Campbell Biology
12th Edition
ISBN: 9780135188743
Author: Urry
Publisher: PEARSON
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Textbook Question
Chapter 39, Problem 6TYU
If a long-day plant has a critical night length of 9 hours, which 24-hour cycle would prevent flowering?
- (A) 16 hours light/8 hours dark
- (B) 14 hours light/10 hours dark
- (C) 4 hours light/8 hours dark/4 hours light/8 hours dark
- (D) 8 hours light/8 hours dark/light flash/8 hours dark
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If a long-day plant has a critical night length of 9 hours, which 24-hour cycle would prevent flowering? (A) 16 hours light/8 hours dark (B) 14 hours light/10 hours dark (C) 4 hours light/8 hours dark/4 hours light/8 hours dark (D) 8 hours light/8 hours dark/light flash/8 hours dark
A short-day plant flowers only when exposed to light for less than 12 hours
long. Which of the following would cause the plant to flower? *
O a 13-hour night and 11-hour day with 1 minute of darkness after 6 hours
a 12-hour day and 12-hour night with a flash of red light
an 8-hour day and 16-hour night with a flash of white light after 8 hours
O a 9-hour night and 15-hour day with 1 minute of darkness after 7 hours
24 hours of continuous light
Next, the researcher wanted to determine if the timing of the flash of ight,
whether It was early or late into the dark perlod, had an affect on the flowering
plants. The researcher exposed Xanthlum strumarlum plants to a cycle of 12
hours light/12 hours dark and exposed the plants to a 10 minute burst of light at
different times within the dark perlod. She recorded the percent of flowering
plants post exposure. The data is in the chart below. 6. What conclusions can you
draw from this data? (You do not need to show a graph, but it may help with your
answer.) *
% of
plants
flowering
Time of burst of
light (from the
beginning of
dark period)
100
86
35
41
10
78
12
95
21
4-
8.
Chapter 39 Solutions
Campbell Biology
Ch. 39.1 - Prob. 1CCCh. 39.1 - Cycloheximide is a drug that inhibits protein...Ch. 39.1 - Prob. 3CCCh. 39.2 - Prob. 1CCCh. 39.2 - WHAT IF? If a plant has the double mutation err...Ch. 39.2 - MAKE CONNECTIONS What type of feedback process is...Ch. 39.3 - If an enzyme in field-grown soybean leaves is most...Ch. 39.3 - WHAT IF? If a plant flowers in a controlled...Ch. 39.3 - Prob. 3CCCh. 39.4 - Prob. 1CC
Ch. 39.4 - Prob. 2CCCh. 39.4 - Prob. 3CCCh. 39.5 - Prob. 1CCCh. 39.5 - Chewing insects mechanically damage plants and...Ch. 39.5 - Many fungal pathogens get food by causing plant...Ch. 39.5 - Prob. 4CCCh. 39 - What are two common ways by which signal...Ch. 39 - Is there any truth to the old adage, "One bad...Ch. 39 - Why did plant physiologists propose the existence...Ch. 39 - Plants that have acclimated to drought stress are...Ch. 39 - Prob. 39.5CRCh. 39 - Prob. 1TYUCh. 39 - Prob. 2TYUCh. 39 - Prob. 3TYUCh. 39 - How may a plant respond to severe heat stress? (A)...Ch. 39 - Level 2: Application/Analysis 5. The signaling...Ch. 39 - If a long-day plant has a critical night length of...Ch. 39 - Prob. 7TYUCh. 39 - DRAW IT Indicate the response to each condition by...Ch. 39 - Level 3: Synthesis/Evaluation 9. EVOLUTION...Ch. 39 - SCIENTIFIC INQUIRY A plant biologist observed a...Ch. 39 - SCIENCE. TECHNOLOGY, AND SOCIETY Describe how our...Ch. 39 - Prob. 12TYUCh. 39 - Prob. 13TYU
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Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biology and related others by exploring similar questions and additional content below.Similar questions
- What is the relationship between light intensity and the rate of photosynthesis. Make a prediction about this relationship, and identify both independent and dependent variables in the prediction. What will be a suitable hypothesis predict answers for the following: A) what is the rate of germinating peas versus non-germinating peas. B) what is the effect of temperature on germinating peas?arrow_forwardPredict whether flowering in a short day plant with a minimum critical length of 14 hours would be expected to occur in the following situations. The plant is exposed to 15 hours of daylight and 9 hours of darkness uninterrupted. The plant is exposed to 9 hours of daylight and 15 hours of darkness. The plant is exposed to 9 hours of daylight and 15 hours of darkness, with 10 minutes exposure to red light in the middle of the night.arrow_forwardThe researcher presented her findings to her colleagues. They noted that this experiment falled to provide evidence to support the length of daylight as the critical perlod responsible for the plant knowing when to flower. What If it was length of night, or the absence of light, that was critical for the flowering of the plant? With this information, she revised her experiment by exposing the plants to a flash of light during the periods of darkness, and a flash of darkness during periods of light. 4. What are the controls in this experiment?* Light Dark Shrs 12hrs 24 hoursarrow_forward
- If a plant flowers in a controlled chamber with a daily cycle of 10 hours of light and 14 hours of darkness, is it a short-day plant? Explain.arrow_forwardPlease answer the following parts: (a) Explain what Florigen is. (b) Explain how the floral stimulus, which originates in the minor veins of source leaves, has its effect in the shoot apical meristem. (c) Describe a classic experiment that demonstrated the existence of Florigen.arrow_forwardOne similarity about the chlorophyll content between the low and moderate light seedlings is: A. Both seedling groups have about the same amount of chlorophyll content for the first 12 hours of growth. B. Both seedling groups have the exact same amount of chlorophyll content for the first 8 hours of growth. C. Both seedling groups have the exact same amount of chlorophyll content for the first 3 to 5 hours of growth. D. Both seedling groups have the exact same amount of chlorophyll content for the last 24 hours of growth.arrow_forward
- Will a long-day plant (LDP) bear flowers after it was subjected to nights interrupted by flashing red light followed by far-red light? *arrow_forwardWe know that short-day plants do not really need short days, but actually long nights. Describe the type of treatment that proves this. Is some kind of light given during the night or some period of darkness given during the day?arrow_forwardA long day plant is given a long night, and is interrupted by a light pulse in the middle of the night. Which quality of the light pulse will most likely prevent flowering? Select one: a. UV light b. green light c. red light d. far-red lightarrow_forward
- Why did plant physiologists propose the existence of a mobile molecule(florigen) that triggers flowering?arrow_forwardWill a long-day plant (LDP) bear flowers after it was subjected to nights interrupted by flashing red light?arrow_forwardTobacco plants invest a lot of resources into the production of secondary compounds know as alkaloids (e.g., nicotine) that we believe act as defenses against herbivores. The researchers did an experiment where they added a hormone that reduces the production of alkaloids. In graph (a), the data show that the hormone reduced the proportion of alkaloids as a function of leaf mass relative to controls- so the hormone worked. They also measured the lifetime seed production of the plants in both treatments without any herbivores present (b). They had the following results. What might you conclude/hypothesize/investigate based on the data in graph (b) (a) Chemical defenses (percent of leaf mass) 1.8% 1.4 1.0 0.6 0.2 No hormone added Hormone added (b) Lifetime seed mass (g/plant) -18 14 10 No hormone added Hormone added It would be good to test whether the hormone is very specific or whether it might also cause changes in other metabolic processes The hormone has no effect on the lifetime…arrow_forward
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