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Test your knowledge of the five major classes of plant hormones (auxins, cytokinins, gibberellins, abscisic acid, ethylene) by matching one hormone to each lettered box. (Note that some hormones will match up to more than one box.)
To complete: The given map of the five major classes of plant hormones.
Concept introduction:
Plant hormones are chemical messengers that are produced in trace amounts, but profoundly affect the growth and development of a plant. These include auxins, cytokinins, gibberellins, abscisic acid and ethylene.
The plant hormones perform various functions such as promoting growth, breaking dormancy, mediating fruit ripening and providing tolerance to stress.
Explanation of Solution
Pictorial representation: Fig.1 shows the completed map representing the five major classes of plant hormones.
Fig.1: The five major classes of plant hormones.
(a)
Correct answer: Auxin.
Explanation: Auxins are a group of plant hormones that promotes cell elongation. They are produced by the apical meristems of shoot and root. They promote the growth of root and shoot of the plant. Hence the correct answer is auxin.
(b)
Correct answer: Gibberellins.
Explanation: The gibberellins are a group of plant hormones that stimulate the elongation of stem by promoting cell elongation. Hence the correct answer is gibberellins.
(c)
Correct answer: Auxin.
Explanation: Auxin is produced by the apical bud of the shoot and functions to inhibit the growth of axillary buds, a phenomenon called apical dominance. Hence, the correct answer is auxin.
(d)
Correct answer: cytokinin.
Explanation: The cytokinins are a group of plant hormones that stimulate rapid cell division in roots and shoots of the plant. It also promotes the growth of lateral buds, thereby nullifying the effects of auxin. Hence, the correct answer is cytokinin.
(e)
Correct answer: Auxin.
Explanation: In addition to cell elongation, the auxins also function to retard the abscission of leaves. It also plays a crucial role in nullifying the effects of ethylene. Hence, the correct answer is auxin.
(f)
Correct answer: Ethylene.
Explanation: Ethylene is a gaseous hormone that promotes ripening of fruit and abscission of leaves from trees. Hence, the correct answer is ethylene.
(g)
Correct answer: Gibberellin.
Explanation: The gibberellin is a plant hormone that promotes the germination of seed. It inhibits seed dormancy by nullifying the effects of abscisic acid. Hence the correct answer is gibberellin.
(h)
Correct answer: Abscisic acid.
Explanation: The abscisic acid is a plant hormone that is involved in the stress responses. It inhibits growth, promotes seed dormancy during winter or periods of drought. Hence, the correct answer is abscisic acid.
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Chapter 33 Solutions
Modified Mastering Biology with Pearson eText -- Standalone Access Card -- for Campbell Biology: Concepts & Connections (8th Edition)
- Your concept map must include details about the following topics: types of stimuli plants respond to, 3 stages of cell signaling, 6 major plant hormones Six main types: Auxins, abscisic acid, cytokinins, ethylene gibberellin, and brassinosteroids. and their functions, phytochrome, plant responses to light, statocytes, statoliths, plant responses to gravity, plant responses to touch, plant defenses against herbivores, plant defenses against pathogens (hypersensitive response and systemic acquired resistance)arrow_forwardCan you answer this question, all of the parts please. A. Please explain the phenomenon of apical dominance in plant growth. B. Which plant hormone(s) involved in apical dominance?arrow_forwardExamples of plant hormones includea. cyclic AMP, IP3, and calcium ions.b. calcium, CDPKs, and DELLA proteins.c. auxin, cytokinin, and gibberellin.d. cryptochrome, phototropin, and phytochrome.e. statoliths, pulvini, and aerenchyma.arrow_forward
- Match each hormone to its function or application. NOTE: If none of the options are correct, you MUST select #4for 'none of the above', otherwise it will be graded as incorrect Question 14 options: Auxin Giberellins Cytokinins Ethylene 1. Used in anti-aging skin creams. 2. Ripens fruit. 3. Causes stems to bend towards the light. 4. None of the abovearrow_forwardPlease type the answer to all parts of this question Answer the following question about the Quiescent Center (QC) of the root meristem. (a) What is the QC of the root meristem? (b) How is QC identity established? (Describe the plant hormone(s) and genes that are involved in QC development)arrow_forwardWhen you prune shrubs to make them “bushier”—that is, to prevent apical dominance—you are affecting the distribution and action of which plant hormone? (a) auxin (b) jasmonic acid (c) salicylic acid (d) ethylene (e) abscisic acidarrow_forward
- • On a commercial scale, enhancing the level of _______ (hormone) can help to speed up fruit ripening. • What measure do fruit producers take to slow down fruit ripening that is caused by natural ethylene?• What is a ‘triple response’. Which plant hormone initiates a triple response? • A change in the ratio of ethylene to auxin controls abscission. In the autumn, the amount of __________ decreases, rendering the cells of the abscission layer more sensitive to __________.arrow_forwardMatch the observation with the main hormones.. ___ ethylene a. Your cabbage plants bolt they form elongated flowering stalks. ___ cytokinin b. The potted plant in your room is leaning toward the window ___ auxin c. Lateral buds are sprouting. ___ gibberellin d. The seeds of your roommates marijuana plant do not germinate no matter what he does to them. ___ abscisic acid e. The last of your apples is getting really mushy ___ nitric oxide f. Your lettuce plants develop brown spots on their leaves.arrow_forwardWhich is the correct pairing of a plant hormone and its function? salicylic acid: triggers synthesis of general defense proteins brassinosteroids: promote responses to environmental stress cytokinins: stimulate stomata to close in water-stressed plants gibberellins: slow seed germination ethylene: promotes formation of lateral rootsarrow_forward
- Phytochrome is a plant pigment protein that mediates plant infection promotes plant growth mediates morphological changes in response to red and far-red light inhibits plant growtharrow_forwardMatch the hormone with the observation. ___ ethylene a. Your cabbage plants form ___ cytokinin elongated flowering stalks. ___ auxin b. The potted plant in your room ___ gibberellin is leaning toward the window. ___ ABA c. The last of your apples is getting ___ nitric oxide really mushy. d. The seeds of your roommate’s marijuana plant do not germinate no matter what he does to them. e. Lateral buds are sprouting. f. Your lettuce plants develop brown spots on their leaves.arrow_forwardGaseous hormones are able to enter cells without requiring specialmembrane transporter. Which of the major plant hormones is adiffusible gas?a. auxin b. gibberellin c. cytokinin d. ethylene e. abscisic acidarrow_forward
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