Green revolution semidwarf wheat varieties are shorter because their mutant DELLA protein is not polyubiquitinated they synthesize more gibberellin (GA) they lack phytochrome they do not take up nitrate

Green revolution semidwarf wheat varieties are shorter because their mutant DELLA protein is not polyubiquitinated they synthesize more gibberellin (GA) they lack phytochrome they do not take up nitrate

Biology (MindTap Course List)

11th Edition

ISBN:9781337392938

Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. Berg

Publisher:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. Berg

Chapter38: Plant Developmental Responses To External And Internal Signals

Section: Chapter Questions

Problem 9TYU

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TCE Uptake by Transgenic Plants Plants used for phytoremediation take up organic pollutants, then transport the chemicals to plant tissues, where they are stored or broken down. Researchers are now designing transgenic plants with enhanced ability to take up or break down toxins. In 2007, Sharon Doty and her colleagues published the results of their efforts to design plants for phytoremediation of soil and air containing organic solvents. The researchers used Agrobacterium tumefaciens (Section 15.7) to deliver a mammalian gene into poplar plants. The gene encodes cytochrome P450, an enzyme involved in the breakdown of a range of organic molecules, including solvents such as TCE. FIGURE 28.16 shows data from one test on the resulting transgenic plants. FIGURE 28.16 TCE uptake from air by transgenic poplar plants. Individual potted plants were kept in separate seated containers with an initial level of TCE (trichloroethylene) around 15,000 micrograms per cubic meter of air. Samples of the air in the containers were taken daily and measured for TCE content. Controls included a tree transgenic for a Ti plasmid with no cytochrome P450 in it (vector control), and a bare-root transgenic tree (one that was not planted in soil. 4. Assuming no other experiments were done, what two explanations are there for the results of this experiment? What other control might the researchers have used?
TCE Uptake by Transgenic Plants Plants used for phytoremediation take up organic pollutants, then transport the chemicals to plant tissues, where they are stored or broken down. Researchers are now designing transgenic plants with enhanced ability to take up or break down toxins. In 2007, Sharon Doty and her colleagues published the results of their efforts to design plants for phytoremediation of soil and air containing organic solvents. The researchers used Agrobacterium tumefaciens (Section 15.7) to deliver a mammalian gene into poplar plants. The gene encodes cytochrome P450, an enzyme involved in the breakdown of a range of organic molecules, including solvents such as TCE. FIGURE 28.16 shows data from one test on the resulting transgenic plants. FIGURE 28.16 TCE uptake from air by transgenic poplar plants. Indvioual potted plants were kept in separate seated containers with an initial level of TCE (trichloroethytene) around 15.0C0 micrograms per cubic meter of air. Samples of the air m the containers were taken daily and measured for TCE content. Controls included a tree transgenic for a Ti plasmid with no cytochrome P450 in it (vector control), and a bare-root transgenic tree (one that was not planted in soil. 1. How many transgenic plants did the researchers test?
TCE Uptake by Transgenic Plants Plants used for phytoremediation take up organic pollutants, then transport the chemicals to plant tissues, where they are stored or broken down. Researchers are now designing transgenic plants with enhanced ability to take up or break down toxins. In 2007, Sharon Doty and her colleagues published the results of their efforts to design plants for phytoremediation of soil and air containing organic solvents. The researchers used Agrobacterium tumefaciens (Section 15.7) to deliver a mammalian gene into poplar plants. The gene encodes cytochrome P450, an enzyme involved in the breakdown of a range of organic molecules, including solvents such as TCE. FIGURE 28.16 shows data from one test on the resulting transgenic plants. FIGURE 28.16 TCE uptake from air by transgenic poplar plants. Indvioual potted plants were kept in separate seated containers with an initial level of TCE (trichloroethytene) around 15.0C0 micrograms per cubic meter of air. Samples of the air m the containers were taken daily and measured for TCE content. Controls included a tree transgenic for a Ti plasmid with no cytochrome P450 in it (vector control), and a bare-root transgenic tree (one that was not planted in soil. 2. In which group did the researchers see the slowest rate of TCE uptake? The fastest?
Whos the Pollinator? Massonia depressa is a low-growing succulent plant native to the desert of South Africa. The dull-colored flowers of this monocot develop at ground level, have tiny petals, emit a yeasty aroma, and produce a thick, jellylike nectar. These trails led researchers to suspect that desert rodents such as gerbils pollinate this plant. The researchers trapped rodents in areas where M. depressa grows and checked them for pollen (FIGURE 29.7A,B). They also put some plants in wire cages that excluded mammals, but not insects, to see whether fruits and seeds would form in the absence of rodents (FIGURE 29.7C). A The dull petalless, ground-level flower of Massonia depressa are accessible to rodents, who push their heads through the stamens to reach the nectar at the bottom of floral cups. Note the pollen on the gerbils snout. B Evidence of visits to M. depressa by rodents. Mammals allowed access to plants Mammals excluded from plants Percent of plants that set fruit 30.4 4.3 Average number of fruits per pant 1.39 0.47 Average number of seeds per plant 20.0 1.96 C Fruit and seed production of M. depressa with and without visits by mammals. Mammals were excluded from plants by wire cages with openings large enough for insects to pass through. Twenty-three plants were tested in each group. FIGURE 29.7 Testing pollination of M. depressa by rodents. How many rodents were captured? Of these, how many showed some evidence of ingesting M. depressa pollen?
Volatile Secondary Metabolites in Plant Stress Responses In 2007, researchers Casey Delphia, Mark Mescher, and Consuelo De Moraes (pictured at left) published a study on the production of different volatile chemicals by tobacco plants in response to predation by two types of insects: western flower thrips and tobacco budworms. Their results are shown in FIGURE 30.20. Volatile Compound Produced Treatment C T W WT HV HVT Myrcene 0 0 0 0 17 22 -Ocimene 0 433 15 121 4.299 5.315 Linatod 0 0 0 0 125 178 indole 0 0 0 0 74 142 Nicotine 0 0 233 160 390 538 -Etemene 0 0 0 0 90 102 -Caryophyllene 0 100 40 124 3.704 6.166 -Humutene 0 0 0 0 123 209 Sesquiterpene 0 7 0 0 219 268 -Farnesene 0 15 0 0 293 457 Caryophyltene oxide 0 0 0 0 89 166 Total 0 555 288 406 9.423 13.563 FIGURE 30.20 Volatile (airborne) compounds produced by tobacco plants (Nicotiana tabacum) in response to predation by Different inserts. Plants were untreated (C), attacked by thrips (T), mechanically wounded (W). mechanically wounded and attacked by thrips (WT), attacked by budworms (HVJ, or attacked by budworms and thrips (HVTJ. Values are nanograms/day. 3. Which one of the chemicals tested is most likely produced by tobacco plants in a nonspecific response to predation?
Volatile Secondary Metabolites in Plant Stress Responses In 2007, researchers Casey Delphia, Mark Mescher, and Consuelo De Moraes (pictured at left) published a study on the production of different volatile chemicals by tobacco plants in response to predation by two types of insects: western flower thrips and tobacco budworms. Their results are shown in FIGURE 30.20. Volatile Compound Produced Treatment C T W WT HV HVT Myrcene 0 0 0 0 17 22 -Ocimene 0 433 15 121 4.299 5.315 Linatod 0 0 0 0 125 178 indole 0 0 0 0 74 142 Nicotine 0 0 233 160 390 538 -Etemene 0 0 0 0 90 102 -Caryophyllene 0 100 40 124 3.704 6.166 -Humutene 0 0 0 0 123 209 Sesquiterpene 0 7 0 0 219 268 -Farnesene 0 15 0 0 293 457 Caryophyltene oxide 0 0 0 0 89 166 Total 0 555 288 406 9.423 13.563 FIGURE 30.20 Volatile (airborne) compounds produced by tobacco plants (Nicotiana tabacum) in response to predation by Different inserts. Plants were untreated (C), attacked by thrips (T), mechanically wounded (W). mechanically wounded and attacked by thrips (WT), attacked by budworms (HVJ, or attacked by budworms and thrips (HVTJ. Values are nanograms/day. 4. Are any chemicals produced in response to predation by budworms, but not in response to predation by thrips?
Whos the Pollinator? Massonia depressa is a low-growing succulent plant native to the desert of South Africa. The dull-colored flowers of this monocot develop at ground level, have tiny petals, emit a yeasty aroma, and produce a thick. jellylike nectar. These features led researchers to suspect that desert rodents such as gerbils pollinate this plant. To test their hypothesis, the researchers trapped rodents in areas where M. depressa grows and checked them for pollen. They also put some plants in wire cages that excluded mammals, but not insects, to see whether fruits and seeds would form in the absence of rodents. The results are shown in FIGURE 29.20. A The dull, petalless, ground-level flowers of Massonia depressa are accessible to rodents, who push their heads through the stamens to reach the