RESULTS Research Question #1: Do Standard and Purple Hairy varieties of B. rapa have different salt tolerance? The results obtained from the Welch two-tailed t-test showed that the Purple Hairy variety and the Standard variety didn't have a significant difference in salt tolerance. This was seen through the p-value (0.13) which is greater than 0.05 (Fig. 1, t = - 1.54, df = 44, p = 0.13). Figure 1 - Salt tolerance by variety 0 300 Salt tolerance (%) 8 200 50 100 Purple Hairy Standard variety Fig. 1: Comparison of salt tolerance (%) of two varieties of Brassica rapa plants (Hairy purple, n=20 and Standard, n=20) after 9 days of growth underground in both conditions. The salt tolerance was calculated by measuring the effects of salinity (80mM) on the shoot length of both varieties. Error bars represent standard error of the mean. Research Question #2: Do Standard and Purple Hairy varieties of B. rapa have different genetic variability in salt tolerance? Using the data from Fig.1 we can see that the Purple Hairy variety has a higher genetic variability than the Standard variety. This can be seen by the height of the whiskers on the boxplots, Purple Hairy has taller whiskers. The interquartile range for Purple Hairy is also larger than that of the Standard's (Fig. 1). Research Question #3: Do either Standard or Purple Hairy varieties of B. rapa show evidence of trade-offs between salt tolerance and early life development? Based on the statistical data collected from the Pearson's product-moment correlation test that was done, it can be concluded that the Standard variety
showed no evidence of trade-offs between salt tolerance and early life development. This was concluded because the p-value was 0.41 which is not statistically significant and the value was positive, all signs pointing towards a lack of trade-offs. Also looking at the scatterplot created it is evident that there is no significant correlation (Fig. 2A, r(CI) = - 0.708, t = - 0.83, df = 28, p-value = 0.41). Standard 8 10 12 14 16 . shoot_length.80 . 6 4 5 10 15 20 shoot_length.0 Fig. 2A: Comparison of the shoot lengths (mm) of the Standard variety (n=20) Brassica rapa plants in both the control (0 mM NaCl) and treatment (80 mM NaCl) conditions after 9 days of growth. Error bars represent standard error of the mean. Once again taking a look at the Pearson's product-moment correlation test but for the Purple Hairy variety we can once again see no evidence of trade-offs between salt tolerance and early life development. The p-value is once again positive and not significant as it is greater than 0.05. Now observing the scatterplot created we notice no significant correlation among the data (Fig. 2B, r(Cl) = -0.72, t = -0.92, df = 27, p = 0.37). Purple Hairy 8 7 10 shoot_length.80 5 4 3 5 10 15 20 shoot_length.0
Fig. 2B: Comparison of the shoot lengths (mm) of the Purple Hairy variety (n=20) Brassica rapa plants in both