Volume 6, Spring 2008 - Saddleback College

Fall 2007 Biology 3A Abstracts
inside the greenhouse would contain higher chlorophyll content than the leaves in
their normal environment.
Introduction
Pigments are chemical compounds which
reflect only certain wavelengths of visible light (Speer
95). Chlorophyll a is the type of chlorophyll that makes
photosynthesis possible. It does this by passing on its
energized electrons on to molecules which will
manufacture sugars (Speer 95). A second type of
chlorophyll, chlorophyll b only occurs in plants and
green algae that transfer energy to chlorophyll a.
Photosynthesis is divided into two different and distinct
stages – the Light Reaction, and the Calvin Cycle.
These two stages of photosynthesis are dependent of
each other. The light reactions depends on the NADP+
and ADP and P, that the Calvin cycle generates and
Calvin cycle depends on the NADPH and ATP that the
light reactions generates (Campbell 05).
A previous paper deal with the estimation of
chlorophyll in plant extract by application of
absorption of chlorophyll in plant. In aqueous acetone
dried solid chlorophyll components are dissolved and
made to volume with solvent of identical composition
with extract from wavelength 680nm to 540nm
(McKinney 1941). From his experiment, molar
absorbance coefficients among the range of
wavelengths were found.
Chlorophyll content varies with different
environmental factors. A plant that is healthier will
have a higher amount of chlorophyll overall (Cate
03). The amount of chlorophyll in a leaf is directly
related to the amount of direct sunlight it receives
(Wells 2000). The main purpose of this experiment to
determine which leaves, either the ones in the green
house or the ones in their normal environment, will
contain higher chlorophyll content. It is predicted that
the leaves inside the greenhouse will contain more
chlorophyll than the leaves in their normal
environment. Green house could control factors such as
temperature, carbon dioxide (CO2) concentration and
relative humidity that lead plants as accurately as
possible for optimum crop growth (Bio Medicine).
Materials and Methods
In collecting data for analysis of chlorophyll content
inside a greenhouse and their normal environment of
cyclamen plant (Cyclamen persicum), samples were
collected. Twenty leaves were collected: ten leaves
from inside the greenhouse, and ten leaves from their
normal environment. The greenhouse was built out of
transparent vinyl and wires in form of a bucket. On 31
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Saddleback Journal of Biology
Spring 2008
October 2007, the greenhouse was put on top of plant
and was set up for the experiment. The area from
which samples were taken was from a garden located
in Mission Viejo.
Leaves were prepared for chlorophyll analysis
on 21 November 2007 at Saddleback College. Twenty
scintillation vials were filled with 5 mL of 80%
acetone, measured with the use of a pipette. Two leaf
chads, each with a diameter of 6 mm were added to
each vial and labeled according to their category. All
vials were placed in a 4°C environment for 48 hours.
Chlorophyll readings were taken on 26
November 2007 using a Beckman DU 730
spectrophotometer, calibrated for measurement of
chlorophyll content in acetone at a two wavelengths in
nm. Three milliliters of an 80% acetone was pipetted
into a cuvette, to zero out the spectrophotometer. Then,
three milliliters of each of the sample mixtures were
pipetted into cuvettes, and the readings of chlorophyll
content were taken individually for total combined
chlorophyll content at mg/L.
The Beckman DU 730 spectrophotometer was
set up with the incorrect program and inaccurate
measurements were given. Leaves were prepared for
chlorophyll analysis on 28 November 2007 once again.
This time the machine was calibrated with the correct
wavelengths in nm, and the readings of chlorophyll
content were taken individually for total combined
chlorophyll content at mg/L. We used K 1 A 1 +K 2 A 2
equation to calculate the concentration of chlorophyll a
and b.
Results
The cyclamen leaves inside the green house
did not contain more chlorophyll than the leaves from
their normal environment. The total average
measurement of milligrams of chlorophyll per liter of
80% concentrated acetone of the leaves inside the
green house of the cyclamen plant were 3.754 mg/L
(+0.15 se, N=10). The total average measurement of
milligrams of chlorophyll per liter of 80% concentrated
acetone of the leaves in their normal environment of
the cyclamen plant were 3.822 mg/L (+0.24 se, N=10).
The difference between the average amounts of
chlorophyll between the two leaves was not
significantly different (p value = 0.41). Figure 1 shows
the graph of the average of chlorophyll concentration
of the leaves inside the greenhouse and their normal
environment.