Transpiration

Background All living organisms must carry out a set of basic functions in order to maintain themselves. One of these processes involves the transportation of materials throughout the organism. Therefore, organisms need to exchange materials with the environment, which can be seen on the small scale of cells transporting protein and other materials among one another or on a larger scale such as the water cycle, where water is continuously moving on, above, and below the surface of Earth. In...

Comparing Transpiration Rates of Leaves ExpandTo begin the experiment to measure the transpiration rates of leaves from different plant species, you will first create a tool called a potometer, using a piece of plastic tubing and 5 mL calibrated pipette. To assemble the device, simply attach the rubber tubing to the tip of the pipette. Then, submerge the device into a bucket of water and move the pipette around under the water to fully fill the tube, taking care not to create bubbles. Next, cap...

Comparing Transpiration Rates of Leaves ExpandBefore beginning the experiments, gather leaves from four plant species that represent different ecological strategies, so that you have enough for one set of leaves per student. NOTE: If leaf-bearing plants are not available locally, an alternative is to grow the plant species of interest in the laboratory, or to purchase plants from a gardening store. Next, cut lengths of rubber tubing to make roughly 50 cm sections and place one piece alongside a...

During photosynthesis, plants acquire the necessary carbon dioxide and release the produced oxygen back into the atmosphere. Openings in the epidermis of plant leaves is the site of this exchange of gasses. A single opening is called a stoma—derived from the Greek word for “mouth.” Stomata open and close in response to a variety of environmental cues.Each stoma is flanked by two specialized guard cells that create an opening when these cells take up water. The transport of ions regulates the...

The xylem of vascular plants distributes water and dissolved minerals that are taken up by the roots to the rest of the plant. The cells that transport xylem sap are dead upon maturity, and the movement of xylem sap is a passive process. Tracheids and vessel elements transport xylem sap Tracheary elements are the transport cells of the xylem. They lack cytoplasm and organelles when they are mature and are considered part of the apoplast of the plant because they connect directly with the...