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Effect of Different Colors of Light on Monggo Plant Growth
CHAPTER 1
Introduction
A. Background of the Study
Light is the form of energy visible to the eye that is radiated by moving
charged particles. Light is made of electromagnetic vibrations which have wavelengths
distributed evenly between 14 to 30 millionths of an inch.
Light is very important in a plant's life. Without light a plant could not grow,
reproduce, or produce food and building materials. So all plants would eventually die off if
there was no light for them to use... Which, unfortunately, would lead to the eventual death
of almost all life on earth.
Color is the visual perceptual property corresponding in humans to the
categories called red, green, blue and others. Color derives from the spectrum of light
(distribution of light energy versus wavelength) interacting in the eye with the spectral
sensitivities of the light receptors. See, sunlight contains many colors of the visible specturm,
and the unvisible. Plant growth may be be affected.
The Mung Bean, or commonly known as Monggo Seeds or beans, are small and
ovoid in shape. They are not expensive and they are commonly used in experiments. This
plant is a suitable test subject because of its fast germination period and because it is less
expensive.
Plants are primary food providers; they sit at the bottom of the food chain.
They can harvest their energy almost primarily from the sun's rays. At first glance sunlight
seems to be invisible to the eye but once it is analyzed it can be seen that sunlight is made up
of a spectrum of colors. Varying degrees of these colors have different effects on plant
growth.
B. Statement of the Problem
Main problem:
Does the color of light affect the growth of Monggo plants?
Sub-problems:
1) What are physical characteristics of the monggo plants when exposed to red light, in terms of:
a.
b.
c.
Leaf color
Plant height
No. of Leaves
2) What are physical characteristics of the monggo plants when exposed to blue light, in terms of:
a.
b.
c.
Leaf color
Plant height
No. of Leaves
3) What are physical characteristics of the monggo plants when exposed to yellow light, in terms of:
a.
b.
c.
Leaf color
Plant height
No. of Leaves
4) What are physical characteristics of the monggo plants when exposed to green light, in terms of:
a.
b.
c.
Leaf color
Plant height
No. of Leaves
C. Hypotheses of the Study
There will be no significant difference in the physical characteristics of monggo
plants exposed to different colors of light
D. Objectives
The main objective of this study is to determine whether different colors of
light hinder or aid in the growth of Monggo plants.
E. Significance of the study
The results of this study aware the people that different colors of light can really
affect plant growth. The results of the study could suggest a more efficient way in farming
but in small quantities due to the cost of the material used to change the color of light.
F. Scope and Limitations
The study focused mainly on the height of the plant, number of leaves, color
of the leaves, at the end of a four-week observation period. Only forty seedlings of monggo
are to be used. Ten seedlings every color.
Although many plants might be used in this experiment, we prefer to use Monggo seeds
because it is affordable and available on the market. It grows faster than any other seeds and
will meet the deadline for the experiment.
G. Definition of Terms
1.
Monggo
- Mungbean commonly called monggo, is the cheapest source of vegetable protein with protein
content of 20-25 percent. It is an excellent crop for green manuring, because it matures early,
grows fast and produces abundant vegetative tops.
2.
Soil
-The upper layer of earth in which plants grow, a black or dark brown material typically
consisting of a mixture of organic remains, clay, and rock particles. Loam type.
3.
Height
- The measurement from base(soil) to top (top stem).
4.
Leaf
- A flattened structure of a higher plant, typically green and blade-like, that is attached to a stem
directly or via a stalk. Leaves are the main organs of photosynthesis and transpiration
5.
Red Light
- light emitted through a red colored cellophane
6.
Blue Light
- light emitted through a blue colored cellophane
7
Yellow Light
- light emitted through a yellow colored cellophane
8
Green Light
- light emitted through a green colored cellophane
CHAPTER 2
Review of Related Literature
●
Monggo
The mung bean, in other languages, choroko (in Swahili), monggo, moong,
moog (whole) or moog dal (split) (in Bengali , Marathi), munggo or monggo (in East
Timor), is the seed of Vigna radiate. Mung beans are commonly used in Chinese
cuisine, and are generally eaten either whole (with or without skins) or as bean sprouts,
or used to make the dessert "green bean soup". The starch of mung beans is also
extracted from them to make jellies and "transparent" or "cellophane" noodles.
Mung Beans can germinate within 48-72 hrs. How fast they grow depends on
the temperature, if they are growing in darkness or light, & if they have been soaked
overnight before planting.
"Within the temperatures that mung beans can germinate & grow, the higher the
temperature, the better the mung beans will germinate & grow."
http://en.wikipedia.org/wiki/Mung_bean
http://www.usc.edu/CSSF/History/2004/Projects/J1631.pdf
● Light
Three principal characteristics of light affect plant growth: quantity, quality, and duration.
