Limiting Factor How Co2 effects Plant growth and distribution.

Carbon Dioxide is crucial to photosynthesis, and the levels of carbon dioxide determine the rate of photosynthesis. Photosynthesis is a reactions that occurs within the chloroplasts that provides the plant with the glucose and therefore the energy it needs to grow. Plants have a fairly low efficiency using just 2% to 4% of the energy gained by photosynthesis to grow. Light energy 6CO2 + 6H2O C6H12O6 + 6O2

Plants absorb the gases they need through the stoma, which comes from a Greek word meaning mouth. These are pores, present on the underside of leaves, that open to allow the absorption of gases like carbon dioxide and oxygen needed for respiration and photosynthesis. They can open wider and allow more gases through when hit directly with harsh direct sunlight

As more and more ambient carbon dioxide is added the more the rate of reaction increases as shown below, however the rate of reaction is still limited to other limiting factors such as light, temperature or simply the plants enzymes are already all being utilised at this point the rate of photosynthesis plateaus and shows no increase. This can be directly correlated to the growth of the plant See right: A graph to show CO2 levels vs photosynthesis rate. (ppm meaning parts per million.)

Design an experiment to determine the effect of carbon dioxide concentration on the rate of photosynthesis: Introduction Answer Aim/objective: To determine the effect of carbon dioxide concentration on the rate of photosynthesis. Problem statement: What is the effect of carbon dioxide concentration on the rate of photosynthesis?   Hypothesis: When the concentration of carbon dioxide increases, the rate of photosynthesis also increases until the rate becomes constant. Variables Independent: Concentration of carbon dioxide Dependent: The rate of photosynthesis// The number of bubble released per minute Control: Light intensity, temperature/ Size of plant

Design an experiment to determine the effect of carbon dioxide concentration on the rate of photosynthesis: Equipment and materials Equipment (Apparatus & Materials):   Materials: Elodea/Hydrilla Different concentration of sodium bicarbonate Distilled water  Apparatus: Beaker Boiling tube Clip Table lamp Filter funnel

Design an experiment to determine the effect of carbon dioxide concentration on the rate of photosynthesis: Method 1 Technique: Count and record the number of bubbles produced / released in 20 minutes using a stopwatch. Procedure: Diagram of experimental setup with at least 5 functional labels. Fill a boiling tube with 150ml of 1% sodium hydrogen carbonate solution. Fix a paper clip / plasticine to a sprig of aquatic/hydrilla sp. plant. Submerge / put the aquatic plant into the boiling tube containing 1% sodium hydrogen carbonate solution. Put the boiling tube into a water bath at room temperature (20-30°C).  

Design an experiment to determine the effect of carbon dioxide concentration on the rate of photosynthesis: Method 2 Place the boiling tube at distance of 50 cm from a lighted bulb. Put aside the boiling tube for 5 minute (for the aquatic plant to adjust) Start the stopwatch Count the number of bubbles release in 20 minutes. Record the result is a table. Repeat steps 2 until 1 0 using 2%, 3% and 4% of sodium hydrogen carbonate solutions. Calculate the rate of photosynthesis. (Rate of photosynthesis = Number of bubbles/time) Precaution: Count the bubbles only after the rate becomes constant.

Design an experiment to determine the effect of carbon dioxide concentration on the rate of photosynthesis: Conclusion   Data Include the following titles with units: Concentration of sodium hydrogen carbonates solution (%) Number of bubbles released in 20 minutes Rate of photosynthesis (number / minute) Conclusion: When the concentration of carbon dioxide increases, the rate of photosynthesis also increases until the rate becomes constant. Hypothesis accepted.