All Exams >
ACT >
Biology for ACT >
All Questions
All questions of Plant Growth and Development for ACT Exam
Which one of the following is motivative force for growth ?- a)Turgor pressure
- b)Root pressure
- c)Atmospheric pressure
- d)Osmotic pressure
Correct answer is option 'A'. Can you explain this answer?
Which one of the following is motivative force for growth ?
a)
Turgor pressure
b)
Root pressure
c)
Atmospheric pressure
d)
Osmotic pressure
|
Ved Patidar answered |
Turgor pressure is help in cell growth by osmosis.
Primary precursor of I.A.A is :-- a)Phenyl alanine
- b)Tyrosine
- c)Tryptophan
- d)Leucin
Correct answer is option 'C'. Can you explain this answer?
Primary precursor of I.A.A is :-
a)
Phenyl alanine
b)
Tyrosine
c)
Tryptophan
d)
Leucin
|
Mira Joshi answered |
I.A.A. is auxin. The precursor of auxin is tryptophan and Zn.
Presumptive pathways of IAA biosynthesis from tryptophan:
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.
A hormone delaying senescence is
- a)Ethylene
- b)Auxin
- c)Cytokinin
- d)None of the above
Correct answer is option 'C'. Can you explain this answer?
A hormone delaying senescence is
a)
Ethylene
b)
Auxin
c)
Cytokinin
d)
None of the above
|
|
Vasanth Kumar answered |
Giberrlin should be the answer,it also delay senescence
Which one of the following hormone is concerned chiefly with root initiation?- a)IBA
- b)GA3
- c)ABA
- d)Kinetin
Correct answer is option 'A'. Can you explain this answer?
Which one of the following hormone is concerned chiefly with root initiation?
a)
IBA
b)
GA3
c)
ABA
d)
Kinetin
|
Sounak Saini answered |
The correct answer is option 'A' (IBA).
IBA, or Indole-3-butyric acid, is a type of plant hormone known as an auxin. Auxins play a crucial role in various plant growth and development processes, including root initiation.
Here is a detailed explanation:
1. Role of auxins in plant growth and development:
- Auxins are a class of plant hormones that regulate various physiological and developmental processes in plants.
- They are mainly produced in the apical meristems of plants and are transported to different parts of the plant through a process called polar auxin transport.
- Auxins control processes such as cell elongation, root and shoot growth, apical dominance, tropisms (response to directional stimuli), and root initiation.
2. Root initiation and the role of IBA:
- Root initiation refers to the formation of new roots from plant tissues.
- IBA is specifically involved in promoting root initiation and is commonly used as a rooting hormone in horticulture.
- When IBA is applied to plant cuttings or tissue cultures, it stimulates the formation of roots.
- IBA enhances the development of adventitious roots, which are roots that arise from non-root tissues, such as stems or leaves.
- It promotes cell division and elongation in the cells of the cambium or pericycle, leading to the formation of new roots.
3. Other hormones and their role in root initiation:
- While IBA is primarily responsible for root initiation, other plant hormones also play a role in this process.
- Gibberellins (GA3) promote stem elongation and cell division but are not primarily involved in root initiation.
- Abscisic acid (ABA) regulates seed dormancy, stomatal closure, and stress responses in plants but does not have a major role in root initiation.
- Kinetin is a type of cytokinin hormone that promotes cell division and growth, but its role in root initiation is secondary to that of auxins.
In conclusion, IBA is the hormone primarily concerned with root initiation. It promotes the formation of adventitious roots by stimulating cell division and elongation in plant tissues. Other hormones may have some influence on root initiation, but IBA is the key hormone in this process.
IBA, or Indole-3-butyric acid, is a type of plant hormone known as an auxin. Auxins play a crucial role in various plant growth and development processes, including root initiation.
Here is a detailed explanation:
1. Role of auxins in plant growth and development:
- Auxins are a class of plant hormones that regulate various physiological and developmental processes in plants.
