Water Relations in Two Plant Tissues

Water Relations in Two Plant Tissues

Results:

Table 5

Table to show the sucrose concentration and water potential of each

tissue.

The sucrose solution was extrapolated from graph 1, which shows the

percentage change of mass of the tissues when immersed in the

different sucrose solutions. A line of best fit was drawn, where the

line of best fit intercepts the x-axis (concentration of sucrose

solution) is the sucrose concentration of the tissue because at this

point there is no mass loss of gain (read off of y-axis).

The water potential of each tissue was read off of graph 2. The solute

potential is equal to the water potential because the pressure

potential = 0.

Tissue

Sucrose concentration in tissue based on extrapolated data from graph

1 /mol dm-3

Solute potential read off of graph 2 /Kpa (equal to water potential

/Kpa)

Potato

Swede

Table 6

Table to show the results of the iodine test, Benedict's test and test

for non-reducing sugars for potato and swede tissues.

Tissue

Iodine test for starch

Benedict's test for reducing sugars

Test for non-reducing sugars

Potato

Turned black/blue

Turned green

Turned yellow/pale orange

Swede

Grey/black

Turned orange

Turned dark orange

Analysis:

The aim of the experiment was to find out the water potential of swede

and potato tissues. Firstly 12 potato strips and 12 swede strips were

cut to 7cm long, 0.5cm width and 0.5 cm depth. The strips were weighed

(start mass in results tables). Two potato strips were put in each

petri dish which each contained a different sucrose solution (0.0,

0.2, 0.4, 0.6, 0.8, 1.0 mol dm-3). This was repeated with the swede

strips. So in total 12 petri dishes were used (6 for each tissue).

Diagram 1 shows how the investigation was carried out.

The next day the strips were taken out of the solutions, dried and

weighed (final mass).