Analysis Of Potato Tubers

Table 1 shows the mass of young, old and freeze-damaged potato tubers before and after being incubated in sucrose solutions of different concentrations for 45 minutes. For young potato tubers, the mass increased after being incubated in solutions with concentrations of 0.15M, 0.20M and 0.25M, while the mass decreased after being incubated in solutions with concentrations of 0.30M, 0.35M and 0.50M. For old potato tubers, the mass increased after being incubated in solutions with concentrations of 0.15M, 0.20M, 0.25M and 0.30M, while the mass decreased after being incubated in solutions with concentrations of 0.35M and 0.50M. For freeze-damaged potato tubers, the mass increased after being incubated in solutions with concentrations of 0.15M,

The amount of water which was absorbed and released from the potato tubers was the amount required to maintain the absorbed solute (sucrose) at an isotonic concentration (Curran and Solomon, 1957). A 0% change shows that no water was gained or lost indicating that the point at which the system has reached dynamic equilibrium. The young potato tubers show equilibrium between 0.25M and 0.30M. The old potato tubers show equilibrium at just above 0.30M. The freeze-damaged potato tubers show equilibrium at just below 0.35M. This shows that young potatoes are less negative in water potential than old and freeze-damaged potatoes and old potatoes are less negative in water potential than freeze-damaged potatoes. The above is possible due to young potatoes holding a higher amount of starch than old potatoes and because freeze-damaged potatoes generally have damaged cell

A cork borer was used to cut potato tubers to cylinders of equal diameter and a ruler was used to cut equal lengths. A stop watch was used to measure the time and the same scale was used to measure all the potato tubers. 10ml pipettes were used to measure the volume of the solution. However, confounding factors can play a role in the results obtained. These confounding factors could be due to errors when measuring the length of the potato tubers and inconsistency when weighing the potato tubers. The moisture of the cylinders of potato tubers might have been different and some might have dried a little more than others when removing excess water. The environments in which the potatoes were grown as well as the storage time of the potatoes before use in the lab are unknown. Each treatment contained three potato tuber cylinders so that there were replicates to ensure the accuracy and validity of the data obtained.

Conclusion

The study performed confirms that water moves down a negative water potential gradient, from where water potential is less negative to where it is more negative. It also shows that the water potential of young, old and freeze-damaged potato tubers vary due starch content and damage to the cell