gradient the gradient no longer exists bc it generates high protons in thylakoids space and high concentrations of protons in stomata. Therefore no rpton gradient to dissipate. Reduces ATP production and energy. Disruption of gradient prevents ATP synthase activity. Light reactions disrupted a

111
Q

Why does acidic gases mean high concentration of protons in the stomata

A

Bc oh acidic is negative log hydrogen ion concentration. More hydrogen means more acidity

112
Q

How does acid rain affect souls

A

Increased acidity so hardest to survive

Loss of fertilise as nutrients leached out

113
Q

How does acid rain effect plants

A 
Weathering of waterproof cuticle.
Reduced growth
Leaching of cations from the leaves
Seed germination, early seeding growth.
Flowering/seed formation
114
Q

What is the relationship between soil acidity and nutrients

A

As soil acidity increases and nutrient flow does there’s an increase in loss of nutrients.
High nutrient flow and low soil acidity has high plant uptake of nutrients.

115
Q

What can wet deposition affect

A 
Pine ‘burning’
Castor bean
Grape
Wheat 
Radish
116
Q

What are symptoms of ozone a product of

A

Oxidative damage

117
Q

What are the symptoms, least to worse, of ozone

A

Water soaked appearance - damage to membranes.
Chlorotic flecking.
Stipple of dead or pigmented cells.
Growth suppression, early abscission - Loss of organs through loss of leaves. Damage to biomolecielsz

118
Q

How does ozone oxidatively damage biomolecules

A

Membrane lipids - outside of cell damages.
Proteins - inside.
DNA - nucleic acid.

119
Q

Scientific name for water soaked appeared

A

Chlorosis

120
Q

Examples of ozone damage in crops

A 
Potato
Tomato
Broad bean
Wheat
Oat 
Pine
121
Q

What is global warming

A

An average increase in the earths twmperaturw that in turn causes changes in climate

122
Q

What are greenhouse effect

A

Trapping of infrared radiation, produced when solar radiation is absorbed and then partially re-emitted by the atmosphere

123
Q

What is a greenhouse gas

A

Any gas that absorbs infrared radiation in the atmosphere

124
Q

What is climate change

A

Changes in climate resulting from global warming

125
Q

What is short radiation reradiated as

A

Longradiation

126
Q

What happens if you increase greenhouse gases

A

The greater retention of heat and greater warming

127
Q

What would the temperature of the world be without greenhouse effect

A

-18*C

128
Q

What percentage of global warming does co2 contribute

A

77%

129
Q

What percentage of global warming does n2o contribute

A

8%

130
Q

What percentage of global warming does o3 contribute

A

8%

131
Q

What is the warming potential of co2, n2o and 03 respectively

A

1:310:2000

132
Q

What is the concentration in ppb of co2

A

379 x103

133
Q

What is the concentration in ppb of N20

A

313

134
Q

What is the concentration in ppb of o3

A

20

135
Q

What is the warming potential of CFCs and their concentration in atmosphere

A

10 thousands, 1-2%

136
Q

What are some widespread impacts of climate change

A 
UK floods
Australian coral reefs
Wildfires in Europe
El Niño in Indonesia
Antarctica melts
Coastal flooding in bangladesh

Global Change Biology (6 decks)

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