- They are mainly produced in the apical meristems of plants and are transported to different parts of the plant through a process called polar auxin transport.
- Auxins control processes such as cell elongation, root and shoot growth, apical dominance, tropisms (response to directional stimuli), and root initiation.
2. Root initiation and the role of IBA:
- Root initiation refers to the formation of new roots from plant tissues.
- IBA is specifically involved in promoting root initiation and is commonly used as a rooting hormone in horticulture.
- When IBA is applied to plant cuttings or tissue cultures, it stimulates the formation of roots.
- IBA enhances the development of adventitious roots, which are roots that arise from non-root tissues, such as stems or leaves.
- It promotes cell division and elongation in the cells of the cambium or pericycle, leading to the formation of new roots.
3. Other hormones and their role in root initiation:
- While IBA is primarily responsible for root initiation, other plant hormones also play a role in this process.
- Gibberellins (GA3) promote stem elongation and cell division but are not primarily involved in root initiation.
- Abscisic acid (ABA) regulates seed dormancy, stomatal closure, and stress responses in plants but does not have a major role in root initiation.
- Kinetin is a type of cytokinin hormone that promotes cell division and growth, but its role in root initiation is secondary to that of auxins.
In conclusion, IBA is the hormone primarily concerned with root initiation. It promotes the formation of adventitious roots by stimulating cell division and elongation in plant tissues. Other hormones may have some influence on root initiation, but IBA is the key hormone in this process.
Which of the following is not natural occuring plant hormone ?a)2,4 - Dichlorophenoxyaceticb)GA2c)Gibberellind)I.A.ACorrect answer is option 'A'. Can you explain this answer?
|
Anjali Iyer answered |
2, 4-D (2, 4 dichlorophenoxy acetic acid) is a artificial auxin.
What is the last stage of a plant called?- a)Senescence
- b)Scarification
- c)Dormancy
- d)Vernalisation
Correct answer is option 'A'. Can you explain this answer?
What is the last stage of a plant called?
a)
Senescence
b)
Scarification
c)
Dormancy
d)
Vernalisation
|
|
Gulzar Ahmad answered |
Of course it is senescence (ageing)....
How many cells per hour does a single maize root apical meristem can give?- a)1,75,000
- b)17,500
- c)175
- d)1,750
Correct answer is option 'B'. Can you explain this answer?
How many cells per hour does a single maize root apical meristem can give?
a)
1,75,000
b)
17,500
c)
175
d)
1,750
|
Geetika Shah answered |
One single maize root apical meristem can give rise to more than 17,500 new cells per hour.
Parthenocarpy is the production of :-- a)Fruits with pollination
- b)Fruits with out fertilization
- c)Seeds with fertilization
- d)Only seeds and no fruits
Correct answer is option 'B'. Can you explain this answer?
Parthenocarpy is the production of :-
a)
Fruits with pollination
b)
Fruits with out fertilization
c)
Seeds with fertilization
d)
Only seeds and no fruits
|
Ruchi Chopra answered |
Parthenocarpy (literally meaning "virgin fruit") is the natural or artificially induced production of fruit without fertilisation of ovules, which makes the fruit seedless. Stenospermocarpy may also produce apparently seedless fruit, but the seeds are actually aborted while they are still small. Parthenocarpy (or stenospermocarpy) occasionally occurs as a mutation in nature; if it affects every flower the plant can no longer sexually reproduce but might be able to propagate by apomixis or by vegetative means.
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.
Geocarpic fruits are produced by- a)Watermelon
- b)Onion
- c)Carrot
- d)Groundnut
Correct answer is option 'D'. Can you explain this answer?
Geocarpic fruits are produced by
a)
Watermelon
b)
Onion
c)
Carrot
d)
Groundnut
|
Lavanya Menon answered |
Geocarpy refers to the ripening of fruits underground, In the case of ground nut, the young fruits are pushed into the soil as a result of post-fertilisation curvature of the stalk.
