Biology_2007_Virtual_Lab_Answer_Key-1

Lab 19 plant transpiration analysis the answers are

Info icon This preview shows pages 17–19. Sign up to view the full content.

View Full Document Right Arrow Icon
Lab 19: Plant Transpiration Analysis The answers are intended only as samples. Answers also depend on how students completed the lab and on the random data generated by the computer. Note: The four plants to be tested are randomly chosen; therefore, students’ answers will depend on the randomly chosen four plants but should be consistent with the sample answers shown below. The sample answers assume that the following four plants were tested: coleus, arrowhead, devil’s ivy, and dieffenbachia. 1. Describe the process of transpiration in vascular plants. The process in which water evaporates through the stomata in leaves is known as transpiration. In vascular plants, water is absorbed through the roots and carried upward through the stem to the leaves. The force behind this upward movement is capillary action, a force of attraction between molecules that causes liquids to move up narrow tubes, such as those inside a plant’s stem. During photosynthesis, tiny pores on the surface of the leaves, called stomata, open to permit the intake of carbon dioxide and the release of oxygen. Because the stomata must remain open for the exchange of gases, large amounts of water are lost to the environment through evaporation. 2. Describe any experimental controls used in the Investigation. Allowing the plant to transpire under normal conditions (without added heat, light, or
Image of page 17

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
wind) was the experimental control. 3. What environmental factors that you tested increased the rate of transpiration? Was the rate of transpiration increased for all plants tested? Two of the factors (heat and wind) increased the rate of transpiration for all plant species tested. The third environmental condition (light) increased the rate of transpiration for three of the plant species tested (coleus, arrowhead, and devil’s ivy). The rate of transpiration for dieffenbachia actually decreased slightly when light was added. 4. Did any of the environmental factors (heat, light, or wind) increase the transpiration rate more than the others? Why? Yes. Adding wind increased the transpiration rate more than adding light or heat. Wind blowing over the leaves causes water to evaporate from the leaves faster than increased heat or light. 5. Which species of plants that you tested had the highest transpiration rates? Why do you think different species of plants transpire at different rates? Of the plant species tested, dieffenbachia (a large-leaf plant) had the highest transpiration rate under normal environmental conditions and with added wind and light. When heat was added, the arrowhead plant (medium-leaf) transpired the fastest. Coleus (a small-leaf plant) had the lowest transpiration rate under normal environmental conditions and with added light and heat. When wind was added, devil’s ivy (a medium- leaf plant) had the lowest transpiration rate. In nature, different species of plants transpire at different rates because they have adapted to different environmental conditions.
Image of page 18
Image of page 19
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern