Transpiration pull:
most of the water that is absorbed by the roots of the plants moves up the xylem vessels of the cells in the leaf. Here it evaporates into the intercellular spaces and diffuses out of the plant as water vapour through the stomata. Energy for evaporation of water comes from the surrounding and the cells and the sun.
The continuous flow of water from the roots to the leaves form the transpiration stream. The forces, which maintain the transpiration stream, are very strong. These forces constitute the transpiration pull, which plays an important role in the ascent of water in the xylem vessels of the stem.
FROM LEAVES TO ATMOSPHERE-TRANSPIRATION
Transpiration is the evaporation of water from plants. It occurs chiefly at the leaves, while the stomata are open for the passage of carbon dioxide and oxygen during photosynthesis. Evaporation takes place at three sites.
{1} stomata
{2} cuticle
{3} lenticels
{1} STOMATA:
transpiration occurs rapidly when the stomata are open and the internal tissues of stems and leaves are in contact with the atmosphere. Well over 90% of the total loss from leafy shoot is due to stomatal transpiration.
Mechanism of opening and closing of stomata
The opening and closing of the stomata control the flow of gases in and out of the leaves. This control is necessary to prevent excess loss of water as vapour from the plant body via transpiration. Each stomata is flanked by two guard cells. The cellulose walls of the guard cells are less elastic than those in contact with the epidermis. It is this, which makes the inner walls less able to stretch and thus result in the typical kidney shape of guard cells. Guard cells are different from normal epidermal cells because they possess chloroplasts. An increase in the volume of guard cells, owing, for example to the osmotic uptake, causes increased bowing of the cell and expansion in the outer wall. When this happens in the two guard cells of a stoma, the stomatal aperture enlarges.
During the day, blue light stimulates ATPase found in guard cells. The ATPase then hydrolyses ATP into ADP and Pi and the energy released drives proton {h+} pump. This pumps h+ out of the guard cells.
The protons return on a carrier that brings chloride {cl-} with them. Potassium ions {k+} also enter the guard cells. Due to increased ion concentration in the guard cells water enters by osmosis. The guard cells swells and bends and causes stoma to open. At night or in the absence of light, the proton gradient is no longer maintained so the flow of ions and water is reversed and therefore causes the stoma to open.
{2}CUTICLE:
a little water perhaps 10% is lost through the cuticle, which is impermeable to gases. Thus thicker the cuticle the smaller the water loss, vice versa. This is called cuticular transpiration.
{3} LENTICELS:
woody stems of deciduous plants lose small amounts of water vapour through lenticels by lenticular transpiration before leaf fall. The amount of transpiration through these is relatively insignificant; this is known as lenticular transpiration.
EXTERNAL FACTORS AFFECTING THE RATE OF TRANSPIRATION
This includes all aspects of the environment, which alter the diffusion gradient between the transpiring surfaces and the atmosphere. They are:
{1}HUMIDITY:
the humidity of the atmosphere has an effect on the rate of transpiration. A low humidity means that the air is relatively dry and there is steeper water potential gradient between the external atmosphere and the atmosphere inside the leaf, so the rate of transpiration is increased. A high humidity means that the air is more saturated with water vapour molecules and so the rate of transpiration is reduced.
{2} WINDSPEED:
wind affects the water potential gradient between inside the leaf and outside. In still air, water vapour molecules build up around the leaves, with the effect of reducing the rate of transpiration, as water potential gradient are less steep. Any air movement can move water molecules away from the surface of the leaves thus creating steeper water potential gradient and therefore increasing the rate of transpiration.
{3} LIGHT:
light affects the rate of transpiration because it has an effect on the opening and closing of the stomata. As stomata open in the morning, the rate of transpiration increases, decreasing at a duck when stomata are closed. Since 90% of water loss in transpiration is through the stomata pores, light intensity will have an important effect on the rate of transpiration.
{4} TEMPERATURE:
an increase in temperature increases the kinetics energy and random movement of molecules, leading to a faster rate of diffusion. The rate of transpiration also increases with an increase in temperature, because water evaporates more from cell of the mesopyll tissue. This increases the concentration of water vapour molecules in the air spaces of leaf, producing greater water potential. Higher temperature is associated with a lower humidity of air around the leaf. This leads to an increase in water potential gradient between the leaf and the atmosphere, so water will diffuse out more rapidly.