Native auxin (Endogenous) is transported in the plant- a)From the shoot tip in the downward direction
- b)From the root tip in the upward direction
- c)Through vascular systems in plants
- d)By a special transport system in the root
Correct answer is option 'A'. Can you explain this answer?
Native auxin (Endogenous) is transported in the plant
a)
From the shoot tip in the downward direction
b)
From the root tip in the upward direction
c)
Through vascular systems in plants
d)
By a special transport system in the root
|
|
Riya Banerjee answered |
The term auxin is applied to the indole-3-acetic acid (IAA), and to other natural and synthetic compounds having certain growth regulating properties. They are generally produced by the growing apices of the stems and roots, from where they migrate to the regions of their action. As most important site of auxin synthesis is shoot tips, they frequently migrate in the downward direction.
Thus, the correct answer is option A.
Measurement and the comparison of total growth per unit time is called- a)Arithmetic growth rate
- b)Relative growth rate
- c)Geometric growth rate
- d)Absolute growth rate
Correct answer is option 'D'. Can you explain this answer?
Measurement and the comparison of total growth per unit time is called
a)
Arithmetic growth rate
b)
Relative growth rate
c)
Geometric growth rate
d)
Absolute growth rate
|
Kunal Rane answered |
Absolute and relative growth rates The measurement and the comparison of total growth per unit time is called the absolute growth rate. And the growth of the given system per unit time expressed on a common basis, e.g., per unit initial parameter is called the relative growth rate.
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.
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).
Apical dominance in higher plants is due to -- a)Phyto hormones
- b)Enzymes
- c)Carbohydrates
- d)Photoperiodism
Correct answer is option 'A'. Can you explain this answer?
Apical dominance in higher plants is due to -
a)
Phyto hormones
b)
Enzymes
c)
Carbohydrates
d)
Photoperiodism
|
Anshul Nair answered |
Apical Dominance in higher plants is due to Phytohormones. Phytohormones are naturally occurring organic substances that regulate plant growth and development. They are also known as plant hormones or growth regulators. Phytohormones are synthesized in one part of the plant and transported to other parts where they exert their effects.
Explanation:
1. Definition of Apical Dominance:
Apical dominance is the phenomenon in which the apical bud of a plant inhibits the growth of lateral buds below it. This ensures that the plant grows in a single, upward direction, with a dominant main stem.
2. Role of Phytohormones:
Phytohormones play a crucial role in apical dominance. The apical bud releases a hormone called auxin, which inhibits the growth of lateral buds. Auxin is produced in the apical meristem (the growing tip of the plant) and is transported downwards towards the base of the plant.
3. Mechanism of Phytohormones:
Auxin acts by inhibiting the growth of lateral buds by inducing the production of cytokinins in the roots. Cytokinins are another type of phytohormone that promote cell division and growth. When auxin is transported downwards towards the roots, it induces the production of cytokinins in the roots. These cytokinins are then transported upwards towards the lateral buds, where they promote cell division and growth. However, the concentration of cytokinins is not enough to overcome the inhibitory effect of auxin, so the lateral buds remain dormant.
4. Importance of Apical Dominance:
Apical dominance is an important mechanism for plants because it ensures that the plant grows in a single, upward direction, with a dominant main stem. This is important for plants that need to compete for light and space. By growing upwards, the plant can maximize its exposure to sunlight and outcompete other plants for resources.
Conclusion:
In conclusion, Apical Dominance in higher plants is due to Phytohormones. Auxin is the hormone responsible for inhibiting the growth of lateral buds, while cytokinins promote cell division and growth. The balance between these two hormones ensures that the plant grows in a single, upward direction, with a dominant main stem.
Explanation:
1. Definition of Apical Dominance:
Apical dominance is the phenomenon in which the apical bud of a plant inhibits the growth of lateral buds below it. This ensures that the plant grows in a single, upward direction, with a dominant main stem.
2. Role of Phytohormones:
Phytohormones play a crucial role in apical dominance. The apical bud releases a hormone called auxin, which inhibits the growth of lateral buds. Auxin is produced in the apical meristem (the growing tip of the plant) and is transported downwards towards the base of the plant.
