1. Biology 633 Environmental Plant Physiology
Study of how the environment affects the function of plants
Alpine tundra
Desert
Tropical rainforest

2. 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

3. 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

4. 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

5. Lecture 1 Learning 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

6. Plants: static or dynamic?

7. Visually stunning

8. Their structures respond to changes in environment (e.g. shade)

9. Their metabolism is constantly changing response to large variations in environment

10. Temporal variation in temperature

11. …….and light intensity

12. Global environment is also changing
e.g. greenhouse gases, temperature, nutrients, UV-radiation

13. Rising atmospheric CO2 concentrations
Atmospheric CO2 concentration (ppm)
Year

14. …….enormous flow of CO2 in and out of leaves

15. …….and these are cells that remove CO2 from the atmosphere

16. 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?

17. Question: how do plants cope with excess light when it is very cold?
e.g. avoid the morning sun

18. Question: how do plants cope with soils deficient in phosphorus. e. g
Question: how do plants cope with soils deficient in phosphorus? e.g. grow cluster roots

19. Question: how do plants cope with excessive salt?
e.g. sequester salt in salt bladders

20. Question: how do plants manage to grow in deep shade. e. g
Question: how do plants manage to grow in deep shade? e.g. use light flecks

21. 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

22. Question: what mechanisms enable the barley variety on the left cope better with manganese deficiency than the variety on the right?

23. 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

24. Global atmospheric CO2 concentrations: importance of plants
Plant respiration
Photo- synthesis

25. 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

26. 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

27. 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 environment e.g. short- and long-term changes in temperature
Stress response
Acclimation response
Adaptation/evolution response
Fig. 3. Lambers et al Plant Physiological Ecology, Springer.
Stress response
Occurs over seconds, minutes, hours and days. Will reduce the performance of the plant
Acclimation response
Morphological and physiological adjustments that occur in individual plants to compensate for the decline in performance. Can result in homeostatic adjustment
Adaptation/evolutionary response
Results from genetic changes in a population of a plant species, leading to morphological and physiological compensation for the decline in performance caused by stress.
Note Not all genetic differences among populations reflect adaptation. Plants may differ genetically because their ancestral species or populations were genetically distinct before they arrived in a particular habitat. Also, not all traits exhibited by a species are necessarily beneficial or that they resulted from natural selection in their environment

28. Stress and acclimation (of an individual) vs
Stress and acclimation (of an individual) vs. adaptation (a long-term genetic response)