INTERNAL FACTORS AFFECTING THE RATE OF TRANSPIRATION
There are a number of anatomical and morphological features of a plant, which also affect the rate of transpiration. They are:
{1} LEAF AREA:
since a proportion of water loss occurs through the cuticle, the greater the total leaf area of a plant, the greater the rate of transpiration regardless the number of stomata. In addition any reduction in leaf area certainly involves in the total number of stomata.
{2} CUTICLE:
the cuticle is a waxy covering over the leaf surface, which reduces the rate of transpiration. The thicker cuticle reduces the rate of transpiration.
{3} DENSITY OF STOMATA:
the greater the number of stomata for a given area, the higher the transpiration rate.
IMPORTANCE OF TRANSPIRATION
{1} supplies photosynthesis {1-2%} total
{2} the evaporation of water from the mesophyll cells that accompanies transpiration requires energy and therefore in the cooling of leaves in the same way that sweating cools the skin of mammals.
{3} transpiration stream is necessary to distribute mineral salts throughout the plant, since these moves with water. While this may be true, it seems probable that low transpiration rate would be sufficient. Uptake of mineral salts from the soil is largely independent of the transpiration stream.
Flowering plants have two different types of transport systems, both of which consist of tubes. The first system is the xylem and is concerned with the movement of water and mineral ions, obtained from the soil, from the roots through the stem and the leaves. The other system, is composed of phloem tissue, is concerned with the transport of sugars and other soluble organic products of photosynthesis from where they are formed in the leaves to where they are needed in the developing shoots, flowers fruits and roots. Together are called vascular tissue.
XYLEM
As mentioned earlier xylem conducts minerals salts and water. In addition it also offers support. By doing so, it has structural and physiological role in the plant. It consists of the following types of the cells:
{a} trachieds:
they are single cells that are elongated and lignified. They have tapering end walls that overlap with adjacent tracheids in the same way as scelerenchym fibres. Thus they have mechanical strength, which enables them give support to the plant. The tracheids characterize the original primitive water conducting cells of the vascular plants and are the only cells found in the xylem of most primitive vascular plants. Despite the primitive nature they obviously function efficiently because gymnosperms most of which are trees rely on tracheids to conduct water from root to aerial plants.
{b} vessels:
they are the characteristic conducting units of angioerm xylem. They are long tubular formed by the fusion of several cells, end to end in a row. Each cell forming a xylem vessel is corresponding to a tracheid and so called vessel element. Vessel elements are shorter and wider than tracheids. Each begins life as a normal plant cell in whose wall a substance called lignin is laid down. Lignin is very hard and strong substance and it is impermeable to water. It also built around the cell, leaving an empty space around the cell called lumen.
{c} xylem parenchyma:
it occurs both in the secondary and the primary xylem but it is extensive and assumes greater importance in the latter. The two types of parenchyma exist in secondary xylem derived from meristematic cell and they are called ray initials and fusifrom initials. The ray parenchyma is more extensive. it forms a radical sheet of tissue called medullary rays. Its function includes food storage. deposition of tannis, crystals and so on.
Fusiform initials normally give xylem vessel or phloem sieve tube and companion cell but occasionally give rise to parenchyma cells. They form the vertical rows of parenchyma in secondary xylem.
{d} xylem fibres:
they are shorter and narrower than tracheids and have much thicker walls. Xylem fibres resemble the scelerenchym fibres due to the fact that they have overlapping walls they have narrow lumens than xylem hence they are stronger and offer mechanical strength to the plant.
PHLOEM
They are composed of living cells within the cytoplasm and have no mechanical function. They are five types, which include sieve tube elements, companion cells, parenchyma, fibres and scleroids. But I will be discussing briefly about two of these.
Sieve tubes elements and companion cells: sieve tubes are long tube like structures that translocation solutions of organic solutes like glucose throughout the plant. They are formed end to end by fusion of cells called sieve. Sieve elements have a very distinctive structure. Their walls are made of cellulose and pectile substances like parenchyma cells but they degenerate and are lost as they mature and cytoplasm becomes confined to a thin layer around periphery of cells. Although they lack nuclei the sieve elements remain living but are independent on the adjacent companion cells, which develop from the same marismatic cells. Two cells from the functional unit. The companion cell; maxing dense very active cytoplasm.
FAIR TEST
If this experiment is not a fair test then we will be obtaining wrong results, which will also lead to a wrong conclusion. We have to:
{1} make sure that there are no air bubbles in the photometer as this could lead to us obtaining wrong results. The reason for this will be explained later in this coursework.
{2} the same apparatus will be used for the whole experiment to allow constituency.
