Abscisic acid - class-XI
Description: abscisic acid | |
Number of Questions: 47 | |
Created by: Sanjiv Memon | |
Tags: plants and animal hormones chemical messages for homeostasis chemical coordination in plants biology plants: structure and function |
Which one of the following is produced during stress conditions which leads to closure of stomata?
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Auxin
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ABA
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Cytokinin
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Gibberellin
Abscisic acid is a phytohormone critical for plant growth and development and plays an important role in integrating various stress signals and controlling downstream stress responses. Plants have to adjust ABA levels constantly in response to changing physiological and environmental conditions. ABA causes the closure of stomata. It thus helps in reducing the rate of transpiration.
Which one of the following acids is a derivative of carotenoids?
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Gibberellic acid
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Abscisic acid
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Indole butyric acid
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Indole-3-acetic acid
Abscisic acid is also called as abscism. It is a plant hormone which has carotenoid as precursor. ABA functions in many plant developmental processes, including bud dormancy. ABA is an isoprenoid plant hormone, which is synthesized in the plastidal 2-C-methyl-D-erythritol-4-phosphate (MEP) pathway, unlike the structurally related sesquiterpenes, which are formed from the mevalonic acid-derived precursor farnesyl diphosphate, the C15 backbone of ABA is formed after cleavage of C40 carotenoids in MEP.
Which one is anti transpirant hormones?
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Auxin
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Cytokinin
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Abscisic Acid
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Gibberellin
Abscisic acid is anti-transpirant hormone. It stimulates the closure of stomata in the epidermis and increases the tolerance of plants to various kind of stresses. It is also called stress hormone.
A substance that induces dormancy in seed is
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ABA
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GA
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Thiourea
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Cytokinins
A substance that induces dormancy in seed is ABA. Abscisic acid (ABA), also known as abscisin II and dormin, is an isoprenoid plant hormone. ABA functions in many plant developmental processes, including bud dormancy. It is responsible for seed dormancy by inhibiting cell growth inhibits seed germination.
The hormone produced during adverse environment condition is ...............
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Abscisic acid
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$N^{6}$ - Isopentanyl adenine (CK)
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Dichlorophenoxy acetic acid, (2, 4 - D)
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Gibberellic acid (GA)
Abscisic acid (ABA) was discovered for its role in regulating abscission and dormancy. But like other PGRs, it also has other wide ranging effects on plant growth and development. It acts as a general plant growth inhibitor and an inhibitor of plant metabolism. ABA inhibits seed germination. ABA stimulates the closure of stomata in the epidermis and increases the tolerance of plants to various kinds of stresses.Therefore, it is also called the stress hormone. ABA plays an important role in seed development, maturation and dormancy. By inducing dormancy, ABA helps seeds to withstand desiccation and other factors unfavourable for growth. In most situations, ABA acts as an antagonist to gibberellins.
Which of the following is a stress hormone?
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Benzyl aminopurine
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Dichlorophenoxy acetic acid
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Ethylene
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Abscisic acid
Despite its name, abscisic acid does not induce abscission in most plants. Instead, abscisic acid is involved in a plants response to stress and in seed dormancy, a temporary state of arrested physiological activity. As an environmental stress hormone, abscisic acid particularly promotes changes in plant tissues that are water stressed.
Abscisic acid induces .......................
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Shoot elongation
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Cell elongation and cell wall formation
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Cell division
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Leaf fall and dormancy
In autumn leaf fall occurs, because
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Formation of abscission layer at the base.
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Leaf becomes heavy.
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Leaf does not remain green.
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Of low temperature.
Deciduous plants shed leaves in autumn. The shedding of leaves is a controlled and orderly process preceded by the formation of abscission layer at the base of leaf or fruit.
Hormone produced during leaf fall is
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IAA
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ABA
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Florigen
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Kinetin
Abscisic acid (ABA) was discovered for its role in regulating abscission and dormancy. It is the hormone believed to be responsible for controlled abscission of mature leaves and fruits from plants. But like other PGRs, it also has other wide ranging effects on plant growth and development. It acts as a general plant growth inhibitor and an inhibitor of plant metabolism. ABA inhibits seed germination. ABA stimulates the closure of stomata in the epidermis and increases the tolerance of plants to various kinds of stresses. Therefore, it is also called as the stress hormone.
