CHAPTER I
INTRODUCTION
A.
Background of the Study
Philippines is an agricultural country. The geographical location of this country in
the Tropic plays the major role to this fact. Aside from rice, Filipinos produce most of the
crops that they use to make food that they serve in their dining tables. In the
countryside, houses have different kinds of vegetables, fruits and root crops planted on
their backyards. Because of this, majority of families in the countryside just pick their
dishes from these plants.
Philippines has been going through the industrialization process of social and
economic change. It is a part of a wider modernization process where social change
and economic development are closely related with technological innovation,
particularly with the development of large-scale energy and metallurgy production.
CEA (controlled-environment agriculture) is any agricultural technology that
enables the grower to manipulate a crop's environment to the desired conditions.
Philippines can use this kind of agriculture to use as an advantage of being an
agricultural country.
In most urbanized areas, houses do not have a permanent place that sunlight
can pass through. There are a few plants that will grow with only one light in a
windowless office or a one-room apartment whose single window faces into an air shaft.
(House Plants, 1975) Artificial lighting is the answer for almost any kind of plant that can
be grown if enough artificial light is provided, even in situations where no other light is
available. Artificial lights allow regular people to plant whole gardens in places where no
plant would ordinarily grow.
Sunlight is a mixture of all visible wavelengths of light and if it hits the plants the
pigments of the plants can absorb or reflect the selected wavelength. The researchers
would like to know if separating each color and making it the only light it will have, would
have an effect on the plant’s growth
This study aimed to find a significant difference in the sprouting of a mongo plant
when exposed to different colors of light specifically red, orange, yellow, green, blue,
violet and white. In this case, the researchers chose the mongo plant since it grows
quickly and the researchers can quickly gather the needed data immediately.
A lesson in Biology I (You and the Natural World: Biology, p.107) on Chapter 7,
Cell Metabolism-Energy and Photosynthesis stated that “chlorophyll absorbs most red,
orange, blue, and violet light. It reflects green and yellow light, giving its body a green
coloring”. This statement got the researchers curious and wondered if plants act
differently to the green and yellow colors of light, then they should have different
reactions and effects to every color of light. The researchers decided to pursue this
study to determine whether plants have different reactions to different colors of light and
identify these reactions individually.
B.
Statement of the Problem
This study will determine and compare the effect of different colors of light on the
growth of mongo plants.
Sub-Problems:
1) What is the growth of the mongo plants exposed to different colors of light
in terms of:
a. Onset of true leaf
b. Number of leaves
c. Sprout height
d. Biomass
2) Is there a difference between the growths of the experimental plants in
each set-up in terms on onset of true leaf, number of leaves, sprout height
and biomass?
3) Is there a difference between the growth of the controlled plant and the
experimental plant in terms on onset of true leaf, number of leaves, sprout
height and biomass?
4) Which color of light would be the best for the plant’s to grow?
C.
Hypothesis
1) There are different results because they are exposed to different colors of
light.
2) There is difference between the controlled set-up is exposed to sunlight
which has colors red, orange, yellow, green, blue and violet while the
experimental set-ups are only exposed to one color.
3) There is a difference between the growths of the plants in each set-up.
During the photosynthesis, colors yellow and green are reflected by the
chlorophyll which means that the plants react differently to different colors
of light.
4) The color red or blue is the best for the plant’s growth since this color. The
colors orange, yellow and green don’t have any effects on the plant’s
growth.
D.
Objectives of the Study
This study aims to assess the growth of a mongo plant when exposed to different
colors of light specifically red, yellow, green, blue, and white and verify if there is a
significant difference. Furthermore, it aims to determine the best color of artificial light in
growing mongo plants in terms of onset of true leaf, number of leaves, sprout height,
and biomass
D.
Significance of the Study
This study determines which color of light can give a better effect to the sprouting
growth of mongo plants. This study improves CEA by minimizing the expenses but still
having the same results. Using CEA in the Philippines’ agriculture could cause great
improvements to the economy.
Common housewives that like gardening inside their house can benefit from this
study. Artificial lighting is useful when natural window light is insufficient. They make it
possible to grow healthy plants in any spot in the house. They could plant flowering
plants inside their home and make it as an alternative decoration or they could rather
plant vegetable gardens and fruit trees in their backyard or just on pots to save money
in preparing food.
The results of this study could also help gardeners make plants grow healthier
and flower abundantly. Businessmen more specifically flower shop owners could
introduce artificial lighting to their gardens to sell beautiful flowers for their shops.
Farmers could apply artificial lighting in their farms to industrialize their agriculture. This
could help them produce fine rice, crops, fruits, vegetables and etc.
E.
Scope and Limitations
This study is only limited to the determination of the effect of the different colors
of light such as red, orange, yellow, green, blue and violet on the growth of the mongo
plant (Vigna radiata) in terms of a) onset of true leaf, b) number of leaves, e) sprout
height and f) biomass. The differences must be recorded in each pot of plant. There
would be three pots assigned to a single color. By using different colors of light, the
researchers can determine the light that can give a better effect to the sprouting growth
of the mongo plant. Since mongo plant grows in a short span of time, the researchers
can record and gather the information and data that they need.
F.
Definition of Terms
Mongo Plant (Vigna Radiata)
It Is the test subject. Used to determine if
different color of light can affect its growth
Plant Growth
The basis of comparison for the researchers to
distinguish which of the different color of light
can be best for the plant’s growth. Factors to
be compared are onset of true leaf, number of
leaves, sprout height, and biomass.
Colors of light
Colors to be use are red, yellow, green, blue,
and white. This will serve as the only light that
the plant can have during growing process.
Experimental group
The group that is given a special treatment. In
this study, the experimental group is the pot of
plants that is given one different color of light.
Controlled group
The group that is not given any special
treatment. In this study, the experimental group
is the pot of plants that is exposed to the
sunlight.
Onset of true leaf
the particular time that leaves may appear
during photosynthesis using the artificial lights.
Number of leaves
the total number of leaves of the mongo plant
after the investigation
Sprout height
height of the mongo plant after the
investigation
Biomass
the mass of the mongo plant after the
experimentation
CHAPTER II
REVIEW OF RELATED LITERATURE AND RELATED STUDIES
According to Andrew Zimmerman Jones (1991), visible light spectrum is the
section of the electromagnetic spectrum that can be seen by the human eye. It is also
known as the optical spectrum of light with wavelength ranging from approximately 400
mm to 700 mm. The perceived color is dependent on the wavelength of the light. We
actually interact with light in the form of white light which contains many or all of these
wavelength ranges within them. When shining white light passes through a prism
causes the wavelength to bend at slightly varying angles due to optical refraction.
Therefore, the resulting light is split across the visible color spectrum. This results to
rainbow characterized by airborne water particles acting as the refractive medium. The
order of wavelength is best remembered by “Roy G Biv for Red, Orange, yellow, green,
Blue, Indigo and violet. (http://physics.about.com/od/lightoptics/a/vislightspec.htm)
When sunlight strikes the leaves of a plant, the light-wave energy is absorbed by
the chlorophyll. The chlorophyll absorbs most red, orange, blue, and violet light. It
reflects green and yellow, giving its body a green coloring (You and the Natural World,
p.107). This means that plants react differently to different colors of light.
With this in mind, artificial light was considered in this study. Artificial lighting is
any lighting that is not sunlight. Generally speaking, artificial lighting is lighting which is
man made, such as fluorescent, tungsten, mercury vapor, sodium vapor, halogen,
compact fluorescent, et cetera. It can be turned on and off at a flick of a switch. There
are also very special types of artificial light for specific purposes like infrared heat
lamps,
ultraviolet
lights
for
plant
growth
http://wiki.answers.com/Q/What_is_artificial_lighting). The researchers would use colors
red, blue, green, yellow and white as basis for the colors of the light bulbs in conducting
this study.
Natural daylight from the blue part of the spectrum is optimum for the initial stage
of plant growth. Artificial light will work almost as well--fluorescent, incandescent, LED
or high-intensity discharge lamps (like metal halide or high pressure sodium) as stated in
the study “The Effect of Light on Plant Growth”. High intensity discharge lamps offer the
best indoor lighting option, allowing for a controlled environment with faster production
and quick growth from seed. (http://www.ehow.com/about_5251025_effect-lightplant-growth.html)
Mung bean is commonly known in the Philippines as munggo or monggo is the
seed of vigna radiata which is native to India. These beans are small, ovoid in shape
and green in color. Mung bean seeds are either sprouted for fresh use or canned for
shipment to restaurants. The sprouts are high in protein about 21-28%, calcium,
phosphorus and certain vitamins. Because these beans can easily be digested it can
replace scarce animal protein in our diet. Due to its major use as sprout, a high quality
seed with excellent germination is required. The food industry prefers about 9-10 grams
of fresh sprout for each gram of seed. Larger seed characterized with glassy and green
color is oftentimes a preference.
In mung bean, both upright and vine type of growth habit occur with plants
varying from one to five feet in length. The pale yellow flowers are borne in clusters of
12–15 near the top of the plant. Mature pods are variable in color (yellowish-brown to
black), about five inches long, and contain 10 to 15 seeds. Mungbeans grow best on
fertile sandy, loam soils with good internal drainage; their growth is poor on heavy soils
with poor drainage.
