Radish Competition Lab

Abstract
The purpose of this experiment was to examine how low and high densities of radish and wheat seeds affect the plants growth rate and competition. The competition occurs when resources are limited to the plants. The two types of competitions that occur are interspecific and intraspecific. Interspecific is a competition between two different species and intraspecific is a competition between the plants own species. This experiment was conducted by taking 6 pots containing soil and placing certain amount of seeds, radish or/and wheat seeds, in each pot. A total of 384 seeds were needed for this experiment; 192 for radish and 192 for wheat seeds. The first three sets of pots had a total of 32 seeds in each pot consisting of radish or/and wheat seeds, which represented the low density and the other three sets of pots had a total of 96 seeds in
each pot consisting of radish/or and wheat seeds, which represented the high density. These 6 pots were put in the incubator at 20 degree Celsius on a 14 to 10 light cycle (14 hours in light and 10 hours in the dark), and were watered daily at adequate amounts for three weeks. After three weeks, the number of seeds that germinated were noted and the shoots mass was noted based on the number of shoots that grew. The results showed that the higher the density was the more competition there was between the two species except for the wheat species since it tripled in density (from 5.4 to 20.9) which meant that there was no competition as the resources were enough.
Introduction
Plants need nutrients, light, and water for their enhanced growth (Craine and Dybzinski 2013) . But if the seeds are sown closely enough (more dense) and some plants need more resources than the others then they are likely to compete for these resources. Plants adapt to light by having broad leaves which take more light for their survival and reduce the growth of their competitors (Craine and Dybzinski 2013). The plants are adapted to compete for nutrients by having long roots which allow them to absorb more nutrients from soil as compared to their neighboring competitors’ plant (Craine and Dybzinski 2013). The plants with more root hairs and long root are able to well survive as compare to others. Lastly, plants adapt to compete for water for those who also have long roots (Craine and Dybzinski 2013). The adaptions are same in a plant which is grown under dry conditions like a plant grown in desert. These adaptations, broader leaves and long roots, is important because it provides better chances of survival and growth as compared to their competitors which are not adapted. Competition and adaptation affects the productivity by giving the plant chance to live but at a cost of productivity. This means that plants may survive but the production is less as compared to the plant which is grown without any competition because most of the energy of the plant is relocated in the process of adaption and surviving the competition (Craine and Dybzinski 2013). In this experiment the two types of competition are intraspecific and interspecific. In this experiment, intraspecific competition may occur when wheat or radish seeds compete with their same kind and interspecific competition may occur when the wheat or radish seeds compete with one another (Walsh and Walsh 2015). This competition is based on the density of the seeds in the pot and plant growth after germination (Walsh and Walsh 2015). If the plants have limited resources because of competition, the growth of the plant is affected (Walsh and Walsh 2015). Thus, the objective of this experiment is to understand the effect of competition in wheat and radish plants and how it affects the plants growth based on the density (Walsh and Walsh 2015). Based on this information, the hypothesis was that the pot that had the greater amount of seeds, was denser, which would result for the plants to have less resources and more competition.
Methods:
To perform this experiment, 192 radish seeds and 192 wheat seeds were used along with 6 planting pots containing soil.
In the first- three pots a total of seed 32 seeds were placed in each pot (Walsh and Walsh 2015). Each of these pots contained 32 radish seeds, 32 wheat seeds, and 16 seeds of each radish and wheat seeds (Walsh and Walsh 2015). Then, on the other three pots a total of 96 seeds were placed in each pot. Each of these pots contained 96 radish seeds, 96 wheat seeds, and 48 seeds of each radish and wheat seeds (Walsh and Walsh 2015). These pots were placed in a incubator at 20 degree Celsius in a growth chamber at a 14 to 10 light cycle (14 hours in light and 10 hours in dark) and were watered daily for three weeks. Following the three week period, the number of seeds that germinated and the shoots mass were noted from each pot (Walsh and Walsh 2015). This process was conducted by cutting the end of the plant shoot and counting the number shoots which rose (Walsh and Walsh 2015). The shoots mass was noted by, compiling the shoots that were cut, using a digital weighting machine (Walsh and Walsh
2015).
Results
The radish species shoot mass doubled from low (32 seeds) to high density (96 seeds) from 11.1 grams at low density to 22.8 at high density (Figure 1). For the wheat species, the shoot mass tripled from 5.4 grams at low density to 20.9 grams at high density (Figure 1). The density for the first set of radish and wheat species, decreased from low to high density, 14.8 grams to 1.1 grams, and the density for second set of wheat and radish species also decreased from low to high density, from 5.9 to 4.0 (Figure 1). The relative yield (RY) for each radish and wheat species, separately, decreased from low to high density (Table 1). The relative yield for radish went from 2.67 to 0.096 and the relative yield for wheat went from 2.18 to 0.38 (Table 1). The change in contribution index (CC) for radish also decreased from low to high density while the change in contribution index value for wheat increased from low to high density (Table 1). The overall intensity of competition (IC) for radish species were higher than intensity of competition for wheat, at both densities (Table 1).
Discussion
From the results stated, the radish species density doubled from low to high density therefore this shows that there was intra-competition going on between the different densities of seeds that grew. The reason it is intra completion is because the two densities that was compared were the same radish species. The density of the seeds tripled from 32 to 96 therefore the density from low to high for the wheat species also tripled, thus there is no competition between the amounts of seeds. This means that all the seeds grew up to their maximum potential and both densities had more than enough resources. Because there was a decrease from the low and high density for the radish and wheat species there are two types of competition arising at the same time; interspecific and intra specific competition because the radish seeds are facing competition with wheat seeds as well as with the radish seeds also. Similarly for the wheat and radish, the density decreased from low to high thus there is interspecific competition going on in between the wheat and radish seeds because there are 48 seeds. If there was no competition these all will germinate and shoot mass is triple of 5.9 grams but it less than 5.9 grams therefore there is competition going on. The shoot mass of radish was more as compare to wheat because wheat is a small plant with light weight as compared to radish. These plants that had interspecific competition either had low or high nutrient levels (Aerts 1998). The plants that had low nutrients levels strived to compete for high nutrient levels whereas the high nutrient levels strived to compete for light (Aerts 1998).
The relative yield for the radish seed at low density of 32 seeds was greater than one meaning that the radish seed is better off competing with the wheat seed rather than with the radish seed (Walsh and Walsh 2015). The relative yield for wheat seed at low density of 32 seeds was also greater than one; the wheat seed is better off competing with the radish seed rather than with the wheat seed(Walsh and Walsh 2015). At high densities, at 96 seeds, the relative yield for radish seed was less than one which meant that if the wheat seed were to compete with the radish seed than it would be harmful which would lead towards interspecific competition and vice versa for the wheat seed (Walsh and Walsh 2015). The change in contribution index were inversely proportional between the radish and wheat species at low and high densities. The radish seed at low density and wheat seed at high density had a positive number, which meant there was 6.2% and 63.99% more biomass if the plant was grown in a mixture (Walsh and Walsh 2015). And the radish seed at high density and the wheat seed at low density had a negative number which meant there was 12.9% and 63.9% more biomass if the plant was grown in a monoculture (Walsh and Walsh 2015). Lastly, the intensity of competition were both positive for radish and wheat seeds which means that there was a very large effect between the densities of the two species (Walsh and Walsh 2015).

Thus, the hypothesis was supported by the fact that the more dense the planting pot was the more competition there is based on plant growth. Some of the errors that could have happened were human errors such as not watering it regularly or not enough water, not counting the right amount of seeds, and lastly the plants may not have had the adequate room for the plant growth or the seeds from one