Planting Science Lab Sara, Holly, Garrett

Background  Photosynthesis is the biological conversion of light energy into chemical energy. It occurs in green plants and photosynthetic bacteria through a series of many biochemical reactions (Ensminger).  Photosynthesis requires a lot of sunlight and water to happen. In order to convert water and carbon dioxide into glucose, photosynthesis must take place and oxygen must be given off (“Photosynthesis”).  The equation for photosynthesis is carbon dioxide + water --> glucouse + oxygen.

Purpose  The process of photosynthesis can be evaluated and studied. Different variables will be explored and changed, coming to the conclusion of what factor(s) most effectively help the process of photosynthesis happen more efficiently and adequately.  There are many ways to test the amounts of photosynthesis in a plant. One of the most common ways is the Floating leaf disk assay.  As a group, it was decided that the types of water would be altered and observed for outcomes. Sugar water and salt water became the experimental groups and filtered water was the control group. Our thinking was by adding sugar water to one of the plants, it would provide the needed glucose and make the plants grow faster.  By giving the plant the sugar supplement it needs, our thinking was that the rate of photosynthesis would increase and be productive.  Salt water was our second experimental group, the alternative to sugar water. We predicted little to no growth out of the salt water plant. Although the water will be beneficial, the constant addition of salt will be bad for the plant and potentially dry it out. Because we aren’t expecting growth out of the plant, we also assumed that the rate of photosynthesis will be very slow or not happen at all.  Our controlled plant is Filtered water. We predicted that this plant will grow at an average rate. We assumed that the rate of photosynthesis will be at a constant rate.

Hypotheses  hypothesis #1: If salt-water is added to the plant, then the salt will decrease the rate of photosynthesis. hypothesis #2: If sugared water is added to the plant, then the sugar will increase the rate of photosynthesis.

The Procedure  First we prepped the three solo cups with soil and poked holes at the bottom.  Then we planted 2 basil seeds per cup and labeled salt, sugar, and filtered (control) on the cups.  After that we placed the cups in sunlight and watered the plants with each variable solutions until soil was damp.  Lastly after a month recording our data and observing the plants change in photosynthesis, we conducted the Floating Leaf Disk Assay and recorded the data in the next couple of slides.

Sugar watered plants produced more oxygen than salt and filtered watered plants. P value for sugar: P value for salt:

Limitations & Implications  In our particular experiment, we can only base our results on basil plants.  The data we collected only contributes to the amount of oxygen the basil plants produced by photosynthesis, and the varying amounts by adding sugar water or salt water to the plant.  During our experiment, our group ended up over watering our first trial of plants, and they ended up never grew. After multiple weeks of watering, our sugared plant started to give off an unbearable odder which caused us to move the plants into the green-room where they sat in higher temperatures and larger amounts of sunlight.