CHAPTER 1
The Problem and its Settings
Background of the Study
Solar radiation is the primary source of energy that sustains life on earth. The spectral
distribution of solar radiation has a broad waveband ranging from 300 to 1000 nm. However,
only 50% of the radiant energy is available to plants as photosynthetically active radiation (PAR)
and comprises the wavelength region from 400 to 700 nm (Boyle, 2004). Specialized
photoreceptors present in the plant leaves capture the photons and convert the sun’s radiant
energy to chemical energy following the process of photosynthesis. The process utilizes light
absorbed by chlorophyll and b, the most important photosynthetic pigments, at 662 and 642 nm,
respectively.
Plants have also developed intricate mechanisms for transducing the different wavebands
of the incoming solar radiation into specific chemical signals for regulating various complex
growth and developmental processes. Other than high-energy-dependent process of
photosynthesis, photomorphogenesis, photoperiodism, and phototropism are also significantly
influenced by the ambient light conditions. Photomorphogenesis is defined as light-mediated
plant development that also includes differentiation of cells, tissues, and organs and depends on
far-red radiation in the range of 730–735 nm, whereas photoperiodism refers to the ability of
plants to sense and respond to the changes in the photoperiod: the relative lengths of day and
night. The growth movement of the plants toward the direction of its light source is termed as
phototropism. Light in the wavelengths range of 400–500 nm triggers the phototropic processes
.
Artificial light sources are used to augment insufficientsunlight in greenhouse-based open
production system, whereas crop and/or transplant production in closed production system relies
upon electrical lighting as thesole light source. Plant tissue cultures maintained under in vitro
conditions dependentirely upon artificial light sources for illumination.The earliest reports of
plant growth under artificial lighting were published in the1860s by H. Mangon, E. Prilleux, and
others. However, commercial application ofartificial lighting for crop production took place only
after the development of morerobust and long-lasting electrical lamps in the early twentieth
century (Pinho andHalonen, 2014).
The practical implementation of LEDs originated from the experiment of Henry
JosefRound, a radio engineer in Marconi Labs, who observed the emission of light from a silicon
carbide crystal when a current flowed through the material. This was the very first demonstration
of a solid-state lighting, and the light produced is based on an electroluminescence effect (Round
1907). In spite of this breakthrough, tech- nological advancement of LEDs was relatively slow
until the 1960s (Schubert, 2003). Furthermore, Schubert stated that since the invention of the
first commercial LED in the late 1960s, there has been a gradual improvement in LED design
with the advancement of semicon-ductor technology. The new-generation LEDs have also
become a promising light source for plant growth research and cultivation, besides its popular
applications as indicators and optoelectronic devices.
The outcome of these studies unveiled some of the advantageous features of LEDs and
clarified certain plant morphogenic responses related to the spectral quality of lighting source. A
major breakthrough in the LED technology was attained with the development of first viable
high-brightness blue LED by Shuji Nakamura in 1993 (Nakamura and Fasol, 1997; Nakamura et
al. 2000). This achievement paved the way for utilization of LEDs in plant growth and
development.
The earliest reports of plant growth under artificial lighting were published in the1860s
by H. Mangon, E. Prilleux, and others. However, commercial application ofartificial lighting for
crop production took place only after the development of morerobust and long-lasting electrical
lights in the early 20th century (Pinho andHalonen 2014).
However, there is no study yet here in the Philippines that is the same as this. Though
they have use 2 colors of light but compared to this research, it uses 4 colors of lights and with 5
setups to be observed.
Statement of the Problem
This study aims to knowThe Effects Of Colored Light Sequence To The Monggo Seeds
Growth.The researchers came up with this experiment in order to know if the arrangement and
ratio of red, blue, green and, yellow light can affect the growth of the monggo plant. More
specifically, it seeks to answer the following questions:
1. What is the average growth of the monggo plants exposed to different sequence of light
in terms of:
1.1.onset of true leaf;
1.2.Number of leaves; day 10
1.3.sprout height; (mm)
2. Is there a significant difference between the growths of the experimental plants in each
set-up in terms of onset of true leaf, number of leaves, sprout height?
3. Is there a significant relationship between the light sequence and growth of plants?
Hypothesis
Null Hypothesis
H0; There is no significant difference between the growths of the experimental plants in each set-up
in terms of onset of true leaf, number of leaves, sprout height.
H1; There is a significant difference between the growths of the experimental plants in each set-up
in terms of onset of true leaf, number of leaves, sprout height.
