Transcript School`s Plant Science Competition 2006

Aims:
To grow sorghum and mungbeans in pots and undertake an
experiment to record how much water the plants use.
To observe growth and germination rates and analyse limiting
factors to these observations.
To apply knowledge gained to real life situations and suggest
resolutions to future problems.
Hypothesis:
The germination of the sorghum and mungbeans
will occur rapidly due to the small environment in
which they are planted in. Once germinated, the
community of plants will have a fast growth rate
but will depend on the limiting factors such as
available sunlight, water and disease or pests. In
terms of water usage, the mung bean plant will
use more water as it has a greater surface area to
volume ratio.
Prelude:
Plants are a vital part in our existence. Plants, along with trees
produce breathable oxygen for humans and other species on the
planet. Without plants, Carbon dioxide levels in our atmosphere
would be too high for anything to survive. Unfortunately, the increase
in populations around the world has seen an increase in pollution and
global warming, upsetting the natural cycle. These upsets create
major problems such as disturbances to rain seasons and natural
disasters. These problems will continue due to the ever growing
populations and the need to expand the human empire. With
expansion comes destruction to native forest and land and ofcourse,
pollution. Knowing that the past can not be re-written, scientists
have researched the effects humans have on plants and more
specifically, how much water plants use.
Research into two specific plant species have been conducted.
These two species of plants are Sorghum and Mung beans.
OVERVIEW OF PLANTS
OVERVIEW OF PLANTS
Leaves
Leaves make all the food for the plant. They
do this by changing light, water and gases into
food. This process is called photosynthesis.
Stems and branches
Stems and branches hold up the leaves and
space the leaves out. This helps the plant to
get the light it needs.
Roots
Roots help fix the plant to the soil or to other
plants. Roots take in water and nutrients.
Flowers
Flowers contain the male and female parts of
the plants. Successful pollination of the flower
can result in the production of fruit and seeds.
(www.caribbeanedu.com/kewl/science/science04d.asp)
All leaves are responsible for:
- absorbing the sun's rays
- the majority of photosynthetic production
- taking in carbon dioxide and releasing oxygen and water
vapor (breathing)
- removing waste products from the plant
- using osmotic pressure to draw water up from the roots
Parts of a leaf
Tip
The terminal point of the leaf
Blade or lamina
The flattened, green, expanded portion of a leaf.
Margin
Edge of a leaf.
Midrib
The most prominent central vein in a leaf.
Lateral veins
Secondary veins in a leaf.
Petiole
The leaf stalk (connects blade to stem).
Stipules
Leaf-like appendages (at the base of petiole of
some leaves).
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All stems are responsible for:
- Supporting leaves and flowers physically
- Holding the leaves and flowers in the best position for food gathering
and reproduction
- Using xylem and phloem to transport materials from areas of plenty to
areas of need in various parts of the plant
- Storing nutrients for future use
Bud
An underdeveloped and unelongated stem
Terminal bud
A bud at the tip of a stem responsible for terminal growth.
Axillary bud or lateral
bud
Buds along side the axis of a stem
Flower bud
A bud containing a floral meristem which develops into
flowers
Leaf scar
A scar marking the former point of attachment of a leaf or
petiole to the stem.
Internodes
The part of the stem between nodes
Node
Part of stem marking the point of attachment of leaves,
flowers, fruits, buds and other stems.
Lenticels
Rough areas on stems composed of loosely packed cells and
serve as "breathing pores" for gas exchange. Only occur on
young stems.
Growth rings
Scale scars from the last terminal bud and usually denote one
year of growth
All roots are responsible for:
- Anchoring the plant to the ground
- Extracting water and minerals from the soil
Primary root - the thickest . It grows downwards.
Secondary roots - arise from the primary root. They are not as thick as
the primary one. They go sideward.
Root hairs - are minute filaments roots are covered with. They absorb
water and nutrients from the soil.
Root cap - is a kind of protection the roots end with. It is designed to
drill the soil and it is able to guide the root growth by
perceiving gravity.
