Goals and Objectives:
- The following is a list of the new terms in this chapter. Define each of these terms:
- Primary Productivity (PP)
- Gross Primary Productivity (GPP)
- Net Primary Productivity (NPP)
- Carbon Gain
- Carbon Economy
- Growth Respiration
- Maintenance Respiration
- Light Compensation Point
- Sequential Senescence
- Leaf Area Index
- Heliotropism / Solar Tracking
Respiration and Carbon Economy
- Which of the two Primary Productivity measures is the one that is most important to plant productivity?
- Why is plant productivity based on carbon gain, and not rate of the light reactions of photosynthesis or carbon fixation (C3, C4, CAM)?
Factors Influencing Photosynthesis and Productivity
- When determining plant productivity, which of the following has the greatest affect and why? Growth Respiration or Maintenance Respiration
- How does growth and maintenance respiration vary in a plant (i.e. between different plant tissues)?
- How might one control the amount of carbon lost by maintenance respiration?LightPrimary Productivity on a Global Scale
- What is the light compensation point? How does it vary between C3 and C4 plants?
- What is the light saturation point? How does it vary between C3 and C4 plants?
- From these last two questions - what do your answers tell you about productivity in C3 and C4 plants?
- How do plants respond to light over a whole growing season?
- How do C3 and C4 plants differ in their utilization of CO2?
- How does CO2 affect stomatal conductance?
- What can occur in greenhouses with respect to CO2levels?
- What is Q10?
- How does temperature affect the photochemical reactions in the thylakoid membranes?
- How does temperature affect the enzymatic reactions of C3 and C4 plants?
- How does water potential affect productivity?
- How does mineral nutrition affect productivity?
- Which mineral nutrient effects productivity the greatest?
- In what way does growth and maintenance respiration change over the life of a plant leaf?
- Why are evergreen leaves a compromise between not being deciduous and having a high maintenance respiration?
- How does canopy structure affect productivity?
- What is the Leaf Area Index? What relationship exists between an increasing Leaf Area Index and biomass? (Hint: look at Figure 13.9)
- How can the angle of leaf attachment affect productivity?
- How does heliotropism help a plant increase its productivity?
- Why are terrestrial ecosystems more productive than aquatic ecosystems?
- What factors are presently affecting the productivity of agricultural ecosystems?