Phytohormone commonly called as stress hormone is
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Auxin
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Abscissic acid
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Gibberellin
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Cytokinin
Abscisic acid (ABA) was discovered for its role in regulating abscission and dormancy. But like other PGRs, it also has other wide ranging effects on plant growth and development. It acts as a general plant growth inhibitor and an inhibitor of plant metabolism. ABA inhibits seed germination. ABA stimulates the closure of stomata in the epidermis and increases the tolerance of plants to various kinds of stresses. Therefore, it is also called as the stress hormone. ABA plays an important role in seed development, maturation and dormancy. By inducing dormancy, ABA helps seeds to withstand desiccation and other factors unfavourable for growth. In most situations, ABA acts as an antagonist to gibberellins.
Which of the following is produced during water stress condition?
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Cytokinin
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ABA
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Cytochrome
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ATPase
Abscisic acid (ABA) was discovered for its role in regulating abscission and dormancy. But like other PGRs, it also has other wide ranging effects on plant growth and development. It acts as a general plant growth inhibitor and an inhibitor of plant metabolism. ABA inhibits seed germination. ABA stimulates the closure of stomata in the epidermis and increases the tolerance of plants to various kinds of stresses. Therefore, it is also called as the stress hormone. ABA plays an important role in seed development, maturation and dormancy. By inducing dormancy, ABA helps seeds to withstand desiccation and other factors unfavourable for growth. In most situations, ABA acts as an antagonist to gibberellins.
Which of the following is a growth inhibitor hormone?
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Cytokinin
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Gibberellin
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Auxin
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Abscisic acid
The plant hormone that inhibits growth is called as
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Cytokinins
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Gibberellins
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Auxins
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Abscisic acid
Auxin is the plant growth hormone that promotes lengthening and coordinates with other growth hormones to regulate growth; it also causes apical dominance. Cytokinin is the plant growth hormone that promotes cell division in shoot apical meristem and differentiation in root apical meristem. It works antagonistically to auxin to balance the growth with development in the shoot and root apex. Gibberellins are responsible for stem elongation, breaking seed dormancy, mobilization of endosperm reserves as well as regulate sex determination, flower initiation and fruit set. Abscisic acid is a plant growth hormone involved in seed dormancy by suppressing seed germination and growth as well as in responses of plants to stress. This makes option D correct.
Select the wrongly paired one from the following.
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Companion - Helps in the cells tranlocation of phloem
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Antitranspirants - PMA in high concentation increase $CO _2$ and ABA which promote transpiration
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Mineral nutrient - available in both inorganic and organic forms to plants
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Photosynthetically active radiation - 400-700 nm of radiation of sunlight.
Diffusion of CO$ _2$ into the leaf is decreased due to the closure of stomata and reduces the transpiration, which is done by antitranspirants.
The naturally occurring growth inhibitor is
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IAA (indoleacetic acid)
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ABA (abscisic acid)
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NAA (naphthalene acetic acid)
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GA (gibberellic acid)
Which of the following induces dormancy?
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Auxin
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Cytokinin
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Both (A) and (B)
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Abscisic acid
Abscisic acid (ABA) induces dormancy. Robinson and Warming (1964), isolated a substance responsible for dormancy in Acer pseudoplatanus, and named it as dormin. This hormone was similar to abscission It is a naturally occurring hormone that is present in all vascular plants and some mosses but is not present in bacteria, algae fungi and liverworts. This hormone is responsible for dormancy.
In autumn, leaf fall occurs because
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Formation of abscission layer at bases
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Leaf becomes heavy
-
Leaf does not remain green
-
Of low temperature
By the end of summer, the leaves may be damaged by insects, disease or general wear and tear and ready for renewal. They are equipped to self-destruct. At the point where the leaf stem meets twig or branch is an array of cells called the abscission layer. As autumn days shorten, this layer begins to choke off the veins that move water into the leaf and food into the tree. Once the leaf is completely choked off, the layer becomes dry and flakey and, through decomposition, detaches the leaf from the tree.
The following is a naturally occuring growth inhibitors ............
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IAA
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ABA
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NAA
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GA
IAA, NAA - are several forms of auxin hormone which promotes plant growth. At the same time, GA is gibberellic acid which initiates shoot elongation. ABA is abscissic acid which is an inhibiting hormone which causes dormancy and also inhibits the longitudinal growth of plant.
Which of the following is true?
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ABA open stomata.
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ABA and cytiokinin does not effect on stomata.
