FS561 – Physiology of Woody Plants  Fall 2009

OBJECTIVES AND REFERENCES FOR October 27:

Photosynthesis and light response

Reading:  Chapter 5 of Pallardy's book - especially pp. 107-119;

 

Useful additional information:

Taiz and Zeiger chapter 8

Lambers, Chapin and Pons pp. 12-14

Discussion of A/Ci curves from Lambers, Chapin and Pons (pp. 18-20)

Lambers, Chapin and Pons pp. 96-134

 

On the web:

On-line animation of carboxylation

The Dark Reactions of Photosynthesis, Assimilation of Carbon Dioxide And The CALVIN Cycle.

The Carbon fixation cycle

How the carbon cycle was elucidated

Rubisco:  a model enzyme for studying structure and function

Carbon dioxide: some important physicochemical  properties

Rubisco activase

photorespiration

Photorespiration

The Calvin Cycle

Field photosynthesis measurement systems

Role of respiration in desiccation tolerance

The distribution of chlorophylls and other photosynthetic pigments

Chlorophyll biosynthesis

Chloroplasts

Chlorophylls and Carotenoids

The science of color in autumn leaves

Powerpoint presentation on canopy reflectance, LAI and remote sensing

 

Other interesting links that are more tangentially related to this lecture:

list of publications dealing with leaf display and orientation

 

Feild et al. 2001.  Why leaved turn red in Autumn.  The role of anthocyanins in senescing leaves of red-osier dogwood.  Plant Physiology 127:566-574

 

Galvez and Pearcy.  2003.  Petiole twisting in the crowns of Psychotria limonensis:  implications for light interception and daily carbon gain.  Oecologia 135:22-29.

 

Learning Objectives:

After this lecture and any supplementary reading you find useful, you should be able to:

  1. Define and appropriately use these terms (at least to the level of detail that these terms were presented in lecture):  electron transport; photophosphorylation, thylakoid membranes, lumen, stroma, chloroplast, grana, lipid bi-layer; photoinhibition; ATP; NADPH; ATP synthase; RUBISCO; Calvin-Benson cycle (aka, "Calvin" cycle" and PCR),  RUBP, 3 PGA (aka "3 phosphoglycerate"), triose phosphate
  2. Explain how the intercellular air spaces in plant leaves in combination with plant pigments make the spectral properties of plants unique, and how this is useful in remote sensing and “false color” photography.
  3. Describe some of the most important controls over light absorption by plants on the canopy scale, the leaf scale, the cellular scale and the biochemical scale.
  4. Describe where, within a chloroplast, photosynthetic electron transport and the PCR cycle (AKA the “photosynthetic carbon reduction cycle, or “Calvin Cycle”) take place.
  5. Describe general characteristics of chlorophyll and caratenoid molecules that help them function as pigments (you do NOT need to memorize the structures!); explain why chlorophyll absorption in leaves covers a much broader spectrum than absorption of extracted chlorophyll in a test tube.
  6. Explain why the entire electron transport change (both photosystems I and II) can operate in only red light, but only photosystem I can operate in only far-red light
  7. Explain what causes the lumen of the grana to have a lower pH compared with the stroma, and why this is important in photophosphorylation
  8. Describe how photochemistry causes a flow of photons to be transformed into a flow of electrons.  Where do the electrons in the electron transport chain come from?  Where do they go?
  9. Name the two primary products of photochemistry that are required in carbon fixation and describe in very general terms how they are produced through photochemistr

    10.  Describe in general terms the major steps of the Calvin cycle and how it connects with the light harvesting process (i.e., where ATP and NADPH from light harvesting is used in the Calvin cycle

    11.  Discuss unusual and important characteristics of the Rubisco enzyme, including its capacity for both oxygenase and carboxylase activity, the relationship between the oxygenase activity of Rubisco and photorespiration