Quantity
Light quantity refers to the intensity, or concentration, of sunlight. It varies with the seasons. The
maximum amount of light is present in summer, and the minimum in winter. Up to a point, the
more sunlight a plant receives, the greater its capacity for producing food via photosynthesis.
You can manipulate light quantity to achieve different plant growth patterns. Increase light by
surrounding plants with reflective materials, a white background, or supplemental lights.
Decrease it by shading plants with cheesecloth or woven shade cloths.
Quality
Light quality refers to the color (wavelength) of light. Sunlight supplies the complete range of
wavelengths and can be broken up by a prism into bands of red, orange, yellow, green, blue,
indigo, and violet.
Blue and red light, which plants absorb, have the greatest effect on plant growth. Blue light is
responsible primarily for vegetative (leaf) growth. Red light, when combined with blue light,
encourages flowering. Plants look green to us because they reflect, rather than absorb, green
light.
Knowing which light source to use is important for manipulating plant growth. For example,
fluorescent (cool white) light is high in the blue wavelength. It encourages leafy growth and is
excellent for starting seedlings. Incandescent light is high in the red or orange range, but
generally produces too much heat to be a valuable light source for plants. Fluorescent growlights attempt to imitate sunlight with a mixture of red and blue wavelengths, but they are costly
and generally no better than regular fluorescent lights.
http://extension.oregonstate.edu/mg/botany/light.html
● Light Triggers Photosynthesis
Plants require sunlight to produce food. Leaves are green because the pigment
in them---called the chlorophyll---absorbs all other colors of light and reflects green light.
When the chlorophyll absorbs light energy, it triggers the photosynthesis process
through which that light energy is converted into sugars. For the plant to grow, it needs
to have this process operating at its prime, with the maximum amount of food being
made to give the plant the fuel to grow.
● Sources of Light
Natural sunlight has a lot of blue and red coloring in it, but these are
imperceptible to the human eye. The plant uses blue wavelengths of light to create food
for leaf production, and the red and orange wavelengths will encourage flowers. Plants
most effectively use sunlight to grow. Fluorescent lights can be used to grow plants
before they flower, since this lighting source is full of blue light. Red spectrum lights will
encourage flowers to grow. Many incandescent light bulbs have red light, but heat from
the bulb being placed too near the plant can cause damage.
● Rate of plant growth due to color of light
Plants grow faster under certain colors of light. The reason for this is because
chloroplasts can only absorb certain wavelengths of light because of the pigments they contain.
There are 2 photo systems in plants called photo system I and II. PS I absorbs light on the
wavelength of 700nm while PS II absorbs 680nm because of their utilization of chlorophyll A
and B. These two frequencies are known as the peak absorption points because they are the
wavelength at which light is most strongly absorbed. Different forms of chlorophyll and other
photosynthetic pigments absorb other other frequencies of light but PS I and PS II are what is
used for synthesizing ATP and reducing power which plants use to grow. The visible spectrum
of light is between 380-750nm for humans. Therefore PS I and II require red light to perform
photosynthesis. As stated before, however, there are other photosynthetic pigments present in plants
and other phototrophic species such as bacteria and algae that absorb other pigments. An example of
this is the carotenoid pigment that absorbs primarily blue light as do chlorophyll A and B. Blue light
contains more energy than red light but for PS I and II and plant growth both are needed. Studies in
the 50's showed that the rate of photosynthesis increased under far-red and red light compared to
other frequencies
http://wiki.answers.com/Q/Do_plants_grow_faster_under_certain_colors_of_light#ixzz1U9AczkLF
● Colors Absorption
Natural sunlight gives off the entire light spectrum and offers plants what they need in
terms of lighting. Blue lighting is most notable in summer and will encourage the plant to grow
vegetation. Red and blue light combined as seen in spring encourages a plant to flower. A
combination of other spectrum colors or dark light will see the plant grow leggy and sparse and
eventually inhibit the plants ability to photosynthesize eventually killing the plant. Plants need a
limited spectrum of at least blue or red light to thrive.
● Artificial Lighting
Plants can be grown naturally outdoors in a sunny spot where they will receive full or
partial sunlight during the day. Plants can also be grown indoors under artificial lighting. Metal
halide bulbs produce blue light, which encourages growth. They are good for leafy plants such
as salad greens and herbs. High pressure sodium bulbs produce red light, which encourages
the plant to flower and fruit. These bulbs are good for flowers or fruiting plants. Growing plants
indoors means the hours of sunlight can be manipulated achieving faster growth and out-ofseason crops.
Plants need light for three different processes. Phototropism is the plant's ability to
move towards sunlight to maximize its sunlight uptake. Photoperiodism is the plant's reaction
to the length of daylight it receives, which triggers the plant to flower at the appropriate
time of year. The third process is photosynthesis which is the plant's ability to produce its
own food by absorbing and converting the sun's energy into sugars.
http://www.ehow.com/info_8038497_light-color-affecting-plant-growth.html#ixzz1U9Eex6Hd