(www.caribbeanedu.com/kewl/science/science04d.asp)
PLANT ATTIRBUTES AND FACTORS
Surface area to volume ratio
Plants require minerals and nutrients to survive and in order to acquire these, they use diffusion through
their roots and leaves. Diffusion is the process by which substance, or nutrients in this case, travel from
an area of high concentration to low concentration across a membrane. The diffusion of water is known
as osmosis and is found in plants as they absorb water from the soil. The effectiveness of this process
is highly limited by the surface area versus the volume of the organism. If the surface area is large, and
the volume small, then the greater opportunity for diffusion to take place. It comes as substances in the
soil become absorbed into the roots and travel up the plant in order for it to photosynthesise. Nutrients
and water become absorbed into the plant’s fine root hairs as previously mentioned. These fine hairs all
add up to create a greater surface area for the plant giving it an optimum chance for survival. If these
hairs become damaged, they do not function properly and limit the intake for the plant. These features
along with other processes all control the health and growth of the plant. Transpiration is the process by
which gaseous carbon dioxide is taken in by the plant and released as oxygen.
SORGHUM & MUNG BEAN
Background Information:
Sorghum:
Kingdom:
Subkingdom:
Superdivision:
Division:
Class:
Subclass:
Order:
Family:
Genus:
Click on pictures
Plantae
Tracheobionta
Spermatophyta
Tracheophyta
Angiospermae
Monocotyledons
Cyperales
Poaceae
Sorghum Moench
Plants
Vascular plants
Seed plants
Flowering Plants
Grass family
Sorghum
Sorghum is a widely cultivated tropical cereal grass. It originated
in Africa and in certain environments, can grow up to 3 metres
tall. Sorghum is the fifth major cereal crop in the world.
Sorghum has an extensive root system, waxy leaves and has the
ability to temporarily stop growing in periods of drought, which
means that it is able to withstand very arid conditions.
Sorghum shares similarities with maize, and corn and therefore
share physical structures. Its grains have a very similar structure
to that of maize, although they are smaller and generally oval in
shape. It has a horny and floury endosperm and a large fat-rich
germ, but lack a true husk.
Similar Species Root System
Background Information:
Mung Bean:
Kingdom:
Subkingdom:
Superdivision:
Division:
Class:
Subclass:
Order:
Family:
Genus:
Species:
Variety:
Plantae
Tracheobionta
Spermatophyta
Magnoliophyta
Magnoliopsida
Rosidae
Fabales
Fabaceae
Vigna Savi
Vigna radiata (L.) R. Wilczek
Vigna radiata (L.) R. Wilczek var. radiata
Plants
Vascular plants
Seed plants
Flowering plants
Dicotyledons
Pea family
Cowpea
Mung bean
Mung bean
The Mung Bean is part of a large family and consists of many
different types of beans, legumes and peas. In some cases, it is
difficult to classify mung beans as they have striking characteristics
similar to the common pea.
There are many different species of mung bean each having a
unique flower and can be grown almost anywhere. Because they
produce a bean and not a husk like sorghum, it uses more water
and nutrients to grow the bean and therefore requires an excessive
amount of water.
Because mung beans are part of the legume family, they are vital
when it comes to the nitrogen cycle. As they perform nitrification
where they shed leaves after converting excess nitrogen into nitrates
and nitrites entering the soil through the shed leaves. These nitrates
and nitrites then perform their special tasks.
Similar Species Root System
Nitrogen Cycle and Plants:
Animated cycle
The nitrogen cycle represents one of the
most important nutrient cycles found in
terrestrial ecosystems. Nitrogen is used by
living organisms to produce a number of
complex organic molecules like amino
acids, proteins, and nucleic acids. The
store of nitrogen found in the atmosphere,
where it exists as a gas (mainly N2), plays
an important role for life. This store is
about one million times larger than the total
nitrogen contained in living organisms.
Other major stores of nitrogen include
organic matter in soil and the oceans.
Despite its abundance in the atmosphere,
nitrogen is often the most limiting nutrient
for plant growth. This problem occurs
because most plants can only take up
nitrogen in two solid forms: ammonium ion
(NH4+ ) and the ion nitrate (NO3- ). Most
plants obtain the nitrogen they need as
inorganic nitrate from the soil. Ammonium
is used less by plants for uptake because
in large concentrations it is extremely toxic.
Animals receive the required nitrogen they
need for metabolism, growth, and
reproduction by the consumption of living
or dead organic matter containing
molecules composed partially of nitrogen.
(www.physicalgeography.net/fundamentals/9s.html)
Pathway of Nitrogen:
Photosynthesis:
Photosynthesis is an important biochemical
process in which plants, algae, and some
bacteria convert the energy of sunlight to
chemical energy. The chemical energy is used to
drive synthetic reactions such as the formation of
sugars or the fixation of nitrogen into amino
acids, the building blocks for protein synthesis.
