Introduction: An organism’s response to an external or an internal stimulus is known as its behavior. Plant movement is one of the examples of plant behavior. The plants respond to light, gravity, and sometimes touch. Chemical signals which are transported within the body of a plant are known as plant hormones. Plant hormones are employed to provide a response to a stimulus.
Answer to Problem 1TY
Correct answer: Auxin, cytokinin, and gibberellin are some of the examples of plant hormones. Hence, the correct answer is option c.
Explanation of Solution
Reason for correct answer:
Some of the examples of plant hormones are auxins, cytokinins, gibberellins. Auxins are known as the master plant hormones. They influence the structure, development, and behavior of the plant in many ways. They induce vascular tissue development, mediate phototropism, promote the formation of adventitious roots, establish apical-basal polarity, and stimulate fruit development. The cell division and the aging of the cells are promoted with the help of cytokinins. Seed germination and flowering are promoted with the help of gibberellins.
Option c. is given as “auxin, cytokinin, and gibberellin”.
Auxin, cytokinin, and gibberellin are employed to provide a response to a stimulus, thus referred to as plant hormones. Hence, the correct answer is option c.
Reasons for incorrect answer:
Option a. is given as, “cyclic AMP, IP3, and calcium ions”.
Cyclic AMP, IP3, and calcium ions are examples of secondary messengers that are employed to transmit messages in plant cells. Their primary responsibility is to transmit messages from various receptors and they are not referred to as plant hormones. Hence, option a. is incorrect.
Option b. is given as, “calcium, CDPKs, and DELLA proteins”.
CDPKs are involved in influencing cellular responses and are known as effector molecules. CDPKs turn off transcription of particular genes. DELLA proteins are involved in restricting cell division in the presence of gibberellin. These are not involved in responding to a stimulus, therefore they are not considered as plant hormones. Hence, option b. is incorrect.
Option d. is given as, “cryptochrome, phototropin, and phytochrome”.
Cryptochrome, phototropin, and phytochrome are involved in assisting a plant’s response to light. Cryptochromes are involved in assisting the growth of young seedlings. Plants respond to blue light with the help of phototropin. The receptor absorbing visible light of red and far-red light wavelengths is known as phytochrome. They are light receptors and not plant hormones. Hence, option d. is incorrect.
Option e. is given as, “statoliths, pulvini, and aerenchyma”.
Statoliths assist the root to grow downward by sensing gravity. Pulvini help plant cells in responding to touch. Aerenchyma refers to the spongy tissues that contain air spaces. It is found mainly in aquatic plants. Aerenchyma allows gas exchange and provides buoyancy. Therefore, these are not considered as plant hormones. Hence, option e. is incorrect.
Hence, the options a., b., d., and e. are incorrect.
Thus, auxin, cytokinin, and gibberellin are referred to as plant hormones.
Want to see more full solutions like this?
Chapter 37 Solutions
Biology
- 1, Choose, Which part of the plant is not included in the shoot systems of plants? a, stem b, leaves c, fruit d, roots 2, Choose, Which of the following is not a plant hormone? a, amylase b, auxins c, gibberellins d, cytokininsarrow_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_forwardWhich of the following is false about the phytochrome protein?a. There are two convertible forms.b. It primarly absorbes blue wavelengths of light.c. It is involved in seed germination.d. It is involved in plant sensing of spacing.arrow_forward
- Ethylene respond synergistically with another plant hormone ‘X’ for promoting shedding of leaves, flowers and fruits. The hormone ‘X’ can be used in agriculture for a.Inducing fruit ripening b.Increasing internode elongation c.Reducing requirement of irrigation d.Promoting floweringarrow_forwardWhich of the following is the role of iron in plants? A. endosperm development and dehydrogenase activity B. photodestruction of chlorophyll and chloroplast structure C. energy transferring process for photosynthesis and respiration D. regulatory component of proteins and metabolites in roots and leavesarrow_forwardWhich of the following plant hormones is produced in the root meristems, travel upward and in higher concentration counter the apical dominance caused by ____________? a. Gibberellins b. Ethylene c. Cytokinin d. Abscisic acidarrow_forward
- Gaseous 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_forwardPruning plants can promote lateral stems and increased plant biomass by _____________. Select one: a. suppressing cytokinin transport b. suppressing auxin transport c. promoting cytokinin transport d. promoting auxin transportarrow_forwardSome plant hormones oppose the effect of each other. Auxins and cytokinins for example. Whereas auxins prevent shoots from branching, cytokinins promote the development of branches. What other hormones also exhibit such opposing effects? Explain your answer briefly.arrow_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_forwardWhich of the following may stimulate the growth of the roots in plant cuttings? Select one: a. The use of auxins. b. A decrease in soil minerals. c. A decrease in enzymes. d. The use of endocrine secretions.arrow_forwardElevated levels of this hormone promote seed dormancy? Select one: a. gibberellin b. abscisic acid c. ethylene d. salicyclic acid e. auxinarrow_forward
- Biology (MindTap Course List)BiologyISBN:9781337392938Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. BergPublisher:Cengage Learning