Every transformation is an energy that occurs at the cellular and molecular
levels. In cells, there are two basic patterns by which organisms transform energy, the
autotrophic and heterotrophic pattern. In autotrophic cells, light energy is transformed to
chemical energy that can be used by cells. Green plants contain this type of cell.
Photosynthesis is a process by which living plant cells combine carbon dioxide and
water in the presence of chlorophyll and light energy (You and the Natural World:
Biology, Chapter 7, Cell Metabolism-Energy and Photosynthesis, p.107). The light
excites the electrons to receive NADP and also splits water into oxygen and hydrogen.
The light is the primary key to photosynthesis.
Cold frames are less expensive than greenhouses, take up less space and are
cheaper to keep warm. Their main disadvantage is that the gardener works outside and
not inside in the warm and dry as with a greenhouse. In the vegetable garden, cold
frames are frequently used for producing winter or early crops of such vegetables as
carrots. The frame can be in a permanent position in the garden or moved, rather like a
large cloche, onto the vegetable bed itself. The vegetables can be grown either directly
in the soil or in growing bags. Another basic use is to afford protection and warmth to
trays
of
seeds
or
seedlings.
(http://mangorevolution.com/98/house-
home/gardening/building-and-using-cold-frames-in-your-vegetable-garden)
The researchers’ study relates to the study titled ‘The Effect of Different Genres
of Music to Mongo Plant’s Growth’ by Generev Zerna Jungao and Rhoie Jhannarie
Omlero which also determines the significant difference in plants’ growth but only using
genres of music instead of colors of light. The researchers of the study aimed to know
the best genre of music for growing plants by exposing mongo plants to a genre of
music changed weekly, the first week was classical music, second week was jazz, third
week was pop and the last was rock. The study concluded that jazz is the best and rock
music was not good for plants.
In a study on “The Effect of Short-Wavelength Light on Plant Physiology” the
cultivation of lettuce and radish was experimented using different combinations of red
and short-wavelength components and high pressure sodium lamps and it was found
out that red and blue components are favorable for growth and nutritional quality of
lettuce. The most striking sensitivity to illumination spectrum was observed for
production of carbohydrates. In respect to the reference plants, content of nitrates in
lettuce grown under the bicomponent illumination in red and short wavelength regions
was by 15-20% lower with no significant difference among treatments where the shortwavelength was cyan, blue or UV. The results of this study confirmed that plant growth
can be modulated by employing tailored spectrum provided by emission of different
LEDs. Even illumination with spectrum consisting of two (2) components (one in red
region and another in short-wavelength region) when properly selected can be
beneficial
in
respect
to
illumination
using
conventional
lamps.
(http://www.lightinglab.fi/enlighten/publications/internetui_akvile.pdf
In the study “Plant Growth Factors: Light”, states “light quality refers to the color
or wavelength reaching the plant's surface. A prism (or raindrops) can divide sunlight
into respective colors of red, orange, yellow, green, blue, indigo and violet.” The study
also concluded that blue light is considered to be the primary responsible for vegetative
leaf
growth
while
red
light
encourages
flowering.
(http://cmg.colostate.edu/gardennotes/142.pdf)
Synthesis
In this research, significant differences between the growths of mongo plants
exposed to different colors of light is observed. The researchers will monitor the growth
of the plants exposed to artificial light from the very beginning of the growth stage;
seeds, to sprouts, and to full grown plants. The researchers will observe and record
significant differences between each plant to determine the important effects of different
colors of light to plant growth.
From the different related studies, the researchers have gathered different ideas.
It is possible that the blue and red colors can greatly affect the growth of a plant. A
study says that blue is responsible for leaf growth and red develops flowering.
This study is somehow similar to the study ‘The Effects of Different Genre of
Music to Mongo Plants Growth’ since both observe the significant differences of plant
growth when exposed to different factors. This study focuses on the effects of colors of
light while the other focuses on effects of genres of music. Also, the researchers of the
other study used the same samples for the different treatments; they exposed the same
mongo plants to different genres of music which is changed weekly. This study aims to
determine the significant difference of the effects colors of light to plant growth at the
same time.
CHAPTER III
METHODOLOGY
A.
Research Design
This study aims to determine the best color of light for growing plants by comparing the
growth of mongo from seeds to sprouts and to a plant which is exposed to different colors of
lights. To attain this, the researchers would use two groups, the controlled group where a plant
would only be exposed to sunlight and the experimental group where artificial lights would be
used as an alternative for sunlight. The artificial lights in this study has variations of colors such
as colors red, orange, yellow, green, blue, violet, and white. A plant would be exposed just to a
single color throughout this whole study.
Since this study is concerned about the significant effects of a color of light to a growing
plant, the researchers would observe the growth of the mongo plant weekly from the very
beginning of the experiment. Extraneous variables or factors that could affect on the behaviour
of the subject being studied such as amount of water or intensity of light should be strictly
maintained to be able to get the desired data from this investigation. All subjects would be
watered everyday by 500mL of water. The plants from the experimental and controlled group
would be exposed to the light for only six to eight hours per day for four weeks.
