A Comparison of the Effects of Phosphate Concentrations on Population Growth Dynamics of the Duckweed Lemna Minor Grown in Distilled and Spring Water
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Title
A Comparison of the Effects of Phosphate Concentrations on Population Growth Dynamics of the Duckweed Lemna Minor Grown in Distilled and Spring Water
Abstract
In this experiment duckweed Lemna minor was grown for 31 days under controlled laboratory conditions. Duckweed was grown in test tubes as control or treatment groups in the following solvents: spring water, lab-distilled water, or commercial-distilled water. Control groups had no additional phosphate. Treatment groups had phosphate added to make various phosphate concentrations. Five tubes were made for every nutrient condition with three-frond duckweed plants placed into each. The number of fronds was counted throughout the experimental period. Carrying capacity and rmax were calculated to determine growth levels.
Results for spring water showed a significant (P ≤ 0.05) difference in the carrying capacity for 10ppm compared to each treatment group. Carrying capacity followed Liebig’s law of the minimum and r-max Shelford’s law of tolerance. Lab-distilled water showed less growth and lower rmax values compared to spring water. The results showed that 50-100 ppm had a significantly higher (P ≤ 0.05) carrying capacity and r-max compared to 0 ppm. However, trends were not followed while using lab-distilled water. When comparing the controls of each solvent, it was found that lab-distilled water had a significantly lower carrying capacity compared to spring water and commercial-distilled water. It is most likely due to issues with the filtration system or plasticizers from the carboy. These results show the importance of determining phosphate concentrations required for optimal population growth and which concentrations have negative growth effects.
Results for spring water showed a significant (P ≤ 0.05) difference in the carrying capacity for 10ppm compared to each treatment group. Carrying capacity followed Liebig’s law of the minimum and r-max Shelford’s law of tolerance. Lab-distilled water showed less growth and lower rmax values compared to spring water. The results showed that 50-100 ppm had a significantly higher (P ≤ 0.05) carrying capacity and r-max compared to 0 ppm. However, trends were not followed while using lab-distilled water. When comparing the controls of each solvent, it was found that lab-distilled water had a significantly lower carrying capacity compared to spring water and commercial-distilled water. It is most likely due to issues with the filtration system or plasticizers from the carboy. These results show the importance of determining phosphate concentrations required for optimal population growth and which concentrations have negative growth effects.
Creator
Heather McLean
Date
5/1/2022
Contributor
Donald Stearns
Biology
Rights
U.S. and international copyright laws may protect this work. It is provided by Wagner College for scholarly or research purposes only. Commercial use or distribution is not permitted without prior permission of the copyright holder.
Format
application/pdf
Extent
49 pages
Language
eng
Type
text
Identifier
2022_Biology_McLean - Sara Guariglia
Rights Holder
Wagner College, Staten Island, NY
Document Item Type Metadata
Original Format
Thesis
Date Digital
2022
Collection
Citation
Heather McLean, “A Comparison of the Effects of Phosphate Concentrations on Population Growth Dynamics of the Duckweed Lemna Minor Grown in Distilled and Spring Water,” Wagner College Archives and Special Collections, accessed January 22, 2025, https://wagnercollections.omeka.net/items/show/19410.