CP6-Water Potential

Question 1

Objective-investigate plant water relations

Answer 1

Objectives:
-know how to carry out an investigation to determine the osmotic potential and therefore the water potential of plant epidermal cells

Question 2

Risks?

Answer 2

• glassware can break

- be careful and dispose of broken glass as soon as possible

Question 3

Method?

Answer 3

• take very thin 1cm long sections of the plant, it must only be one cell thick to be able to examine
• label 6 watch glasses with the concentrations of salt solution made up using serial dilution and one solution with 0
• transfer some of the solution onto each watch glass and add the plant tissue section to it, and leave for 20 minutes
• using forceps, remove tissue and place on microscope slide and cover with coverslip
• observe 25 cells and record how many are plasmolysed and record in a table for each salt solution

Question 4

Variables?

Answer 4

IV-concentration of salt solution
DV-% of plasmolysed cells
CV-number of cells counted, species of plant, pretreatment is the same

Question 5

What is plasmolysis?

Answer 5

Contraction of the chloroplast away from the cell wall of a plant in response to loss of water due to lower water potential outside the cell than inside