{3} the leaves should not be wet as this could alter the rate of transpiration.
{3} to make this experiment as accurate as possible an average will be taken of the two results.
VARIABLES
The different conditions for the experiment are independent variable. These conditions will change, also causes changes in the dependent variable. The variables are listed below:
LIGHT:
as this increases {light intensity}, the rate of transpiration increases.
WIND:
in still air the rate of transpiration decreases, while air movement increases the rate of transpiration.
TEMPERATURE:
the temperature is not constant as it varies for the different conditions.
The DEPENDENT VARIABLE is the changing volume of water, which will also change as the different conditions change. The volume was chosen as the dependent variable as the changes are visible.
TIME LEFT IN THE SOLUTION:
This will be kept constant as possible. This is to reduce the chance of irregular results being obtained.
MEASURING METHOD:
there are a number of ways of measuring the volume of water given off during transpiration. The fundamental method is using a ruler to measure it. This is inaccurate as you may take readings above the meniscus. A better way to measure the volume of water is at eye level. If the volume of water is not measured at eye level, then the volume of water uptake would be wrong, this could lead to lead to wrong results being obtained, which could also lead to a wrong graph, and wrong conclusions.
EQUIPMENT USED:
a potometer was used to measure the rate of transpiration from the mesophyte and the xerophyte plant. The potometer is very reliable in measuring the rate of transpiration and should be set up carefully. It should be set up underwater to prevent air bubble forming. If a n air bubble forms it will form an air bubble form in the column, then the column of water breaks then the and the difference in pressure between the water at the top and the water at the bottom cannot be transmitted through the vessel. We say that there is ‘air lock’. This can significantly reduce the rate of transpiration in the mesophyte and xerophyte plants, and hence reduce both the accuracy and reliability of results.
An electric fan was used as opposed to a hair dryer, so you do not have to take into account heat. This is because the hair dryer not only provides a source for wind but also heat as well and this could alter the results obtained.
Using a plant such as a plant such as the cactus to measure the rate of transpiration in xerophytes would have given us a different result. The rate of transpiration would have been much lower because cactus are xerophytes that are found in the desert and they have more feature to minimise the loss of water such as flattened photosynthetic stems that store water. Their leaves are reduced to spines, which reduces the surface area from which transpiration can take place and protects the plant from being eaten by plants.
CONTROL
Laboratory temperature was kept constant as constant as possible throughout the experiment.
The same plastic bag was used for both the xerophytes and mesopyhtes plant.
For both sets of plants, the distance of the wind speed was constant
Amount of water was constant: I did not change the volume of water in the photometer.
Finally, another control for the experiment was by placing the mesophyte and the xeropyte under normal conditions. The normal condition for the mesophyte should be about {200C} because they are land plants. While that of the xerophyte should be dry place because xerophytes are found in dry places such as the desert.
TRIALS/RUNS:
the experiment was repeated twice with the same apparatus. It enabled me to get a more accurate result than carrying out the experiment once. Carrying out the experiment will reduce the risk of getting anomalous result. for the experiment to be reliable all the results have to be consistent, and repeating the experiment twice helps to increase the chances of getting consistent result.
PRELIMINARY WORK
Prior to the experiment, a leaf from both mesophyte and xerophyte’s plant was viewed using a microscope. The leaves of the plant were cut before being viewed as this gave me detailed structure, showing me how water enters the xylem.
Also alongside carrying out the experiment on transpiration I also testes for transpiration using an alternative method. I did this by placing a dry cobalt chloride paper on the surface. The paper changed from blue to pink after some time showing that water was given off. Also by doing this will notice that the rate of transpiration is greater on the lower than on the upper surface of the leaf. This is because most leaves have more stomata on the lower surface than the upper surface of the leaf.
RISK ASSESMENT
This involves not only personal, but for the safety of others as well.
{1} Handle scissors with care when cutting leaves from the shoot, so as not to cut you and injure others as well.
{2} Electrical objects should be handled with care because of water, as this could lead to electric shock, which is very dangerous.
{3} Laboratory coats should be worn at all times to prevent your dangerous chemicals from getting into our clothing and also to minimise the risk of them getting into our body.
{4} Allergic reactions due to the plants: avoid too much contact or rubbing eyes with hands.
{5} Safety goggles should be worn at all times to chemicals from getting into our eyes.
