Tag: plant growth and development

Questions Related to plant growth and development

The terminal phase of ageing is called as

senescence senescence and death plant growth plant growth and development biology

  1. Dedifferentiation

  2. Senescence

  3. Abscission

  4. None of the above

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Correct Option: B
Explanation:

Ageing is the result of a sequential switching on and off of certain genes. Ageing results in senescence. Senescence refers to a number of controlled processes which finally culminate in the death of the plant part. The senescence is considered as the last phase in the process of ageing. 

Thus, the correct answer is option B. 

During senescence of a plant.

senescence senescence and death plant growth plant growth and development biology

  1. The plant displays sequential senescence of the leave

  2. Metabolites like carbohydrates, proteins etc. Are transported from young leaves to the aging leaves

  3. Metabolites like carbohydrates, proteins etc. Are transported out of the aging leaves to the young leaves

  4. Secondary plant products accumulate in the tissues are organs during aging

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Correct Option: A

Senescent phase of an organism's life span can be recognised by

senescence senescence and death plant growth plant growth and development biology

  1. Slow metabolism

  2. Cessation of reproduction

  3. Decreased immunity

  4. All of the above

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Correct Option: D
Explanation:
The terminal irreversible stage of ageing is called senesence. This is the last phase of life span, that ultimately leads to death. This phase can be recognised by slow metabolism, cessation of reproduction and decreased immunity.

So, the correct answer is 'All of the above'.

When a plant undergoes senescence, the nutrients may be ____________.

senescence senescence and death plant growth plant growth and development biology

  1. Accumulated

  2. Bound to cell wall

  3. Translocated

  4. None of these

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Correct Option: C
Explanation:

When a plant part undergoes senescence, nutrient resources(minerals and carbohydrates) shift away or are translocated from the senescened part to other parts. In leaves at the time of senescene we observe loss of chlorophyll, RNA and protein, transport of nutrients and then abscission.

Senescence in plants leads into .......... of cells.

senescence senescence and death plant growth plant growth and development biology

  1. Increase in size

  2. Increase in number

  3. Death

  4. Differentiation

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Correct Option: C
Explanation:

Senescence in plants is a process of aging. During process of senescence, cells undergo differentiation. It ultimately leads into the death of cells. 

Thus, the correct answer is option C.

Apical dominance in higher plants is due to 

apical dominance auxins and gibberellins growth and development plant growth and development biology

  1. Enzyme activity

  2. Photoperiodism

  3. Carbohydrate-nitrogen ratio

  4. Balance between auxin and cytokinins

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Correct Option: D
Explanation:

Apical dominance is a phenomenon in which central stem is dominant and lateral stems are suppressed. It is due to plant hormones produced in the tip of the shoot. Auxin hormone is responsible for apical dominance and cytokinin hormone is responsible for breaking the apical dominance. Hence, apical dominance depends on the auxin to cytokinin balance. 

Thus, the correct answer is option D.

Study the following statements and select the correct ones.

apical dominance auxins and gibberellins growth and development plant growth and development biology

  1. Auxin is transported from base to tip in large quantities.

  2. Cells on the dark side expand farther than those on the light side.

  3. Apical dominance can be removed the decapitation

  4. Tropic movements in plants are under the control of gibberellins

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Correct Option: C
Explanation:

Decapitation involves cutting of apical bud in plants. When the apical bud is removed, the source of auxin is removed. Auxin causes apical dominance. Since the auxin concentration is much lower, the lateral buds can now grow. In fact, their growth will be stimulated by a relatively small drop in auxin concentration. Thus, decapitating a shoot will cause it to branch.

So, the correct option is 'Apical dominance can be removed the decapitation'.

Which of the following characterstic is not represented in 'Inheritance of seed characters' like shape and starch grain size in garden pea ?

apical dominance auxins and gibberellins growth and development plant growth and development biology

  1. Dominance

  2. Incomplete dominance

  3. Polygenic inheritance

  4. Pleiotropy

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Correct Option: A

Select the correct one.

apical dominance auxins and gibberellins growth and development plant growth and development biology

  1. Beer produced by distillation of fermented broth

  2. Bottled juices are cleared by protease and pectinase

  3. Methanogens digest cellulose aerobically

  4. Streptokinase is used to lower the blood cholesterol

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Correct Option: B

Which growth hormone is responsible for apical dominance?

apical dominance auxins and gibberellins growth and development plant growth and development biology

  1. Auxin

  2. Cytokinin

  3. Gibberellin

  4. Ethylene

Show answer
Correct Option: A
Explanation:

Auxin exerts profound effects on plants. For example, some plants tend to branch out very little when they grow. Growth in these plants occurs almost exclusively from the apical meristem rather than from axillary buds, which do not develop as long as the terminal bud is present. Such plants are said to exhibit apical dominance, the inhibition of axillary bud growth by the apical meristem. In plants with strong apical dominance, auxin produced in the apical meristem inhibits axillary buds near the apical meristem from developing into actively growing shoots. When the apical meristem is pinched off, the auxin source is removed and axillary buds grow to form branches. Apical dominance is often quickly re-established, however, as one branch begins to inhibit the growth of others.

Thus, the correct answer is option A.