· Web viewstrength to plant fibres. The xylem and phloem are also responsible for plant fibres’ thick cell wall and hardness. This is because the lignin on the outer part of their

Edexcel Biology Practical 2009

INTERNATIONAL EDUCATION CENTRE INTECKAMPUS SEKSYEN 17, 40200 SHAH ALAM, SELANGOR DARUL EHSAN.

TEL: 603-55227000

A REPORT ON THE EFFECT OF CAFFEINE ON HEART RATE

PREPARED FOR BIOLOGY PRACTICAL 1.1

BY GAAJEEN

(NRIC: 910513-07-5335)

(SID NO: 2009803502)

IN GROUP 10M13

UNDER MADAM IDA MURYANI

SUBMITTED ON 3 NOVEMBER 2009

1 The Effect of Caffeine on Heart Rate


Title

The strength of plant fibres.

Objective

To investigate the strength of plant fibre as compared to concrete strength.

Problem Statement

What is the difference in strength of plant fibres and concrete?

Hypothesis

Concrete has the greatest strength followed by plant fibres and hair.

Introduction

Diagram 1: Lemna Plants1

Plant fibres are long, stretched, thick and lignified cell walled tubes. One component of the plant fibre is its cell wall made of cellulose microfribils in a net-like arrangement which gives strength to the plant fibres. Slerenchyma fibres are also present in plant fibres. They form secondary cell wall which are dead cell with lignin which provides even more strength to plant fibres. The xylem and phloem are also responsible for plant fibres’ thick cell wall and hardness. This is because the lignin on the outer part of their vessels.1 Image source: www. aquapage.eu


http://www.aquapage.eu/


Retting is a stage in the manufacturing of vegetable fibres, especially the bast fibres. It is a process that employs water and microbial action to separate the bast fibres from the woody core (the xylem), and sometimes from the epidermis as well. Retting can be done by letting the cut crop stand in the fields in the wet Fall, called "dew retting". Bacterial action attacks pectin and lignin, freeing the cellulose fibres. The stems are monitored during retting to avoid excessive degradation of the fibres, making it a very labour-intensive process. The stems can now be removed and processed mechanically to produce fibres. These fibres can be tested to measure the amount of tensile stress it can cope before it breaks. This is known as tension strength. Knowing the tensile strength of a fibre can make it suitable for different uses. E.g.ropes for climbing have to have a certain amount of stress tolerant for it to be suitable to carry a person.

All plants require certain mineral elements to develop and mature in a healthy state. Macronutrients such as nitrogen, potassium, phosphorus, sulfur, calcium, and magnesium are required in substantial quantities, while micronutrients or trace elements such as boron, iron, manganese, copper, zinc, and molybdenum are needed in much smaller quantities.

Table 1: Relative amounts of mineral elements compared to nitrogen in dry shoot tissue. May vary depending on plant species.2

Nitrogen is about 1/3 as abundant as carbon. It occurs principally as diatomic N2 in the atmosphere. It is the lightest element with 5 e- in outer orbital shell, 3 valence electrons and one unshared pair. It makes + charged groups possible.

In resonating rings, it acts as the focal point for redox reactions (NAD+). Amine N is important in complexing metals (eg., binding Fe in cytochromes, or binding Mg in chlorophyll). Nitrogen acts as a donor atom in many enzymatically catalyzed reactions.

In peptide bond formation the -C--N- is constrained in its rotation and permits a planar structure important to helix formation and H-bonding. N can be viewed as a C substitute which introduces an essential distortion into the symmetry of C, providing compounds with additional properties of coordination, basicity, charge, chemical reactivity, oxidation-reduction properties, and structure. Without these distortions, there could be no life as we know it.

In living things, N is found almost exclusively in the fully reduced state. Most of the N absorbed from the soil by higher plants is in the fully oxidized form of NO3, and must be reduced for assimilation (we will discuss the reduction reactions in more detail in association

2 Adapted from: W.F. Bennett (editor), 1993. Nutrient Deficiencies & Toxicities in Crop Plants, APS Press, St. Paul, Minnesota.



with photosynthesis). Two enzyme complexes are involved, one in the cytoplasm, the other in plastids. If available, plants will absorb and assimilate ammonium (NH4

+).

