• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Water Flow in Plant Tissue.

Extracts from this document...


Water Flow in Plant Tissue. Introduction and Background. Water Potential ? is the difference in intramolecular pressure exerted in a given specimen with reference to the intermolecular pressure exerted between molecules of pure free water at atmospheric pressure and the same temperature. The plant cell vacuole may be considered as a homogenous phase, separated by the tonoplast, cytoplasm and plasma membrane from the surrounding fluid. These may be considered as a single complex membrane, which is permeable only to water, that s for the purposes of this experiment. The cellulose wall which surrounds the cell is regarded as being completely permeable but of considerable strength and elasticity. Any pressure exerted by the cytoplasm on the vacuole is ignored in this experiment but is about 200 Kpa. The main pressure is exerted by the wall. In solutions of high water potential or in pure water the vacuole takes in water and expands. As a result the cytoplasm is pressed against the cell wall until the wall prevents any further expansion. Plasmolysed cell A plant cell can therefore come into equilibrium with pure water. At this point the cell has the same waster potential, as pure water i.e. ...read more.


1. A standard solution of sucrose is prepared using the formulae weight of sucrose as C11H22O11. 2. Dilutions are obtained so as to obtain a range of concentrations shown in the table below. 3. Sample of potato are freshly cut into rectangular pieces and measured for length, breath and width . As a working guide the aim was to use a length of five centimetres and a cross section of 1.4cm in other words a regular chip. A micrometer screw gauge was thought to be inappropriate here in view of the overall accuracy required in the experiment, a normal ruler was used measurements to the nearest 1mm. While working on other aspects of the experiment freshly cut chips are stored in distilled water to prevent aerial oxidation. 4. Two sample chips are placed in a constant volume of sucrose solution (10ml). 5. Thus two replicates are used for each sucrose concentration. 6. The samples are stored for 24 hours. The potato discs are removed dried between sheets of filter paper lightly and re-measured for their linear dimension. 7. A table of results will be drawn up to m record volumes before and after the experiment. ...read more.


Although the main driving force is often the transpiration rate driven by the sun. Seed germination may be slowed or prevented for example by a water deficit.. The seed surface contact is a significant factor. The seed coat is likely to be permeable to most common osmotica. Natural soil osmotica such as sodium chloride show some relationship with the nature of the habitat. Halophytes for example will germinate in relatively high sodium chloride concentrations that are inhibiting to glycophytes for example. Some desert plants are sensitive to rain. The Californian Filago californica will not germinate in moist cells, but any rainfall up to 20cm increases germination. Mass flow of solutes to the root surface may be controlled especially if elements not supplied by diffusion. For example Hoth and Norrish found the silicon content of Triticum vulgare (lemmas and glumes) to be strongly correlated with the total transported during growth. Appendix Table of Osmotic Potential in KPa of sucrose versus molarity mol dm -3 Molarity mol dm -3 Osmotic Potential Kpa 0.05 -130 0.10 -260 0.115 -410 0.20 -540 0.25 -680 0.30 -860 0.35 -970 0.40 -1120 0.45 -1280 0./50 -1450 0.55 -1620 0.60 -1800 0.65 -1980 0.70 -2180 0.75 -2370 0.80 -2580 0.85 -2790 0.90 -3000 0.95 -3250 1.0 -3500 ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Green Plants as Organisms section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Green Plants as Organisms essays

  1. Marked by a teacher

    An investigation into the effect of a germination inhibitor on the germination of seeds.

    3 star(s)

    place all 3 groups of pots should be similar because the temperature and light intensity needs to be the same conditions for all 3; reasons for this are given in the variables section). Call these pots Group 3. 7. Now there are the 3 sets of seeds and they have been watered.

  2. Determine the water potential of potato tuber cell with the varying affect of solute ...

    With the extra energy and collisions, the reaction happens at a faster rate. This means that if I leave the substance for 24 hours, I must ensure that it does not come directly under sunlight at this will change the rate of reaction.

  1. Determine the Water Potential of Potato tissue.

    This also applies to graph/result 2 and 3. Comparing result 1 and 2, you can see that at 1.0 Molar concentration of sucrose solution more water has been lost by potato tissue in result 1 when compare with result 2. But as you go down concentration more water is lost by potato tissue in result 2 than in result 1.

  2. The relationship between flow rate and temperature difference

    big and long so time taken to measure the temperature difference would be quite huge. * My physics knowledge allowed me to know the fact that because the tube was metallic there would be a substantial increase in the error associated with the loss of heat to the environment because metals are good conductors of heat and electricity.

  1. Investigate and find the water potential of baking potatoes and sweet potatoes in (N/mm2) ...

    Five minutes gives sufficient time for the water to enter the cell. Drying the potato slices removes excess water that was not absorbed. Pressing the reset button on the scales prevents inaccuracy, as does drying the weighing plate it and then pressing the reset button.


    HOW CAN YOU MAKE IT A FAIR TEST? To make this a fair test, the following points must be put into consideration: * Use same size cork borer to cut all six potatoes. * Put potatoes in sucrose solution at the same time and for the same period of time.

  1. An investigation in to the effect of temperature on the release of pigment from ...

    In this experiment the temperature is the independent variable (IV) and the amount of the colour that diffuses out from the beetroot cells into a test fluid is the dependant variable (DV).

  2. The investigation is aiming to look at transpiration.

    This increases the concentration of water vapour molecules in the air spaces of leaf producing greater water potential. This leads to an increase in water potential gradient between the leaf and the atmosphere, so water will diffuse out more rapidly.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work