Ultimately, nearly all living things depend on
energy produced from photosynthesis for their
nourishment, making it vital to life on Earth. It is
also responsible for producing the oxygen that
makes up a large portion of the Earth's
atmosphere. Organisms that produce energy
through photosynthesis are called
photoautotrophs. Plants are the most visible
representatives of photoautotrophs, but it should
be emphasized that bacteria and algae also
contribute to the conversion of free energy into
usable energy.
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6H2O + 6CO2 --> C6H12O6+ 6O2
CARBON
WATER
OXYGEN
SUCROSE
DIOXIDE
(H
(O220)
)
(C
(CO
6H12
2)06)
Materials:
Free planting kits provided by DPI&F Hermitage Research Station:
• 1 x packet of sorghum seed.
• 1 x packet of mung bean seed.
• Reference material.
Own Choice Items:
• 8 x empty plastic 2.4 ‘Berri’ juice containers or 3 litre ‘golden circle’ juice containers or
3 litre milk containers (with caps).
Note: Please don’t use containers with long necks as they will not stand up properly for the
experiment.
•
•
•
•
•
•
•
•
•
•
Extra empty plastic containers (as above) if adding extra garden plants for a
comparison. (not compulsory).
A set of scales (that give readings in grams would be ideal).
500ml or 1 litre measuring jug.
A small funnel to water the pots through a small opening.
Scissors/knife for cutting containers.
Small amount of newspaper.
Soil from your school garden/paddock.
Masking tape and permanent marker to label containers.
Plastic shopping bags to cut up and cover your containers when required
Procedure:
Preparing pots for planting:
1.
Mark each container 12 cm from bottom and continue all around the
container.
2.
Cut all 8 containers at this 12 cm mark (keep tidy and neat)
3.
Place the top half of the container inside the bottom half.
4.
Make some holes in the bottom half of the containers so any excess
water can drain through.
5.
In each of the 8 containers, place a small ball of scrunched
newspaper at the opening of the container so the soil won’t fall out.
6.
Fill the 8 containers evenly with good paddock/garden soil (until
there is about 4cms left to the top of the container).
7.
Water each container until soil is saturated (note this will vary
depending on soil quality or type)
Procedure:
Planting:
1.
Draw a circle into the soil of each container about 2 cm in from the outside of the
containers.
2.
Evenly spread 6 sorghum seeds around this circle in four of the containers and cover
them with around 2cm of soil
3.
Label these four containers “sorghum 1 - 4”.
4.
Repeat this process with the mung beans.
There should now be eight labelled containers:
Sorghum 1
Sorghum 2
Sorghum 3
Sorghum 4
Mung bean
Mung bean
Mung bean
Mung bean
1
2
3
4
5.
Place pots somewhere warm (preferably outside in a sunny spot, protected from wind
with some shelter from rain if possible, but not in the shade). Plants will grow best in full
sun, but you can grow them in a greenhouse if need be.
6.
Note germination rates and record any irregularities.
Procedure:
The Experiment:
1.
Once all the plants have grown for about 3 weeks, you need to pull some
plants out until you are left with 1 healthy plant per container.
2.
On the same day you thin the plants back to one per container, water each
container to full capacity until the soil is fully wet and water begins seeping
through the bottom of the containers. Do not water for 24 hours.
3.
Once 24 hours have passed, carefully remove the top half of the
containers from their bases and screw on the lids. Sit the top halves back
into the bottom halves of the juice containers.
4.
Seal the top of the container to make sure no water is being evaporated
from the soil surface.
5.
Cut the plastic shopping bags into two square pieces that will fit over your
container and place them side by side over the containers, just leaving a
very small gap for the stem of the plant to poke through.
6.
Weigh each pot and record the weight (this is the starting weight).
7.
Leave the plants for one week and observe plant growth
8.
In a week’s time weigh each plant again and record the new weight in your
journal. Work out the difference in weight from the starting weight.
9.
Leave the plant sit for another week and observe plant growth.
Procedure:
Plant Pressing:
1.
After the plants have grown for about 6-10 weeks, remove plants and
washed off any excess soil left on the roots.
2.
Weigh the plants making sure that none of the roots were damaged or
taken off. This will be the wet weight.
3.
Once all weighed, place each individual plant between roughly three sheet
of newspaper and place heavy weight on it.
4.
Let stand for two days.
5.
If paper is wet, change paper.
6.
