AP OUTLINE: STRUCTURE AND FUNCTION IN PLANTS WITH EMPHASIS ON ANGIOSPERMS 1. Root, stem, leaf, flower, seed, and fruit 2. Water and mineral absorption and transport 3. Translocation and storage 4. Tropism and photoperiodicity ESSAY QUESTIONS 1959: Considering the respective foles played by the root, stem, and leaf in the life of a dicotyledonous plant, contrast the organization of these three organs. 1960: With regard to photoperiodism in plants discuss: a) one type of plant phenomenon affected; b) the mechanism of the operation of photoperiodism; c) the relative importance of intensity and duration of light; 1961: Discuss the movement of water from the soil through a vascular plant during transpiration with regard to: a) tissues traversed b) processes and forces involved c) environmental factors which are conducive to a high rate of transpiration d) the effects of this process upon the plant 1962: The opening and closing of the stomata are, in part, associated with the changing osmotic relationships existing between the guard cells and the surrounding epidermis and mesophyll. a) Describe the structure of a guard cell and discuss the osmotic relationships that tend to result in stomatal opening. Labeled diagrams may be used as aids in explanation. b) Stomata are usually closed in the dark but tend to open in the light. Describe two possible causes of change in the guard cells or in their environment which result in stomatal opening. 1964: Each of the five leaf structures indicated in the diagram below is related to either the raw materials of, or by-products of, or regulation of the rate of leaf photosynthesis. a) Name the five structures in order. b) Discuss how each may regulate or in some way affect the rate of photosynthesis. 1969: For plants, adaptations to a land environment are different from adaptations to a fresh water environment. Using your knowledge about anatomy, development, and physiology of angiosperms, discuss the problems in a land existence and adaptations of angiosperms that have evolved as solutions to these problems. 1970: Since the days when Charles Darwin and his son Francis initiated an investigation of the phototropic response of stems and of grass coleoptiles, subsequent investigators have added much to our knowledge of this response. Describe the mechanism now proposed to explain phototropism in stems or coleoptiles and one crucial experiment that provided evidence for this mechanism. 1973: Seeds that are randomly positioned when planted in a pot of soil placed on a window sill produce seedlings with downward growing roots and upward growing shoots. Above ground, the shoots are oriented toward light. Describe the physiological mechanisms that occur to produce: a) the downward growth of the roots b) the upward growth of the shoots c) the bending of the shoots toward the light 1974: Individual organisms make short-term adjustments to temporary environmental changes in temperature, moisture, light, or the chemical environment. Choose any one of these environmental factors and describe mechanisms by which plants may adjust to changes in that factor. 1976: Discuss the manner in which water, minerals, and organic compounds are transported in flowering plants. 1978: Discuss the structural and functional adaptations found in higher plants that enable them to conserve water under different environmental conditions. 1979: In relation to plants, describe in detail one way of: a) measuring the rate of transpiration b) measuring the rate of photosynthesis c) separating pigments 1980: In flowering plants, describe in detail the transport of water, carbohydrates, and inorganic solutes (nitrates, for example). Discuss the theories that have been proposed to explain how these substances are transported. 1983: Relate the structure of an angiosperm leaf to each of the following: a) Adaptations for photosynthesis and food storage b) Adaptations for food translocation and water transport c) Specialized adaptations to a desert environment 1984: Define the following plant responses and explain the mechanism of control for each. Cite experimental evidence as part of your discussion. a) Phototropism b) Photoperiodism 1987: Describe the effects of plant hormones on plant growth and development. Design an experiment to demonstrate the effect of one of these plant hormones on plant growth and development. 1988: Trace the pathway in a flowering plant as the water moves from the soil through the tissues of the root, stem, and leaves to the atmosphere. Explain the mechanisms involved in conducting water through these tissues. 1990: Discuss the adaptations that have enabled flowering plants to overcome the following problems associated with life on land. a) The absence of an aquatic environment for reproduction. b) The absence of an aquatic environment to support the plant body c) Dehydration of the plant 1991: A group of students designed an experiment to measure transpiration rates in a particular species of herbaceous plant. Plants were divided into groups and were exposed to the following conditions. Group I - Room conditions (light, low humidity, 200 C, and little air movement) Group II - Room conditions with increased humidity Group III - Room conditions with increased air movement (fan) Group IV - Room conditions with additional light The cumulative water loss due to transpiration of water from each plant was measured at 10-minute intervals for 30 minutes. Water loss was expressed as milliliters of water per square centimeter of leaf surface area. The data for all plants in Group I (room conditions) were averaged. The average cumulative water loss by the plants in Group I is presented in the table below. Average Cumulative Water Loss by the Plants in Group I Time (minutes) Average Cumulative Water Loss (milliliters H2O/centimeter2) 10 3.5 x 10-4 20 7.7 x 10-4 30 10.6 x 10-4 a. Construct and label a graph using the data for Group I. Using the same set of axes, draw and label three additional lines representing the results that you would predict for Groups II, III, and IV. b. Explain how biological and physical processes are responsible for the differences between each of your predictions and the data for Group I. c. Explain how the concept of water potential is used to account for the movement of water from the plant stem to the atmosphere during transpiration. 1995: Angiosperms (flowering plants) and vertebrates obtain nutrients from their environment in different ways: (A) Discuss the type of nutrition and the nutritional requirements of angiosperms and vertebrates. (B) Describe 2 structural adaptations in angiosperms for obtaining nutrients from the environment. Relate structure to function. (C) Interdependence in nature is evident in symbiosis. Explain two symbiotic relationships that aid in nutrient uptake, using examples from angiosperms and/or vertebrates. (Both examples may be angiosperms, both may be vertebrates, or one may be from each group.