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All questions of Plant Growth and Development for NEET Exam
Plants bend toward the light because -- a)They need light for photosynthesis
- b)They need light for respiration
- c)Light attracts them
- d)Cells on the shaded side elongate more
Correct answer is option 'D'. Can you explain this answer?
Plants bend toward the light because -
a)
They need light for photosynthesis
b)
They need light for respiration
c)
Light attracts them
d)
Cells on the shaded side elongate more
 | Shiksha Academy answered |
For a plant organ to bend in response to a stimulus, differential growth of cells on either side of the organ is required.
Example: For the stem of a plant to bend toward a light source, cells on the shaded side of the stem near the shoot tip must elongate faster than cells on the lighted side.
The natural plant hormones were first isolated from- a)Cotton fruits, spinach leaves and rice plant
- b)Avena coleoptiles, spinach leaves and fungus Gibberella
- c)Human urine and corn germ oil
- d)Human urine and rice plant
Correct answer is option 'C'. Can you explain this answer?
The natural plant hormones were first isolated from
a)
Cotton fruits, spinach leaves and rice plant
b)
Avena coleoptiles, spinach leaves and fungus Gibberella
c)
Human urine and corn germ oil
d)
Human urine and rice plant
 | Preeti Iyer answered |
Auxins were first isolated from human urine. The term auxin is applied to the indole-3-acetic acid (IAA), and to other natural and synthetic compounds having certain growth-regulating properties.
Cytokinins have specific effects on cytokinesis and were discovered as kinetin from the autoclaved herring sperm DNA.
Kinetin does not occur naturally in plants. Search for natural substances with cytokinin-like activities led to the isolation of zeatin from corn kernels (corn germ oil) and coconut milk.
Kinetin does not occur naturally in plants. Search for natural substances with cytokinin-like activities led to the isolation of zeatin from corn kernels (corn germ oil) and coconut milk.
Hence option C is correct.
Seedless fruits can be obtained by treating the unpollinated ovaries with :-- a)Colchicine
- b)Sucrose solution
- c)Hormones
- d)Pure lanolin
Correct answer is option 'C'. Can you explain this answer?
Seedless fruits can be obtained by treating the unpollinated ovaries with :-
a)
Colchicine
b)
Sucrose solution
c)
Hormones
d)
Pure lanolin
 | Stepway Academy answered |
Seedless fruits like grapes and papaya are called Parthenocarpic fruits. These fruits are developed from unfertilized ovaries.
Plant hormones like auxins induce parthenocarpy.
Example: Tomatoes.
Plant hormones like auxins induce parthenocarpy.
Example: Tomatoes.
Leaf fall occurs when the content of :-- a)Auxin increases
- b)Auxin decreases
- c)Abscisic acid decreases
- d)Gibberellic acid decreases
Correct answer is option 'B'. Can you explain this answer?
Leaf fall occurs when the content of :-
a)
Auxin increases
b)
Auxin decreases
c)
Abscisic acid decreases
d)
Gibberellic acid decreases
 | Rajeev Saxena answered |
Due to a reduction in photosynthesis, this may trigger the abscission of leaves (separation of leaves) and this abscission layer is produced when auxin content falls below a minimum causing leaf or other plant part to fall off.CORRECT OPTION IS B.
Stem elongation is affected by :-- a)Gibberellin and florigen
- b)Auxin and gibberellin
- c)Florigen and kinin
- d)Kinin and auxin
Correct answer is option 'B'. Can you explain this answer?
Stem elongation is affected by :-
a)
Gibberellin and florigen
b)
Auxin and gibberellin
c)
Florigen and kinin
d)
Kinin and auxin
| | Pooja Mehta answered |
Auxins promote stem elongation, inhibit growth of lateral buds (maintains apical dominance). They are produced in the stem, buds, and root tips. Example: Indole Acetic Acid (IA). Auxin is a plant hormone produced in the stem tip that promotes cell elongation.
Gibberellic acid is a simple gibberellin, a pentacyclic diterpene acid promoting growth and elongation of cells. .Gibberellins have a number of effects on plant development. They can stimulate rapid stem and root growth, induce mitotic division in the leaves of some plants, and increase seed germination rate.
Apical dominance means :-- a)Suppression of growth of apical bud by axillary buds
- b)Suppression of growth of axillary buds by the presence of apical bud.