H2; There is no significant relationship between the light sequence and growth of plants.
H3; There is no a significant relationship between the light sequence and growth of plants.
Directional Hypothesis
Setup A will cause the plants to grow more leaves and a taller height.
Setup B will cause the plants to grow more leaves and a taller height.
Setup C will cause the plants to grow more leaves and a taller height.
Setup D will cause the plants to grow more leaves and a taller height.
Setup E will cause the plants to grow more leaves and a taller height.
Significance of Study
This study determines which color of light sequence can give a better effect to the
sprouting growth of mongo plants.
This study improves CEA (Controlled Environment Agriculture) 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.
Students can also benifit something in this study on how things are going to work for them and
on how the process of this research can help them learn something new.
School Administrators the school can also learn the process on how this research is made and
can add more knowledge for the to also learn something new.
Future Researchers can also use this research as a guide if ever they can find simillar ideas on
their on process research paper.
Scope and Limitation of the Study
Scope of the Study:
This study is all about the determination of The Effects Of Colored Light Sequence To
The Monggo Seeds Growth. in terms of (a. onset of true leaf, b. number of leaves, c. sprout
height) and The differences must be recorded in each pot of plant. Since monggo plant grows in
a short span of time, the researchers can record and gather the information and data that they
need. There would be thirty seeds assigned to a single lights sequence color. Soil will also be
measured in (grams) which is 50 grams and distilled water will be use for the plants. The
subjects should be observed in 10 days only.
Limitations of the Study
This research will only be limited to the following, first onset of true leaf. A dead leaf is
still considered and counted as a true leaf for it has done its part. Second, number of leaves if the
plant dies the leaves will be counted up to the day it lived. But, succeding days after the death of
the plant th number of leaves shall be consired as 0. Mostly third, the base of the stem to the base
of the first leaf will be measured in millimeter (mm).
Operational Definition of Terms
Adaptive Lighting- Lighting that varies light levels automatically and precisely in response to
changes such as the level of use or occupancy of a specific location.
Chlorophyll- the most abundant plant pigment and is most efficient in capturing red and blue
light.
Color Temperature– Commonly referred to as Kelvin or color temperature of visible light.
Color temperatures over 5,000 K are cool (bluish white, shorter wavelengths) while lower color
temperatures are warm (red through warm white, longer wavelengths).
Controlled Environment Agriculture – Producing plants in a greenhouse or other space.
Plant- a living organism of the kind exemplified by trees, shrubs, herbs, grasses, ferns, and
mosses, typically growing in a permanent site, absorbing water and inorganic substances through
its roots, and synthesizing nutrients in its leaves by photosynthesis using the green pigment
chlorophyll.
Light Emitting Diodes (LEDs) – A semiconductor device (diode) that emits visible light when
an electric current passes through it.
Photomorphogenesis- development of form and structure in plants that is affected by light,
other than that occurring for photosynthesis.
Photoperiodism- the response of an organism to seasonal changes in day length.
Phototropism- the orientation of a plant or other organism in response to light, either toward the
source of light ( positive phototropism ) or away from it ( negative phototropism ).
Photosynthesis- the process by which green plants and some other organisms use sunlight to
synthesize foods from carbon dioxide and water. Photosynthesis in plants generally involves the
green pigment chlorophyll and generates oxygen as a byproduct.
Photosynthetic Active Radiation (PAR) light - designates the spectral range (wave band) of
solar radiation from 400 to 700 nanometers that photosynthetic organisms are able to use in the
process of photosynthesis. This spectral region corresponds more or less with the range of light
visible to the human eye. Photons at shorter wavelengths tend to be so energetic that they can be
damaging to cells and tissues, but are mostly filtered out by the ozone layer in the stratosphere.
Photons at longer wavelengths do not carry enough energy to allow photosynthesis to take place.
Solar radiation- often called the solar resource, is a general term for the
electromagnetic radiation emitted by the sun. Solar radiation can be captured and turned into
useful forms of energy, such as heat and electricity, using a variety of technologies.
CHAPTER II
Review of Related Literature and Studies
Related Literature
According to Gary et al. (2008) light-emitting diodes (LEDs) are based on a
semiconductor technology that convert electricity to light. Te light from LEDs is emitted from a
solid object of semiconductor material, rather than from vacuum or gas tubes as in traditional
incandescent or fluorescent lights. Another difference between LED light and the traditional
lights is that LEDs are not inherently white. White light is a mix of wavelengths in the visible
spectrum, but LEDs only emit light in a very narrow range of wavelengths, and are therefore
ideal for producing coloured light. LED technology has been available since the 1960’s, and
today it is widely used to create colourful light in devices such as digital clocks, televisions and
trafc lights. One of the signifcant advantages with LEDs is the potential for energy savings.
