Duckweed Research Paper

9 September 2016

Common duckweed is a plant found floating in compact colonies in ponds, marshes, lakes, and slow moving streams. Duckweed is a very tiny pale green, seed bearing plant (Wang and Messing 2012). Duckweed consists of 1 to 3 fronds, or an oval shaped leave–like structure (Wedge and Burris 1982). These fronds grow no bigger than 10 millimeters and usually serve to attach to other fronds, which create massive thick mats of duckweed (Wedge and Burris 1982).

A small root-like structure, known as a rootlet, hangs below the fronds (Wedge and Burris 1982). Duckweed can spread very quickly and can cover the entire surface of a pond in a short amount of time. The growth of duckweed is common when the water contains high levels of nitrogen and phosphates (Wang and Messing 2012). Small amounts of duckweed will not harm a water source, but large amounts will stop the sunlight from entering the water. This can cause oxygen depletion, which can harm fish and submerged plants (Wang and Messing 2012).

Duckweed Research Paper Essay Example

Studies have found that duckweed is able to survive under several different temperatures. Duckweed is more cold tolerant than other aquatic vascular plants. There are conditions such as seasonal temperature change that can result in a morphological alteration to another form, called turions (Wang and Messing 2012). When the temperature lowers the energy stored in the duckweed during photosynthesis is transferred to starch biosynthesis, causing the starch to gather in turions (Wang and Messing 2012).

Due to the amount of intercellular air space becoming less and starch increases the density of the tissue, the duckweed is able to sink to the base of the water where the organism is still able to live even if the surface of the water freezes (Wang and Messing 2012). When the warm conditions return the duckweed will return to the surface of the water (Wang and Messing 2012). This is an evolved adaption that duckweed has formed to be able to survive in several conditions. Our hypothesis was that the survival of duckweed would be more successful in warmer climates, rather than colder climates.

We generated this hypothesis due based on the fact that duckweed needs sunlight to gain the nutrients it needs to survive, and warmer climates commonly have more sunlight to help the growth and reproduction. Also, duckweed is eaten by birds and ducks, which they then spread to other water sources (Appenroth 2002). This is one of the best ways of spreading duckweed and would be done mostly in warmer areas where the bird and duck populations are the highest. Methods This experiment was conducted on March 14, 3013 inside a laboratory of the Boyd Science Hall at Plymouth State University.

We received the duckweed (Lemna Minor) organisms from Carolina Biological Supply. We then filled three beakers with 200mL of spring water, and then drew a line on each of the beakers where the water level was. Each beaker was labeled with different colored tape to differentiate the beakers. After all beakers were properly filled with water and labeled, we placed 20 duckweed organisms in each of the three beakers. The first beaker was the control and was kept at room temperature, while the second beaker was placed under a florescent light with medium heat, and the third beaker was placed under a florescent light with high heat.

The three beakers were subjected to these conditions for 29 days with 14 repetitions. The data was analyzed through an ANOVA statistical summary. Results There was not a significant difference in the change in the number of living duckweed between different treatments (F = 0. 415; df = 2, 38; P = 0. 664). (Fig 1. ) Figure 1. The mean number of living duckweed found in each temperature. Discussion This experiment did not show any strong evidence that the survival and growth of duckweed is more successful in different temperatures.

The average number of living duckweed actually decreased when subjected to the three different treatments. According to Appenroth (2002), when duckweed is place into lower or higher temperatures, the turion-inducing factor needs proper phosphate levels. Therefore, when we placed the duckweed under the florescent light treatments, the water may not have contained the correct amount of phosphate causing the duckweed to not be able to form into turion. Without being able to use this adaptation, the duckweed will not be able to survive under certain temperatures.

Although the average number of living duckweed did result to be higher when at room temperature, the difference was not significant enough to be conclusive. While our hypothesis was not proven to be correct through this experiment, other studies have found conclusive data on the effects of temperature with duckweed. Appenroth (2002) found that duckweed could survive and have normal growth within 15 to 25 degrees Celsius. Thus, duckweed has a high range of survival under different temperature, but requires the appropriate elements. Multiple factors could have affected the accuracy of the results of this experiment.

If we had more time to conduct the experiment, we could have had the duckweed under the treatments for a longer period of time, which would have given us more precise and accurate answers. This would have made sure the duckweed was being kept at the proper temperature for the entire duration. Along with additional time, the spring water used may have not had the nutrients that duckweed needs to survive. Duckweed thrives off nutrients and grows best when the water contains higher levels of nitrogen and phosphate (Wedge and Burris 1982).

In the future studies should apply the problems that I have stated before. If the duckweed is kept under the treatment for a longer period and is placed in the appropriate nutrient filled water, the experiment could be much more effective on giving a better result. In addition to those corrections, the results could have been broader if the study had a below room temperature treatment. All in all, these additions to the experiment would be very detrimental to the accuracy and understanding of the results.

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