- c)Stimulation of growth of axillary buds by removal of apical bud
- d)Inhibition of growth of axillary buds by removal of apical bud.
Correct answer is option 'B'. Can you explain this answer?
Apical dominance means :-
a)
Suppression of growth of apical bud by axillary buds
b)
Suppression of growth of axillary buds by the presence of apical bud.
c)
Stimulation of growth of axillary buds by removal of apical bud
d)
Inhibition of growth of axillary buds by removal of apical bud.
 | Lalit Yadav answered |
Auxins are generally produced by the growing apices of the stems and roots, from where they migrate to the regions of their action. In most higher plants, the growing apical bud inhibits the growth of the lateral (axillary) buds, a phenomenon called apical dominance.
Auxanometer is meant for measuring -- a)Respiratory activity
- b)Photosynthetic activity
- c)Growth activity
- d)Osmotic pressure
Correct answer is option 'C'. Can you explain this answer?
Auxanometer is meant for measuring -
a)
Respiratory activity
b)
Photosynthetic activity
c)
Growth activity
d)
Osmotic pressure
 | Hansa Sharma answered |
Auxanometer is a simple instrument to measure growth of a plant. Most common type of auxanometer is arc auxanometer, which measures growth as the increase in length of axis. This increase can be caused due to increase in mass of protoplasm (cell division) or simply by absorption of water (increase in length or surface of existing cells).
Auxin inhibits the growth of -- a)Apical bud
- b)Lateral axillary buds
- c)Roots on stem cutting
- d)Parthenocarpic development of fruits
Correct answer is option 'B'. Can you explain this answer?
Auxin inhibits the growth of -
a)
Apical bud
b)
Lateral axillary buds
c)
Roots on stem cutting
d)
Parthenocarpic development of fruits
| | Pooja Shah answered |
The apical bud produces an auxin hormone that inhibits the growth of the lateral buds further down on the stem towards the axillary bud.
In a growing plant, the first phase during the process of growth is -- a)Cell division
- b)Cell enlargement
- c)Cell differentiation
- d)Cell maturation
Correct answer is option 'A'. Can you explain this answer?
In a growing plant, the first phase during the process of growth is -
a)
Cell division
b)
Cell enlargement
c)
Cell differentiation
d)
Cell maturation
| | Pooja Mehta answered |
Phases Of Plant Growth
Meristematic Phase
The cells in the root and shoot apex of a plant are constantly dividing. They represent the meristematic phase of growth. The cells in these regions have large nuclei and are rich in protoplasm and their cell walls are thin and contain cellulose.
Elongation Phase
The cells in the zone just after the meristematic region represent the phase of elongation. The characteristics of cells in this zone are cell enlargement, increased vacuole formation and new cell wall deposition.
Maturation Phase
Just close to the phase of elongation, but away from the apex lies the phase of maturation. The cells in this region reach their maximum size with respect to their protoplasm and cell wall thickening.
Coconut milk contains a cytokinin called ____ which promotes plant growth.- a)Naphthalene acetic acid
- b)Indole-3-acetic acid
- c)Gelatin
- d)Zeatin
Correct answer is option 'D'. Can you explain this answer?
Coconut milk contains a cytokinin called ____ which promotes plant growth.
a)
Naphthalene acetic acid
b)
Indole-3-acetic acid
c)
Gelatin
d)
Zeatin
| | Priya Menon answered |
trans-zeatin riboside is the most abundant type of cytokinin found in coconut water (Table 2). trans-zeatin is normally used to induce plantlet regeneration from callus in plant tissue culture. Based on experimental data, trans-zeatin plays a key role in the G2-M transition of tobacco cells.
Which of the following instrument can be used to record plant growth by seconds ?- a)Arc auxanometer
- b)Arc indicator
- c)Space marker disc
- d)Crescograph
Correct answer is option 'D'. Can you explain this answer?
Which of the following instrument can be used to record plant growth by seconds ?
a)
Arc auxanometer
b)
Arc indicator
c)
Space marker disc
d)
Crescograph
| | Pooja Mehta answered |
Crescograph is a sensitive devise, devised by J.C. Bose. It records primary growth very accurately. It magnifies growth upto 10,000 times giving information of growth per second.
