Plant Primary Productivity Laboratory

Devan O’HaganCassandra MirandaJustin Stanford

Why are we doing this Experiment?

We should see a correlation between mass gain in plants to the formula of photosynthesis.

Why are we doing this Experiment?

If we are to believe photosynthesis and what we know about the carbon cycle then mass gain in plants (net ecosystem production) must occur from carbon in the air being incorporated into the plant (glucose).

Importance of Plants in Ecosystems Plants use the energy from the sun to make

sugars (GPP). Plants then respire and use some of their

sugar to sustain life. It will take the rest of the sugar to make

new molecules or grow bigger. Plants need to start the food chain because

systems will always loose energy due to entropy. Plants take sunlight and convert it into usable energy that can be used by other species.

Why do most plants need soil?

Plants need soil to hold water needed for growth, transport, and photosynthesis in the plant.

Plants need soil to supply nutrients to the plant for molecules like amino acids, cellulose, and DNA.

Hypothesis In this laboratory we wanted to measure

the amount of mass gain in a plant and separate it into mass gain from the air and that of the soil.

If we see that the mass gain in the plant is more than the mass lost to the soil then the rest of the mass gain has to come from the air.

We believe that there will be a significant mass gain in the plant that will come from the air prooving what we have learned about photosynthesis.

What we did.

We dehydrated the soil and took the mass of the seeds, soil, and canister.

We then grew the sunflower, watering when necessary, for the next three weeks.

What we did.

We then seperated the plants from the soil.

We used the dehydrator to remove the water from the plants, soil, and canister.

Took the mass of each. We then compared the results. The data is as seen in table 1.

Table 1: Data TableItem Mass   Before

Seeds 0.4 grams  

Soil 140 grams  

Canister 10 grams  

Sum 150.4 grams  

End

Plant 4.6 grams  

Soil 139.2 grams  

Canister 10 grams  

Sum 153.8 grams  

Results

Mass gain total 3.4 grams  

Mass gain by soil 0.8 grams  

Mass gain by air 2.6 grams  

Graph 1: Mass Gain in Plants

Mass Gain in Plants

0

0.5

1

1.5

2

2.5

3

3.5

4

Mass gain total Mass gain by soil Mass gain by air

Gra

ms

Discussion:

When we looked at the results it is obvious that we had some mass gain in the plant, but we also saw some significant mass lost in the soil with initial mass being 140 grams and final being 139.2, a loss of .8 grams.

We did not expect to see such a high loss from the soil.

Discussion: The mass gain from the air must be

calculated by taking the total mass gain and subtracting the mass lost by the soil.

This results in a mass gain from the air of 2.6 grams.

This follows our hypothesis that there is significant amounts of mass gain from carbon fixation due to photosynthesis.

Conclusion

We saw that there was a mass gain in plants that can be explained by the process of photosynthesis fixing carbon in the air and incorporating it into the plant.

We saw that there is significant mass loss to the soil, this was unexpected.

Future Steps We would definitely do this laboratory

again to verifiy our results. We only accomplished one trial.

We need to compare our results to that of the rest of the class.

We need to compare our results to any research that pertains to this type of test that has been documented by other scientists.

References

www.forbes.com marijuanagrowguide.net jrscience.wcp.muohio.edu rchemistry.wikispaces.com buzzle.com