ABSTRACT

The aim of the investigation is to find the effect of different amountof water on the growth of a Gazania plant. The hypothesis states that the Gazania plant wouldn’t grow if we increase the amount of water. Gazania plant were kept in full sunlight every day for three weeks. Plants height was measured after every 1 weeks. Water were given afterevery once a week for three weeks. There are two graph drawn. First graph is drawn based on experiment results and second one is finding the height change of plants vs different amount of water given to plant. The graphs shows that the large amount of water grow faster than less amount of water. According to the results, the investigationdid not supports the hypothesis that an increase in amount of water will decrease plant growth.

Contents

Aim

Theory

Hypothesis

Variables

Apparatus

Procedure

Results

Analysis

Discussion

Conclusion

Appendices

References

Bibliography

Aim:

The aim of this investigation is to determine the effect of water on plant growth using different amount of water.

Theory:

Plants are living organisms that survive in various regions and climates throughout the world. Plants are one of two major kingdoms oflife forms. There are about 300,000 plant species on earth. Plants arethe only life forms that can produce their own food using energy from sunlight. Plants produce almost all of the oxygen in the air that humans and other animal’s breathe. Plants are also an important sourceof food, building materials and other resources that make life possible for earth animals and human being. Water and soil is monetaryand most commonly used to grow plants, they reproduce through root spread and their offspring which are seedlings most often. Plants needwater to require performing the process of photosynthesis.

I have chosen Gazania plant for my biology experiment. Gazania is a genus of flowering plants in the family Asteraceae, native to southernAfrica. They produce large, daisy-like composite flowers in brilliant shades of yellow and orange, over a long period in summer (wiki 2012).Flowering plants include many of the most familiar plants. The distinctive feature of this plant group is the flower, a cluster of specialized leaves that help in reproduction. I have chosen this plantfor my experiment to investigate the reaction of plant physiological system. Using the different amount of water into the each Gazania

plant to determine whether the different amount of water affect the plant growth or not.

Plants need large quantities of water for growth. The most important factor driving water movement in plants is a process known as transpiration. Transpiration is the loss of water from plants in the form of vapour (evaporation). Plant utilize most of the water absorbedfrom the soil for transpiration (95%), but a small portion of the water absorbed is used during photosynthesis for producing the carbohydrates necessary for plant growth (5%). Since transpiration is the process of water movement through a plant and its evaporation fromaerial parts especially from leaves but also from stems and flowers. Leaf surface are dotted with pores which are called stomata, and in most plants they are more numerous on the undersides of the foliage. Transpiration occurs through the stomata apertures, associated with the opening of the stomata to allow the diffusion of carbon dioxide gas from the air for photosynthesis.

Water play very vital role in plant growth. A plant needs water in order to grow properly. They use water energy into food substances andsunlight energy to carbon dioxide. This process is called photosynthesis. Organisms need energy to survive. Some organisms are capable of absorbing energy from water and sunlight and using it to produce sugar and other organic substances such as lipids and proteins. Since plant need photosynthesis in order to survive.

In plants, photosynthesis occurs mainly within the leaves. Since photosynthesis requires carbon dioxide, water, and sunlight, all of those substances must be obtained by or transported to the leaves. Carbon dioxide is obtained through tiny pores in plant leaves called stomata. Oxygen is also released through the stomata. Water is obtained by plant through the roots and delivered to the leaves through vascular plant tissue system. Vascular tissue is the supportive and conductive tissue in plants, consisting of xylem and phloem. The xylem which conduct water and nutrients up from the roots and phloem which distributes food from the leaves to other parts of the plants. Sunlight is absorbed by chlorophyll, a green pigment located in plant cell structures called chloroplasts.

Since sunlight, water and carbon dioxide are important to the process of photosynthesis. Photosynthesis takes place in two stages, the firstwhich captures the energy, and the second which makes sugars. The first one requires water, because the plant uses the hydrogen atoms in

water to collect the energy. The second requires both sugar contain carbon, oxygen, and hydrogen, of which the first two come from carbon dioxide and the last, comes from water. The excess oxygen is released as oxygen gas. Since water play very vital role in photosynthesis process since it provide electrons to replace those removed from chlorophyll. Water is usually absorbed by roots and root hairs and trans-located up to the leaves through the xylem tissues in the stem. The equation for photosynthesis is - Carbon dioxide + Water --> Glucose + Oxygen

CO2 + H2O --> C6H12O6 + O2

Without water photosynthesis cannot happen. So photosynthesis needs water In order to complete its process. The parts of plant are also important part in process of the photosynthesis like roots, shoots andleave system.