Diagram 1: Plant uptaking Nitrogen3

Plants containing enough nitrogen to attain limited growth exhibit deficiency symptoms consisting of general chlorosis, especially of older leaves. In severe cases these leaves yellow and die. Younger leaves remain green longer, because they receive soluble forms of nitrogen transported from older leaves. In many plants, excess nitrogen often stimulates shoot growth more than root growth and may favor vegetative growth over flowering and seed formation.

Calcium (Ca++) is often the most abundant divalent cation in plants. It is important component of cell walls. It stabilizes the polysaccharides by forming intermolecular complexes with -COO- groups of pectins. Calcium is also important for maintaining the integrity of membranes, especially the plasma membrane.

Free calcium concentration in the cytosol is normally very low, about 10-7 M. Some hormonal or environmental signals raise the free Ca++ concentration to 10-6 to 10-5 M, which activates certain enzymes. (The increase is brought about by increased influx or release from vacuoles). Because changes in calcium are associated with hormonal and environmental signals it is often referred to as a secondary messenger.

If plants experience calcium defficiency, meristematic regions die. Margins of younger leaves become chlorotic then necrotic. Necrosis is the death of plant tissue sometimes in spots. Young leaves are malformed. Symptoms appear first in young tissues since Ca++ is not very mobile.

Phosphorous (P) occurs and reacts as orthophosphate, the fully oxidized and stable form. It participates in metabolism by forming water-stable phosphate esters and anhydrides. In these forms phosphorus has several fundamental roles: linkage (as in nucleic acids), substrate mobilization (particularly of non-polar compounds, energy conservation (phosphorolysis instead of hydrolysis conserves bond energy), source of free energy in bond formation, H+ pumping, etc.3 Image source: www. nitrogenfree.com


http://www.nitrogenfree.com/


Reactivity during enzymatic catalysis is provided by binding to a divalent cation (primarily Mg++), bringing the ==O groups into a plane and introducing enough polarization for nucleophilic attack (electron donation). Mg++ (or Mn++) is a required cofactor in reactions involving phosphate transfer. Mg++ also commonly neutralizes polyphosphate compounds.

Phosphorous-deficient plants are stunted and , in contrast to those lacking nitrogen, are often dark green. Maturity is often delayed. Phosphate is easily redistributed in most plants from one organ to another and is lost from older leaves, accumulating in younger leaves, developing flowers and seeds. As a result, deficiency symptoms occur first in more mature leaves.

Iron (Fe++) is important for its oxidation-reduction properties (Fe+++ to Fe++). Iron forms a locus for electron transfer in many enzymes (eg., cytochromes, peroxidases, catalyses). It is also required for chlorophyll synthesis. Iron is a difficult cation for plants to handle since it readily precipitates. Internally it is thought to be transported in the form of chelates with organic acids such as citrate.

Plants with iron defficiency often have extensive interveinal chlorosis, starting with younger leaves (iron is relatively immobile. It will also cause initial distinct yellow or white areas between veins of young leaves leading to spots of dead leaf tissue.

Sulfur (S) occurs primarily in reduced form in living things. Reduced S can be viewed as a less electronegative O substitute (-SH vs. -OH) forming more stable complexes with certain metals (Cu and Fe containing metalloproteins important for electron transfer reactions). Also, disulfides are more stable than dioxides (or peroxides), permitting -SH participation in redox reactions (-SH + HS- ---- -S-S-). SH groups are also unlikely to form hydrogen bonds. Sulfhydryl groups (SH) can be the reactive sites of enzymes or coenzymes (Coenzyme A). Sulfhydryl groups are important for protein conformation.

Sulfate (SO4=) from the soil is the primary source of S, although some SO2 is absorbed from the atmosphere (too much SO2 can be quite toxic to plants. Sulfate reduction is very energy intensive and occurs mainly in chloroplasts (we will see this later along with photosynthesis).

Plants that lack sulphur will have general chlorosis of leaf, including vascular bundles. Sulfur is not easily redistributed from mature tissues in some species, so deficiencies are usually noted first in younger leaves.