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ABA open, cytokinin close stomata.
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ABA close and cytokinin open the stomata.
ABA is an inhibiting hormone which helps in the closure of stomata. It thus helps in control of transpiration. Whereas cytokinin promotes the opening of stomatal pore. It also initiates mitotic cell divisions.
Match List I and List II and select the correct option.
List I | List II | ||
---|---|---|---|
A | Auxin | 1 | Herring sperm DNA |
B | Cytokinin | 2 | Inhibitor of growth |
C | Gibberellin | 3 | Apical dominance |
D | Ethylene | 4 | Epinasty |
E | Abscisic acid | 5 | Induces amylase synthesis |
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A- 3, B- 1, C- 5, D- 4, E- 2
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A- 1, B- 2, C- 3, D- 4, E- 5
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A- 5, B- 4, C-2, D- 3, E- 1
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A- 2, B- 3, C- 1, D- 4, E- 5
Auxin plant hormone induces apical dominance. Apical dominance is the growth of the shoot apex of plant. It increases the height of the plant.
Cytokinins were first discovered in 1955 as promoters of cell division in the DNA of Herring sperm. Since, that discovery many different compound with cytokinin activity have been discovered, both natural and synthetic (diphenylurea).
Gibberellin induces the synthesis of $\alpha$-amylase in the aleurone layers. GAs are plant hormones that regulate growth and influence various developmental processes, including stem elongation, germination, dormancy, flowering, sex expression, enzyme induction and leaf and fruit senescence.
Epinasty is the downward bending of a leaf or other plant part, resulting from greater growth of the upper side than of the lower side. Ethylene is the phytohormone which promotes epinastic movement in plants. It also promotes early ripening of fruits.
Which one of the following plant hormones (phytohormone) is known as a stress hormone?
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Gibberellins
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Kinetin
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Auxin
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Abscisic acid
The synthesis of ABA is stimulated by drought, water logging and other adverse environmental condition. Therefore, it is also called as stress hormone. It is also called as 'growth inhibitor hormone', because it causes inhibition of seed germination, flowering and so on.
Abscisic acid treatment results in ..................
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Leaf expansion
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Stem elongation
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Stomatal closure
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Root elongation
One hormone helps in ripening of fruits while the other stimulates closure of stomata. These are respectively ..................
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Abscisic acid and auxin
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Ethylene and abscisic acid
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Anscisic acid and rthylene
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Ethylene and gibberellic acid
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Gibberellic acid and abscisic acid
Ethylene hormone in plants helps in ripening of fruits. Abscisic acid is known for its inhibiting nature in growth. It causes bud dormancy in several plants. It also causes closure of stomata to minimize the loss of water by transpiration.
In the extreme drought condition, which of the following plant hormone is produced, due to which stomata closes?
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ABA
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IAA
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Gibberellin
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Ascorbic acid
ABA is a plant hormone which is inhibiting in nature. It causes the closure of stomata, in order to reduce the rate of transpiration and the loss of water thereby. It is also well known for its dormant activity. ABA promotes early aging in the plant and also inhibits flowering, fruiting, germination, etc.
Match the items in Column I with Column II and choose the correct option.
List I | List II | ||
---|---|---|---|
A | Human urine | 1 | Cytokinin |
B | Gibberella fujikuroi | 2 | Auxin |
C | Herring fish DNA | 3 | Ethylene |
D | Ripening fruits | 4 | Abscisic acid |
E | Aged leaves of plants | 5 | Gibberellins |
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A- 2, B- 5, C- 1, D- 3, E- 4
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A- 1, B- 2, C- 3, D- 4, E- 5
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A- 3, B- 5, C- 1, D- 2, E- 4
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A- 5, B- 2, C- 1, D- 3, E- 4
Human urine - auxin. Human urine commonly shows the presence of Indole acetic acid, compound having similar properties to that of auxin.It was first discovered in 1931 by Kogl and Haagen Smit, five years earlier the discovery of auxins.
Gibberella fujikori - Gibberellin. G.fujikori is a fungal plant pathogen. It causes bakane disease in rice seedlings, by overloading them with the phytohormone; gibberellin as its own metabolic product.
Herring fish DNA - cytokinin. Cytokinins were first discovered in 1955 as promoters of cell division in the DNA of Herring sperm. Since, that discovery many different compound with cytokinin activity have been discovered, both natural and synthetic (diphenyurea).
