tailieunhanh - Lecture Biology (6e): Chapter 39 - Campbell, Reece

Chapter 39 - Plant responses to internal and external signals. This chapter presents the following content: Signal transduction pathways link internal and environmental signals to cellular responses, research on how plants grow toward light led to the discovery of plant hormones. | CHAPTER 39 PLANT RESPONSES TO INTERNAL AND EXTERNAL SIGNALS Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Section A: Signal Transduction and Plant Responses 1. Signal transduction pathways link internal and environmental signals to cellular responses At every stage in the life of a plant, sensitivity to the environment and coordination of responses are evident. One part of a plant can send signals to other parts. Plants can sense gravity and the direction of light. A plant’s morphology and physiology are constantly tuned to its variable surroundings by complex interactions between environmental stimuli and internal signals. Introduction Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings At the organismal level, plants and animals respond to environmental stimuli by very different means. Animals, being mobile, respond mainly by behavioral mechanisms, moving toward positive stimuli and away from negative stimuli. Rooted in one location for life, a plant generally responds to environmental cues by adjusting its pattern of growth and development. Plants of the same species vary in body form much more than do animals of the same species. At the cellular level, plants and all other eukaryotes are surprisingly similar in their signaling mechanisms. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings All organisms, including plants, have the ability to receive specific environmental and internal signals and respond to them in ways that enhance survival and reproductive success. Like animals, plants have cellular receptors that they use to detect important changes in their environment. These changes may be an increase in the concentration of a growth hormone, an injury from a caterpillar munching on leaves, or a decrease in day length as winter approaches. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings In order for an internal or external stimulus to elicit a physiological . | CHAPTER 39 PLANT RESPONSES TO INTERNAL AND EXTERNAL SIGNALS Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Section A: Signal Transduction and Plant Responses 1. Signal transduction pathways link internal and environmental signals to cellular responses At every stage in the life of a plant, sensitivity to the environment and coordination of responses are evident. One part of a plant can send signals to other parts. Plants can sense gravity and the direction of light. A plant’s morphology and physiology are constantly tuned to its variable surroundings by complex interactions between environmental stimuli and internal signals. Introduction Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings At the organismal level, plants and animals respond to environmental stimuli by very different means. Animals, being mobile, respond mainly by behavioral mechanisms, moving toward positive stimuli and away from negative stimuli. Rooted in one location