Potassium (K+) is a dominant cation in plants. K+ ion is an activator of many enzymes that are essential for photosynthesis and respiration, and it also activates enzymes needed to form starch and proteins.

K+ is quite mobile in the plant, presumably because there are many membrane carrier systems adapted to K+. It is so abundant that it is a major contributor to the osmotic potential of cells and therefore to their turgor pressure. K+ regulation of osmotic potentials forms the basis for turgor movements in plants (eg., stomate opening, leaf movements). K+ serves as a



counter ion during movement of other ions: it moves with anions and as a counter-current to ion fluxes like H+.

As with Nitrogen and Phosphorus, potassium ion is easily redistributed from mature to younger organs, so symptoms first appear in older leaves. Leaves develop necrotic lesions and light chlorosis. The tips often die first. K+ deficient cereals develop weak stems so they are easily lodged.

Magnesium (Mg++) is the most important divalent cation in enzymatic catalysis. It is involved in most reactions involving ADP and ATP. It activates enzymes for DNA and RNA synthesis. It is a constituent of chlorophyll. It activates key enzymes involved in CO2 fixation. Magnesium also has structural roles in membranes, especially in organelles.

Deficiency of magnesium causes extensive interveinal chlorosis which starts with basal leaves and progresses to younger leaves (it is mobile). More precisely, it will cause initial yellowing of older leaves between leaf veins spreading to younger leaves. Fruit development and production would be poor.

VariablesManipulated variable (Independent variable): Different type of solution

Responding variable (Dependent variable): Lemna plant in normal culture solution shows greatest number of green leaves and general growth compared to Lemna plants in solutions lacking nutrients and distilled water.

Fixed variables: Period of testing, initial number of plants used, size and shape of Lemna plant



ApparatusPetri dish, droppers, cotton wool, forceps, scissor, measuring cylinder

Diagram 5: A dropper 4 Diagram 6: A forcep5

MaterialsLemna plant, solution lacking nitrogen, lacking phosphorus, lacking potassium, lacking magnesium, lacking calcium, lacking iron, lacking sulphur, normal culture solution, distilled water

Diagram 7: Lemna plants6

Procedures1. Lemna that have to be transferred is trimmed with scissors if there are small buds

developing.2. 4 pairs of Lemna plants is transferred to 8 petri dish respectively. It must have same

colour, size and shape.

4 Image source: www.muchobeets.com 5 Image source: www.hoahocdoisong.com 6 Image source: www.vitiligo-vitilem.eu


http://www.vitiligo-vitilem.eu/

http://www.hoahocdoisong.com/

http://www.muchobeets.com/


3. Measuring cylinder is used to transfer 15ml of different solution into each petri dish respectively.a) Lacking nitrogenb) Lacking calciumc) Lacking phosphorusd) Lacking irone) Lacking sulphurf) Lacking potassiumg) Lacking magnesiumh) Normal culture solutioni) Distilled water

4. The petri dish is labeled and covered with lids.5. It is placed on a tray and put outside the laboratory. 6. The growth of Lemna is observed for 14 days. 7. Observation and records included are:

a) General growthb) Change in colour of leavesc) Shape of leavesd) Change in number of leaves

Results

LACKING NITROGEN

Day

General growth Change in colour of leaves

Shape of leaves Change in number of

leaves

Green Yellow/dead



0 - 8 82 Increase 10 2 124 Increase 11 5 166 Increase 13 7 208 Increase 15 9 2410 Increase 20 8 2412 Increase 21 8 3114 Increase 22 9 32

Table 1: Data showing growth of Lemna in solution lacking nitrogen

LACKING CALCIUM

DayGeneral growth Change in colour of leaves Shape of leaves Change in

number of leaves

Green Yellow/dead0 - 8 82 - 8 84 - 8 86 - 8 88 - 8 810 - 8 012 - 8 014 - 8 0

Table 2: Data showing growth of Lemna in solution lacking calcium

LACKING PHOSPHORUS

DayGeneral growth Change in colour of leaves

Shape of leaves

Change in number of

leaves

Green Yellow/dead0 - 8 0 82 Increase 9 0 94 Increase 20 0 206 Increase 21 0 218 Increase 34 0 3410 Increase 36 0 36