The Climate Group (2012) also stated that LED saves between 50-70 percent in energy
consumption and carbon emissions compared to other conventional technologies. Other
advantages of using LEDs are the superior control over light col-LED plant lighting for
household environments 15 our, intensity and directions as well as the lifespan of 50 000-100
000 hours (two to fve times longer thanadvanced fluorescent light). the most efficient LEDs on
the market are producing 148 lumens per watt, but according to the Climate Group (2012) the
efficiency will be doubled by 2020, resulting in light 2-2.5 times as efficient as today’s best
fluorescent lamps. Tis could increase energy savings with as much as 90 percent.
The LED technology does however, according to Gary et al. (2008) and Te Climate
Group (2012), have some drawbacks, one of which is the price. LEDs are still a more expensive
choice of light compared to the traditional lighting technologies, however according to The
Climate Group (2012) the price of LED is falling 15-20 percent per year and are expected to
have fallen in price by more than 80 percent over the next eight years. Another drawback with
the LED technology is the heat conduction. According to Gary et al. (2008) traditional fixtures
are designed to radiate the heat generated by incandescent bulbs outwards; however the heat
generated by an LED must be conducted through and away from the device using heat sinks.
Also according to Massa et al. (2008) LEDs are ideal as supplemental or sole-source
lighting systems forcrop production. Because of their small size, durability, long operating
lifetime, low thermal output, low energy consumption, high photoelectric conversion efficiency
and the possibility to adjust light intensity and quality, these light sources have tremendous
potential in plant lighting designs. Another advantage of using LEDs as a source of light in areas
of cultivation is, according to Yeh and Chung (2009), that LEDs enables the possibility to
eliminate excessive wavelengths found within normal white light, which reduces the amount of
energy required to power the cultivation lamps. With the technology of LEDs, it is possible to
optimize the production as well as influence plant morphology and composition. According to
Vänninen et al. (2010) LEDs can, in principle, be configured to produce light more specified for
plants and in levels well in excess of sunlight.
In addition to light quality, Massa et al. (2008) also states the importance of light
positioning as a factor of crop productivity. The radiation energy intercepted by a surface from a
point source is related to the inverse square of the distance between them. Therefore a reduction
of the distance will have a large impact on the incident light level. Since LEDs have a lower
thermal output compared to other light sources, they can be brought much closer to plant tissues.
Therefore, LEDs can be operated at much lower energy levels, while still subjecting the plants to
an adequate amount of light.
Andrew Zimmerman Jones (1991), stated that 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.
(Andrew Zimmerman Jones, 2018, Visible Light Spectrum—Overview and Chart)
Related Studies
Bula et al. 1991 at the University ofWisconsin first suggested using LEDs to
grow plants and reported that growth oflettuce plants under red LEDs supplementedwith blue
fluorescent (BF) lamps was equivalent to that under cool-white fluorescent(CWF) plus
incandescent lamps. At the timeof that study, blue LEDs were not yet widelyavailable, so BF
lamps were used as analternative. Subsequent testing by that groupshowed that hypocotyls and
cotyledons oflettuce seedlings under red (660 nm) LEDsbecame elongated, but that effect could
beprevented by adding at least 15 mmolm–2s–1of blue light (Hoenecke et al., 1992).
Thesefindings inspired continued development ofLED lighting systems for small plant
growthchambers that flew several times aboardNASA’s Space Shuttle (Barta et al., 1992)and
which were used to grow wheat (Triticumaestivum L.) and Brassica rapa L. seedlings
(Morrow et al., 1995), potato (Solanumtuberosum L.) leaf cuttings (Croxdale et al.,1997),
Arabidopsis thaliana (Stankovic et al.,2002), and soybeans [Glycine max (L.) Merr]
(Zhou, 2005). The potential of LEDs forterrestrial plant research continued to build,in which
comparisons of red LED and xenonarc-illuminated kudzu [Pueraria lobata(Willd.) Ohwi] leaves
showed slight differences in stomatal conductance (gS) but similarphotosynthetic responses to
photosyntheticphoton flux (PPF) and CO2 (Tennessen et al.,1994).