3. Mechanism of Phytohormones:
Auxin acts by inhibiting the growth of lateral buds by inducing the production of cytokinins in the roots. Cytokinins are another type of phytohormone that promote cell division and growth. When auxin is transported downwards towards the roots, it induces the production of cytokinins in the roots. These cytokinins are then transported upwards towards the lateral buds, where they promote cell division and growth. However, the concentration of cytokinins is not enough to overcome the inhibitory effect of auxin, so the lateral buds remain dormant.
4. Importance of Apical Dominance:
Apical dominance is an important mechanism for plants because it ensures that the plant grows in a single, upward direction, with a dominant main stem. This is important for plants that need to compete for light and space. By growing upwards, the plant can maximize its exposure to sunlight and outcompete other plants for resources.
Conclusion:
In conclusion, Apical Dominance in higher plants is due to Phytohormones. Auxin is the hormone responsible for inhibiting the growth of lateral buds, while cytokinins promote cell division and growth. The balance between these two hormones ensures that the plant grows in a single, upward direction, with a dominant main stem.
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.
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.
Substances which originate at the tip of the stem and control growth elsewhere are :- a)Food material
- b)Auxins or hormones
- c)Vitamins
- d)Enzymes
Correct answer is option 'B'. Can you explain this answer?
Substances which originate at the tip of the stem and control growth elsewhere are :
a)
Food material
b)
Auxins or hormones
c)
Vitamins
d)
Enzymes
|
|
Ruchi Chopra answered |
A chemical substance produced in one part of body and regulates the activity of other parts is called as hormones. Plant hormones are produced in the stem, bud and root tips and control the plant growth, formation of flowers, stems, leaves, development, and ripening of fruit, etc. Auxins are specialized hormones which acts on the tip.
Thus, the correct answer is option B.
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
|
|
Pooja Mehta answered |
Seedless fruits like grapes and papaya are called as parthenocarpic fruits. These fruits are developed from unfertilized ovaries. Plant hormones like auxins induce parthenocarpy, e.g., in tomatoes.
Auxin is mainly produced by -- a)Apical root meristem
- b)Root cambium
- c)Apical shoot meristem
- d)Phloem in shoot tip
Correct answer is option 'C'. Can you explain this answer?
Auxin is mainly produced by -
a)
Apical root meristem
b)
Root cambium
c)
Apical shoot meristem
d)
Phloem in shoot tip
|
Dilip Chaurasiya answered |
Auxin is synthesized by shoot apical meristem but later transported to root.
All are extrinsic factors responsible for the development of an organism except- a)Light
- b)Amount of oxygen
- c)Temperature
- d)Hormones
Correct answer is option 'D'. Can you explain this answer?
All are extrinsic factors responsible for the development of an organism except
a)
Light
b)
Amount of oxygen
c)
Temperature
d)
Hormones
|
|
Raghav Bansal answered |
Light, amount of oxygen and temperature are extrinsic factors responsible for the development of an organism but hormones are intrinsic factors.
So the correct option is 'Hormones.'
So the correct option is 'Hormones.'
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.
Which one of the following nutrients is concerned with the growth of the plants in view of their role in synthesis of auxin - [AIPMT 2003]- a)S
- b)Mn
- c)Zn
- d)K
Correct answer is option 'C'. Can you explain this answer?
Which one of the following nutrients is concerned with the growth of the plants in view of their role in synthesis of auxin - [AIPMT 2003]
a)
S
b)
Mn
c)
Zn
d)
K
|
Om Desai answered |
Zinc is an essential micronutrient required for the growth and development of plants. It is involved in the synthesis of indoleacetic acid (IAA), which is a natural auxin.
The function of zinc is to activate the enzyme tryptophan synthetase which is responsible for auxin biosynthesis from tryptophan.