12 Increase 38 0 3814 Increase 42 0 42

Table 3: Data showing growth of Lemna in solution lacking phosphorus

LACKING IRON

Day

General growth Change in colour of leaves

Shape of leaves Change in number of

leaves

Green Yellow/dead

0 - 8 0 82 Increase 12 2 144 Increase 17 2 196 Increase 20 3 238 Increase 30 4 3410 Increase 45 5 5012 Increase 51 6 5714 Increase 55 8 63

Table 4: Data showing growth of Lemna in solution lacking iron

LACKING SULPHUR

DayGeneral growth Change in colour of

leavesShape of leaves Change in

number of leaves

Green Yellow/dead0 - 8 0 82 Increase 13 2 154 Increase 18 4 226 Increase 21 5 268 Increase 23 6 2910 Increase 24 7 3112 Increase 25 8 33



14 Increase 26 9 35

Table 5: Data showing growth of Lemna in solution lacking sulphur

LACKING POTASSIUM



number of leaves

Green Yellow/dead0 - 8 0 82 Increase 15 0 74 Increase 18 0 36 Increase 23 0 58 Increase 25 0 210 Increase 44 0 1912 Increase 46 0 214 Increase 55 2 11

Table 6: Data showing growth of Lemna in solution lacking potassium

LACKING MAGNESIUM



number of leaves

Green Yellow/dead



0 - 8 0 82 Increase 10 2 124 Increase 17 3 206 Increase 20 4 248 Increase 24 5 2910 Increase 30 4 3412 Increase 32 5 3714 Increase 35 8 6

Table 7: Data showing growth of Lemna in solution lacking magnesium

NORMAL CULTURE SOLUTION

DayGeneral growth Change in colour of leaves Shape of leaves Change in

number of leaves

Green Yellow/dead0 - 8 0 8

2 Increase 15 0 7

4 Increase 18 0 3

6 Increase 20 0 2

8 Increase 24 0 4

10 Increase 30 4 1012 Increase 45 5 5014 Increase 50 6 56

Table 8: Data showing growth of Lemna in normal culture solution

DISTILLED WATER



number of leaves

Green Yellow/dead0 - 8 0 8

2 Increase 8 4 4



4 Increase 10 3 1

6 Decrease 9 4 0

8 Decrease 8 5 0

10 Decrease 7 6 012 Decrease 6 5 -114 Decrease 4 3 -4

Table 9: Data showing growth of Lemna in distilled water solution



DiscussionAnalysis and Interpretation of Results

In this experiment to examine the effect of different nutrient deficiency on Lemna plant growth, the period of observing the growth is fixed at 14 days. Every observation and recording is made on alternate days. The solutions that are used are solution lacking nitrogen, calcium, phosphorus, iron, sulphur, potassium, magnesium, normal culture solution, and distilled water. Table 1 to Table 9 shows the growth of Lemna plant in all the different solutions respectively.

In table 1, it shows the growth of Lemna in solution lacking nitrogen. Nitrogen is needed to form amino acid and thus in the synthesis of protein. The initial numbers of plants are 4 with 8 leaves. The growth increased steadily in the period of 14 days. At the 14th day, the number of leaves increased to 32. The number of green leaves observed is 22 whereas the number of dead leaves observed is 9. The chlorotic symptoms shown by this leaf resulted from nitrogen deficiency. A light red cast can also be seen on the veins and petioles. Under nitrogen deficiency, the older mature leaves gradually change from their normal characteristic green appearance to a much paler green. As the deficiency progresses these older leaves become uniformly yellow (chlorotic). Leaves approach a yellowish white color under extreme deficiency. In some plants the underside of the leaves and/or the petioles and midribs develop traces of a reddish or purple color. In some plants this coloration can be quite bright.

