Bioassay of Radish Seeds free essay sample

The lab seeks to determine the potency of NaCl by determining its effect in different concentrations on the growth of the seed roots. This served to give us a cheap and quick way to experience a bioassay experiment from our classroom. Hypothesis I believe that a greater concentration of NaCl will correlate with a lower seed germination rate, as well as a shorter radicle length. Procedure 1. Label petri dishes with the appropriate concentration levels and place filter paper in each dish. 2. Treat each dish with 2mL of the appropriate concentration of the bleach solution 3. Place 6 seeds in each dish. Make sure they do not touch the sides of the dish or each other. 4. Leave the dish in a dark place so that the roots can grow. 5. Dishes were left in the dark for four days due to the blizzard. 6. Recover dishes and measure the length of the roots at different concentrations 7. We will write a custom essay sample on Bioassay of Radish Seeds or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page Calculate the averages of the roots and number of germinated seeds with those of the different groups 8. Create graphs for both the root length and number of germinated seeds Results length of radicle (mm) Group 1Group 2Group 3Group 4Group 5Group 6Average % NaClM NaCl 100. 00. 2008. 420. 241. 418. 211. 820. 420. 1 50. 00. 10031. 66. 072. 034. 232. 46. 640. 4 37. 50. 07532. 067. 481.. 842. 245. 011. 239. 6 25. 00. 05045. 269. 691. 839. 839. 429. 252. 5 12. 50. 02552. 063. 0129. 241. 457. 452. 465. 9 0. 00. 00040. 075. 057. 660. 254. 26. 048. 8 # of germinating seeds % NaClM NaClGroup 1Group 2Group 3Group 4Group 5Group 6Average 100. 00. 2003555354. 3 50. 00. 1004555534. 5 37. 50. 0755553544. 5 25. 00. 0505454544. 5 12. 50. 0255454544. 5 0. 00. 0004555534. 5 Based on this experiment, the TC50 for seed germination cannot be found. Discussion/Conclusion Essentially, what the data tells me is that our hypothesis was correct. The toxicity of NaCl has a great effect on the length of the radical via limiting its growth. It lowers germination as well – though with much less effect. Radicle length was certainly more affected than germination rate, though both were lowered. Interestingly, radicle length at 12. 5% for example, was clearly much higher than at 100% a trend for radical length was seen through the graph, but the 0% concentration broke that trend. A reason for this could be that the seed needs a slight amount of NaCl to flourish properly – but as levels increased above minimal ones, diminishing returns were clearly noted. This is true for many things in science – too little of something is not conducive, but at the same time, slightly too much could absolutely ruin everything. As stated above, the hypothesis was certainly validated. Though it is not too shocking, it certainly was proven to be correct that the more NaCl, the lower germination and growth rates we would observe. I think there could be some error in possibly not writing down the data correctly, and also from allowing the seeds to sit for so long due to the blizzard. Regardless, I think the hypothesis was certainly validated and that the lab was a good way to understand the effects of NaCl on radicle length and germination rate. 1. 1. Did at least 80% of the seeds in the control dishes germinate? If not, what would you recommend doing differently next time to try to get a better germination rate? Yes, all of our seeds in the control dish germinated. 2. Did radish seed germination respond in a predictable way to concentration? Describe any trends you observed. I felt that the germination was predictable. The higher the concentration of the NaCl Bleach solution, the lower the number of germinated seeds. . Do any of your data not fit the trends you observed? If so, can you think of any reasons why these data might lie outside the range you would expect? Yes my data in the Average Radicle Length area doesn’t make a lot of sense. I think this was not due to anything regarding the experiment, but human error in recording the data. 4. What is you r estimate of the TC50 based on your radish seed germination data? What is your estimate of the TC50 based on your radicle length data? Which shows a greater response to the chemical you tested: germination rate or radicle length? Describe any similarities or differences that you noticed in trends between these two indicators of toxicity. I believe that the TC50 for both the seed germination was 25% and 50% for the radicle length data. From this it can be seen that the radicle length of the plant reacted more strongly to the chemical than the seed germination. In both instances it can be clearly seen that large doses of the chemicals had negative effects on the germination and radicle length of the plant. 5. What can you conclude about the toxicity of the substance you tested? Is this what you expected? Was your hypothesis supported by the data? I concluded that the higher the concentration of the chemical, the smaller the radicle length will be and the less likely the seed will be to germinate. This was exactly what I hypothesized at the start of the lab 6. Based on this experiment, would you say that radish seed germination or root length would provide a useful bioassay for water samples from the environment? Why or why not? I think the radicle length would provide a more useful bioassay as it is more sensitive to the concentration of the chemical. 7. If you were going to repeat this experiment, what would you do differently? How might you improve the experimental design to reduce the variability of your data or lead to more reliable results? I think I would have paid more attention while writing the data for the lab. I feel as if some of the data was skewed as a result of carelessness while recording my lab data. As for the lab itself, I feel the data might have been a little more reliable had we taken less time to return to the lab. This was not a problem with the lab itself, but due to the blizzard the lab was truncated.