nectar at the bottom of floral cups. Note the pollen on the gerbils snout. Type of rodent Number caught # With pollen on snout # with pollen in feces Namaqua rock rat A 3 2 Cape spiny mouse 3 2 2 Hairy-footed gerbil A 2 A Cape short-eared gerbil 1 0 1 African pygmy mouse 1 0 0 B Evidence of Visits to M. depressa by rodents. Mammals allowed Mammals excluded access to plants from plants Percent of plants that set fruit 30.4 4.3 Average number of fruits par plant 1.39 0.47 Average number of seeds per plant 20.0 1.95 C Fruit and seed production of M. depressa with and without visits by mammals. Mammals are excluded from plants by wire cages with openings large enough for insects to pass through. Twenty-three plants were tested in each group. FIGURE 29.20 Testing pollination of M. depressa by rodents. 2. Would this evidence alone be sufficient to conclude that rodents are the main pollinators for this plant?
Whos the Pollinator? Massonia depressa is a low-growing succulent plant native to the desert of South Africa. The dull-colored flowers of this monocot develop at ground level, have tiny petals, emit a yeasty aroma, and produce a thick. jellylike nectar. These features led researchers to suspect that desert rodents such as gerbils pollinate this plant. To test their hypothesis, the researchers trapped rodents in areas where M. depressa grows and checked them for pollen. They also put some plants in wire cages that excluded mammals, but not insects, to see whether fruits and seeds would form in the absence of rodents. The results are shown in FIGURE 29.20. A The dull, petalless, ground-level flowers of Massonia depressa are accessible to rodents, who push their heads through the stamens to reach the nectar at the bottom of floral cups. Note the pollen on the gerbils snout. Type of rodent Number caught # With pollen on snout # with pollen in feces Namaqua rock rat A 3 2 Cape spiny mouse 3 2 2 Hairy-footed gerbil A 2 A Cape short-eared gerbil 1 0 1 African pygmy mouse 1 0 0 B Evidence of Visits to M. depressa by rodents. Mammals allowed Mammals excluded access to plants from plants Percent of plants that set fruit 30.4 4.3 Average number of fruits par plant 1.39 0.47 Average number of seeds per plant 20.0 1.95 C Fruit and seed production of M. depressa with and without visits by mammals. Mammals are excluded from plants by wire cages with openings large enough for insects to pass through. Twenty-three plants were tested in each group. FIGURE 29.20 Testing pollination of M. depressa by rodents. 3. How did the average number of seeds produced by caged plants compare with that of control plants?
Whos the Pollinator? Massonia depressa is a low-growing succulent plant native to the desert of South Africa. The dull-colored flowers of this monocot develop at ground level, have tiny petals, emit a yeasty aroma, and produce a thick. jellylike nectar. These features led researchers to suspect that desert rodents such as gerbils pollinate this plant. To test their hypothesis, the researchers trapped rodents in areas where M. depressa grows and checked them for pollen. They also put some plants in wire cages that excluded mammals, but not insects, to see whether fruits and seeds would form in the absence of rodents. The results are shown in FIGURE 29.20. A The dull, petalless, ground-level flowers of Massonia depressa are accessible to rodents, who push their heads through the stamens to reach the nectar at the bottom of floral cups. Note the pollen on the gerbils snout. Type of rodent Number caught # With pollen on snout # with pollen in feces Namaqua rock rat A 3 2 Cape spiny mouse 3 2 2 Hairy-footed gerbil A 2 A Cape short-eared gerbil 1 0 1 African pygmy mouse 1 0 0 B Evidence of Visits to M. depressa by rodents. Mammals allowed Mammals excluded access to plants from plants Percent of plants that set fruit 30.4 4.3 Average number of fruits par plant 1.39 0.47 Average number of seeds per plant 20.0 1.95 C Fruit and seed production of M. depressa with and without visits by mammals. Mammals are excluded from plants by wire cages with openings large enough for insects to pass through. Twenty-three plants were tested in each group. FIGURE 29.20 Testing pollination of M. depressa by rodents. 4. Do these data support the hypothesis that rodents are required for pollination of M. depressa? Why or why not?
Tree rings occur because_____ a. there are droughts during the time the rings form b. environmental conditions influence xylem cell size c. heartwood alternates with sapwood d. periderm replaces epidermis
Photoperiodism, when a plant responds to: A. In order to flower, long day plants need: B. In order to flower, short day planys need:
Which plant are a natural source of dye. It was also cultivated during the British rule.