Ripening fruits - ethylene. Ethylene is the only phytohormone present in gaseous state. It helps in inducing early ripening when sprayed to fruits.
Aged leaves of plants - ABA. Abscissic acid promotes the early aging of leaves, also called as senescence. Aging, dormancy of buds, inducing stomatal closure, inhibiting fruit ripening, etc, are the functions of ABA.
Senescence as an active developmental cellular process in the growth and functioning of a flowering plant, is indicated in
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Annual plants
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Floral parts
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Vessels and tracheid differentiation
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Leaf abscission
An antitranspirant is
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Phenyl mercuric acid
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Abscisic acid
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Salicylic acid
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All the above
Antitranspirants are compounds applied to the leaves of plants to reduce transpiration. Some examples are phenylmercury acetate, abscisic acid (ABA), and aspirin (acetyl salicylic acid). ABA is a well-known antitranspirant.
Thus, the correct answer is an option (D).
Hormone involved in the formation of winter buds is
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GA
-
CK
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ABA
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Ethylene
ABA is Abscisic acid. It is a plant hormone. In formation of winter buds, ABA is produced in terminal buds. It helps the conversion of the apical meristem into a dormant bud.
Which one is not a growth promoter?
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ABA
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GA
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IAA
-
CK
There are various plant hormones which act as growth regulators. Hormones like gibberellic acid (GA), Indoleacetic acid (IAA), a type of auxin, cytokinin (CK) are growth promoter. Hormones like Abscisic Acid (ABA), ethylene are growth inhibitor. These hormones accelerate abscission process.
Abscisic acid causes
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Stomatal closure
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Stem elongation
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Leaf expansion
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Root elongation
It inhibits root elongation, stem elongation and seed germination. It brings out the stomatal closure when soil water is insufficient to keep up with transpiration. It binds to receptor present on the guard cells and hence closes stomata.
Abscisic acid causes
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Seed dormancy
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Apical dominance
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Root initiation
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Phototropism
Abscisic acid is a plant hormone. It is involved in various physiological processes of the plant. It acts as a plant growth inhibitor. It is also called as stress hormone as its concentration increases during stress condition. Under the unfavourable condition, it induces seed dormancy. When favourable condition returns, seed dormancy is broken.
During drought, plants develop hormone
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Indole acetic acid
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Naphthalene acetic acid
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Indolebutyric acid
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Abscisic acid
-
Ethylene
Stress hormone is a hormone produced during adverse environmental conditions. Abscisic acid (ABA) is called as stress hormone. Due to this hormone, plants respond to stresses conditions like cold, drought. It increases the tolerance of plants toward various stresses. It is found in high concentration in roots during drought and later translocated to leaves. It causes stomatal closure during water stress. It also promotes seed dormancy under adverse condition.
Which one is wrongly matched?
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Auxins - to grow
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Gibberellins - Gibberella fujikuroi
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Cytokinins - Herring sperm DNA
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ABA - flowering hormone
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Ethylene - gas hormone
Auxin is a plant hormone that is involved in growth and development of plant. Kinetin, a type of cytokinin was isolated from autoclaved herring sperm DNA by Miller and Skoog. Gibberellin hormone was first isolated from fungus Gibberella fujikuroi. Ethylene is a gaseous hormone which helps in ripening process and hence also called as ripening hormone. ABA is responsible for abscission of leaves, fruits and flowers. Florigen is a flowering hormone that is responsible for flowering in certain plants.
Leaf abscission is brought about by
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Auxin
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Cytokinin
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Gibberellin
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ABA
Leaf abscission is a detachment or fall of older leaves.It occurs at the base of the petiole. During abscission, high synthesize of abscisic acid is observed along with decrease in the concentration of auxin. ABA loosens the cell wall and cells separate which ultimately leads to leaf abscission.
Hormone antagonistic to ABA is
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Gibberellin
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Auxin
-
Ethylene
-
Cytokinin
Abscisic acid is a plant hormone. It causes abscission of leaves. It induces dormancy of seed under unfavorable condition. Gibberellin is a plant hormone that is an antagonist to the abscisic acid hormone. It regulates plant growth. It stimulates stem elongation, germination, flowering. it breaks the seed dormancy and initiates germination process.
Which one demonstrates process associated with abscission of a leaf?
