Five sets of six radish seeds that were pretreated with various doses of gamma radiation of zero negative control, 50,000 (50K); 150,000 (150K); 500,000 (500K); and 4,000,000 (4M) rads were acquired. A square container with a paper towel on the bottom was filled with dirt. Using wooden sticks, the dirt were separated into six sections and labeled according to the radiation dose. Each individual seed was planted about one inch deep into the soil and two inches apart from one another. The seeds were watered and placed under the lamp. For two weeks the radish seeds were watered in every class period. At the end of the two weeks period the radish plants' phenotypes of total plant length, stem length, and leaf length were measured in millimeters that were recorded for each radiation section respectively. The average length, standard deviation, and p-value were calculated which were used to construct tables and graphs for each phenotype.
Results
After two weeks only 4 out of 6 control (0 rads) radish plants grew, while 50K, 150K, and 500K dose sections 5 out of 6 grew. The 4M dose no growth was observed. According to Table 1 the average total radish plant lengths and standard deviations were 9.7:7.6, 7.45:4.65, 5.83:3.42, 3.25:1.86, and 0:0 mm respectively (Figure 1). The average stem length and standard deviations were calculated to be 4.88:4.05, 4.05:2.42, 3.08:1.86, 1.67:0.93, and 0:0 mm respectively (Table 2, Fig. 2). Average leaf length and standard deviations were calculated to be 3.6:2.82, 2.35:1.90, 1.33:1.08, 0.67:.052, and 0:0 mm respectively (Table 3, Fig 3). The P-value was found to be greater than 0.05 in all phenotypes tested when compared to the control radish plant (Table 1-3).
Table 1: Total Radish Plant Length
Dose
Length of each plant (mm)
Average length (mm)
Standard deviation (mm)
p-value (Wilcoxon Rank Sum)
Control (no rad)
13.3, 15.3, 13.3, 16.3, 0, 0
9.7
7.6
N/A
50,000 rads
8.5, 11.5, 3.6, 11.3, 9.8, 0
7.45
4.65
>0.05
150,000 rads
4.5, 5.0, 8.0, 8.5, 9.0, 0
5.83
3.42
>0.05
500,000 rads
2.5, 3.5, 4.0, 4.0, 5.5, 0
3.25
1.86
>0.05
4,000,000 rads
No Growth
0
0
>0.05
Table 1 visualizes the total length of radish plants' according to radiation dose. Measurements were made for each individual plant in mm which the average length, standard deviation, and p-value were calculated.
Table 2: Radish Stem Length
Dose
Length of each plant (mm)
Average length (mm)
Standard deviation (mm)
p-value (Wilcoxon Rank Sum)
Control (no rad)
8.5, 6.5, 9.2, 5.1, 0, 0
4.88
4.05
N/A
50,000 rads
4.7, 2.4, 5.7, 6.5, 5, 0
4.05
2.42
>0.05
150,000 rads
2.0, 3.0, 4.5, 5.0, 4.0, 0
3.08
1.86
>0.05
500,000 rads
1.5, 1.5, 2.5, 2.0, 2.5, 0
1.67
0.93
>0.05
4,000,000 rads
No Growth
0
0
>0.05
Table 2 shows the stem length of radish plants' according to radiation dose. Measurements were made for each individual plant in mm which the average length, standard deviation, and p-value were calculated.
Table 3: Radish Leaf Length
Dose
Length of each plant (mm)
Average length (mm)
Standard deviation (mm)
p-value (Wilcoxon Rank Sum)
Control (no rad)
6.0, 4.7, 5.6, 5.3, 0, 0
3.6
2.82
N/A
50,000 rads
2.9, 4.5, 3.5, 0, 3.2, 0
2.35
1.90
>0.05
150,000 rads
0.5, 1.0, 1.5, 3.0, 2.0, 0
1.33
1.08
>0.05
500,000 rads
0.5, 0.5, 0.5, 1.5, 1.0, 0
0.67
0.52
>0.05
4,000,000 rads
No Growth
0
0
>0.05
Table 3 visualizes the leaf length of radish plants' according to radiation dose. Measurements were made for each individual plant in mm which the average length, standard deviation, and p-value were calculated.
Figure 1: Total Radish Plants' Length Under Different Doses of Radiation. Graph shows the comparison of different doses of radiation according to average length and standard deviation after two weeks of growth.
Figure 2: Radish Stem Lengths Under Different Doses of Radiation. Graph shows the comparison of different doses of radiation according to average length and standard deviation after two weeks of growth.
Figure 3: Radish Leaf Lengths Under Different Doses of Radiation. Graph shows the comparison of different doses of radiation according to average length and standard deviation after two weeks of growth.
Discussion
The radish seeds that were pretreated with various doses of gamma radiation caused the plants to grow slower compared to the control plant. Our hypothesis was supported on the increase dose of radiation yields shorter radish plants compared to the control plant. According to Figure 1-3 average length and standard deviation of all 3 phenotypes decrease significantly as the radiation dose increases. In addition the seeds that were subjected to 4 million rads did not show any signs of growth. The more radiation that was received the shorter the phenotype of stem and leaf lengths expressed. Also the phenotype color of the radish plant exhibit lighter shades of green as the rads dose increases. Since the P-value was greater than 0.05, all radiation doses are not significantly close to the control plant, therefore radiation has a profound effect on radish seeds growth.