A comparison of photosynthetic ratesof strawberry (Fragaria ·ananassa L.)
leaves with red (660 nm) or blue (450 nm)LEDs showed higher quantum efficiencies
under the reds (Yanagi et al., 1996a). Spectralmeasurements of red (660 nm) LEDs,red LEDs
plus BF, red LEDs plus far-red(FR, 735 nm) LEDs, and metal halide (MH)lamps indicated
similar phytochrome photostationary states but significantly higher levels of long-wave radiation
from the MHlamps, indicating the thermal advantages ofusing LEDs in plant growth systems
(Brownet al., 1995). More recent studies haveshowed that rice plants grown under a combination
of red (660 nm) and blue (470 nm)LEDs sustained higher leaf photosynthetic
rates than did leaves from plants grown underred LEDs only (Matsuda et al., 2004). The
authors attributed this to higher nitrogencontent of the blue light-supplemented plants.
The use of red LED light to power photosynthesis has been widely accepted for two
primary reasons. First, the McCree curves (Sager and McFarlane, 1997) indicate that red
wavelengths (600 to 700 nm) are efficiently absorbed by plant pigments; second, early LEDs
were red with the most efficient emitting at 660 nm, close to an absorption peak of chlorophyll.
They also saturated phytochrome, creating a high-Pfr photostationary state in the absence of FR
or dark reversion. The other main wavelength included in early studies has been in the blue
region (400 to 500 nm) of the visiblespectrum.
The amount of blue light required or optimal for different species is an ongoing
question.Bluelighthasavarietyofimportant photomorphogenic roles in plants, including
stomatal control (Schwartz and Zeiger, 1984), which affects water relations and CO2 exchange,
stem elongation (Cosgrove,1981), and phototropism (Blaauw and Blaauw-Jansen, 1970).
Initial studies by the Wisconsin group demonstrated the need to supplement highoutput
red LEDs with some blue light to get acceptable plant growth (Hoenecke et al., 1992). (Tripathy
and Brown, 1995). Potato plantletsgrown in vitro increased in chlorophyll under red LEDs when
PPF was increased from 11to 64 mmolm–2s–1, but all plants under red LEDs increased in shoot
length compared with control plants under white fluorescent
lighting (Miyashita et al., 1997). Studies by Yanagi et al. (1996b) showed that lettuce plants
grown under red LEDs alone had more leaves and longer stems than plants grown under blue
LEDs only. Goins et al. (1997)used LEDs as sole-source lighting for chamber grown wheat and
compared red LEDsalone, red with 1% BF, and red with 10% BF with daylight fluorescent
lamps. Plantswere grown under a 24-h photoperiod at 350 mmolm–2s–1PPF in each case. The
findings showed that wheat could complete a life cycle with red light alone, although added blue
light produced larger plantswith greater numbers of seeds.
(Goins et al., 1997). Shoot dry matter and photosynthetic rates increased with increasing
levels of blue light. Yorio et al. (1998) summarized previous blue light work and reported that
yield oflettuce, spinach, and radish crops grown under red LEDs alone was reduced compared
with when 35 mmolm–2s–1 of blue fluorescence was included to give the same final PPF (Yorio
et al., 1998). Although the potato work was not carried out with LEDs, it has implications for the
use of narrow-waveband LEDs in horticultural crop production. It is possible that certain
cultivars might grow well with less costly and more efficient single-wavelength
LED lighting systems. Goins et al. (1998) examined the growth and seed yield of Arabidopsis
plants grownfrom seed to seed under LED lights. Yorio et al. (2001) grew lettuce, radish, and
spinach plants under red LEDs with or
without 10% BF (30 mmolm–2s–1) and compared growth with that of plants grown under CWF
at the same PPF. Spinach andradish plants grown under CWF had significantly higher dry
weights than plants grown under LEDs. Their results indicated that
adding blue to the red LED light produced growth of lettuce nearly equal to that under
CWF, but this was not sufficient for spinach and radish plants. Measurements of leaf
photosynthetic rates and showed no cleardifferences, although those rates tended to be lower for
plants lighted solely with red LEDs (Yorio et al., 2001).