EQUIPMENT
{1} Potometer
{2} Large transparent polyethene bag
{3} Thermometer
{4} Electric lamp
{5} Vaseline
{6} Stop clock
{7} Leafy shoot of mesophyte and xerophyte plant
{8} Hair dryer
METHOD
Setting up the potometer
- Immerse the potometer and make sure that it is completely filled with water.
- Put the cut stalk {but not the leaves} of your leafy shoot into the water and cut off the last centimetre stalk under water
- Attach the stalk to the potometer
- The objective is to make sure to make the water in the xylem elements of the plants is continuous with the water in the potometer: there must be no air bubbles.
- Remove the potometer and plant from water and mount in a fixed position.
- If necessary smear Vaseline on joints between the stalk and the potometer to avoid leakage.
MESOPHYES
- All the apparatus needed for the experiment was collected
- Fix the potometer inside water to prevent air bubbles from entering
- A good mesophyte was selected
- The shoot was cut under water quickly to avoid air bubbles from entering
- The shoot was then fitted into the bung of the potometer, this was done under water to avoid the risk of water entering
- There was no leakage and the syringe, which was pushed into the rubber holding the potometer, was locked properly.
- The potometer was gently carried out of the sink to avoid splashing water and messing up the laboratory
- The rate of transpiration was measured under normal conditions for a period of five minutes
- The experiment was also carried out using other conditions
- Lastly the experiment was carried out again using no leaf at all
- The leaves were drawn out and the results were recorded in the table
XEROPHYTES
The experiment was also carried out using the same apparatus and method as that of the mesophyte.
RESULTS
Table {1} to show the rate of transpiration in mesophytes using a range of different conditions.
The average volume of water was calculated by working out the change per volume for each reading, the two values for each volume was added and divided by two. Meanwhile the average volume per unit time was calculated by dividing the average volume by the taken for each condition {5mins}. This is a better way to know the exact rate of transpiration for each condition as it tells us the volume of water lost per minute from the mesophyte plant. It also shows us how the volume of water lost per minute varies with the different conditions.
Rate of water uptake per unit surface area:
Total time = 5mins + 5mins + 5mins + 5mins + 5mins + 5mins
= 30 mins
1hour = 60 mins
X = 30 mins
X = 30/60
= 0.5hours
Total volume of water lost = 1.25 + 1.1 + 1.0 + 1.2 + 0.95 + 0.85
= 6.65cm3
Leaf surface area = 816 + 564 + 916 + 1104 + 1048 + 288 + 504 + 440 + 832 + 2336
= 8848mm2
1000mm = 1m
8848mm2 = 8848/1000
= 8.848m2
Therefore the rate of water loss per unit surface area
= Volume/ {time * leaf surface area}
= 6.65cm3/{0.5*8.848} h/m2
= 6.65cm3/4.424
= 1.503m3h-1m2
Table {2} to show the rate of transpiration in xerophytes, using a range of different conditions.
Adding the initial and final volume, and then dividing it by two calculated the average rate of water uptake. The average volume per unit time was the calculated by dividing the average volume by the time tkane for the experiment which is 5minutes.
Rate of water uptake per unit surface area of the xerophyte plant
Total time = 5min + 5mins + 5mins + 5mins + 5mins + 5mins
= 30 mins
1 hour = 60 mins
Therefore 30minues will be 0.5 hours.
Total; volume= 0.75 + 0.9 + 0.6 + 0.9 + 0.55 + 0.65
= 4.35cm3
Total surface area of leaves = 3600 +740 + 1216 + 1120 +
= 6676mm2
1000mm = 1m
6676mm2 = 6.676m2
Therefore the rate of water loss per unit surface area of the leaves
= Volume/ {time* leaf surface area}
= 4.35/{0.5*6.676} h/m2
= 1.303cm3h-1m
ANALYSIS
From the results, in the table when you compare the rates of transpiration in mesophyte and xerophytes under normal condition, you will notice that the rate of transpiration in mesophyte is higher than that in xerophytes. This corresponds with my initial prediction, which states that the rate of transpiration in mesophytes would be higher than that in xerophytes, because mesophytes are plants that are found in areas where there is adequate supply of water and so do not have adaptations to minimise the rate of water loss.
From my tables an average of the final and the initial volume of water were taken to minimise error by cancelling out any anomalous result. This is not possible with simple unadjustable data.
A bar chart was used as opposed to a pie chart as this will enables you to make a better comparism.