Plants follow different pathways in response to the environment or phases of life to form different kinds of structures. This ability is called:- a)Plasticity
- b)Maturity
- c)Elasticity
- d)Flexibility
Correct answer is option 'A'. Can you explain this answer?
a)
Plasticity
b)
Maturity
c)
Elasticity
d)
Flexibility
 | Shanaya Sengupta answered |
Understanding Plasticity in Plants
Plasticity refers to the ability of plants to adapt their growth and development in response to environmental conditions or internal signals. This adaptability allows plants to optimize their structure and function throughout different life stages.
Key Features of Plasticity
- Environmental Response: Plants can modify their growth patterns, such as root depth or leaf size, depending on factors like light availability, water supply, and nutrient levels. For example, a plant may grow taller in shaded conditions to access more sunlight.
- Developmental Flexibility: During different phases of life, plants can alter their morphology. A seedling may exhibit different traits compared to a mature plant, such as changing from a vegetative to a flowering state in response to seasonal changes.
- Survival Strategy: Plasticity is crucial for survival in dynamic environments. It allows plants to cope with stressors like drought, flooding, and herbivory by changing their growth strategies.
- Evolutionary Advantage: The ability to exhibit plasticity can enhance a plant's fitness by allowing it to thrive in various habitats and conditions, thereby increasing its chances of reproduction and survival.
Conclusion
In summary, plasticity is the remarkable ability of plants to adjust their growth and development according to environmental conditions or life stages. This characteristic is essential for their survival and adaptation, making it a fundamental aspect of plant biology.
Plasticity refers to the ability of plants to adapt their growth and development in response to environmental conditions or internal signals. This adaptability allows plants to optimize their structure and function throughout different life stages.
Key Features of Plasticity
- Environmental Response: Plants can modify their growth patterns, such as root depth or leaf size, depending on factors like light availability, water supply, and nutrient levels. For example, a plant may grow taller in shaded conditions to access more sunlight.
- Developmental Flexibility: During different phases of life, plants can alter their morphology. A seedling may exhibit different traits compared to a mature plant, such as changing from a vegetative to a flowering state in response to seasonal changes.
- Survival Strategy: Plasticity is crucial for survival in dynamic environments. It allows plants to cope with stressors like drought, flooding, and herbivory by changing their growth strategies.
- Evolutionary Advantage: The ability to exhibit plasticity can enhance a plant's fitness by allowing it to thrive in various habitats and conditions, thereby increasing its chances of reproduction and survival.
Conclusion
In summary, plasticity is the remarkable ability of plants to adjust their growth and development according to environmental conditions or life stages. This characteristic is essential for their survival and adaptation, making it a fundamental aspect of plant biology.
Gibberellic acid is a/an:- a)lndole compound
- b)Terpene
- c)Adenine derivative
- d)Carotenoid
Correct answer is option 'B'. Can you explain this answer?
Gibberellic acid is a/an:
a)
lndole compound
b)
Terpene
c)
Adenine derivative
d)
Carotenoid
 | Ashutosh Rane answered |
Terpene
Gibberellic acid is a type of plant hormone known as a terpene. Terpenes are a large and diverse class of organic compounds produced by a variety of plants, particularly conifers and flowering plants. They are often responsible for the characteristic scents of plants and have a wide range of biological functions.
Role of Gibberellic Acid
Gibberellic acid plays a crucial role in plant growth and development. It is involved in various processes such as seed germination, stem elongation, leaf expansion, and flowering. This hormone promotes cell division and cell elongation, leading to overall plant growth and development.
Chemical Structure
Gibberellic acid is a diterpenoid compound with a complex structure. It is derived from the terpene precursor geranylgeranyl pyrophosphate. The unique structure of gibberellic acid allows it to interact with specific receptors in plant cells, triggering various physiological responses.
Applications
Due to its role in promoting plant growth, gibberellic acid is widely used in agriculture. It is used to increase crop yields, improve fruit quality, and promote flowering in ornamental plants. Additionally, gibberellic acid can be applied to induce seed germination and break seed dormancy in certain plant species.
In conclusion, gibberellic acid is a terpene compound that plays a crucial role in regulating plant growth and development. Its unique chemical structure and biological functions make it an important plant hormone with various applications in agriculture and horticulture.