Table 2 shows the growth rate of lemna in solution lacking calcium. The initial number of plants are 4 with 8 green leaves. By the 14th day, all the leaves have died and showed zero groth. This shows the major importance of calcium in the growth of lemna plant. Calcium is needed to combine with pectin in middle lamellae to form calcium pectate. It helps to hold neighbouring cells together. These calcium-deficient leaves show necrosis around the base of the leaves. The very low mobility of calcium is a major factor determining the expression of calcium deficiency symptoms in plants. Classic symptoms of calcium deficiency include blossom-end rot of tomato (burning of the end part of tomato fruits), tip burn of lettuce, blackheart of celery and death of the growing regions in many plants. All these symptoms show soft dead necrotic tissue at rapidly growing areas, which is generally related to poor translocation of calcium to the tissue rather than a low external supply of calcium. Very slow growing plants with a deficient supply of calcium may re-translocate sufficient calcium from older leaves to maintain growth with only a marginal chlorosis of the leaves. This ultimately results in the margins of the leaves growing more slowly than the rest of the leaf, causing the leaf to cup downward. This symptom often progresses to the point where the petioles develop but the leaves do not, leaving only a dark bit of necrotic tissue at the top of each petiole. Plants under chronic calcium deficiency have a much greater tendency to wilt than non-stressed plants.

Table 3 shows the growth of Lemna plant in solution lacking phosphorus. The initial number of plants are 4 with 8 leaves. However, this plant undergone steady growth and it has grown to 42 leaves by the 14th day. It does not have any yellow leaves. It is essential for all plant growth, for instance,energy transfer. These phosphorus-deficient leaves show some necrotic spots. As a rule, phosphorus deficiency symptoms are not very distinct and thus difficult to identify. A major visual symptom is that the plants are stunted. Phosphorus deficient plants develop very slowly in relation to other plants growing under similar environmental conditions but without phosphorus deficiency. Phosphorus deficient plants are often mistaken for unstressed but much younger plants.



Table 4 shows the growth rate of lemna plant in solution lacking iron. The initial number of plants are 4 with 8 leaves. The plant in this solution grown rapidly with 63 plants in 14 days. The number of green leaves are 55 and the number of dead leaves are 8. The growth rate is high because iron is micronutrient and is only needed small amount in plants for growth. However there are plants that turn yellow. These iron-deficient leaves show strong chlorosis at the base of the leaves with some green netting. Because iron has a low mobility, iron deficiency symptoms appear first on the youngest leaves.

Table 5 shows the growth rate of lemna plant in solution lacking sulphur. The initial number of plants are 4 with 8 leaves. There is a slow growth of plants in this solution and in the 14th day, the number of leaves increased to 35 leaves. the number of green leaves are 26 and the number of leaves turn yellow are 9. The visual symptoms of sulfur deficiency are very similar to the chlorosis found in nitrogen deficiency. However, in sulfur deficiency the yellowing is much more uniform over the entire plant including young leaves. With advanced sulfur deficiency brown lesions and/or necrotic spots often develop along the petiole, and the leaves tend to become more erect and often twisted and brittle.

Table 6 shows the growth rate of lemna plant in solution lacking potassium. The initial number of plants are 4 with 8 leaves. The number of leaves increased to 57 in the 14th day. The number of green leaves are 55 whereas the number of yellow leaves observed are 2. Potassium is the major ion inside every living plant. The onset of potassium deficiency is generally characterized by a marginal chlorosis progressing into a dry leathery tan scorch on recently matured leaves. This is followed by increasing interveinal scorching and/or necrosis progressing from the leaf edge to the midrib as the stress increases. As the deficiency progresses, most of the interveinal area becomes necrotic, the veins remain green and the leaves tend to curl and crinkle. In contrast to nitrogen deficiency, chlorosis is irreversible in potassium deficiency, even if potassium is given to the plants. Because potassium is very mobile within the plant, symptoms only develop on young leaves in the case of extreme deficiency. Potassium deficiency can be greatly alleviated in the presence of sodium but the resulting sodium-rich plants are much more succulent than a high potassium plant. In some plants over 90% of the required potassium can be replaced with sodium without any reduction in growth.

