Duckweed Lab Report

• N. Dirilgen, 1994, Cobalt-copper and Cobalt-zinc effects on duckweed growth and metal accumulation. Different concentrations of Cobalt2+, Zinc2+ and Copper2+ as well as Co2+Cu2+ and Co2+Zn2+ were added to nutrients given to a species of duckweed, Lemna minor L. the effects of these metals on the growth of the duckweed was recorded. A change in growth was not very noticeable until the concentration of Cobalt (Co) and Copper (Cu) reached 2.00 ppm (parts per million), where the growth of the duckweed was inhibited. It was also discovered that Cu and Co work together to inhibit growth when they are at a certain concentration, and at other concentrations, the one would neutralise the other, creating less of an effect on the growth of the duckweed. The conclusion the I took from this study is that as the

They tested to see the effects of different concentrations of NH3 and NH4. They tested the growth of duckweed under different concentrations of ammonium (NH4) and ammonia (NH3). They also tested different pH levels of the ammonia and ammonium that they used. They tested these experiments on Spirodela polyrrhiza. The effect of the ammonia and ammonium was determined by the pH levels, as the pH level lent towards a stronger acid, the duckweed experienced less growth. What also affected the growth was the combination of the ammonium and ammonia at different concentrations. The conclusion that I made of this study was that ammonia and ammonium are duckweeds best source of nitrogen which they need for survival, but in high enough concentrations and with a strong enough acid, the effects the NH3 and NH4 had on the duckweed could be damaging towards its growth. All of the people who were involved with this study have their doctorates in water research, meaning that the results obtained will be accurate and reliable, making this a valid