After a week, weigh the plants again. This will be the dry weight.
7.
Observe the differences.
LOG BOOK & RESULTS
Day / Date
1
Analysis
Procedure
1.
Added soil into 3 L juice containers
that have been cut in half.
2.
Added soil at a mixture ratio of 1:1
soil to potting mix.
3.
Weighed container for constant.
4.
Saturated the soil. ≈ 250 ml
5.
Planted seeds as per instructions
Observations / Results
Mass of container with soil was 992
grams.
Day / Date
Procedure
1.
2
Observed growth
Observations / Results
Germination of each container:
Mung
Mung
Mung
Mung
bean
bean
bean
bean
1:
2:
3:
4:
5
2
4
5
out
out
out
out
2
3
3
6
out
out
out
out
of
of
of
of
6
6
6
6
sprouted
sprouted
sprouted
sprouted
6
6
6
6
sprouted
sprouted
sprouted
sprouted
06.03.06
Sorghum
Sorghum
Sorghum
Sorghum
1:
2:
3:
4:
of
of
of
of
Analysis
Both types of plants have had, on average, a rapid rate of germination with only a few yet to
germinate and produce sprouts. The mung beans are visibly larger than the sorghum.
Day / Date
Procedure
1.
3
Observed growth
Observations / Results
Germination of each container:
Mung
Mung
Mung
Mung
bean
bean
bean
bean
1:
2:
3:
4:
5
4
6
5
out
out
out
out
2
5
4
6
out
out
out
out
of
of
of
of
6
6
6
6
sprouted
sprouted
sprouted
sprouted
6
6
6
6
sprouted
sprouted
sprouted
sprouted
09.03.06
Sorghum
Sorghum
Sorghum
Sorghum
1:
2:
3:
4:
of
of
of
of
Height of mung beans: 15 – 19 cm with
2 leaves present
Height of sorghum: 10 – 13.5 cm with 2
leaves present
Analysis
Day / Date
Procedure
1.
2.
4
Added 100 ml of water to each
container.
Measured run off in bottom of
containers.
Observations / Results
Run off:
Mung
Mung
Mung
Mung
bean
bean
bean
bean
1:
2:
3:
4:
33ml
25 ml
24 ml
38 ml
11.03.06
Sorghum
Sorghum
Sorghum
Sorghum
1:
2:
3:
4:
45
70
36
40
ml
ml
ml
ml
Analysis
The mung beans seem to be growing at a steady rate but without any stem support, continue to
crease and damage from falling onto edge of containers. On average, it seems that sorghum are
using less water and letting more flow through to the catchment .
Day / Date
5
Procedure
1.
Added 50 ml of water to each
container.
2.
Moved all of them to the
greenhouse.
Observations / Results
The greenhouse is a safe environment
for the plants.
17.03.06
Analysis
The move to the greenhouse is mainly due to the lack of sunshine the plants received inside the
classroom. When culling begins, stems will be added. Stem supports will provide stability and
hopefully provide enough support in order for them to grow to good health.
Day / Date
Procedure
1.
Added 50 ml of water to each
container.
Observations / Results
Germinations:
Mung bean 1: 6 out of 6 sprouted
6
20.03.06
Analysis
The greenhouse is proving to be the correct place for the plants to be. Another germination in M1
shows that the greenhouse is having an effect on the plants. It seems to be the most suited
environment for the plants but rainfall and insects could alter our outcome.
Day / Date
Procedure
1.
Took out all plants except for the
healthiest one (1).
2.
Placed plastic covers on each
container.
3.
Added stakes for stem supports.
7
22.03.06
Observations / Results
The sorghum have grown secondary
roots (adventitious roots).
Analysis
We kept the strongest plant by factors of leave numbers, the overall size of the plant and how
thick the stem was. This was the case for all except in M1 (mung bean 1) as it had a late
germination but was large for its age. We will test the affect of having a full container to grow has
on the plant.
Day / Date
8
23.03.06
Procedure
1.
Measured heights of plants.
2.
No water added.
Observations / Results
50 ml of rain overnight.
Height of mung beans:
M1: 14 cm
M2: 25 cm
M3: 25 cm
M4: 27 cm
Height of sorghum:
S1: 28 cm
S2: 25 cm
S3: 21.5 cm
S4: 27 cm
Analysis
The plants are growing at a steady rate. The rainfall overnight left us with no need to water the
plants in fear of the occurrence of root rot.
Day / Date
Procedure
1.
