Preview

Measuring the Water Status of Potato Tubers

Good Essays
Open Document
Open Document
636 Words
Grammar
Grammar
Plagiarism
Plagiarism
Writing
Writing
Score
Score
Measuring the Water Status of Potato Tubers
Measuring the Water Status of Potato Tubers
Objectives: Upon completion of this laboratory you should be able to:
1. determine the water potential of a plant tissue by the Chardokov and gravimetric techniques and understand the underlying theory.
2. determine the osmotic potential of a plant extract by the freezing point depression method and understand the underlying theory.
3. describe techniques for measuring the pressure potential of a plant tissue.
4. describe techniques for measuring plant water status such as the pressure bomb, vapor pressure osmometer, and psychrometer.
Introduction
Water potential (Ψw, psi), which is a measure of the energy state of water is affected by dissolved solutes, pressure and matrix particles. The contribution to water potential by dissolved solutes, termed osmotic potential (Ψs ), is always negative in sign. In other words, solutes decrease the water potential. The contribution of pressure (Ψp) may be positive, negative or zero, but is generally positive since most plant cells are turgid (turgor pressure). The contribution due to the binding of water to colloidal particles (matric) and surfaces, termed matric potential (Ψm), also lowers the water potential. Although it is often small enough to be ignored, matrix potential is important when considering soil water relations. Thus, the water potential of a plant system can be arithmetically represented by the equation:
Ψw = Ψs + Ψp + Ψm
In this lab we will use the Chardakov and Gravimetric techniques to determine the water potential (Ψw) of a potato tuber cells. We will determine the solute potential (Ψs ) by the Freezing Point DepressionMethod. Pressure in the cells can be arithmetically calculated once Ψs and Ψw are known. If time permits, we will also measure the water conductivity of potato tubers, determine the Q10 for water transport into potatoes and prepare a Hofler diagram.
Pre-Lab:
1. Email to me before lab begins the answers to questions 1-6 in the



References: Barcelo, AR, AA Calderon and R Munoz (1994) Measuring water conductivity coefficients in plant tissues. Journal of Biological Education 28: 83 – 85. Bland, W. and C. B. Tanner (1985) Measurement of the water potential of stored potato tubers. Plant Physiology 79: 891-895. Boyer, JS (1969) Measurement of the water status of plants. ARPP 20:351-364. Koning, R (1999)  Web Site: Osmosis Lab. Kramer, P (1983) Water Relations of Plants. Academic Press, NY. Meidner, H (1984) Class Experiments in Plant Physiology. George Albert Unwin, Boston. Reiss, Carol (1994) Experiments in Plant Physiology. Prentice-Hall, Englewood Cliffs, NJ. Ross, C (1974) Plant Physiology Lab Manual. Wadsworth.

You May Also Find These Documents Helpful

  • Good Essays

    The aim of our experiment was to investigate the water potential of swede and then use our results to help us determine the water potential of plant tissue.…

    • 1139 Words
    • 5 Pages
    Good Essays
  • Better Essays

    Biolab 1208 Lab Report

    • 840 Words
    • 4 Pages

    The purpose of this experiment is to calculate the mass/change in mass of plant tissue, in our case potato tubers. The change in mass of the potato tuber disk determines the osmotic concentration. After soaking the potato tubers in different concentrations of sucrose, then calculating the percent change in mass, we can determine the osmotic concentration. The…

    • 840 Words
    • 4 Pages
    Better Essays
  • Good Essays

    Ap Biology Lab Report

    • 620 Words
    • 3 Pages

    In a flowering plant, the water travels from the soil, then to the root hairs, next to the xylem, then into the stomata, to the mesophyll cells, next to the stoma, then finally into the atmosphere. Osmosis is the diffusion of water through semipermeable membranes. Transpiration is the evaporation of water from the leaf. Cohesion is when water molecules stick together. Adhesion is when water molecules stick to, not attract. Root pressure is force made by root on water columns. Water potential is the negative pressure in leaves, which is positive in roots.…

    • 620 Words
    • 3 Pages
    Good Essays
  • Good Essays

    The objectives of this experiment are to determine the water potential of apple cells and to better understand the movement of water through cells. This will be done by putting cores of apple tissue in sucrose solutions of different concentrations and measuring the changes in mass of the apple cores. The changes in mass reflect the movement of water into or out of the tissue. After determining the concentration of sucrose solution at which there is no net gain or loss of water from the apple tissue, the osmotic potential can be calculated. This will then tell the water potential of the apple cells.…

