Tag: plant hormones

Questions Related to plant hormones

Ethylene is involved  in .........................

  1. Aerobic respiration

  2. Anaerobic respiration

  3. Climacteric respiration

  4. Fermentation


Correct Option: C
Explanation:

Ethylene is an important natural plant hormone, used in agriculture to force the ripening of fruits. Binding of ethylene to the receptors unleashes a signaling cascade that leads to activation of transcription factors and the turning on of gene expression. The climacteric is a stage of fruit ripening associated with increased ethylene production and a rise in cellular respiration.

The most efficient precursor of ethylene is ................

  1. Adenine

  2. Thiocarbarnate

  3. Zeatin

  4. Methionine


Correct Option: D
Explanation:

Ethylene is a plant hormone which is present in gaseous form. It is formed by the breakdown of methionine, which is in all cells. Thus, methionine is called as the precursor of ethylene hormone. Ethylene hormones helps in the ripening of fruits when sprayed onto it. Ethylene hormone is present mainly in rapidly dividing cells, which is usually in darkness due to the action of methionine, which is the precursor molecule.

Ethylene is a ............

  1. Gaseous hormone

  2. Largest hormone

  3. Liquid-gas mixture

  4. Solid hormone


Correct Option: A
Explanation:

Ethylene is a gas that forms through the breakdown of methionine, which is in all cells. Ethylene has very limited solubility in water and does not accumulate within the cell but diffuses out of the cell and escapes out of the plant. Its effectiveness as a plant hormone is dependent on its rate of production versus its rate of escaping into the atmosphere. Ethylene is produced at a faster rate in rapidly growing and dividing cells, especially in darkness.

Pine apple can made to flower in off season by the application of ................

  1. Zeatin

  2. Ethylene

  3. Short day

  4. Low temperature


Correct Option: B
Explanation:

Ethylene is a simple gaseous PGR. It is synthesised in large amounts by tissues undergoing senescence and ripening fruits. Ethylene is used to initiate flowering and for synchronising fruit-set in pineapples. It also induces flowering in mango. Since ethylene regulates so many physiological processes, it is one of the most widely used PGR in agriculture. The most widely used compound as source of ethylene is ethephon. Ethephon in an aqueous solution is readily absorbed and transported within the plant and releases ethylene slowly. Ethephon hastens fruit ripening in tomatoes and apples and accelerates abscission in flowers and fruits (thinning of cotton, cherry, walnut). It promotes female flowers in cucumbers there by increasing the yield.

Which one of the following is a gaseous plant hormone?

  1. Auxin

  2. Gibberellin

  3. Ethylene

  4. Cytokinin


Correct Option: C
Explanation:

Ethylene is a simple gaseous plant growth regulator (PGR). It is synthesised in large amounts by tissues undergoing senescence and ripening fruits. Influences of ethylene on plants include horizontal growth of seedlings, swelling of the axis and apical hook formation in dicot seedlings. Ethylene promotes senescence and abscission of plant organs especially of leaves and flowers. Ethylene is highly effective in fruit ripening. It enhances the respiration rate during ripening of the fruits. This rise in rate of respiration is called as respiratory climactic.

Thus, the correct answer is option C.

A natural growth regulator is 

  1. Ethylene

  2. NAA

  3. 2, 4-D

  4. Benzyladenine


Correct Option: A
Explanation:

Ethylene is a simple gaseous plant growth regulator. It is synthesised in large amounts by tissues undergoing senescence and ripening fruits. Influences of ethylene on plants include horizontal growth of seedlings, swelling of the axis and apical hook formation in dicot seedlings. Ethylene promotes senescence and abscission of plant organs especially of leaves and flowers. Ethylene is highly effective in fruit ripening. It enhances the respiration rate during ripening of the fruits. This rise in rate of respiration is called as respiratory climactic.

Thus, the correct answer is option A.

Among the following which helps in early ripening of fruits?

  1. Methane

  2. Ethylene

  3. CO$ _{2}$

  4. CO


Correct Option: B
Explanation:

Ethylene is a simple gaseous plant growth regulator. It is synthesised in large amounts by tissues undergoing senescence and ripening fruits. Influences of ethylene on plants include horizontal growth of seedlings, swelling of the axis and apical hook formation in dicot seedlings. Ethylene promotes senescence and abscission of plant organs especially of leaves and flowers. Ethylene is highly effective in fruit ripening. It enhances the respiration rate during ripening of the fruits. This rise in rate of respiration is called as respiratory climactic.

Thus, the correct answer is option B.

Ethylene is used for 

  1. Decrease the senescence

  2. Increase the height of stem

  3. Ripening of fruits

  4. Prevention of leaf fall


Correct Option: C
Explanation:

Ethylene is a simple gaseous plant growth regulator (PGR). It is synthesised in large amounts by tissues undergoing senescence and ripening fruits. Influences of ethylene on plants include horizontal growth of seedlings, swelling of the axis and apical hook formation in dicot seedlings. Ethylene promotes senescence and abscission of plant organs especially of leaves and flowers. Ethylene is highly effective in fruit ripening. It enhances the respiration rate during ripening of the fruits. This rise in rate of respiration is called as respiratory climacteric.

Thus, the correct answer is option C.

Which of the following is used for ripening of fruits?

  1. Auxin

  2. Abscisic acid

  3. Ethylene gas

  4. Cytokinin


Correct Option: C
Explanation:

Ethylene is a simple gaseous plant growth regulator (PGR). It is synthesised in large amounts by tissues undergoing senescence and ripening fruits. Influences of ethylene on plants include horizontal growth of seedlings, swelling of the axis and apical hook formation in dicot seedlings. Ethylene promotes senescence and abscission of plant organs especially of leaves and flowers. Ethylene is highly effective in fruit ripening. It enhances the respiration rate during ripening of the fruits. This rise in rate of respiration is called as respiratory climactic.

Thus, the correct answer is option C.

Which plant hormone causes fruit ripening?

  1. Indole acetic acid

  2. Cytokinin

  3. Ethylene

  4. Gibberellic acid


Correct Option: C
Explanation:

During the early 20th century, scientists observed that the gas ethylene (C$ _2$H$ _4$) has several effects on plant growth, but not until 1934 did they demonstrate that plants produce ethylene. This natural hormone influences many plant processes. Ethylene inhibits cell elongation, promotes seed germination, promotes apical dominance and is involved in plant responses to wounding or invasion by disease causing microorganisms. Ethylene also has a major role in many aspects of senescence, including fruit ripening. As a fruit ripens, it produces ethylene, which triggers an acceleration of the ripening process. This induces the fruit to produce more ethylene, which further accelerates ripening.

Thus, the correct answer is option C.