Table of Contents
Abstract
This research investigated intraspecific competition and its effect on growth and biomass in Raphanus Sativus, Radishes. Radishes were used based on their ability to germinate and grow quickly and reliably, also they are good for demonstrating the effects of different level of plant nutrition. This experiment had four variables (control, 2 seed, 4 seed, 8 seed). After planting the seeds, they were watched, watered and moved to ensure optimal growth. After a 4-week period the specimens were measured in average biomass, leaf length, and width. (what stats do I need). The Hypothesis is that with the crowding of planters of radish and forcing these plants to go through competition will inhibit growth of the radish. The hypothesis was rejected, and the null hypothesis was accepted.
Introduction
Intraspecific competition is the competition or struggle between individual organisms of the same species for limited resources. (ScienceDirect) There are two different types of intraspecific competition; interference and exploitation. This research focused on exploitation intraspecific competition, which occurs when individuals of the same species are competing for and exploiting the same limited resource such as food and decreasing the availability for other organisms including its own species. (ScienceDirect) This competition leads to delayed growth in certain plants and dying of other organisms due to the fight for nutrients. Such as for this experiment tested Raphanus Sativus and the effect of intraspecific coemption on growth through biomass, leaf length, and leaf width. (elaborate more on the radishes in competition, different pots how it is competition) Radishes were used based on their ability to germinate and grow quickly and reliably and are good for demonstrating the effects of different level of plant nutrition. (Saps)
It has been observed that intraspecific competition restrains organisms from growing (Khan). Based on this observation the objective is to determine whether intraspecific competition actually does arrest development. The hypothesis is that with the crowding of planters of radish and forcing these plants to go through competition will inhibit growth of the radish. However, the null hypothesis states intraspecific competition will play no role and will not affect the growth of the radishes.
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Methods and Materials
In this experiment, there was in total sixteen containers of radish being observed. The containers were gathered and labeled accordingly (control, 2 seed, 4 seed, or 8 seed). These four different scenarios were tested at a multitude of four, n=16. After the gathering the containers, they were filled approximately ¾ with the potting mix. All of the seeds were then gathered. In four of the containers one seed was planted, this was the control. In the next four containers, two seeds were planted. For the four containers, four seeds were planted in, and in the final 4 containers 8 seeds were planted.
When planting the seeds, the seeds were pushed approximately 2.5 centimeters below the surface of the potting soil and covered loosely. Then the specimens were placed under the 24/7 fluorescent growth light. The placement of the organisms was ensured to be random and intermixed with the other organisms(?). They were also rearranged periodically to ensure each got equal amount of opportunity for light nutrients. The soil was watered until moist and was watered when needed through ought the rest of the experiment. After 4 weeks the plants were taken out from the light and the variables: average leaf length, average leaf width, and biomass where measured. To measure the average leaf length two leaves were chosen at random and then the measurements were divided by two. Same procedure for the width is done to both leaves. The measurement for biomass was taken by uprooting the plant and measuring the weight in grams. These figures were calculated to determine whether the data was significant. These measurements where then entered into a program called ANOVA to see the variation between the data points.
All figures are representations of the measurements taken after the data was submitted into ANOVA. In figure 1 The average leaf width in centimeters of (radish) plants across the different treatments is shown. The control had an average leaf width of 2.821cm (+/- .3891cm). The 2 seed treatment had an average leaf width of 3.042cm (+/- .2089cm). The 4 seed treatment has average leaf width of 2.873cm (+/- .1983cm). The 8 seed treatment had an average leaf width of 2.492cm (+/- .1688cm). The p-value of the average leaf width data is 0.4970.
In figure 2 the average leaf length in centimeters of the (radish) is across the different treatments is shown. The control had an average leaf length of 8.704 cm (+/- 1.089cm). The 2 seed treatment had an average leaf length of 9.115 cm (+/- .4929cm). The 4 seed treatment had an average leaf length of 8.861cm (+/- .5119cm). The 8 seed treatment had an average leaf length of 8.071cm (+/- .4132cm). The p-value for the average leaf length in centimeters is 0.7360.
In figure 3 the average biomass in grams of (radish) plants across four treatments is represented. The control the biomass was 1.548 g (+/- .2126g). The 2 seed treatments biomass was 2.648 g (+/- .2575g). The 4 seed treatment had a biomass of 3.733 g (+/- .1755g). The 8 seed treatment had a biomass of 5.083g (+/- .435g). The p-value for the average biomass in grams of radish is less than 0.0001.
Discussion
Based on the data from the average leaf width, all of these treatments had average lengths between 2 and 3 centimeters which shows that there wasn’t much difference between the treatment. The p-value was 0.490 which signifies that this data is not statistically significant. For leaf length the average length was between 8 and 10 centimeters for all treatments showing minimal difference between the treatments. The p-value for the average leaf length was 0.7360 and it is not statistically significant. The third variable, biomass, had an average between 1.5 and 5.5 grams. These results had a p-value of 0.0001 which makes them statistically significant. However, the reason the biomass is statistically significant is based on the treatments, there were more plants growing in the container. Based on the data, the hypothesis that intraspecific competition would inhibit growth is rejected and the null hypothesis is accepted.
While this research disproved the effects of intraspecific competition, other research supports the initial hypothesis. Miller (1995) concludes that intraspecific competition did play a role in growth but differed among species. Also, at Ohio State University, their research showed that the biomass in Atriplex postrata was inhibited due to the plant density. (Khan)
This research could have been improved with a larger sample size, larger range of samples, or having a higher density of Raphanus Sativus in the containers. This would provide credibility as well as more accurate results.
References
- Intraspecific Competition. (2008). Retrieved from https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/intraspecific-competition
- Khan, M. A., Ungar, I. A., & Showalter, A. M. (2005). Salt Stimulation and Tolerance in an Intertidal Stem-Succulent Halophyte. Journal of Plant Nutrition,28(8), 1365-1374. doi:10.1081/pln-200067462
- New AMz brochures about EnEV 2016 and constructional fire protection according to Eurocode 6 / Neue AMz-Broschüren zu EnEV 2016 und baulichem Brandschutz nach Eurocode 6. (2016). Mauerwerk,20(5), 408-408. doi:10.1002/dama.201690051 (get cite)
- Using Radishes in the Lab. (n.d.). Retrieved from http://www.saps.org.uk/secondary/teaching-resources/747-using-radishes-in-the-lab
