. Advanced biology. Biology; Physiology; Reproduction. 204 THE NERVOUS SYSTEM Problem. What is the response of plants to water f Prepare a pocket garden filled with cotton. Plant mustard seeds in a verti- cal line across the middle of it. Water the seeds by moistening the cotton on one side of the garden. Try to keep one part of the cotton always moist and the other part dry. I. A. Describe the growth of the root and of the shoot. A response to water is called hi/drotropism. B. What is the value of hydrotropism to the plant? C. Describe any evidence in the experiment that shows whether gravity
. Advanced biology. Biology; Physiology; Reproduction. 204 THE NERVOUS SYSTEM Problem. What is the response of plants to water f Prepare a pocket garden filled with cotton. Plant mustard seeds in a verti- cal line across the middle of it. Water the seeds by moistening the cotton on one side of the garden. Try to keep one part of the cotton always moist and the other part dry. I. A. Describe the growth of the root and of the shoot. A response to water is called hi/drotropism. B. What is the value of hydrotropism to the plant? C. Describe any evidence in the experiment that shows whether gravity or water is the stronger stimulus. D. If you have ever seen willow trees growing along the bank of a river, describe how hydrotropism tends to affect their growth ? The uses of tropisms. Plants make responses to other stiniuH. The response to cheniicalf^ is chemotropism, response to heat, therviO' tropism, and to touch or contact, thigmotropism. All the activities of living plants and animals involve a series of responses. As we have already learned, the responses of plants are definite for given stimuli. Leaves always grow toward the light, roots grow toward gravity, and stems grow away from gravity. Responses are divided into two kinds of reactions, one toward the force or stimulus, positive tropisms, and the other reactions away from the stimulus, nega- tive tropisms. In general, tro- pisms are protective. Without sunlight, the leaves would not be able to make starch; without the pull of gravity, roots would be unable to anchor the plant in the ground. Tropisms help the or- ganism make the best possible adjustments to its 3lirection Light influences the growth of plants. Most stems and leaves turn toward the light and a large area of leaf surface is Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the
Size: 1176px × 2125px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, booksubje, booksubjectphysiology