A plant hormone used for inducing morphogenesis in plant tissue culture is- a)Gibberellin
- b)Ethylene
- c)Abscisic acid
- d)Cytokinin
Correct answer is option 'D'. Can you explain this answer?
A plant hormone used for inducing morphogenesis in plant tissue culture is
a)
Gibberellin
b)
Ethylene
c)
Abscisic acid
d)
Cytokinin
|
|
Pooja Mehta answered |
Morphogenesis allows the organism to grow and take its shape by the process of cell division and differentiation.
Cytokinins are the group of plant hormones which promotes cell division and differentiation in root and stem of the plant. It is involved in inducing morphogenesis. Auxin and cytokinin are used in equal quantity in the growth media of callus it promotes shoot and root formation and finally leads to organogenesis.
So, the correct answer is option D.
Indole acetic acid generally inhibits the growth of- a)Roots
- b)Leaves
- c)Shoots
- d)Plants in general
Correct answer is option 'A'. Can you explain this answer?
Indole acetic acid generally inhibits the growth of
a)
Roots
b)
Leaves
c)
Shoots
d)
Plants in general
|
Vijay Bansal answered |
In horticulture, auxins, especially NAA and IBA, are commonly applied to stimulate root initiation when rooting cuttings of plants. However, high concentrations of auxin inhibit root elongation and instead enhance adventitious root formation. Removal of the root tip can lead to inhibition of secondary root formation.
Type of cambium located between phloem and xylem is classified as- a)shoot cambium
- b)root cambium
- c)vascular cambium
- d)cork cambium
Correct answer is option 'C'. Can you explain this answer?
Type of cambium located between phloem and xylem is classified as
a)
shoot cambium
b)
root cambium
c)
vascular cambium
d)
cork cambium
|
|
Ankit Patel answered |
The vascular cambium is a type of cambium located between the phloem and xylem in plants. It is responsible for secondary growth in plants, which results in an increase in girth of the stem or root.
Structure of vascular cambium:
The vascular cambium consists of a single layer of meristematic cells that divide to form secondary xylem cells towards the inside and secondary phloem cells towards the outside.
Function of vascular cambium:
The vascular cambium is responsible for the production of new xylem and phloem cells, which allows for the growth of the plant. It also helps in the transportation of water and nutrients from the roots to the rest of the plant.
Importance of vascular cambium:
The vascular cambium plays a crucial role in the life of a plant as it is responsible for the growth and development of the stem and root. Without the vascular cambium, plants would not be able to grow taller or wider, and they would eventually die.
Conclusion:
The vascular cambium is a vital part of the plant's anatomy as it is responsible for the growth and development of the stem and root. Its role in the production of new xylem and phloem cells is essential for the transportation of water and nutrients throughout the plant.
Structure of vascular cambium:
The vascular cambium consists of a single layer of meristematic cells that divide to form secondary xylem cells towards the inside and secondary phloem cells towards the outside.
Function of vascular cambium:
The vascular cambium is responsible for the production of new xylem and phloem cells, which allows for the growth of the plant. It also helps in the transportation of water and nutrients from the roots to the rest of the plant.
Importance of vascular cambium:
The vascular cambium plays a crucial role in the life of a plant as it is responsible for the growth and development of the stem and root. Without the vascular cambium, plants would not be able to grow taller or wider, and they would eventually die.
Conclusion:
The vascular cambium is a vital part of the plant's anatomy as it is responsible for the growth and development of the stem and root. Its role in the production of new xylem and phloem cells is essential for the transportation of water and nutrients throughout the plant.
Fruit drop is caused by -- a)Less auxin in fruit than in stem
- b)More auxin in fruit than in stem
- c)Equal distribution of auxin in stem and fruit
- d)Absence of auxin in stem and fruit
Correct answer is option 'A'. Can you explain this answer?
Fruit drop is caused by -
a)
Less auxin in fruit than in stem
b)
More auxin in fruit than in stem
c)
Equal distribution of auxin in stem and fruit
d)
Absence of auxin in stem and fruit
|
|
Raza Great answered |
Auxins are an important class of phytohormones. 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. Less auxin in fruit than in stem specially in early stages will lead to premature fruit fall.