Added 100 ml of water to each
container.
Observations / Results
No visible results.
No run off.
Plants are growing.
9
27.03.06
Analysis
No change to the experiment has occurred except for the heights of the plants.
Day / Date
Procedure
1.
2.
Measured run off in bottom of
containers.
3.
Measured heights.
10
28.03.06
Added 50 ml of water to each
container.
Observations / Results
Run off and heights:
M1:
M2:
M3:
M4:
27
25
25
16
cm
cm
cm
cm
r/o
r/o
r/o
r/o
18 ml
32 ml
7.5 ml
1 ml
S1:
S2:
S3:
S4:
27
27
14
25
cm
cm
cm
cm
r/o
r/o
r/o
r/o
25
29
11
37
ml
ml
ml
ml
Average:
Mung bean: 23.25 cm
r/o 16.63 ml
Sorghum: 23.25 cm r/o 25.5 ml
Third set of leaves appear on mung
beans
Analysis
Plants are growing well. The 50 ml water additions every two to three days seem to be the right
amount needed by the plants. After calculating the average heights and run offs, it is clear that
the mung bean uses more water.
Day / Date
Procedure
1.
Added 20 ml of water to each
container.
Observations / Results
Soil is more damp with covers. The
damaged mung bean plants are now
healed back to health.
11
29.03.06
Analysis
Stem supports were successful. Only 20 ml was added due to saturated soil.
Day / Date
Procedure
1.
12
31.03.06
Measured run off in bottom of
containers.
Observations / Results
Run off:
Mung bean
Mung bean
Mung bean
Mung bean
1:
2:
3:
4:
Sorghum
Sorghum
Sorghum
Sorghum
0 ml
7.5 ml
8 ml
1 ml
1:
2:
3:
4:
3ml
1 ml
0 ml
0 ml
Ants in and around containers. Nest
inside S4.
Analysis
Having little run off is a good indication of how much water is used by the plants and therefore
with the new set o results, the mung beans again use the most water. The ants have nested within
the container in S4 and we had to use ant killer to control the situation.
Day / Date
Procedure
1.
13
Measured run off in bottom of
containers.
Observations / Results
Run off and heights:
M1:
M2:
M3:
M4:
28.5 cm
29.5 cm
30 cm
22 cm
r/o 150 ml
r/o 160 ml
r/o 135 ml
r/o 120 ml
S1:
S2:
S3:
S4:
41
36
44
33
r/o
r/o
r/o
r/o
06.04.06
cm
cm
cm
cm
130
120
145
190
ml
ml
ml
ml
Analysis
Due to heavy rainfall previous night, run off is a large amount. The plants are growing steadily with
the sorghum the tallest. The mung beans have grown three sets of large leaves.
Day / Date
Procedure
HOLIDAY PERIOD
1.
Added 50 ml of water to each
container every two to three days
Observations / Results
Mung bean died.
Mung beans are starting to show signs
of loopers.
Analysis
No measurements were taken but water was given on regular intervals.
Day / Date
Procedure
1.
14
03.05.06
Added 60 ml of water to each
container.
Observations / Results
Heights:
M1: Dead
M2: 30 cm
M3: 35 cm
M4: 12 cm
S1:
S2:
S3:
S4:
60
57
62
47
cm
cm
cm
cm
Mung beans are showing signs of
loopers with all o them now starting to
be eaten away form the inside out.
Analysis
The sorghum are growing well but the mung beans are close to dying.
Day / Date
15
Procedure
Observations / Results
1.
Removed plants form containers.
Wet Weight:
2.
Washed roots carefully without
breaking any roots off.
3.
Weighed wet weights of each plant
M1:
M2:
M3:
M4:
N/A
4.4 grams
6.16 grams
N/A
4.
Placed between sheets of papers
for pressing.
S1:
S2:
S3:
S4:
23.4 grams
19 grams
29 grams
14.88 grams
09.05.06
Analysis
Drying the plants will indicate how much matter is within the actual plant when the water is dried
off.
Day / Date
Procedure
1.
Observations / Results
Performed chlorophyll extraction
experiment.
16
10.05.06
Analysis
The experiment will stand over night and the results will show the different chlorophylls within
different plants.
Day / Date
17
Procedure
Observations / Results
1.
Observed chlorophyll experiment.
Dry Weights:
2.
Removed plants from pressing to
weigh.
3.
Weighed dried plants.
M1:
M2:
M3:
M4:
N/A
1.33 grams
2.00 grams
N/A
4.