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In the leaf concentration of both auxin and ABA decreases
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In the leaf concentration of both auxin and ABA increases
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Reduction in ABA concentration and increase of auxin concentration in the leaf
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Reduction in concentration of auxin and increase of concentration of ABA in the leaf
Hormone antagonist to gibberellins is
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IAA
-
ABA
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Zeatin
-
Ethylene
Choose the correct answer from the alternatives given.
Which of the following statements is false?
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Auxins and gibberellins promote stem elongation.
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Cytokinins promote cell division but retard leaf ageing
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Abscisic acid promotes water loss and dormancy
-
Ethylene promotes fruit ripening and abscission
ABA helps seeds to withstand desiccation and other factors unfavorable for growth.
Choose the correct answer from the alternatives given.
Which of the following plant hormones is called the stress hormone because it produces dormancy in seeds and buds?
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Abscisic acid
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Auxin
-
Cytokinin
-
Ethylene
Abscisic acid inhibits seed germination and stimulates the closure of stomata in the epidermis and increases the tolerance of plants to various kinds of stresses. Therefore, it is also called the stress hormone.
Choose the correct answer from the alternatives given.
Abscisic acid is derived from
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carotene
-
methionine
-
ethylene
-
amatene
The C15 backbone of ABA is formed after cleavage of C40 Carotenoids.
Seed dormancy is caused by ______________.
-
$C _2H _4$
-
ABA
-
IAA
-
$GA _3$.
Seed dormancy is mainly caused by ABA. Dormancy allows seeds to tolerate desiccation and extremes of temperature better. Due to its action of inducing dormancy in seeds, buds etc. ABA is also called as dormin.
Which one prevents over-ripening of banana and browning of cut fruits?
-
Gibberellic Acid
-
Indole-3 Acetic Acid
-
Ascorbic Acid
-
Abscisic Acid
Lemon juice helps keep the apple from browning, because it is full of ascorbic acid (Vitamin C) and it has a low (acidic) pH level. Ascorbic acid works because oxygen will react with it before it will react with the polyphenol oxidase. However, once the ascorbic acid gets used up, the oxygen will start reacting with the enzyme and browning will occur. Lemon juice's low pH level also helps prevent browning. Polyphenol oxidase works best when the pH level is between 5.0 and 7.0. However, below a pH level of 3.0, the enzyme becomes inactivated. The pH of lemon juice is in the 2.0 range, making it very effective against browning.
Abscisic acid controls
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Cell elogation and cell wall formation
-
Shoot elogation
-
Leaf fall and dormancy
-
Cell division
Abscissic acid regulates abscission (the shedding of leaves, flowers and fruits from the living plant) and dormancy. It acts as general plant growth inhibitor and also inhibit plant metabolism. It inhibits closure of stomata in epidermis, and increase tolerance of plant to various kinds of stresses, and therefore called as stress hormone.
ABA plays an important role in seed development, maturation and dormancy. By inducing dormancy, ABA helps seeds to withstand dessication and other factors favourable for growth.
State whether the following statements are true or false.
Dormancy of winter buds in temperate trees is caused by abscisic acid.
-
True
-
False
Abscisic acid is the hormones also called as stress hormones as they function in stress conditions. They are also known as dormant as they induce dormancy in buds. It mostly induced bud dormancy at the start of the winter season. They are generally growth hormone which inhibits growth normally.
State whether the following statements are true or false.
Dormancy of plants occurs in relation to abscisic acid.
-
True
-
False
Dormancy is the period when the physiological activities of the plant slow down for some time. Abscisic acid is a stress hormone that is responsible for the protection of plants in drought conditions. They are generally growth inhibitors and are also called as dormants. They are mainly responsible for the bud dormancy at the time of winter season and also cause seed dormancy and protect it from desiccation.
Choose the correct answer from the alternatives given.
Which of the following plant hormones is associated with the closure of the stomata in a plant under water stress?
-
Abscisic acid
-
Auxin
-
Cytokinin
-
Ethylene
Abscisic acid inhibits seed germination and stimulates the closure of stomata in the epidermis and increases the tolerance of plants to various kinds of stresses. Therefore, it is also called the stress hormone.
Leaf abscission is caused by
-
ABA
-
cytokinin
-
auxin
-
gibberellin
A plant will abscise apart either to discard a membrane that is no longer necessary, such as a leaf during autumn or a flower following fertilization or for the purpose of reproduction. Most deciduous plants drop their leaves by abscission before winter, whereas evergreen plants continuously abscise their leaves.