APPROVAL SHEET
The complete report of Plant Physiology experiment with title “Potential of Water“, was created by:
name : Yusmar Yusuf
reg. no. : 081404172
group : V (fifth)
class : Biology ICP
department : Biology Department
After checked by assistant and assistant coordinator, so this report is accepted.
Makassar, 2010
Coordinator Assistant Assistant
Sulfianto Ilyas Nelsiani To’bungan
Reg. No. 061414025 Reg. No. 071404053
Lecturer
Drs. Ismail, MS
NIP : 196112311986031015
CHAPTER I
INTRODUCTION
A. Background
Water potential is the chemical potential of water in a system or part of the system. Expressed in units of pressure and chemical potential compared to pure water (also in the units of pressure) at atmospheric pressure and the temperature and the same height of pure potential is determined to be zero. Contributing factors are the gradient of concentration or activity, temperature, pressure, solution to the potential effects of chemical solvents, matrices. Measuring methods of water by the method of tissue volume, chordate method, vapor pressure method
The relationship between water potential is to engage the event due to osmose is osmose diffusion events between the 2 places where the availability of diffusion separated by a membrane or membranes. It can mean that the cell wall or membrane of protoplasm is a membrane barrier between the diffusing substance because the cells are generally higher plants have cell walls so most of the phytochemicals in plants is a process of osmose
Most of the unique properties of water comes from an interesting fact, namely that the cut line connecting the two centers of hydrogen atoms with oxygen atoms center not straight lines. The line angle of about 105 degrees, more like a corner rather than a line. Two electrons that form covalent bonds between hydrogen atoms and oxygen atoms are closer to the core of the oxygen leaving the two hydrogen nuclei to each other. This creates a bit of positive charge on the molecule side, and negative charge as much on that side. Then the net charge becomes neutral molecule. So called polar molecules. As a result, the positive side of one water molecule is attracted by negative side of the other water molecules form a weak bond called a hydrogen bond.
B. Purpose
Measure the amount of water potential in Solanunm tuberosum’s tissue.
C. Benefit
1. Can explain about the water potential.
2. Know the method to measure water potential in plant tissue.
3. Know the influence of different concentration of NaCl solution in determine the water potential in plant tissue.
CHAPTER II
PREVIEW OF LITERATURE
Plant will develop normally and thrive as well as active when the cells are filled with water. one time when at the time of development, lack of water supply plants, the water content in plants decreased and the rate of growth that is determined by the rate of all functions which are also declining. If the situation is prolonged drought can kill the plants. Even in plants that are actively growing, water shortages could become a limiting factor for its development, but dry conditions and still have a positive impact on life and survival of the organism. Together with reduced cell activity, its sensitivity to physical factors and chemicals from the environment jugfa reduced. Therefore, although the dry seeds will not germinate, they will not die by the high temperatures or low temperatures can make lethal for vegetative growth. In fact the plant adaptation to dry conditions and low temperature conditions often involves low water content (Ismail, 2010).
Cell wall structure and cell membranes are different. Membrane allows water molecules to pass more quickly than the solute elements; primary cell walls are highly permeable to both. Plant cell membrane is possible duration of osmosis, but the tough cell wall that is causing pressure. Animal cells do not have walls, so that when the pressure arising therein, the cells often rupture, as happened in the red blood cells inserted into the water. Turgid cells play a role in establishing many parts that are not woody plants. if the diffusion of the solvent particles is more limited than the diffusion of solvent molecules, there will be water potential gradient. if the pure water on one side of the membrane and other solvents on the other side, then the solution water potential will be lower than the water potential of pure water. according to the agreement, the water potential of pure water at atmospheric pressure and temperature are the same as the solution is equal to zero, then the water potential of a solution of water at atmospheric pressure will be negative or less than zero (Salisbury, 1995).
Diffusion is a physical process that the process can occur at any time in nature and in the plants or other organisms. To be able to imagine the process of diffusion, we suppose that there are two rooms connected to each other with a hole. One room contains white balls which are freely exercise and other spaces containing black balls that also move freely. Opportunity black balls move through the hole, into the next room in a certain time interval depends on the speed and concentration (number per unit volume) of black balls and the size of the hole. The same thing happened to the white balls. The direction of diffusion of each type of ball before reach balance, independent of each other means that one does not preclude the other. The balance is dynamic, because the balls are still cross through the hole, only to re-cross with the same amount (Ismail, 2008).