Leaves are a plant’s main photosynthesis organs. The internal layers of the leaf (from top to bottom) include the cuticle, the upper epidermis, the mesophyll and the lower epidermis. Veins and bundle sheath cells are located in the mesophyll. Stomata’s, which regulate the flow of carbon dioxide and oxygen into and out of the leaf, are located in the lower epidermis. External stem structure includes buds,bud scale scars, lenticels, and leaf scars. Internal stem structure includes pith, xylem, and phloem. (Minor revisions, August 2010). Leafstructure is closely related with its photosynthesis function. Leaves must permit carbon dioxide access to the photosynthesis cells but block water from diffusing out. The oxygen that is a waste product of photosynthesis is must be allowed to escape from leaf. (Biocoach Activity). The epidermis is the dermal tissue of young plants undergoing primary. It is generally composed of specialized, flattenedpolygonal cells that occur on all plant surfaces. Shoot surfaces are usually coated with a waxy cuticle to prevent water loss and are oftencovered with plastic. The guard cells and pores are called stomata andthey permit gas exchange (water loss, CO2 uptake, and O2 release or uptake) between the atmosphere and the interior of the leaf. The root epidermis is adapted for absorption of water and minerals, and its outer wall surface typically does not have a waxy cuticle. (Plant Physiology, Lincoln Taiz, Eduardo Zeiger (2010). Flowering plants exchange gases through their leaves. In the light there is a net intake of carbon dioxide for photosynthesis and a net output of oxygen from respiration and in the dark there is a net

intake of oxygen for respiration and a net output of carbon dioxide. This is shown in figure below.

http://www.rsc.org/Education/Teachers/Resources/cfb/gas.htmAll plants cells respire all the time, and when illuminated plant cells containing chloroplasts also photosynthesise, so plants also need to exchange gases. The main gas exchange surfaces in plants are the spongy mesophyll cells in the leaves.

http://www.rsc.org/Education/Teachers/Resources/cfb/gas.htm

Gases enter the leaf through stomata-usually in the lower surface of the leaf. Stomata are enclosed by guard cells than can swell up and close the stomata to reduce water loss. The gases then diffuse throughthe air spaces inside the leaf, which are in direct contact with spongy and palisade mesophyll cells. It hypothesized that an increase in the amount of water will decrease plant growth. All plants need water in order to grow. Water is

essential to plants because it is the method through which plants transport nutrients and it is also essential to the process of photosynthesis. If a plant gets too much water, the roots can rot and if the water is inadequate, it might wilt.

Hypothesis:

An increase in the amount of water will decrease plant growth.

Variables:

Independent Variable: Amount of sunlight that each plant receives and amount of water.

Dependent Variable: Plant growth rate (Height of each plant).

Controlled Variables:

The shape and size of the pots. The type of plant that were used. The type of soil used. The amount of soil used.

Uncontrolled Variable: Air temperature Weather Animal interference.

Apparatus:

3 plants

Sunlight

Labelling tape

Meter ruler

Water in ml

1-100 ml graduated cylinder

Procedures

1. Obtain 3 plants of equal height

2. Label the plants A, B, and C with the labelling tape.

3. Measure the height of each plant

4. Place each plant where plant can receives full sunlight

5. Using a graduated cylinder, give plant A 10 ml of water oncea week for three weeks.

6. Using a graduated cylinder, give plant B 20 ml of water oncea week for three weeks.

7. Using a graduated cylinder, give plant C 30 ml of water oncea week for three weeks.

8. Measure the height of the plant twice in each week for threeweeks.

9. Record the results.

Results:

Table 1

Observations:

Plant Amount of Water (mL)

Week Height (cm)

A 10 1 122 133 14

B 20 1 122 13.53 14.7

C 30 1 122 14.1

3 15.5

Analysis:

Table 2

Change in height of plants given different amounts of water

Plant amount of water mL

week Height cm

change in height cm

A 10 1 122 13 23 14

B 20 1 122 13.5 2.73 14.7

C 30 1 122 14.1 3.53 15.5

Sample calculation of plant change in height

Change in height for plant A = 14 – 12 = 2 cm

Calculation of average height of plants

Average height for plant A = 12 + 13 + 14/3 = 13 cm

Calculation of average height of all plant

Average height of all plants = 12 + 13 + 14 + 12 + 13.5 + 14.7 + 12+ 14.1 + 15.5/9 = 13.42 cm

0 2 4 6 8 10 120

2

4

6

8

10

12

PlantAmount of Water (mL)WeekHeight (cm)

Graph 1 observation of the result

1.8 2 2.2 2.4 2.6 2.8 3 3.2 3.4 3.60

5

10

15

20

25

30

35

Change in Height (cm)

Amou

nt o

f wa

ter

(mL)

Graph 2 changes in height of plants given different amounts of water

Discussion:

According to the result of all three plants showed very similarheight, and height change. As you seen in the table and graph inthe analysis page, the amount of the water that was given to theplant each week did effect the plant growth. From the results ofthe experiment it was observed that the plants which receivedless water (10 mL) showed bad growth. The plant (A) which hasreceived less water (10 mL) had the lowest averaged total growthof the three investigations (13 cm). The plant (B) which received20 mL of water showed consistent growth with the average total

growth (13.4 cm). The plant (C) which received 30 mL of watershowed good growth with the average total growth (13.8 cm).Plant C which was received highest amount of water had bigger 0.8cm than group B and 1.5 cm than the group A. This it determinesthat plants which have received highest amount of water do growfast in the same amount of period. The results showed that the plant get highest water is increasingquickly as the day goes and same for plant that received 10 mL ofwater and 20 mL of water increasing bit slow. This is because plant’s soil has too much water, the roots can rot and plant can’t get enough oxygen from the soil. If there is not enough water for plant, the nutrients it needs cannot travel through theplant. Oxygen and water which helps plants to photosynthesis and help to produce sugar which is important for plants to grow properly. As the amount of water given to the plant increased, the overall change in the height of the plant increased. As can be seen in graph 2, plant C has a greatest height change and as can be seen in graph 1, plant C has a greatest height. It grows faster than other two plants. The plants that were water 10 ml, 20 ml, and 30 ml of water had a change in height of 2 cm, 2.7 cm and 3.5 cm, respectively.

As can be seen in graph 1, shows that the plant get less water(10 mL) is growing slower in constantly than plant which received10 ml and 20 ml. Plant (B) grows faster than plant (a) inconstantly. These result did not support the hypothesisexamined, this is because it hypothesized that an increase in theamount of water will decrease plant growth. As Plant C growquickly than plant (B) and (A). As can be seen in graph 1. Theplant (C) has greater height changed than plant (A) and plant(C).

This results did not give as expected this is because is waterplay very vital role in plant growth. A plant needs water inorder to grow properly. They use water energy into foodsubstances and sunlight energy to carbon dioxide. This process iscalled photosynthesis. Organisms need energy to survive. Someorganisms are capable of absorbing energy from water and sunlight

and using it to produce sugar and other organic substances suchas lipids and proteins. Since plant need photosynthesis in orderto survive. Plants require sunlight, water and carbon dioxide togrow. These are the necessary in the process of photosynthesis,which makes glucose for plant. The glucose is then used by theplant in the process of cellular respiration in order to makeenergy. Thus, the more water the plant receives, within reason,the more capable the plant of photosynthesizing.The major controlled variables in this investigation were light, water and soil that were taken up through the roots. Light has tobe controlled in plants because when light energy is absorbed by the pigments of the green leafs of plant, that causes a chemical reaction in the leafs that converts carbon dioxide (from the surrounding air) and water (absorbed through the roots) into glucose (sugar) while expelling oxygen to the surrounding ait. The plant cells need this sugar energy for growth and survivals. So without the light, there can be no chemical conversion. Plantsneed sunlight in order to grow fast and properly. Sunlight is so important for plant growth, its helps to allows photosynthesis tohappen. The leaves absorb the sunlight and make it into energy. Plants make their own food by process of photosynthesis. Plants make their own food by converting light energy to chemical energyand further storing it in bonds of sugar. Photosynthesis takes place in the leaves of plants. I have control the water by putting some amount of water like 10 ml, 20 ml and 30 ml for three different investigations. I kept all plants in full sunlight. Water is essential to all life on earth. Organism cannot exist without water. Water is used to transport the metabolic products from one part to other where they are needed. So it acts as a vehicle for the transportation. Plants use water to carry moisture and nutrients from the roots to the leave and food from the leaves back down to the roots. Water is important for plant growth in order to grow fast and properly. Similarly soil has to be control to provide strong stems and nutrient for plants and I have control soil by putting same soil for every three investigation. Soil is the main source of nutrients and minerals for the plants. Soil protects the plants from not getting uprooted. But it depends on what plant you’re trying to grow. Some plants don’t need soil like epiphytes plant.

A major uncontrolled variable was this investigation is air temperature. Air temperature is very critical for plant growth. There are two types of air temperature hot and cold. If temperature rises too high the plant could lose growth potential as ground water is evaporated and plant would wither and eventually die. If the plant temperature falls too low, the plantwill slow growth, since the water’s intake is constrained. The water will stop its intake, thereby decimating the intake of nutrients, causing the plant to die. But cannot controlled air temperature, since plant needs air temperature for plant growth. Another uncontrolled variable is animal which is outside the house. Animals is birds, insect etc may eat the plants leaves which are incredible to control.

The most difficult part of this assessment was measure the height of the plants and watering the plants. A possible source of error in this experiment was not measuring each plant from thebase of the soil. This could result in getting smaller height measurements since less of plant was measured. Another possible error in this experiment was watering. I have to give 10 ml, 20 ml, and 30 ml amount of water to plants. There could be some measuring issue that could affect the experiment.

Conclusion:

The data gathered from this experiment is not relevant as with result of it show that less amount of water is not usefulness forGazania plant for growth. As seen from the result above, the hypothesis, an increase in the amount of water will decrease plant growth, was not supported. The plants that were water 10 ml, 20 ml, 30 ml of water had change in height of 2 cm, 2.7 cm and 3.5 cm respectively. Therefore, an increase in amount of

water will increase plant growth. This this how this experiment can improved in the future.