Required Practical 3

Question 1

How to calculate a dilution

Answer 1

• dilution factor = desired concentration / stock concentration
• volume of stock solution = dilution factor x final desired volume
• volume of distilled water = final desired volume - volume of stock solution

Question 2

Describe a method to produce a calibration curve to identify water potential of plant tissue

Answer 2

• create dilution series using 1mol dm-3 sucrose solution
• use cork borer to cut potato into identical cylinders
• blot dry and recited initial mass
• immerse each piece in each solution for set time in water bath
• blot dry and record final mass
• plot calibration curve with concentration on x axis and % change in mass on y axis
• identify where line crosses x axis
• use textbook to identify water potential of that solution