Biology 633
Environmental Plant Physiology
Study of how the environment affects the
function of plants
Alpine tundra
Desert
Tropical rainforest
[email protected]
Module overview
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Discuss interplay between the genetic
potential of plants and environments in which
they grow
Impact of short-term changes in the
environment on physiology, morphology and
growth of plants
Stress response, acclimation and adaptation of
plants in response to changes in environment
16 lectures and 4 practical sessions
Overview of lectures
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Introduction to Environmental Plant Physiology
Response of plants to their environment
Plant growth analysis
Photosynthesis; mostly C3 plants
C4 and CAM plants
Respiration
Water, drought and plant growth
Adaptation of plants to growth on the sea floor
Recommended texts
 Lambers, Chapin & Pons (1998)
Plant Physiological Ecology
 Atwell, Kreidemann & Turnbull
(1999) Plants in Action
 Fitter & Hay (1987)
Environmental Physiology of Plants
 Larcher (1995)
Physiological Plant Ecology
 Taiz & Zeiger (1991)
Plant Physiology
Lecture 1
Learning objectives
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Define Physiological Ecology
Appreciate dynamic nature of the
plant/environment interaction
Be familiar with variations in environmental
conditions between and within habitats
Importance of time scales in determining
response of plants to their environment
Plants: static or dynamic?
Visually stunning
Their structures respond to changes in
environment (e.g. shade)
Their metabolism is constantly changing
response to large variations in
environment
Temporal variation in temperature
…….and light intensity
Global environment is also changing
e.g. greenhouse gases, temperature,
nutrients, UV-radiation
Atmospheric CO2 concentration (ppm)
Rising atmospheric CO2 concentrations
Year
…….enormous flow of CO2 in and out of leaves
…….and these are
cells that remove
CO2 from the
atmosphere
What is Environmental Plant
Physiology (EPP)?
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Study of how the environment affects the
function of plants
Requires knowledge of biochemistry, physiology,
anatomy and morphology of plants
Provides causal, mechanistic explanations for
ecological questions such as:
- Why does a species live where it does?
- How does it survive, and why is that
species absent from other environments?
Question: how do plants cope with excess light
when it is very cold?
e.g. avoid the
morning sun
Question: how do plants cope with soils deficient in
phosphorus?
e.g. grow cluster roots
Question: how do plants cope with excessive salt?
e.g. sequester salt
in salt bladders
Question: how do plants manage to grow in deep
shade?
e.g. use light flecks
Environmental Plant Physiology &
Agriculture/Forestry
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EPP is also closely linked to the study of plant
performance in agriculture
Agricultural production is limited in many
countries by stresses such as drought, nutrient
availability, salinity, temperature
Need to develop crops that are less sensitive to
those stresses, so we can grow them in less
favorable environments
Understanding required of the physiological
mechanisms that enable plants to cope
Question: what mechanisms enable the barley variety on
the left cope better with manganese deficiency than the
variety on the right?
Environmental Plant Physiology &
Global Change
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Need to predict effect of future changes in
global environment on crop productivity,
competitive interactions among species etc
Also need to know the extent to which plants
could reduce future increases in elevated
atmospheric CO2
Global atmospheric CO2 concentrations: importance of plants
Photosynthesis
Plant
respiration
Environmental Plant Physiology &
Molecular Biology
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Mutants/transgenics
may allow a rigorous
test of hypotheses
e.g. transgenic tobacco
plants to assess
importance of Rubisco
(CO2 fixing enzyme in
plants) for plant growth
Why so few plant species in one
place?
Filters
Some species do not
occur in the UK, because
they were never
introduced
Others arrived, but never
made it to maturity
Some evolved locally, or
were introduced and
‘made it’
Filters are constantly
changing/interacting
Response of plants to their
environment: time scales
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Time scale of physiological response is important
in determining how a plant copes with changes
in the environment
e.g. short- and long-term changes in
temperature
Stress response
Acclimation response
Adaptation/evolution response
Stress and acclimation (of an individual) vs.
adaptation (a long-term genetic response)