From the graph the rate of water uptake when Vaseline was applied to the mesophyte plant {0.95cm3} was high compared to that of the xerophytes {0.55cm3}. There could be a number of explanations for this. Firstly it could be because xerophytes have adaptations to minimise the rate of water loss. Secondly it could be because for my mesophyte experiment I did not cover the lower layer of the leaves with Vaseline. This might have lead to loss of water through the lower layer {more stomata situated at the lower surface of the leaf}; meanwhile for my xerophytes experiment the lower surface of the leaf was smeared with Vaseline.
Also from the graph the highest rate of water uptake for the mesophyte plant, was when the mesophyte was placed in front of an electric fan {1.4cm3}. This is simply because under that condition of transpiration. mesophytes tend to lose more water, because wind speed affects the potential gradient between inside the leaf and outside. air movement can move water molecules away from the surface of leaves thus creating a steeper water potential gradient and therefore increasing the rate
That of xerophytes was when when radiator and electric fan was used {0.9cm3}. this is because as temperature increases water evaporates more from the cell of the mesopyll tissue. 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.
The lowest reading for the mesophyte was taken when all the leaves were cut from the plant. This is because transpiration occurs chiefly through the stomata, which is found on the leaf of the plant. While that of xerophytes, which is also when Vaseline is added as it blocks the evaporation of water through the stomata.
When you look at the calculations, you notice that the leaf surface is for the mesophyte is larger than that of the xerophytes. This means that the rate of transpiration in mesopyte will be higher than that in the xerophytes. This is because as the leaf area increases the rate of transpiration increases {since a proportion of water is lost through the leaves}
Also the total volume of water lost from the mesophyte plant and the rate of water loss per surface area is lost is much more than that, it corresponds with my initial prediction: the rate of water loss in mesophyte will be greater than that in the xerophyte plant.
the main reason for transpiration stream is photosynthesis. The rate of transpiration in neophytes is higher than that in xerophyte. There are a number of logical explanation for this; on could be that mesophyte more stomata than the xerophyte. They have to keep their stomata open during the day when the leaves are actively photosynthesizing, so that gases can be exchanged; when stomata are open, transpiration is unavoidable. Xerophytes are also able to minimise the rate of water loss because they can keep their stomata closed during the day.
The experiment was repeated twice with the same apparatus. It enabled me to get a more accurate result than carrying out the experiment once. Carrying out the experiment will reduce the risk of getting anomalous result. for the experiment to be reliable all the results have to be consistent, and repeating the experiment twice helps to increase the chances of getting consistent result. Repeating the experiment more than two times would have been beneficial and accurate as this would give me a better range and average to work with.
EVALUATION
The experiment was useful in testing my hypothesis. The results prove that my predictions were correct. there were not many sources of error, the little involved are listed below:
The type of plant used was a limitation{ cold climate xerophytes}: if for example a cactus was used, the rate of transpiration would have being a lot lower because they have flattened photosynthetic stems that store water. The leaves are also reduced to spines {this reduced the surface area for transpiration to take place}.
Both plants while carrying out the experiment at normal condition: I left both plants at room temperature, this could have led to me obtaining wrong results because the normal conditions for mesophyts is different from that of the xerophytes because xerophytes are found in dry places like the desert while mesophyte are land plants.
I carried out the experiment two times with the same method and apparatus. My results if compared are quite alike. It would have been beneficial to repeat the experiment about two to four times in a reliable manner as possible thereby the chances of anomalous results occurring and this will give me a better range of result to work with and hence increase the accuracy of my next result.
Also next time I will keep the experiment running for a longer time as this will increase the accuracy of my result.
To obtain reliable results, I avoided the following mistakes:
When the leaf was cut from the plant I quickly immersed it in water to prevent air bubbles. I also inserted the leaf into the bung of the potometer. If an air bubble forms in the column, then the column of water breaks and the difference in pressure between the water at the top and water at the bottom cannot be transmitted through the vessel. An ‘air lock’ is said to be formed and this prevents water from going up.
An electric fan was used as opposed to a hair dryer, this helps increase the reliability of my result because the hair dryer also generates heat.
Overall I believe that my results are accurate as it is possible to obtain them with the apparatus available.
Overall my techniques and methods used are reliable. there were only a few errors that might have caused inaccuracy of my results, and this contributed to my anomalous results:
From table {1} I recognised two anomalous results. The first one was when I cut off all the leaves, I expected the rate of transpiration to be decreased because by removing the leaves there will be no stomata for the water vapour to escape, instead it was increased.
My second anomalous reading is when the polyethene bag was used to cover the plant; the rate of transpiration was also increased. This might have been due to the fact that the polyethene bag was not airtight and hence increasing the rate of transpiration.