Table 7 on the other hand shows the growth rate of lemna plant in solution lacking magnesium. The initial number of plants are 4 with 8 leaves. The number of leaves increased to 43 in the 14th day. 35 leaves remain green whereas 8 leaves turn yellow. Magnesium is the key element in the chlorophyll molecule. The Mg-deficient leaves show advanced interveinal chlorosis, with necrosis developing in the highly chlorotic tissue. In its advanced form, magnesium deficiency may superficially resemble potassium deficiency. In the case of magnesium deficiency the symptoms generally start with mottled chlorotic areas developing in the interveinal tissue. The interveinal laminae tissue tends to expand proportionately more than the other leaf tissues, producing a raised puckered surface, with the top of the puckers progressively going from chlorotic to necrotic tissue.

Table 8 shows the growth rate of lemna plant in normal culture solution. Normal culture solution is used as positive control in this experiment. The initial number of plants are 4 with 8 leaves. In this solution, all the essential nutrients needed for the growth of the plant is present. There is no presence of yellow leaves up until the 8th day. On the 10th day, the number of green leaves are 30 and there is also 4 yellow leaves. This is because most of the nutrients might have finished by this time and leading to the development of yellow leaves. At the 14th day, number of green leaves observed are 50 and the number of yellow leaves are 6.



Table 9 shows the growth rate of lemna plant in distilled water solution. The initial number of plants are 4 with 8 leaves. In this solution, the plants general growth increased for the first 4 days, and decreased after that. It is because plants need essential nutrients for growth. If there is lacking of nutrients, or nutrient defficiency, then plants will experience stunted growth. Distilled water is used as negative control solution in this experiment.

As an overall trend, plants show rapid growth in normal culture solution and solution lacking iron only. The most affected plants are the plants in solution lacking calcium and distilled water. In distilled water, some of the plants die causing the change in number of leaves to be negative.

EvaluationLimitations and Improvements

Assumingly that we have done the experiment under full attention, there are still some techniques that are faulty. One of limitations of the experiment is that the health condition of the Lemna plant is not known. As similar lemna plant must be used for all these experiment, different health conditions of the plant might result in the experiment becoming not valid. So it is very important to make sure all the lemna plant are in the same health condition to obtain a more valid experiment.

Besides, the Lemna plant is also not oriented equally to obtain the sunlight. Some plants tend to get more exposure to sunlight than others because of their arrangement. Some of the petri dish is stacked in order to save space. This also could result in different sunlight exposure. Hence, all the lemna in the petri dish should be arranged in order they get equal exposure to sunlight.

Rate of photosynthesis can also be a limitation in this experiment. All the lemna plants would have different rate of photosynthesis. This is because of the difference in the exposure to sunlight, presence of carbon dioxide and others. It is important that all the factors for photosynthesis is controlled as much as possible.

Diagram 8: Photosynthesis of plant7

7 Image source: www.ieslosremedios.org


http://www.ieslosremedios.org/


In adddition, temperature can also be a limitation in this experiment. Different temperature will result in different rate of photosysnthesis. This will result in different plant growth in different solutions. So, temperature must be fixed to enable equal rate of photosynthesis for growth.

Source of Errors

One big error in this experiment is the type of Lemna plant is not kept constant. We know that the type and condition in of lemna plant is not constant. The health condition of the plants are not exactly known. So in order to prevent this, all the Lemna plant must be kept at the right condition.

Moreover, the culture solution that is used is not actually fixed. It is actually added until all the lemna plant is fully impregnated with the solution. In order to prevent this, 15ml of culture solution must be measured using measuring cylinder and added to the petri dish. It is very important to avoid parallax error during the measurement of the solution. Make sure eyes are parallel with the reading of the measuring cylinder.

There is also error because of miscalculations. Most of the recordings are not calculated precisely and this could lead to mistakes in data. So, calculations have to be done more carefully.

There is also high chance that misjudgement could have occured during the observations. As there are many leaves, certain colour of leaves might be missed out and the number of leaves calculated could not be very accurate. So, observations must be done more precisely.

Validity and Reliability of Results

It is hard to state whether there are anomalies in our results, because it is hard to define a trend for our results. Consequently, the validity and reliability of our results is not known until they are endorsed by a scientist.

