Research Problem 2: Plant Physiological Ecology (Bio 31)

Objectives

1. Conduct a hypothesis-driven investigation of patterns and/or processes in plantphysiological ecology.

2. Write a research paper, in the form of a contribution to the primary literature, describing thestudy.

3. Learn the methods and analyses that are fundamental to studies of plant growth, allocation,carbon flux, water balance. Specifically, the:

! Principles, measurement, calculation, and interpretation of measuring photosyntheticrates with an infrared gas analyzer (Appendix 1; more technical information at:http://en.wikipedia.org/wiki/Photosynthesis_system);

! Principles, measurement, and interpretation of plant water potential using a pressurebomb (some technical information: http://fruitsandnuts.ucdavis.edu/pressure_chamber/

! Gross anatomy of plants, including leaves, stomata, stems, vascular tissue (xylem andphloem), apical and cambial meristematic tissue, coarse roots, fine roots, and root hairs;

! Principles, measurement, calculation, and interpretation of plant growth and allocation(Figs. 1-2);

! Principles, measurement, calculation, and interpretation of photosynthetically activeradiation (Appendix 2; http://en.wikipedia.org/wiki/Photosynthetically_active_radiation

Materials

! Potted plants of numerous plant species grown under an assortment of environmentalconditions (see Table 2 in handout for RP-1)

! Several electrobalances (± 0.1/ 0.01 mg and coarser).! An infrared gas analyzer with cuvette configured for measurements of CO2 flux.! A pressure bomb for measuring plant water potential.! Dissecting scopes, compound scopes, and hand-lenses.! Assorted tools for measuring leaf area, leaf thickness, and other aspects of plant

morphology.! “Claw” with PAR sensor; see Appendix 2.

Appendix 1. Schematic of a photosynthesis measurement system. More info here:http://en.wikipedia.org/wiki/Photosynthesis_systemhttp://www.cid-inc.com/products/photosynthesis/handheld-photosynthesis-system

What is the principle of operation of the CO2 analyzer (IRGA)?

What is the equation used to calculate photosynthetic rate and what are the units?

Appendix 2: Typical spectral response of LI-COR quantum sensors vs. wavelenght and theideal quantum response (equal response to all photons in the 400-700 nm waveband. From: http://www.licor.com/env/Products/Sensors/quan.jsp. See also:http://en.wikipedia.org/wiki/Photosynthetically_active_radiationv

Appendix 3. Nitrogen decanting procedure (for pressure bomb).

Procedure:1. Connect flex line ot cylinders.2. Close all valves on field cylinder.3. Open fully main value #2.4. Open main valve #1 just enough to cause needle of gauge to move very slowly.5. Allow field cylinder to slowly fill to limit. Fill amount depends upon gas pressure in supply

cylinder.6. When needle stops and slight sound of gas moving through flex line stops, field tank is full.7. Close main valve #2 and main valve #1.8. Crack open bleed valve to release pressure.9. Disconnect flex line from field cylinder.10. Do not open valve #2 of field cylinder before connecting to pressure bomb.