Measured whole plants.
5.
Compared sizes.
S1:
S2:
S3:
S4:
7.00 grams
7.5 grams
10.6 grams
3.48 grams
12.05.06
Analysis
The chlorophyll experiment showed a range of different colours. The dry weights were
considerably less than the wet weights.
ANALYSIS OF RESULTS
SORGHUM ANALYSIS:
Growth Rate (Sorghum)
70
60
50
Height (cm)
40
S1
S2
S3
S4
30
20
10
0
0
1
2
3
4
5
6
7
8
Day Number
9
10
11
12
13
14
15
Watering Rates (M & S)
300
250
200
M1
M2
Volume (ml)
150
M3
M4
S1
S2
100
S3
S4
50
0
0
1
2
3
4
5
6
7
8
-50
Day Number
9
10
11
12
13
14
15
Run Off Water (Sorghum)
200
180
160
140
Volume (ml)
120
S1
100
S2
S3
80
S4
60
40
20
0
0
1
2
3
4
5
6
7
8
-20
Day Number
9
10
11
12
13
14
15
Water Absorption (Sorghum)
245
195
Volume (ml)
145
S1
S2
S3
S4
95
45
-5 0
1
2
3
4
5
6
7
8
Day Number
9
10
11
12
13
14
15
Click on pictures
Growth Rate (Sorghum)
70
60
This graph clearly shows the growth rates of the sorghum in the
experiment. It shows that during the first few days, the growth rate was
steady but fluctuated a little from there onwards indicating watering
patterns and a change in environment. Possibly, this rise and fall could
have been triggered by the move from the classroom to the greenhouse.
50
Height (cm)
40
S1
S2
S3
S4
30
20
10
Click on pictures
0
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Day Number
Water Absorption (M & S)
300
250
200
M1
M2
150
Volume (ml)
The graph shows the water input of both plants and illustrates
that both received the same amount throughout the
experiment. This graph does not account for rainfall.
M3
M4
S1
S2
100
S3
S4
50
0
0
1
2
3
4
5
6
7
8
9
10
11
-50
Day Number
Click on pictures
Run Off Water (Sorghum)
200
180
160
140
Volume (ml)
120
S1
100
S2
S3
80
S4
60
40
20
0
0
1
2
3
4
5
6
7
8
-20
Day Number
9
10
11
12
13
14
15
This graph shows the water run off in the bottom of the
containers. It is evident that when comparing the input from the
output, one can see that when the water is added, roughly
around the same time, water seeps through into the run off
section of the containers.
12
13
14
15
MUNG BEAN ANALYSIS:
Growth Rate (Mung Bean)
40
35
30
25
Height (cm)
M1
M2
M3
20
M4
15
10
5
0
0
1
2
3
4
5
6
7
8
Day Number
9
10
11
12
13
14
15
Watering Rates (M & S)
300
250
200
M1
M2
Volume (ml)
150
M3
M4
S1
S2
100
S3
S4
50
0
0
1
2
3
4
5
6
7
8
-50
Day Number
9
10
11
12
13
14
15
Run Off Water (Mung Bean)
180
160
140
120
Volume (ml)
100
M1
M2
80
M3
M4
60
40
20
0
0
1
2
3
4
5
6
7
8
-20
Day Number
9
10
11
12
13
14
15
Water Absorption (Mung Bean)
245
195
Volume (ml)
145
M1
M2
M3
M4
95
45
-5 0
1
2
3
4
5
6
7
8
Day Number
9
10
11
12
13
14
15
Click on pictures
Growth Rate (Mung Bean)
40
35
This graph clearly shows the growth rates of the sorghum in the
experiment. It shows that during the first few days, the growth rate was
steady but fluctuated a little from there onwards indicating watering
patterns and a change in environment. Possibly, this rise and fall could
have been triggered by the move from the classroom to the greenhouse.
30
25
M2
M3
M4
15
10
5
Click on pictures
0
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Water Absorption (M & S)
15
Day Number
300
250
200
M1
M2
150
Volume (ml)
The graph shows the water input of both plants and illustrates
that both received the same amount throughout the
experiment. This graph does not account for rainfall.
