 |
|
|
|
 |
A place for everything and everything in its place
|
|
 |
Informations |
 |
Project:
A place for everything and everything in its place |
 |
Developed By:
Hugo Villeneuve |
 |
Type of Project:
Experiment |
 |
Category:
Life science |
 |
Class:
Intermediate |
 |
Age of Participant:
14 |
 |
School:
Séminaire de Chicoutimi |
 |
Teacher:
Carol Tremblay |
 |
Has Won:
Bronze medal for a life science project |
|
|
Project presented at the 1998 Saguenay—Lac-Saint-Jean
regional final of the Bell Science Fair
Selected for the 1998 Quebec final (Montreal) of the Bell Super
Science Fair
Selected for the 1998 Pan-Canadian Science Fair in Timmins, where
the participant won a bronze medal for a life science project, intermediate
level
 |
Introduction |
Is it possible that each part of a plant forms a highly
complex architectural and mathematical arrangement? How is this arrangement
formed? Why does this phenomenon occur?
These are the questions that piqued my curiosity and led me to present
a project on plant phyllotaxy.
 |
Development |
I divided my research into two distinct parts:
Part 1: Explaining and observing plant phyllotaxy
Part 2: Experimenting with the phenomenon using various plants and
plant parts
 |
Part 1 |
Phyllotaxy (from the Greek terms phyll meaning leaf and
taxis meaning arrangement) is defined as the arrangement of leaves
on a stem and in relation to one another. This branch of science, related
to botany,
is not very well known. It dates back several centuries to when Leonardo
da Vinci and Kepler, to name just two, observed that the arrangement of plant
components followed a mathematical structure.
Some French physicists recently conducted experiments to find a
plausible explanation for this most impressive arrangement.
This arrangement has three main characteristics:
 1. The arrangement
of plant parts in spirals, both clockwise and counterclockwise.
2. The number
of positive spirals (parastichy), in relation to those that are negative,
corresponds to two consecutive numbers in the Fibonacci series (a mathematical
sequence in which each number is the sum of the two preceding numbers).
3. The angle
of divergence between parts that have grown consecutively is 137.5°, known
as, the golden angle (a mathematical constant).
This entire arrangement is predetermined, not by the plant’s genetic
code, but by the dynamics of plant growth.
Each time a primordium (young bud) is produced, it grows in such
a way as to be as far as possible from the other primordia. The angle
that appears (137.5°) corresponds to the golden angle.
 |
Part 2 |
To solve my initial problem, which was to discover how
phyllotaxy manifested in all plants, I designed and conducted a few
experiments.
Experiment
1:
Experiment involving the arrangement of leaves on a plant
I chose to examine an African violet because, with this plant, it
is easy to observe and identify plant spirals. I began by photographing
the plant from above (bird’s eye view). Then, I identified each of the
spirals, as well as the angle of divergence between the leaves that had grown
consecutively.
Experiment
2:
Arrangement of the scales of cones from coniferous trees
I conducted this experiment with three cones of various sizes from
different coniferous trees by photographing them from above. I then
reproduced each parastichy (spiral) on a transparency. Taking into account
the characteristics
identified previously, I was able to observe that phyllotaxy is also
present in the cones of coniferous trees.
Experiment
3:
Calculation of the angle of divergence in flower petals
With the African violets, I was able to clearly see each angle of
divergence between the petals that had grown consecutively and to
reproduce them on a transparency. I was also able to measure an angle of approximately
140°, which is close to the golden angle of 137.5°.
Experiment
4:
Do the eyes of potatoes also follow this arrangement?
To conduct this experiment, I traced the spirals that form eyes
on potato skins. It is easy to observe that parastichies form. The
numbers that form in a clockwise and counterclockwise direction correspond
to consecutive
numbers in the Fibonacci series. I concluded that even the eyes of
potatoes grow according to a structured pattern that is consistent with the
rules of
plant phyllotaxy.
Experiment
5:
Are physical elements arranged in the same way in our environment?
Following the experiments described previously, I wondered whether
the physical elements in our environment followed these same rules.
I designed an experiment in which this type of arrangement could be observed
by placing
beads in a glass. As a result, I observed that the beads arranged
themselves in positive and negative spirals.
Experiment
6:
Calculation of the phyllotaxy of a plant observed at various growth
stages
This experiment enabled me to discover that phyllotaxy applies to
all growth stages of a plant and that it progresses as the plant
grows.
 |
Conclusion |
This experimental research on plant phyllotaxy enabled
me to discover that mathematics plays a significant role, not only
in our lives, but also in botany.
|
© 2002, Conseil de développement du loisir scientifique (CDLS). This
document is distributed by the Conseil de développement du loisir scientifique.
For more information, visit our Web site at www.cdls.qc.ca. |
The opinions expressed
in this section are those of the authors and do not necessarily
reflect the opinions of Merck Frosst or its employees. |
| |
|
|
|
1. The arrangement
of plant parts in spirals, both clockwise and counterclockwise.