Selective permeability of the plasma membrane of plant cells controls the movement of solutes between the cells with extracellular solution. Solutes tend to diffuse down a concentration gradient, and when it occurs across the membrane, this process is called passive transport. However, most of the solute through the membrane extremely slow unless these substances work by transport proteins embedded in the membrane in it. Some of these proteins facilitate the diffusion of a way to selectively bind themselves to a solute on one side of the membrane and the release of that substance on the opposite side of the membrane (Campbell, 2004).
Chemical potential is the free energy per mole of substance in a chemical system. Therefore, the chemical potential of a compound under conditions of constant pressure and temperature depends on the number of moles of substance there. In the case of water and plant relationships, chemical potential of water is often expressed by the term "water potential". Furthermore, if the chemical potential can be expressed as a measure of the energy of a substance that will react or move, then the water potential is a measure of the available enegi in the water to react or move. In other words, the water potential is the ability of water molecules to molecular diffusion.
Potential of pure water is zero (0), the existence of some substances dissolved in the water will lower the water potential, so that the water potential of a solution is less than zero. This definition applies only to atmospheric pressure. When the pressure surrounding the system at increased or scaled back, then automatically the water potential will rise or fall in accordance with the pressure changes (Anonyma, 2010).
Potential of pure water is zero (0), the existence of some substances dissolved in the water will lower the water potential, so that the water potential of a solution is less than zero. This definition applies only to atmospheric pressure. When the pressure surrounding the system at increased or scaled back, then automatically the water potential will rise or fall in accordance with the pressure changes (Anonyma, 2010).
In a cell, the water potential has two components, namely the pressure potential and osmotic potential. Potential pressure can increase or decrease the water potential, osmotic potential while the solution shows the status of the cell. By entering a network into a series of solution has the potential of water in the know; the water potential plant connects it can be discovered. Driving force for the movement of water is the water potential difference between one place to another place, where water is always moving from places with high water potential to water potential is lower. In fact the water potential of the atmosphere is almost always lower than soil water potential, except when the air relative humidity is 100%. whereas the soil water potential in conditions that are available for rare plants is less than -1.5 MPa, it is clear that differences in soil water potential in air water potential is generally very large ( Anonymb, 2010).
Water potential not only determines the end of the process of diffusion of water movement., but also indirectly determines the water mass transfer occurs because of the pressure gradient, while the pressure gradient arising from the movement by diffusion. furthermore, in principle and in practice, water may be a potential component of the osmotic system of the easiest on the measure. Osmosis is diffusion through a semipermeable membrane. The entry of solution into the endodermis cells is an example of osmosis process. In the body of multicellular organisms, move water from one cell to another in private. Besideswater, the molecules are small such as O2 and CO2 are also easily through cell membranes. These molecules will diffuse from areas of high concentration to low concentration. Osmosis process will stop if the concentration of substances on both sides of the membrane has reached equilibrium. Osmosis can also occur from the cytoplasm to the membranous organelles (Salisbury, 1995).
CHAPTER III
EXPERIMENT METHOD
A. Place and Time
Day/ date : Wednesday/ 17th March 2010
Time : 01.00 pm until 04.00 pm
Place : the 2nd floor of Biology laboratory, Mathematics and Science Faculty, State University of Makassar
B. Tools and Materials
1. Tools
a. Drill potatoes,
b. Analytical scales,
c. 8 of petri dish
d. Razor
e. Stopwatch
2. Materials
a. Solanum tuberosum
b. Sucrose solution 0,1 M, 0,2 M, 0,3 M, 0,4 M, 0,5 M, 0,5 M, 0,6 M, 0,7 M, and 0,8 M.
c. Filter paper.
C. Work Procedure
1. 8 cups prepared boxes each with 100 ml of solution on offer.
2. 12 cylinders made of potatoes using a potato drills, each with a length of 4 cm.
3. By razor blade, cut the potato cylinder into thin slices with 1-2 mm thick.
4. Rinse the potato slices lightly with aquades quickly, dry with filter paper, then weigh it.
5. Enter it into the potato slices in a sucrose solution that had been prepared. And do this on each cylinder of potato for each of the next solution.