M3
M4
S1
S2
100
S3
S4
50
0
0
1
2
3
4
5
6
7
8
9
10
11
-50
Click on pictures
Day Number
Run Off Water (Mung Bean)
180
160
140
120
100
Volume (ml)
Height (cm)
M1
20
M1
M2
80
M3
M4
60
40
20
0
0
1
2
3
4
5
6
7
8
-20
Day Number
9
10
11
12
13
14
15
This graph shows the water run off in the bottom of the
containers. It is evident that when comparing the input from the
output, one can see that when the water is added, roughly
around the same time, water seeps through into the run off
section of the containers.
12
13
14
15
EXTENDED ANALYSIS:
Both plants proved to be good test subjects and provided substantial data for
analysis. Comparing the mung bean to the sorghum will provide information that
will ultimately answer the topic question. The comparison shows that both plants
have distinct water absorption patterns but the most obvious similarity exits where
the plants receive water. When the plants are watered, they absorb the needed
amount of water and the rest pass through the soil and into the run off in the
bottom of the container. This is illustrated in the Run Off graph. The absorption
was documented in the Absorption graph.
The growth rates of both plants were strikingly high given the small environment
they are planted in. Overall, the sorghum grew to the greatest height and with no
deaths. The mung beans grew well up until the stage where they produced beans
but then was subject to loopers. They died shortly after being exposed. Their
growth comparisons were documented in the Growth Rate graph.
DRIED PLANT PHOTOGRAPHS
Discussion:
This experiment proved to be a success. The aims that were set, were achieved and the
hypothesis, proven. Although some plants died throughout the experiment, enough data was
collected to comment on trends and future issues. Among the plants only two mung beans died
before the pressing stages as they were exposed to cabbage loopers.
After analysing the data, trends associated with water usage and absorption became visibly
evident. These trends highlighted that after watering the plants, the expected amount needed, a
high volume ran straight through the soil. This could have been prevented with a better soil quality
or the introduction of more clay. Another evident trend was that related to the growth rates. The
growth of each plant was dependant of the water and available sunlight. The data graphs show
that when watering the plants a very high volume of water in a short space of time, they grew at a
slower rate compared to when watering them at a constant rate with less water. This information
could be used in the agricultural field and applied to situations where water is scarce.
The environment that the plants were placed in also contributed to some limiting factors. These
factors included, wind, rain, sunlight, temperature and pests. The rainfall was overcome by the
covers placed on the plant containers. The temperature did not really effect the experiment as
both plants could survive in climatic extremes. The sunlight was the most important attribute
along with water and was plentiful after placing each plant inside the greenhouse. The wind was
also overcome by providing shelter around the area and supports for each plant helped sustain
their strength in the stems.
Discussion:
The main limiting factor was introduced when
the plants were placed in the greenhouse and
was the cabbage loopers. It affected the
mung beans by slowly engulfing the leaves
damaging the photosynthesizing cells, leaving
the plant with no way of obtaining vital
sunlight and ultimately starving the plant of
nutrients.
This experiment could be improved by incorporating more plants in order to
gather a wider range of data and information. Also, a better design or equipment
could be used to improve the effectiveness and could come in the form of larger
bottles for an increase in root space or normal pots having catchment devices
on the bottom. Another way is including controls like empty containers
containing just soil which could measure water retention. This could be extended
by introducing other species of plants as comparisons.
Discussion:
The obtained results and gathered information could be adapted to relate to real life
situations in the agricultural world. Countries having upset rain season or little
rainfall could benefit from these results as they are a clear indication of watering
trends.
Farmers could use watering techniques similar to the experiment or in other words,
water smaller volumes on a regular basis. This would in turn increase the annual
yield. In countries affected by drought, these watering principles would decrease
water usage and evaporation into the air. Studying farmers’ watering techniques
show that the preferred method is using the large spray guns to target a large
ground surface. This in fact is proven to be ineffective with major water loss to the
atmosphere due to evaporation. This water process does not happen on a regular
basis and therefore the farmers tend to water for very long periods of time to make
up for the dry time between watering spells, in turn, evaporating more water and not
providing the most sufficient or economical way.
Therefore, having watering patterns consistent with the experiment would prove to
generate the most economical, effective and sufficient outcome.
Questions:
1.
How much water did the sorghum use?
The sorghum used approximately 47 ml of water a day when working out the averages and adding them all
up. Overall, for the whole experiment, the sorghum used or absorbed 2610.5 ml of water. (excluding run off)
2.
How much water did the mung beans use?
The mung beans used approximately 49 ml of water a day when not considering the run off and working out
the average and adding them up. Overall, for the whole experiment, the mung beans used or absorbed
2737.5 ml of water (excluding run off)
3.