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 is a stress hormone?- a)Ethylene
- b)Dichlorophenoxy acetic acid
- c)Benzyl aminopurine
- d)Abscisic acid
Correct answer is option 'D'. Can you explain this answer?
Which is a stress hormone?
a)
Ethylene
b)
Dichlorophenoxy acetic acid
c)
Benzyl aminopurine
d)
Abscisic acid
|
|
Diya Khanna answered |
Stress hormone:
Abscisic acid is a plant hormone that is produced in response to stress conditions like drought, high salinity, and low temperature. It regulates various physiological processes in plants to help them cope with stress.
Functions of Abscisic acid:
1. Closing of stomata: Abscisic acid causes the stomata to close, reducing water loss through transpiration.
2. Seed dormancy: Abscisic acid maintains seed dormancy until the environmental conditions are favorable for germination.
3. Inhibition of shoot growth: Abscisic acid inhibits shoot growth, which helps plants conserve energy during stress conditions.
4. Induction of stress-responsive genes: Abscisic acid induces the expression of stress-responsive genes, which help plants cope with stress conditions.
Conclusion:
Thus, Abscisic acid is a stress hormone that plays a crucial role in helping plants cope with adverse environmental conditions.
Abscisic acid is a plant hormone that is produced in response to stress conditions like drought, high salinity, and low temperature. It regulates various physiological processes in plants to help them cope with stress.
Functions of Abscisic acid:
1. Closing of stomata: Abscisic acid causes the stomata to close, reducing water loss through transpiration.
2. Seed dormancy: Abscisic acid maintains seed dormancy until the environmental conditions are favorable for germination.
3. Inhibition of shoot growth: Abscisic acid inhibits shoot growth, which helps plants conserve energy during stress conditions.
4. Induction of stress-responsive genes: Abscisic acid induces the expression of stress-responsive genes, which help plants cope with stress conditions.
Conclusion:
Thus, Abscisic acid is a stress hormone that plays a crucial role in helping plants cope with adverse environmental conditions.
Which of the growth substance acts as a stimulant during nodule formation in leguminous plant- a)Ethylene
- b)ABA
- c)IAA
- d)Morphactin
Correct answer is option 'C'. Can you explain this answer?
Which of the growth substance acts as a stimulant during nodule formation in leguminous plant
a)
Ethylene
b)
ABA
c)
IAA
d)
Morphactin
|
Dilip Chaurasiya answered |
IAA is actually a type of Auxin hormone so it help in nodule formation.
Coconut milk (coconut water) is widely used in tissue culture because it contains- a)Ethylene
- b)Cytokinin
- c)Auxins
- d)Gibberellins
Correct answer is option 'B'. Can you explain this answer?
Coconut milk (coconut water) is widely used in tissue culture because it contains
a)
Ethylene
b)
Cytokinin
c)
Auxins
d)
Gibberellins
|
|
Geetika Shah answered |
Cytokinins are a group of hormones that promote cell division in plant roots and shoots and the growth of buds. Coconut milk is at times used in some tissue culture medium as it is rich in cytokinins.
Growth is primarily affected by two climatic factors which are ?- a)Light and temperature
- b)Temperature and relative humidity
- c)Light and wind
- d)Rainfall and temperature
Correct answer is option 'A'. Can you explain this answer?
Growth is primarily affected by two climatic factors which are ?
a)
Light and temperature
b)
Temperature and relative humidity
c)
Light and wind
d)
Rainfall and temperature
|
|
Rohan Singh answered |
The climatic factors include rainfall and water, light, temperature, relative humidity, air, and wind. They are abiotic components, including topography and soil, of the environmental factors that influence plant growth and development.
In plants growth is -- a)Restricted to certain regions or structure
- b)Irreversible
- c)Change in size
- d)All the above
Correct answer is option 'D'. Can you explain this answer?
