How Much Oxygen Do Petunias Give Off?

Photosynthesis

• Plants get much of their energy from photosynthesis. The green pigment in a petunia leaf is made by the chlorophyll, which is inside of the chloroplasts. The chlorophyll absorbs the sunlight and harvests carbon dioxide and water from the air. A complex chemical process changes the energy, carbon dioxide and water into plant sugars or carbohydrates and oxygen. The sugars are used to create more complex sugars and a portion is also stored to fuel stages of growth like flowering. The oxygen is released into the air.

Oxygen Equation

• There is a scientific formula for the production of oxygen by plants. It is: 6 carbon dioxide molecules + 6 water molecules give C6H12O6 plus 6 oxygen molecules. The formula, C6H12O6, is the composition of the energy that is made by the conversion process. The photosynthetic process causes two reactions. The first is the light reaction, which requires sun and water to produce oxygen. The second is called the Calvin cycle and uses ATP -- a high energy molecule produced in the light reaction -- and carbon dioxide to produce sugars.

Oxygen Production

• You can make an educated guess on how much oxygen the petunia plant produces each hour. The average leaf can produce 5 ml. of oxygen per hour. If the petunia has 30 leaves it is producing 5 ml./per leaf times 30 leaves or 150 ml. total for the plant per hour. The larger leaves have the capacity to produce a bit more oxygen per hour. Smaller leaves have less surface area and will gather less energy, thus producing less energy per hour.

Educated Guesses

• On average, it is assumed that 80 percent of a plant is water. Of the remaining 20 percent, 40 percent is carbon, so for every 150 grams of plant tissue the petunia makes 32 grams of oxygen. Use the scientific formula to ascertain this. In order to be certain about the amount of oxygen a particular petunia is producing you would have to weigh it, roots and all, to get a gram weight. Then divide the total gram weight by .80 and the remaining amount by .40. This gives you the number of grams of oxygen produced by the petunia.