Effects of Plant Population Density
The Effect of Population
Density Among Plants
Ilustre M.N. and Pianka A.J. 2014
Effects of Plant Population Density
Table of contents
Line your pages numbers up
Table of contents…………………………………………………………………
2
Abstract…………………………………………………………………………………..
3
Introduction……………………………………………………………………………….3-4
Question………………………………………………………………………………….4
Hypothesis…………………………………………………………………………………4
Control variable…………………………………………………………………………….4-5
Independent variable ………………………………………………………………………….5
Dependent variable …………………………………………………………………………..5
Procedure………………………………………………………………………………………5
Material list…………………………………………………………………………………….5-6
Charts…………………………………………………………………………………………6-8
-
Growth Chart…………………………………………………………………..6-7
Average/Final Biomass……………………………………………………………7
Line Graph ………………………………………………………………………….78
Eliminate the above and below
Pictures ………………………………………………………………………………………9-10
Conclusion………………………………………………………………………………10-11
Sources of error…………………………………………………………………………….11
Literature Cited …………………………………………………………………………….12
Effects of Plant Population Density
Abstract: Population density is one of the many general a limiting factors existent in many
of the living organisms in the environment. which influences the growth of organism
population growth. If a population is gone grows unchecked in a certain environment, the
population density in of a species may swell and cause major problems for other members of
the population such as a lack of food or reduction in living space. The same problem of
density in a population is possible in organisms such as plants. To test this possibility, 3 three
groups of 8 eight green bean seeds were placed into casings in which they were planted at
different distances (save for one) from the recommended spaces. Each group of plants were
was subjected under to the same growing conditions, from amount of water given, to the
amount of sunlight each plant received. Once the green bean seeds were fully grown, they
were removed harvested and measured for their height and biomass and height. The results
from each group were then used to calculate an average biomass for each. From these results,
it is shown that plants grown at 5 five centimeters closer to each other had a mass .625 grams
two values? This confuses me. What’s going on? (4.375 g) less than that of the plants grown at
the recommended distance. The plants grown at 10 centimeters further had an average mass
of 5 grams, .125 grams less than that of the plants grown at the recommended spacing. OK,
now give me your conclusions too.
Introduction: All experienced farmers know that weather and temperature does not just
affect plant growth. There are many other factors that contribute to a successful harvest than just
the simple weather and temperature. One in particular is plant population density. High
population density is a common problem in forests. Efforts to combat fires have led 9.5 million
Effects of Plant Population Density
acres of Oregon forest to become overgrown and more fire-prone, according to Russ Hoeflich,
(have to have a date)director of the Nature Conservancy in Oregon. He said that many trees are
competing for water and becoming susceptible to disease and insect infestation because wildfires
have not been allowed to thin forests naturally. But, this raises questions for farmers and
botanists about, "Does population density affect plant growth? Will planting certain species of
plants farther apart actually make the plants grow better?" Knowing the answer to this question
just could mean a better quality product for farmers and botanists about. Previous research and
field observations have shown that some plants will not be affected by population density at all"
Harper (1977): summary, p. xvi; Ch. 7, pp. 195-235. Some may have a high level of tolerance to
certain tightly knit or loosely knit communities. But, this may not be true for most plants. Does
varying population density for plants really affect their growth?
Question: Can space be a limiting factor in plant growth?
Hypothesis: If bean seeds are planted closer than the recommended distance, then bean
plants will have a lower biomass. This was predicted because Commercial seed producers
recommended specific planting distances on their seed packets. Presumably this is because they
have researched ideal growing conditions, including distance between plants. Seeds that are
planted closer than recommended should experience intense competition for resources and
therefore should have a lower biomass.
Just state the hypothesis
Control Variables:
-Water
-Light
-Soil type
-Tray size
Effects of Plant Population Density
-Temperature
Independent variable: Space between seeds
Dependent variable: Plant biomass
Procedure:
The procedure in this experiment consisted of these steps:
-Put the same amount of soil specify in each of the nine containers.
-Plant the seeds closer than the recommended distance, plant seeds the recommended -distance and plant
seeds further than recommend distance. Specify the distances
-Give all the seeds the same exact amount of water specify
-Set up the florescent grow lights
-recorded the height and biomass of each plant every 7 days
- Give the all the plants the same amount of water each day. Didn’t you already say this?
-give all the plants the same amount of light each day. Expose the plants to the same amount of light
- When plants get to flowering stage pull them out by the roots.
-Allow the plants to dry
- Measure the final biomass and make conclusion
Material List: The materials used in order to orchestrate this experiment were:
-Green Bean seeds of the same phenotype
-9 containers 55 cm by 18 cm (3 for each spacing)
-Soil (to fill containers) specify soil type. Potting soil?
Effects of Plant Population Density
-Water (to water the plants) well it’s not for you to drink!!
-Florescent grow light (regulated sunlight)
-Measuring cup (to measure water given to plants)
-Scale (to measure biomass of plants) specify. Triple beam?
-data sheet
-pen or pencil to write
-Labels to label containers
-ruler in cm to make measurements cm ruler
The results of the experiment proved the hypothesis is plausible, but not solid enough to be true.