In plants growth is -
a)
Restricted to certain regions or structure
b)
Irreversible
c)
Change in size
d)
All the above
|
|
Rajat Kapoor answered |
The key to plant growth is meristem, a type of plant tissue consisting of undifferentiated cells that can continue to divide and differentiate. Meristem allows plant stems and roots to grow longer (primary growth) and wider (secondary growth).
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.
A student culture a callus from the tobacco pith in sterilized minimal nutritive medium but add more Cytokinin than Auxin. What would develop first from callus- a)Roots
- b)Leaves
- c)Shoots
- d)Buds
Correct answer is option 'C'. Can you explain this answer?
A student culture a callus from the tobacco pith in sterilized minimal nutritive medium but add more Cytokinin than Auxin. What would develop first from callus
a)
Roots
b)
Leaves
c)
Shoots
d)
Buds
|
|
Raza Great answered |
The callus consists of undifferentiated tumor like cells. If the concentration of auxin with respect to that of cytokinin ratio is changed, the cells of the callus undergo transformation to produce organs like roots or shoots. If the level of cytokinin is high as compared to the auxin level, the callus cells undergo transformation and produces shoots.
High concentrations of cytokinin generally inhibit or delay root formation and also prevent root growth. High levels of cytokinin usually causes many small shoots to be produced.
Hence, shoot would develop first from the callus.
High concentrations of cytokinin generally inhibit or delay root formation and also prevent root growth. High levels of cytokinin usually causes many small shoots to be produced.
Hence, shoot would develop first from the callus.
Differentiation of the shoot is controlled by- a)High gibberellin-cytokinin ratio
- b)High auxin-cytokinin ratio
- c)High gibberellin-auxin ratio
- d)High cytokinin-auxin ratio
Correct answer is option 'D'. Can you explain this answer?
Differentiation of the shoot is controlled by
a)
High gibberellin-cytokinin ratio
b)
High auxin-cytokinin ratio
c)
High gibberellin-auxin ratio
d)
High cytokinin-auxin ratio
|
|
Preeti Iyer answered |
High cytokinin to auxin ratio responsible for shoot differentiation.
The xylem which differentiates has a thick secondary wall made of- a)Suberin
- b)Cellulose
- c)Pectin
- d)Lignin
Correct answer is option 'D'. Can you explain this answer?
The xylem which differentiates has a thick secondary wall made of
a)
Suberin
b)
Cellulose
c)
Pectin
d)
Lignin
|
Kritishna Samal answered |
Well the correct answer is 'D'. because as you know xylem is the principle water conducting complex tissue in higher plants . so the water present in the xylem cells will be surely under negative pressure and to just avoid collapsing of walls of xylem cells , lignin is present. liginin is also less hydrophillic then other polysacchrides like cellulose and hemicellulose hence prevents absorption of water by them and allow an efficient pathway for transport of water in xylem.
You forget to add Cytokinin the culture medium, there will be very little growth as Cytokinin is essential for- a)Cell division and cell differentiation
- b)Cell division and cell elongation
- c)Cell maturation and cell expansion
- d)Cell differentiation and cell elongation
Correct answer is option 'A'. Can you explain this answer?
You forget to add Cytokinin the culture medium, there will be very little growth as Cytokinin is essential for
a)
Cell division and cell differentiation
b)
Cell division and cell elongation
c)
Cell maturation and cell expansion
d)
Cell differentiation and cell elongation
|
|
Raza Great answered |
Cytokinin is a plant growth hormone that promotes cell division or cytokinesis in the roots and shoots of the plants. In plant tissue culture, ratio of auxin and cytokinin affects root and shoot formation. If auxin is more then root formation is promoted whereas if cytokinin is more then shoot formation is promoted.
If cytokinin is not added to the culture medium, the plants will not grow as desired. It will decrease the growth of the plant and its differentiation into various parts like shoots, buds, fruits and seeds.
