Pondweed photosynthesis

For one of the control plants, cover the test tube or glass completely with aluminum foil to block out any light.

Some of the environmental factors that have played an enormous role in the relative fitness of these underwater plant species include light availability, water temperature, pH, and enhancing the uptake of carbon from the environment.

This is a fast growing aquarium plant, which appreciates bright light and an aquarium tank at room temperature. The temperature is too low in the winter. Allow the plants to remain under the lamps until the uncovered control has turned dark blue about hours. Coloured filters can be used, but these will affect light intensity by different amounts depending on the colour.

Curly Leaf Pondweed

Check the weed to see if it is bubbling. Plants can make food by photosynthesis. Some days or even weeks latera disk is cut out of the other Pondweed photosynthesis of the leaf, dried and weighed.

Greg Foot explains the effect of temperature, light intensity and carbon dioxide concentration on the rate of photosynthesis Investigating photosynthesis The effect of light intensity on photosynthesis can be investigated in water plants.

It does, though tend to break apart very easily, and fish may eat it very quickly. Download the resources from the link on the right.

The ground is too soft in the winter. LED lamps produce less heat. Use Cabomba or Elodea, which are sold in aquarium shops. Read a full protocol on how to investigate photosynthesis using pondweed. Make sure that each piece looks healthy and has plenty of green leaves.

In this experiment, the student will place aquatic plants under different colors of light in a solution of bromothymol blue. Egeria densa formerly Elodea densa. To do this, place Cabomba pondweed in an upside down syringe in a water bath connected to a capillary tube you can also use Elodea, but we find Cabomba more reliable.

Elodea Photosynthesis Lab

Why does grass not grow in the winter? Extension activities The volume of oxygen produced could be measured by collecting the gas produced in a gas syringe. Repeat the count five times and record your results. Light intensity or distance of the Elodea from the lamp. This could give a comparison between several plants.

Ceratophyllum demersum hornwort A British native species, suitable for growing in a school pond, or in an indoor tank.


Use coloured acetate filters to investigate the effects of the blue, green and red parts of the spectrum on photosynthesis. Read the full protocol on using immobilsed algae to measure photosynthesis. To maximize light uptake for use in photosynthesis, the leaves of curly leaf pondweed are only a few cells thick with thin membranes.

The changes in the oxygen concentration in the water could be measured using datalogging equipment. Sometimes cutting 2—3 mm off the end of the Elodea will induce bubbling from the cut end or change the size of the bubbles being produced.

Measuring photosynthesis via the production of oxygen Oxygen can be measured by counting bubbles evolved from pondweed, or by using the Audus apparatus to measure the amount of gas evolved over a period of time.

The pondweed should be cut end uppermost. Calculate the average number of bubbles produced per minute.

Aim To investigate the effect of light intensity on the rate of photosynthesis. Naturally, the soil and roots must NOT be in the bag as they respire.Pondweed Simulation. Pondweed or Elodia is an aquatic plant typically used to measure the rate of photosynthesis. Oxygen bubbles are given off by the plant in response to photosynthesis.

Counting the bubbles helps determine the rate of photosynthesis. During photosynthesis, these plants utilize different organic acids to break down carbon dioxide in order to make essential sugars.

Investigating factors affecting the rate of photosynthesis

Curly leaf pondweed must also overcome the difficulty of obtaining carbon from the environment. Practical - Effect of light intensity on photosynthesis in pondweed. Greg Foot explains the effect of temperature, light intensity and carbon dioxide concentration on the rate of.

Dependant variable - the number of oxygen bubbles given off (the rate of photosynthesis). Controlled variables - the size of the pondweed, the volume of water used and its temperature. Risks.

A brief outline of various ways to measure the rate of photosynthesis - including measuring photosynthesis via the uptake of carbon dioxide (e.g. using immobilised algae), via the production of oxygen in pondweed, via the increase in dry mass, and via the production of carbohydrates.

Demonstrating oxygen formation during photosynthesis can be a tricky process. One common way is to gather bubbles of gas given off by an aquatic plant. This teaching resource introduces Cabomba, a pondweed which is much more effective than the traditional Elodea.

Pondweed photosynthesis
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