Results
Plant Height
Growth Chart
Date
Spacing (CM)
Heights(CM)
October 5, 2013
5cm
N/a seeds planted not
germinated
October 5, 2013
10cm
N/a seeds planted not
germinated
October 5, 2013
20cm
N/a seeds planted not
germinated
October 12, 2013
5cm
2,3,1,3,3,2,1,2
October 12, 2013
10cm
3,2,2,1,2,3,2,3
October 12, 2013
20cm
1,3,2,3,3,1,1,3
October 19, 2013
5cm
2,5,4,4,6,5,4,7
October 19, 2013
10cm
6,4,3,3,5,6,8,6
October 19, 2013
20cm
4,6,7,5,8,6,4,7
October 26, 2013
5cm
10,12,9,14,10,11,2,13
October 26, 2013
10cm
12,11,12,13,17,16,14,21
October 26, 2013
20cm
13,13,14,19,23,16,19,14
November 2, 2013
5cm
24,2,13,10,19,11,25,19
November 2, 2013
10cm
16,17,16,30,15,15,18,17
Effects of Plant Population Density
November 2, 2013
20cm
15,23,26,14,14,18,20,17
November 9, 2013
5cm
2,20,17,9,21,13,27,25
November 9, 2013
10cm
20,32,21,21,19,19,18,17
November 9, 2013
20cm
23,19,24,21,23,21,23,21
November 16, 2013
5cm
2,19,22,17,12,22,26,29
November 16, 2013
10cm
35,21,23,23,24,23,22,21
November 16, 2013
20cm
26,24,30,22,20,22,20,20
November 23, 2013
5cm
28,14,26,29,16,23,31,2
November 23, 2013
10cm
22,22,25,23,22,24,22,32
November 23, 2013
20cm
20,20,21,22,23,29,18,22
November 30, 2013
5cm
27,22,29,23,23,16,20,2
November 30, 2013
10cm
21,21,22,25,24,23,19,34
November 30, 2013
20cm
24,19,24,22,24,28,7,23
December 7, 2013
5cm
15,30,21,7,27,24,27,27
December 7, 2013
10cm
29,20,24,27,14,23,23,36
December 7, 2013
20cm
22,21,23,21,29,20,6,22
December 14, 2013
5cm
15,31,22,7,28,24,28,27
December 14, 2013
10cm
30,21,24,27,15,23,23,38
December 14, 2013
20cm
22,21,23,29,21,6,22,39
Final Biomass Charts
Plant Spacing(CM)
Masses( in Grams)
5cm
4,4,4,4,4,5,5, 5
10cm
5,5,5,5,5,5,5,6
20cm
4,5,5,5,5,5,5,6
Final Average Biomass Average Chart
Plant Spacing (CM)
Mass Average( in Grams)
5cm
4.375
10cm
5.125
Effects of Plant Population Density
20cm
5.000
Plant Length
height?Average
5 cm
10 cm
20 cm
Week Week Week Week Week Week Week
Week
Week Week Week
1
2
3
4
5
6
7
8
9
10
11
0 2.215
4.625 12.125 15.375
16.75 18.625
21.125
20.25
20.5 21.375
0 2.215
5.125
14.5
18 20.875
24
24 23.625 23.25 23.625
0 2.215 11.375 16.315 18.375 21.875
23 21.1875 21.375 22.25
20.25
You need to label the x and y axis
Effects of Plant Population Density
This is a picture of plants a few days after planting. Plants after specific number of days
These are pictures of the plants after 3 weeks.
Effects of Plant Population Density
This is a picture after 11 weeks after the plants were pulled out and weighed for their
biomass. Plants drying prior to measuring biomass
Conclusion: Although the Green Bean plants show that there would be a slight difference in
plant growth when it comes to population density, the numbers seem to be too close to actually
show that giving more space to a plant doesn’t actually benefit it. Yikes! Quite the run on
sentence! Fix it! And you do not really tell me anything! However, the difference in the average
biomasses of the plants grown at the recommended spacing of 10 cm and spacing at 5 cm shows
that a densely populated area hinders growth in plants. beans
However, research shows by whom? that corn is heavily dependent on a rising population
density and depending on the hybrid and the population density, the plants will yield a larger
biomass and/or height. This evidence may point to the carrying capacity of Green Beans green
Effects of Plant Population Density
beans to be smaller due to a different demand in nutrients necessary for growth. Competition
due to population density is also evident in other members of the kingdom Plantae. For example,
trees in densely packed forests are in competition for the most sunlight. Those who are blocked
out by other trees that have already grown won’t no contractions survive or grow as much. The
same can be said for other members of the Plant kingdom. Lower case
In conclusion, the test results were not solid enough what the heck does this mean??
Solid as in ice??? Lead?? Give me values!!! to prove that plant populations face pressures in
Population Density, why are you capitalizing ? but evidence in nature, such as tightly packed
forests show that population density has certain limits.
Sources of Error:
 Sample size is too small
 Beets, and Basil never fully germinated like the Green Beans.
 The conditions were suitable, but not beneficial for plant growth
 Plants started to die during the later weeks and were still measured after.???
Effects of Plant Population Density
Literature Cited
Dekker.J, 2011, Plant Density, Plant Form and Community Diversity, December 5, 2013,
http://agron-www.iastate.edu/~weeds/ag517/Content/LifeHistory/Competition/densityform.html
Martin.P, 2013, What Plants Grow the Fastest From Seeds?, December 5, 2013
http://homeguides.sfgate.com/plants-grow-fastest-seeds-53378.html
Anonymous, 2013, U.S. Corn Yields Growth Dependent On Increasing Plant Population
Density, December 5, 2013 http://www.croplife.com/crop-inputs/u-s-corn-yields-growthdependent-on-increasing-plant-population-density/
Lyon J.D.2009, How Do Plant Populations Affect Yield?, December 5, 2013,
http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1017&context=panpressrel
Hakeet.K,et al,1991, Plant Population, December 5, 2013,
http://www.cotton.org/tech/physiology/cpt/variety/upload/CPT-Feb91-REPOP.pdf
Effects of Plant Population Density