How much water did the sorghum use in relation to their dry weight?
Sorghum’s dry weight on average was 7.15 grams and when the wet weight is compared it shows that the
plants, over the whole experiment used 14.43 grams of water after everything has been evaporated off or
used to keep the plant growing. In other words, the wet weight minus the dry weight gives the amount of
water that was inside the plant and therefore gives an indication of how much water was actually used.
4.
How much water did the mung beans use in relation to their dry weight?
The mung beans’ dry weights on average were 1.6 grams and when the wet weight is compared it shows that
the plants, over the whole experiment used 3.6 grams of water after everything has been evaporated off or
used to keep the plant growing. In other words, the wet weight minus the dry weight gives the amount of
water that was inside the plant and therefore gives an indication of how much water was actually used.
Questions:
5.
Do you think some plants are more efficient than others? Why?
It is obvious that some plants use and need more water to survive than others. This could be purely due to its
size or location. More in depth reasoning could indicate that some plants store water more efficiently and
transpire under enhanced microclimates due to having fine hairs on the leaves creating such a climate. The
plant’s surface area compared to its volume is also a key factor as the greater the surface area, the more
water it will absorb. Therefore, plants like mung beans and sorghum would be more efficient then a rose
bush as roses produced flowers needing more water in order to produce such a flower.
6.
Is too much or too little water a problem to some plants?
Too much water could cause serious problems for plants especially when the soil is a clay loom where the
water gets trapped close to the plant roots and become rotten. Damage to the roots mean no water or
nutrient intake leaving the plant to die. Too little water is an obvious problem for all plants as water is one of
the most important elements needed to survive. Not enough water makes the plant search for more water
with its roots and in turn using more nutrients to produce those roots ultimately leading to death due to lack
of nutrients and water.
7.
How do plants use water?
A plant requires water as an essential ingredient of photolysis, the photochemical stage of photosynthesis
where water is split using light energy. This is the part of the process in which a plant obtains its' energy, and
thus illustrates the importance of water to a plant. Plants obtain water through their roots. In a root the
vascular tissue is located in the middle. Water passes from the epidermis to the middle. There are two
pathways by which this can happen, via the cell walls (apoplastic) or through the cytoplasm (symplastic). The
water gets transported via the xylem up the stem of the plant due to capillary action.
Questions:
8.
Does the weather have an impact on how much water the plants use?
The weather determines rainfall and temperature. Based on obtained results, the weather does affect the
water usage of plants. Higher temperatures means more evaporation into the atmosphere therefore more
transpiration takes place. If the weather was cooler and overcast, less evaporation will occur compared to a
hot sunny day where a lot will take place due to the available sunlight.
9.
Can we adapt our gardens or crops to cop with our extreme weather conditions?
With modern technology almost anything is possible and therefore with more research into the topic of plants
and their water usage a solution will derive. At present, the only thing able to be done would be to have
watering patterns that best suit each plant variety and use fertilizers to enhance their quality but also to build
up some strength in order to battle arid conditions.
CASE STUDY (Years 8 – 12)
Many wheat farmers like Mr Stevens are struggling to find the right balance between rain and drought in order
to yield a good a good crop. Unfortunately the weather cannot be altered and therefore solutions for Mr
Stevens and many others come in the form of suitable shelters, watering patterns, incorporating different
varieties of crops, or spend money on different farming aspects in order to cope in the future. Shelter form
the rain seems to be the easiest fixed problem but will come at a price. Distinct watering patterns and
following the bureau would help the seasons of drought but not for the rainy seasons. There in lies why
shelters would be successful. Incorporating different crops would prove expensive but if one were to keep the
ordinary wheat but also farm sorghum fields as they love water, they can temporarily stop to grow and they
produce edible grains or could be made to live stock feed which one could sell. Introducing a crop such as
sorghum would be the best idea if one were to maintain a healthy income in order for expenditure into the
future.
Bibliography:
Documents on the World Wide Web:
1. www.google.com (image search: plants, plant physiology, photosynthesis, roots, root hairs, transpiration, stems,
osmosis, sorghum, mung beans. Nitrogen cycle, cabbage looper)
2. www.caribbeanedu.com/kewl/science/science04d.asp
3. www.physicalgeography.net/fundamentals/9s.htm
Homework Helper CD
Acknowledgements:
Mr. Nick Johnstone (monitoring draft copy)
Ben Rackermann, Ryan Droney (group members)