Gibberellic acid is a type of plant hormone known as a terpene. Terpenes are a large and diverse class of organic compounds produced by a variety of plants, particularly conifers and flowering plants. They are often responsible for the characteristic scents of plants and have a wide range of biological functions.
Role of Gibberellic Acid
Gibberellic acid plays a crucial role in plant growth and development. It is involved in various processes such as seed germination, stem elongation, leaf expansion, and flowering. This hormone promotes cell division and cell elongation, leading to overall plant growth and development.
Chemical Structure
Gibberellic acid is a diterpenoid compound with a complex structure. It is derived from the terpene precursor geranylgeranyl pyrophosphate. The unique structure of gibberellic acid allows it to interact with specific receptors in plant cells, triggering various physiological responses.
Applications
Due to its role in promoting plant growth, gibberellic acid is widely used in agriculture. It is used to increase crop yields, improve fruit quality, and promote flowering in ornamental plants. Additionally, gibberellic acid can be applied to induce seed germination and break seed dormancy in certain plant species.
In conclusion, gibberellic acid is a terpene compound that plays a crucial role in regulating plant growth and development. Its unique chemical structure and biological functions make it an important plant hormone with various applications in agriculture and horticulture.
Cytokinin does not help in:- a)Lateral shoot growth
- b)Promoting leaf senescence
- c)Adventitious shoot formation
- d)Overcoming apical dominance
Correct answer is option 'B'. Can you explain this answer?
Cytokinin does not help in:
a)
Lateral shoot growth
b)
Promoting leaf senescence
c)
Adventitious shoot formation
d)
Overcoming apical dominance
 | Bs Academy answered |
- Cytokinin does not help in promoting leaf senescence.
- Cytokinin production slows down the process of senescence. However, the accumulation of sugars during senescence, due to the breakdown of accumulated starch or the preferential export of N2 from the leaf, can block the effect of cytokinin, especially in low light.
- Ethylene is regarded as a multifunctional phytohormone that regulates both growth, and senescence.
- It promotes or inhibits growth and senescence processes depending on its concentration, timing of application, and the plant species.
Which of the following is essential for fruit ripening?- a)Ethylene
- b)Cytokinin
- c)Auxin
- d)Abscisic acid
Correct answer is option 'A'. Can you explain this answer?
Which of the following is essential for fruit ripening?
a)
Ethylene
b)
Cytokinin
c)
Auxin
d)
Abscisic acid
 | Lead Academy answered |
The following are plant growth regulators or phytohormones that control various developmental as well as physiological functions of a plant:
Auxin:
- It helps in cell elongation, growth, and differentiation.
- It is present mainly at the root and shoots apices.
- It is responsible for the phenomenon of apical dominance, where the apical buds inhibit the growth of lateral buds.
- It results in increasing the height of a plant due to apical dominance.
- It can also initiate root growth in stem cuttings.
- It may also promote flowering and prevent early fruit drop.
Cytokinin:
- It is mainly associated with cell division and is present in regions of rapid cell division.
- It helps to overcome apical dominance and promotes lateral shoot growth.
Ethylene:
- It is a gaseous phytohormone produced in the tissues undergoing senescence.
- It helps in fruit ripening and other senescence-related activities.
- It breaks seed and bud dormancy to initiate germination in some species.
- It also induces leaf epinasty under stress conditions.
- The triple response of ethylene includes reducing the rate of elongation, increasing lateral expansion, and swelling of the region below the hook in seedlings.
Abscisic acid:
- As the name suggests, it helps in abscission and dormancy.
- It inhibits plant growth, metabolism, and seed germination.
- It also plays an important role in the closure of stomata under stress conditions.
Auxin does not:- a)Help to initiate rooting in stem cuttings
- b)Promote female flowers in cucumbers
- c)Prevent fruit and leaf drop in early stages
- d)Promote abscission of older mature leaves and fruits
Correct answer is option 'B'. Can you explain this answer?
Auxin does not:
a)
Help to initiate rooting in stem cuttings
b)
Promote female flowers in cucumbers
c)
Prevent fruit and leaf drop in early stages
d)
Promote abscission of older mature leaves and fruits
 | Nipuns Institute answered |
They help to initiate rooting in stem cuttings, an application widely used for plant propagation. Auxins promote flowering e.g. in pineapples. They help to prevent fruit and leaf drop at early stages but promote the abscission of older mature leaves and fruits
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