B.
Materials and Equipments:
Materials
Equipment
soil
5 water cellophanes (red, yellow, green, blue, and
white)
water
6 cold frames
½ or 1 kilo of mongo seeds
measuring cups
6 big sacks or cloth
popsicle sticks
6 pots
C.
General Procedures:
Preparation of Materials
The flower pots would be filled with loam soil. Loam soil is an equal mix or sand, silt, and
clay. Loam can make the plants grow healthier. Soil should be equal in every pot so that it won’t
affect the subject materials or the factor that is being tested.
Every sack should be divided into six equal parts. The sacks will be assigned to specific
colors of light. The sacks will be used as the place for the seeds to grow into a sprout.
The cold frames should have holes at the side; the holes will serve as the entrance of air
for the plants to breathe. Each cold frame would have different colored water cellophanes: red,
yellow, green, blue and white. The last frame would be assigned to the controlled group which
doesn’t have any light.
Preparation of Set-up
a. Seeds
Prepare the sacks; one sack should be assigned to a particular color of light. Pick
ten mongo seeds for each sack which means there should be sixty mongo seeds for the
five colors (red, blue, green, yellow and white) of light and sunlight. Lay 10 seeds on top
of each sack. Water the seeds. Observe them for the whole day until they grow into
sprouts.
b. Sprout
When the seeds grow and become sprouts, the researchers will transfer them
into to pots. There should be exact distance between the seeds, approximately four
inches away from one another to let the plants breathe when they grow. Remember that
when the sprouts were still seeds, they were already assigned and exposed to different
colors of light that is why the assignments of colors will still be the same. Each pot will be
put into a cold frame. Each frame will be assigned to a specific color of light according to
the previous assignments.
Exposure to Treatment
There should be one color assigned to each cold frame. And since the frames
vary in color, every set-up should be unique and different from one another.
Cellophanes should be attached on top of each frame so that when the light passes
through, another color of light will appear. In the 6 frames, holes should be at least at
one side to give plants natural air from the environment. Since there are only five water
cellophanes, put the remaining cold frame without water cellophane in a spot where it
can receive enough sunlight.
Monitoring of Growth
Now that the preparation for the set-up for this study is done, the next thing to do is to
take care of the plants. All the subject materials should be watered everyday equally with
500mL with water daily. The plants should be exposed to light for only six to eight hours a day.
a. Seed
The researchers would observe the onset of true leaf and the number of sprouts
that grew for each color assignment. The first three mongo plant that would grow
corresponds to the three trials. These three mongo sprouts would be further observed for
other characteristics.
b. Sprout
The researchers would observe the number of leaves, onset of true flower,
number of flowers, and sprout height, at the end of each week. The biomass at the end
of the experimentation would be measured.
For the sprout height, popsicle sticks will be stuck on the soil beside each mongo
plant sample where markings of weekly height level will be marked so as not to disturbed
plant growth while measuring their height. The popsicle sticks would then be removed at
the end of experimentation and each markings per week be recorded.
E.
Procedures/Instrument in Data Gathering
The researchers would conduct observations and record significant differences between
the seven set-ups every week in corresponding tables shown below.
Example:
Seeds
Table # 1 Number of Sprouts & Onset of True Leaf
Number of
Onset of True
sprouts
Leaf
Light
(hours)
Exposed
T1 T2 T3 Tave T1 T2 T3 Tav
e
Red
Yellow
Green
Blue
White
Sunlight
Sprouts
Table # Characteristic of Mongo Plants
Number of Leaves
Sprout Height
Light
(piece)
(cm)
Exposed
T1 T2 T3 Tave T1 T2 T3 Tave
Red
Yellow
Green
Blue
White
Sunlight
F.
Biomass
(g/unit area)
T1 T2 T3 Tave
Statistical Tools for Data Analysis
The data that will be gathered will be analyzed and interpreted using
appropriate tools. The average will be used to declare results of various parameters
such as number of leaves, number of flowers, and sprout height. ANOVA will be used
in order to know if there is a significant difference among results.
FLOWCHART
a. Seeds
Prepare the sacks and
assign colors.
Pick 10 seeds for each
treatment.
Lay seeds on top of
each cloth; expose
seeds to artificial light.
Water the seeds,
observe until seeds
grow into sprouts.
b. Sprouts
Transfer the sprouts
into pots.
Enclose each pot into a
cold frame
Monitor growth, water
the plants with 500mL
of water everyday
Sunlight will change in
color when passing in
the frames glass.
Assign colors to each
frame according to the
previous assignment.
Put water cellophanes
into each frame.