Plant Physiology (Biology 327)  - Dr. Stephen G. Saupe;  College of St. Benedict/ St. John's University;  Biology Department; Collegeville, MN  56321; (320) 363 - 2782; (320) 363 - 3202, fax;    ssaupe@csbsju.edu

Water Potential - Materials List

Plant Materials

• Potatoes (or, students bring own materials)

• freeze some peeled potatoes overnight

Chemicals

• salt (rock or other inexpensive)

• sucrose

• methylene blue

Center table

• Sucrose solutions (0.1 ‑ 0.8 molal; 30 mL per group plus approx. 100 mL)

• 0.1 molal (34.23 g added to 1000 mL water)

• 0.2 molal (68.46 g/1000 mL)

• 0.3 molal (102.70 g/1000 mL)

• 0.4 molal (136.94 g/1000 mL)

• 0.5 molal (171.17 g/1000 mL)

• 0.6 molal (205.40 g/1000 mL)

• 0.7 molal (239.64 g/1000 mL)

• 0.8 molal (273.84 g/1000 mL)

• water

• 25 mL graduate cylinder to measure sucrose, place next to each container (or pipette or other)

• Sucrose dyed blue with methylene blue in small bottles (each with a disposable pipette)

• cork borer sharpener

• balances

Freezing Point Supply Area

• blender and base                                                       

• clinical centrifuge 

• clinical centrifuge tubes & caps (1/person)

• ice + bucket

• rock salt

• glass rod or spatula (to push potato into blender)

• frozen potatoes

• alcohol (denatured, 1 mL per group) � with pipette and pump

Student Tables

• test tube rack (1/group)

• 9 tubes (microfuge or other)

• spoon (1/group)

• label tape

• marker

• weigh boat (2/group)

• cork borer  (1/group)

• ruler

• thermometer (1/group)

• bamboo skewer or probe without needle to push core out of borer

• kimwipes

• paper towels

• disposable pipettes (8/group)

• Freezing point apparatus (ring stand, 600 mL beaker, low temperature thermometer in rubber stopper, 2 clamps, mini stir bar, thermometer, flat bottom tube, glass stir rod)