Biology 633 Environmental Plant Physiology Tropical rainforest Alpine tundra Desert...
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Transcript of Biology 633 Environmental Plant Physiology Tropical rainforest Alpine tundra Desert...
Biology 633Environmental Plant Physiology
Tropical rainforest
Alpine tundra
Desert
Study of how the environment affects the function of plants
Module overview 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 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 1Learning objectives 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 changinge.g. greenhouse gases, temperature,
nutrients, UV-radiation
Year
Atm
osp
he
ric
CO
2 c
on
cen
tra
tio
n (
pp
m)
Rising atmospheric CO2 concentrations
…….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)?
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 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
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
Photo-synthesis
Plant respiration
Global atmospheric CO2 concentrations: importance of plants
Environmental Plant Physiology & Molecular Biology
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?
FiltersSome 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 Time scale of physiological response is
important in determining how a plant copes with changes in the environmente.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)