Schuerger et al. (1997) examined changes in leaf anatomy of pepper under different color
combinations of light. They used red (660 nm) LEDs combined either with FR (735 nm) LEDs
or BF lamps compared with MH controls, all at the same PPF. Their results indicated that leaf
thickness and number of chloroplasts per cell depended much more on the level of blue light than
the red: FR ratio. Treatments without added blue had the lowest leaf cross-sectional area,
whereas red + 1% BF was intermediate in response, and MH controls (at 20% blue) had the
greatest leaf thickness and most chloroplasts (Schuerger et al., 1997). Several other studies using
FR LEDs are discussed by Kim et al. (2005) examining plant morphology, disease development,
and nitrate accumulation. Until recently, it was difficult to obtain LED arrays with a wide light
spectrum tunable at different emission peaks, but with the rapid, ongoing development of LED
technology, such studies can now be conducted using multispectral arrays that generate a variety
of colors or even white light.
Johnson et al. (1996) examined effects of infrared (IR) LEDs of 880 nm and 935 nm on
etiolated oat seedlings. Spectroradiometric analysis of those long-wavelength sources showed
that actual peak emission wavelengths averaged 916 nm and 958 nm, respectively. Compared
with dark-grown controls, seedlings grown with 880 (916)nm LEDs had shorter overall length but more advanced leaf emergence than either dark- or
935 (958)-nm-grown seedlings. Also, the proportion of mesocotyl tissue was significantly higher
for seedlings grown with eitherIR source or dark grown, whereas the proportion of coleoptile
tissue was significantly lower. An ancillary observation was that the IR LED radiation made
seedlings significantly straighter and trained them to the gravity vector. The authors proposed the
activation of a ‘‘gravitropism photon-sensing system’’ with potential involvement of
phytochrome (Johnson et al., 1996).
Many previous studies indicate that even with blue light added to red LEDs, plant growth
is still better under white light. Certainly to humans, plants grown under red plus blue light
appear purplish gray, and disease and disorder become difficult to diagnose (Fig. 1). One
possible solution is using a small amount of green light. To test this hypothesis, Kim et al.
(2004a) grew lettuce plants under red and blue LEDs with and without 5% (6 mmolm–2s–1)
green from LEDs with both treatments at the same total PPF (136 mmolm–2s–1). They observed
no impact on lettuce growth with all measurable characteristics such as photosynthesis rate,
shoot weight, leaf area, and leaf number being the same with and without green. They followed
this work with another lettuce study to determine the effects of higher levels of green light under
a total PPF of 150 mmolm–2s–1 and an 18-h photoperiod (Kim et al., 2004b). They used red and
blue LEDs with and without green fluorescence (GF) (24% green for RGB or 0% green for RB),
GF alone (86% green), and CWF (51% green) and demonstrated that lettuce plants grown with
RGB had higher fresh and dry weights and greater leaf area than those grown with CWF or RB
alone. Plants grown under GF had the least biomass of all treatments.
Further work with the same system (Kim et al., 2004c) examined. Although lettuce
grown under CWF showed greater maximal than under RB, RGB, or GF,drymassaccumulation
was highest in the RGB treatment, indicating that did not limit carbon assimilation under the
growth conditions provided. Additionally, the authors demonstrated that could be changed
reversibly in response to narrow waveband light, even for plants grown under CWF(Kim et al.,
2004c). Kim et al. (2006) summarized the experiments with green supplementation of red and
blue LED light andconcluded that light sources consisting of more than 50% green cause
reductions in plant growth, whereas combinations including up to 24% green enhance growth
forsome species.
CHAPTER III
Research Methodology
Research Design
This study is utilized in an experimental method –in order to achieve the purpose of this
study – which is to determine and describe the effects of lights sequence on monggo seeds
growth. It is an experimental method in a sense that the data obtained is to be analyzed and
described. The kind of experimental design we will use is The One-Shot Case Study which only
focuses on a single group being observed therefore there is no control group against which is to
make a comparison.
Research Subjects
This proposed study will involve monggo seeds which has a total of 150 in all. These
seeds will be just bought in any market. These seeds will be washed with tap water to remove
some dirt. All of these seeds will be divided in each set up which is 30 seeds per set up for we
will be having five set ups. These seeds will be planted on a small yellow cup which has a garden
soil. Also in this research we will be using some colored led lights with has a total of 20 lights in
each color. The color that we are going to use is red, blue, yellow, and green.
Materials and Equipments
This study will utilize the following materials: 5 boxes, packing tape or duct tape,
scissors, small yellow plastic cups, marker, sticky notes, garden soil, tripple A battery and small
thin wires.
Procedures
Plant Collection and Preparation
Seeds will be gathered and will be planted on each yellow small cups with garden soil
inside. All of the planted plants will be put on a box covered with the light sequence in each set
up. These seeds will be observed for 10 days.