    • 1050 Words
    • 5 Pages
    Good Essays
  • Satisfactory Essays

    This exercise involves estimating the osmotic concentration of potato tuber cells by using a change in mass method. The null hypothesis states that there will be no change of mass of the potato disks after they have been incubated in any sucrose solution. This means that the concentration of sucrose that the potatoes are in will no effect the movement of water in or out of the potato cells. However, the alternative hypothesis states that the mass of the potato disks will increase after they have been incubated in a hypertonic solution. The mass of the potato disks will decrease after they have been incubated in a hypertonic solution. After the results have been gathered, appropriate estimations can then be made as to what the osmotic concentrations of the potato tuber cells are. Osmotic concentrations will either be hypertonic, hypotonic or isotonic depending on the results of mass change of the potato tubers.…

    • 367 Words
    • 2 Pages
    Satisfactory Essays
  • Better Essays

    An investigation to find the water potential of potato and carrot tubers in a sucrose solution, of concentration 0.00 – 0.50Mol, over a 24 hour period…

    • 1394 Words
    • 6 Pages
    Better Essays
  • Good Essays

    Purpose: To determine the concentration of solute in the potato’s cytoplasm by measuring the change…

    • 898 Words
    • 4 Pages
    Good Essays
  • Satisfactory Essays

    The transport of water upward from roots to shoots in the xylem is governed by differences in water potential, with water molecules moving from an area of high water potential to an area of low water potential. The movement of water through a plant is facilitated by osmosis, root pressure, and the physical and chemical properties of water. Transpiration creates a lower osmotic potential in the leaf, and the TACT mechanism describes the forces that move water and dissolved nutrients up the xylem (AP Bio Big Idea 4).…

    • 1318 Words
    • 6 Pages
    Satisfactory Essays
  • Powerful Essays

    The objective of this investigation was to determine the effect of one specific environmental condition on the rate of transpiration in plants. This particular investigation looked at the number of leaves in a plant and how it would affect the rate of transpiration in plants. The aim of this investigation was to find out if the larger the number of leaves a plant had, the higher the rate of transpiration would be.…

    • 1816 Words
    • 8 Pages
    Powerful Essays
  • Good Essays

    To investigate the relationship between the structure of vascular tissues (xylem and phloem) and their functions in transporting water and nutrients in plants…

    • 907 Words
    • 6 Pages
    Good Essays
  • Satisfactory Essays

    Potato Osmosis Paper

    • 587 Words
    • 2 Pages

    The purpose of this experiment is to observe the osmosis reaction in a potato with salt and water. In cooking cooks will soak their cut potato's in water if they will not use them immediately. This allows the potato's to be used later without turning color. The experiment shows the flow of water through the membranes of the potato with salt over a period of four hours.…

    • 587 Words
    • 2 Pages
    Satisfactory Essays
  • Satisfactory Essays

    Osmosis Lab Response

    • 310 Words
    • 2 Pages

    As the concentration of a solute in water will, through osmosis, transfer until the concentration is nearly the same both inside the cell, or in this case potato, and outside of the cell, the potato strips both gained and lost mass due to the different concentrations of sugar in water. As expected, the potato strips placed in the concentration of sugar water closest to the concentration of sugar water in a potato had the least amount of change in mass. As the potato strips placed in substance Z and substance A both changed 7%, the concentration of sugar water in a potato must be somewhere in between a concentration of 0.4 and 0.6. One source of error for this lab is that the amount of substance placed into each Dixie cup was not measured and therefore were not consistent. If this lab were repeated, it is suggested that the amount of substance be measured in order to produce more consistent results.…

    • 310 Words
    • 2 Pages
    Satisfactory Essays
  • Powerful Essays

    Potato Osmosis Lab

    • 3353 Words
    • 14 Pages

    Aim To observe and measure the effect of osmosis on the mass of potato using a starch solution. Introduction In order to measure the effect of osmosis, eighteen pieces of potato were cut and placed in six groups, each group of three pieces cut to weigh as close as possible to one another. For each potato group, a test tube was half filled with a starch solution varying in concentration from 0% (water) to 1%. Hypothesis…

    • 3353 Words
    • 14 Pages
    Powerful Essays
  • Good Essays

    vugj

    • 460 Words
    • 2 Pages

    Hypothesis: If the solute inside the potato cell is significantly greater than that outside it, then water will enter the cell, causing it to gain weight. If the solute outside the potato cell is significantly greater than that inside it, then water will leave the cell, causing it to lose weight. If the amount of solute inside and outside of the cell is virtually equal, then there would be no net water movement causing the potato cell to remain the same weight.…

    • 460 Words
    • 2 Pages
    Good Essays
  • Satisfactory Essays

    Meyer, B.S., Anderson, D.P., Bohning, R.H., & Fratanna, D.G., Jr. (1973). Introduction to plant physiology. New York: Van Nostrand.…

    • 3062 Words
    • 13 Pages
    Satisfactory Essays

Related Topics