However, to make sure that the results are more reliable and convincing, besides adhering to the other constant variables and follow all the necessary precautionary steps as mentioned in the beginning of discussion, replication of experiment is very important. Replication of studies helps to support findings and eliminate random errors. If this study is to be repeated, the culture solution used should be measured more accurately, and the lemna plants have to be put in the same environment conditions in order to get equal conditions for the growth of plants. Also, it is better to use Lemna plants that have the same health condition and are similar in all aspect. Lastly, data readings should be taken every day and approximately the same time every day. In this way, the data is would be more accurate.



Safety Precautions and MeasuresThe lemna plant must be handled with care as it can easily rupture. This is to prevent

any ethical issues related with living organism.

The solutions used must be transferred carefully to prevent any spillage. This is to avoid wastage of solutions.

Some of the solutions are harmful. So, it is higly recommended to wear a gloves to avoid harm to the hands.

Care should be taken when trimming the Lemna plant with scissors as it could injure the hands.

Wear labcoat in order to prevent any spillage of harmful and corrosive solutions to the cloth.

ExtensionWe can conduct experiment about the effect of plant mineral deficiency on different

plants such as Mexican Hat (Kalanchoe) plantlets, Brassica plants and others. This activity allows us to conduct research as a scientist would do by creating their own hypothesis about the effect of of plant mineral deficiency on different plants and testing that hypothesis. Our observations and conclusions can be used to create many alternate hypotheses which might show different pattern from what that is expected.

Diagram 9: A Brassica plant8

8 Image source: www.maltawildplants.com


http://www.maltawildplants.com/


ConclusionThe growth rate of Lemna is actually greatest in solution lacking iron compared to the normal culture solution. The highest number of green leaves are also in solution lacking iron compared to normal culture solution. The hypothesis is not accepted.

There is no specific relationship between the caffeine concentration and the heart rate of Daphnia per minute. The hypothesis is not accepted.



References1. Image on website (Aquapage)

Aquapage– Lemna sp. Retrieved February 25th, 2011 from www. aquapage.eu

2. Image on website (NitrogenFree)NitrogenFree – Nitrogen Cycle. Retrieved November 1st, 2009 from www. nitrogenfree.com

3. Article on website (Plant Physiology)Plant Physiology – Nutrients. Retrieved November 1st, 2009 from http://4e.plantphys.net/article.php

4. Article on website (Agriculture and Rural development)Gov. Of Alberta –Plant nutrients. Retrieved November 1st, 2009 from http://www1.agric.gov.ab.ca

5. Image on website (Muchobeets)Muchobeets– Dropper. Retrieved November 1st, 2009 fromwww.muchobeets.com

6. Image on website (Hoahocdoisong) Hoahocdoisong – Forceps. Retrieved November 1st, 2009 fromwww.hoahocdoisong.com

7. Article on website (Madsci)Madsci – Plant nutrients. Retrieved November 1st, 2009 from http://www.madsci.org/posts/archives/jul99/931925101.Zo.r.html

8. Image on website (Vitiligo)Vitiligo. Retrieved November 1st, 2009 from www.vitiligo-vitilem.eu

9. Image on website (Ieslosremedios.org)Ieslosremedios –photosynthesis. Retrieved November 1st, 2009 from www.ieslosremedios.org

10. Article on website (Maltawildplants)Maltawildplants – Brassica. Retrieved November 1st, 2009 from www.maltawildplants.com


http://www.maltawildplants.com/

http://www.ieslosremedios.org/

http://www.vitiligo-vitilem.eu/

http://www.madsci.org/posts/archives/jul99/931925101.Zo.r.html

http://www.hoahocdoisong.com/

http://www.muchobeets.com/

http://www1.agric.gov.ab.ca/

http://4e.plantphys.net/article.php

http://www.nitrogenfree.com/

http://www.aquapage.eu/


11. W.F. Bennett (editor), 1993. Nutrient Deficiencies & Toxicities in Crop Plants, APS Press, St. Paul, Minnesota.

12. C.J.Clegg, Edexcel Biology for AS, (2008). Hodder Education.

13. Campbell, Reece, Urry, Cain, Wasserman, Minorsky, Jackson, Biology Eighth Edition, (2008). Pearson.


Documents

· Web viewstrength to plant fibres. The xylem and phloem are also responsible for plant fibres’ thick cell wall and hardness. This is because the lignin on the outer part of their