I also did not use the Vaseline to cover the lower surface of the leaves when using the mesophyte plant. This increased the rate of transpiration because most plants have stomata on their lower surfaces more than their upper surfaces
I compared my results to the class average, which lead me to believing that my results have a high level of accuracy.
To improve the reliability of my result the following could be done next time:
The experiment could be improved by increasing the number of runs to give a better average. Increasing the number of runs, for example to six, gives a better range to work it, because there would be a higher level of accuracy, and a fairer comparism can be made between the mesophyte and the xerophyte plant.
Also increasing the time for the experiment will allow the rate of transpiration to take place more. It will give me results a greater flexibility that is not possible with 5 minutes.
The experiment could also be improved by using the same number of leaves for both the mesophyte and the xerophyte plant. This would mean that the surface area was taken for the same number and not different number of leaves. If this is done a more reliable result can be obtained and also a fair comparism can be made.
It also helps to cut the end of the stem with a slanting cut, as air bubbles are less likely to get trapped against it.
CONCLUSION
According to my results and explanation, I think that my predictions are correct. I predicted that the rate of transpiration would be higher in mesophyte than xerophyte.i also explained how the different conditions affect the rate of transpiration. generally I think that me experiment is successful as my results correspond with my initial prediction.
USING TWO WAY ANALYSIS OF VARIANCE {randomised Block Design} to compare the rate of transpiration between xerophytes and mesophytes under the different conditions
I carried out experiments to test the rate of transpiration in two plants {xerophytes and mesophyte}. six different conditions were used.
The table below shows the volume of water loss per unit time:
In a two-way analysis each condition affects each of the plants, and in the analysis we can test not only the difference in volume of water loss due to plants but also due to he various conditions.
Xij = μ + αi+ βj + εij ,where
μ = the overall mean
αi= mean effect of the ith level row factor relative to μ {plant i}
βj= mean effect of the jth level of column factor relative to μ {condition j}
εij = the random variation in the observation
Σα = Σβ 0 εij ∼ N(0, σ2)
Total about mean = 0.4342 - 2.202/12 = 0.030867
Between plants = 0.872 + 1.332/6 - 2.202/12 = 0.01763
Between conditions = 0.42 +0.462 +0.322 +0.422 +0.302 + 0.302/2 - 2.202/12 = 0.01187
Test at 5% significant level :
Ho: no difference between plants Ho: no difference between conditions
H1difference between the plants H1: difference between the conditions
F(1,5)(0.95) =6.61 F(5,5)(0.95)= 5.05
Critical region, F• 6.61 critical region, F• 5.05
74.3 • 6.61, so reject Ho and conclude 10•5.05 so reject Ho and conclude
That there is a significant difference that there is low difference between
Between plants the conditions
Using the analysis variance, I was able to prove that there is a difference I volume of water lost from the two plants, and that this volume of water is dependent on the condition. This is because when I was testing for a difference in plants used, my critical region was greater than 6.61, and from the table I calculations I obtained 74.3 which notably greater than 6.61. this will lead to me rejecting Ho{ null hypothesis} and concluding that there is a great difference between the plants.
For my second testing the critical region is greater than 5.05, and I obtained 10 from my calculation, and this would lead to me rejecting Ho and concluding that although there is a difference between the two conditions, it is not very high.
REFERENCES
To make my work possible, I used data found from the following books:
{1}BIOLOGY 1{Cambridge advanced series}
Author: Mary Jones
Richard Fosbery
Series Editor: Mary Jones
Pages: 128 -145
{2}A2 FURTHER STUDIES IN BIOLOGY{AQA biology specification}
Author: Margaret Baker
Bill Indge
Marin Rowland
Pages: 132 -146
{3} BIOLOGICAL SCIENCE 1&2
Author: D.J.TAYLOR B.Sc., Ph.D., C.Biol., F.I.Biol
N.P.O.GREEN B.Sc., C.Biol., M.I.Biol.
G.W.STOUT B.Sc., M.A., M.Ed., C.Biol., F.I.Biol.
Series Editor: R.SOPER B.Sc., C.Biol., F.I.Biol.
Pages: 167 -181
{4}MODERN BIOLOGY
Author: Sarojini. T. Ramlingam B.Sc. {Hons.}, PH.D
Pages: 224 - 226 and 112 -130
{5} ADVANCED BIOLOGY {third Edition}
Author: J.Simpkins
J.I Williams
Series editor: M.K.Sands
Pages: 220 - 227