If cytokinin is not added to the culture medium, the plants will not grow as desired. It will decrease the growth of the plant and its differentiation into various parts like shoots, buds, fruits and seeds.
It is the testing of a biological activity like growth response of a substance by employing a living material like plant or plant part.- a)Separation
- b)Fractionalisation
- c)Bioassay
- d)Autopsy
Correct answer is option 'C'. Can you explain this answer?
It is the testing of a biological activity like growth response of a substance by employing a living material like plant or plant part.
a)
Separation
b)
Fractionalisation
c)
Bioassay
d)
Autopsy
|
Swara Desai answered |
Testing of biological activity like growth response of a substance by employing a living material like plant or plant part is called bioassay. It is used to know the effect of substance on plant growth.
Which of the following events are arranged in correct order?- a)Development,differentiation,growth
- b)Differentiation,growth,development
- c)Growth,differentiation,development
- d)Growth,development,differentiation
Correct answer is option 'C'. Can you explain this answer?
Which of the following events are arranged in correct order?
a)
Development,differentiation,growth
b)
Differentiation,growth,development
c)
Growth,differentiation,development
d)
Growth,development,differentiation
|
|
Srushti Jadhav answered |
Differentiation growth development
Gibberellin was discovered from- a)Bacteria
- b)Roots of higher plants
- c)Fungi
- d)Algae
Correct answer is option 'C'. Can you explain this answer?
Gibberellin was discovered from
a)
Bacteria
b)
Roots of higher plants
c)
Fungi
d)
Algae
|
Jeeshan Ahmed answered |
Gibberelin was 1st discovered in japan by kurusowa.He observed from his field that some of rice seedlings had grown much taller than others. on further observations he found that such taller rice plants had shown unusual internodal elongation.The internal elongation is known as bakane or foolish seedling disease of rice.Later it was discovered that elongation was due to a action of substance produced by fungusGibberella fujikuroi.The substance was successfully isolated from the fungus and it was named as gibberelic acid.
A farmer grows cucumber plants in his field. He wants to increase the number of female flowers in them. Which plant hormones can be applied to achieve this?- a)Abscisic acid
- b)Gibberellins
- c)Ethylene
- d)Auxins
Correct answer is option 'C'. Can you explain this answer?
A farmer grows cucumber plants in his field. He wants to increase the number of female flowers in them. Which plant hormones can be applied to achieve this?
a)
Abscisic acid
b)
Gibberellins
c)
Ethylene
d)
Auxins
|
Bhavya Yadav answered |
Ethylene promotes female flowers in cucumbers thereby increasing the yield.
Auxin was isolated from tips of coloeptile of oat seedlings by- a)Miller
- b)F.W.Went
- c)E.Kurosawa
- d)Skoog
Correct answer is option 'B'. Can you explain this answer?
Auxin was isolated from tips of coloeptile of oat seedlings by
a)
Miller
b)
F.W.Went
c)
E.Kurosawa
d)
Skoog
|
|
Naina Bansal answered |
F. W Went first isolated the Auxins in 1928 from the tips of the coleooptiles of oat seedlings. F.W Went was secondly able to isolate a chemical from coleoptile juice.
Chapter doubts & questions for Plant Growth and Development - Biology for ACT 2025 is part of ACT exam preparation. The chapters have been prepared according to the ACT exam syllabus. The Chapter doubts & questions, notes, tests & MCQs are made for ACT 2025 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests here.
Chapter doubts & questions of Plant Growth and Development - Biology for ACT in English & Hindi are available as part of ACT exam.
Download more important topics, notes, lectures and mock test series for ACT Exam by signing up for free.
Biology for ACT
208 videos|226 docs|136 tests
|
Signup to see your scores go up within 7 days!
Study with 1000+ FREE Docs, Videos & Tests
10M+ students study on EduRev
|
© EduRev
|
Education Revolution
|
|
Signup to see your scores
go up within 7 days!
Access 1000+ FREE Docs, Videos and Tests
Takes less than 10 seconds to signup