Plant Physiology (Biology 327)
- Dr. Stephen G. Saupe; College of St. Benedict/ St.
University; Biology Department; Collegeville, MN 56321; (320) 363 - 2782;
(320) 363 - 3202, fax;
Pre-Lab Preparation: Plant Water Status
Prior to the lab:
- Print and read the
Bring these materials to class
- Review, if necessary, your understanding of the concept of water
III. Pre-Lab Questions:
- Do all potato tubers have the same water potential?
- Do regions of a single potato tuber have the same water potential?
- What do you hypothesize the water potential of
the tubers will be? _____.
- Predict the concentration of the sucrose
solution that will have the same water potential as the tubers.
- What do you hypothesize the osmotic potential
of the tubers will be? _____.
- Predict the likely freezing point
depression for the potato sap that we will collect (show your work).
- Do you hypothesize that the cores incubated in
the 0.7 molal solution will become more turgid or less turgid?
- Do you predict that a drop of dye will sink,
float or hover in the 0.1 molal sucrose solution in which a tuber was
IV. Safety Concerns
1. Biological Materials: Harmless. Obviously, do not eat any lab materials.
- salt - non-toxic
- alcohol - since we are using denatured alcohol it is toxic if imbibed. Avoid skin
contact. Rinse hands after contact.
- sucrose solutions - non toxic
- Sucrose dyed blue with methylene blue wear gloves and goggles when using
methylene blue treated sucrose.
3. Safety Eyewear: Goggles are necessary when using methylene blue
5. Disposal: Compost plant materials in lab composter. Sucrose
solutions can be discarded down the drain
6. Supply list: Click here
01/07/2009 � Copyright by SG