6. After 1 hour, remove the slices from the petri dish, using dry filter paper, and then weigh it. Do for all solution.
CHAPTER IV
OBSERVATION RESULT AND DISCUSSION
A. Observation Result
Weight of paper is 0,55 gram
No. | Solution | A0 | A1 | %ΔA |
1. | 0,1 M | 1,5 gram | 1,96 gram | 30,67 gram |
2. | 0,2 M | 1,86 gram | 1,96 gram | 5,38 gram |
3. | 0,3 M | 1,86 gram | 1,86 gram | 0 |
4. | 0,4 M | 1,7 gram | 1,6 gram | -5,88 gram |
5. | 0,5 M | 1,7 gram | 1,5 gram | -11,76 gram |
6. | 0,6 M | 1,95 gram | 1,46 gram | -25,13 gram |
7. | 0,7 M | 1,6 gram | 1,26 gram | -21,25 gram |
8. | 0,8 M | 1,75 gram | 1,25 gram | -28,57 gram |
9. | 0,9 M | 1,67 gram | 1,24 gram | -25,75 gram |
Analyze of Data
1. % weight changes
a. % ΔA = x 100% = 30,67 %
b. % ΔA = x 100% = 5,38 %
c. % ΔA= x 100% = 0 %
d. % ΔA= x 100% = 5,88 %
e. % ΔA= x 100% = 11,76 %
f. % ΔA= x 100% = 25,13 %
g. % ΔA= x 100% = 21,25 %
h. % ΔA= x 100% = 28,57 %
i. % ΔA= x 100% = 25,75 %
Graphic Compare
a. Weight Changes Graphic
b. Graphic Changes the Persentasion
c. Graphic First Weight and Second Weight
B. Discussion
Knowledge of water potential on a network is very important plant-controlled, it is in because of knowing the potential of water from a plant tissue can be applied to the use of fertilizers on crops. We can provide the dose of fertilizer in accordance without damaging plant cells. In this lab, we tried to determine the water potential in potato tubers. Potatoes chosen with some consideration of potato tubers easily available, easy to make a cylindrical rod with a cork drill stem, and potatoes is a material consisting of a homogenous material, namely, parenchyma tissue that stores food reserves.
The first step is done in this experiment is to make a cylinder of potato tubers using a cork drill with a diameter of 6 mm length of each cylinder 4 cm, was carried out in order to get the number and form a homogeneous potato tissue for the experiment, as many as 4 cylinder potatoes that have been weighed then put in each glass culture that has been filled with a sucrose solution with different concentrations (0.1 M: 0.2 M: 0.3 M: 0.4 M: 0.5 M: 0.6 M: 0.7 M: 0.8 M: 0.9 M and 1.0 M) and aged for 60 minutes, with the treatment we try to find solutions which are isotonic with the pressure in potato tissue, it can be known through a cylinder of potato on how concentration do not experience weight changes, this means there is no flow of water molecules from both inside and out potato tissue.
The first step is done in this experiment is to make a cylinder of potato tubers using a cork drill with a diameter of 6 mm length of each cylinder 4 cm, was carried out in order to get the number and form a homogeneous potato tissue for the experiment, as many as 4 cylinder potatoes that have been weighed then put in each glass culture that has been filled with a sucrose solution with different concentrations (0.1 M: 0.2 M: 0.3 M: 0.4 M: 0.5 M: 0.6 M: 0.7 M: 0.8 M: 0.9 M and 1.0 M) and aged for 60 minutes, with the treatment we try to find solutions which are isotonic with the pressure in potato tissue, it can be known through a cylinder of potato on how concentration do not experience weight changes, this means there is no flow of water molecules from both inside and out potato tissue.
This indicates that the water in the sucrose solution flowing into the network, indicating that the water potential at the higher sucrose solution compared with water potential in potatoes. While in sucrose solution experiencing a reduction of potato tuber weight and physical condition had changed, the potatoes become soft and supple. The greater the concentration of sucrose solution, the weight of potato tubers was decreased. This indicates that the water in the potatoes out onto the sucrose solution as the concentration of sucrose solution more concentrated.
CHAPTER V
CONCLUSION AND SUGGESTION
A. Conclusion
Water potential is probably the most useful parameters to be measured in relation to the soil system, plants, and atmosphere. And more greater the concentration of solution than cell’s fluid the potential osmotic of the water is less greater.
B. Suggestion
1. I hope laboratory equipment can be completed, thus practicant can do observation well.
2. Assistant can give more again information about observation.
3. Practicans must do observation well.
BIBLIOGRAPHY
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co.uk/GCSE/Biology/Life_Processes_Cells/An_Investigation_
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Campbell. Neil A, Reece and Mitchell. 2004. Biologi. Jakarta. Erlangga
Ismail and Abd. Muis. 2010. Penuntun Praktikum Fisiologi Tumbuhan. Makassar:
Jurusan Biologi FMIPA UNM.
Ismail. 2008. Fisiologi Tumbuhan. Makassar: Jurusan Biologi FMIPA UNM.
Salisbury, Frank B. et al. 1995. Plant Physiology 2nd Edition. Mc Graw Hill Company. New York.
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