Investigation of the effect of salt on the growth of duckweedAbstract
Representatives of the Lemnaceae, the Duckweed family, are well adapted for the use as bioindicators for testing soil and water for toxic substances (L.V, 2002). They have a simple anatomy that multiply rapidly, a significant advantage of this usage (L.V, 2002). Duckweeds are freshwater plants (glycophytes) that do not tolerate high salt conditions (L. T. 2002) Hence, any changes such as the yellowing of leaves and withering of the plant due to sensitivity to change in water condition will more than likely occur throughout the experiment. The growth can also be stunted, quoting from Kirchhoff, H. (2016), an ehow contributor. As such, we have used this information to conduct an experiment to find out whether duckweed are truly effective bioindicators in this prospect of which we have deduced based on the above stated characteristics of the plant. In order to determine the adequacy of using duckweeds as bioindicators, we experimented upon how well duckweed can thrive in waters with different salt concentrations. The results of our experiment indicated that duckweed is indeed an effective bioindicator in the conditions we have conducted our experiment in, as varying amounts of duckweed survived in the various levels of salinity in the water. As the salt concentration in the set-ups rose, the Duckweed also grew less healthily. This could be observed from how the leaves turned yellow and white or pale. For example, in the control set-up (the set-up with 0.00g of sea salt), the duckweed thrived and reproduced healthily, totalling the amount of duckweed in the set-up from 8 to 18. However, for the set-ups with 7.00g of salt dissolved in the water, all of the duckweed were eliminated within six days. The results of the experiment also showed varying amounts of surviving duckweed in the set-ups with 2.00g to 7.00g of salt, therefore also proving that the survival rate of the duckweed can indicate the level of contamination in freshwater. With our positive test results, we can use Duckweed as a bioindicator in water bodies to ensure that the water is safe for consumption. By using the above method, chances of disasters such as the Minamata Disaster in Japan recurring would be reduced. The Minamata Disaster in Japan occurred due to the contamination of water by factory waste that was flushed into the Minamata Bay. The fish in the bay area consumed the mercury that had been flushed into the bay, which in turn poisoned the locals who consumed the fish on a regular basis. This information can be backed by the book written by Tsuda, T., et al.(2009), which showed in a table in the book that many of the patients who had come down with strange body abnormalities had the occupation of fishing with fewer patients that were in other occupations such as farming. Henceforth, duckweed can be utilised by breeding the plants in water samples from the water source, and then comparing the survival rate of the duckweed with the aforementioned chart.