Tag: plant hormones

Questions Related to plant hormones

If a rotten fruit gets mixed with unripe fruits, the unripe fruits will _____________.

  1. also be rotten

  2. ripe quickly

  3. remain unchanged

  4. none of these.


Correct Option: B
Explanation:

Ethylene production by plants is autocalalytic, i.e., a small amount of ethylene will stimulate production of its larger amounts. Thus, a few ripe fruits will initiate ripening of nearby fruits. It is, therefore, a common practice to keep few ripe bananas with unripe bananas to hasten ripening.

Ethylene promotes senescence and is found in high concentration in ripened fruits.

  1. True

  2. False


Correct Option: A
Explanation:
Often considered an 'aging' hormone due to its role in accelerating such developmental processes as ripening, senescence, and abscission, the plant hormone ethylene also regulates many aspects of growth and development throughout the life cycle of the plant.

So, the correct answer is 'True'.

Artificial ripening of fruits is carried out by

  1. Auxin

  2. Gibberellin

  3. Abscisic acid

  4. Ethylene


Correct Option: D
Explanation:

Ethylene is a small hydrocarbon gas as well as a phytohormone. Some fruit will produce ethylene as ripening begins. Apples and pears are examples of fruit that produce ethylene with ripening. Ethylene is responsible for the changes in texture, softening, color, and other processes involved in ripening. Ethylene gas is used commercially to ripen tomatoes, bananas, pears, and a few other fruits postharvest. 

Which hormone is used to induce ripening in banana?

  1. Cytokinin

  2. Ethylene

  3. ABA

  4. GA$ _{3}$


Correct Option: B
Explanation:

Ehtylene is a simple gaseous plant growth regulator. It is synthesized in large amounts by tissues undergoing senescence and ripening of fruits. It enhances the respiration rate during ripening of fruit. This rise in rate of respiration is called as respiratory climacteric. 
Exposure of plants to ethylene causes drooping of leaves and flowers, a phenomenon known as epinasty.

Thus, the correct answer is option B.

Flowering in Pineapple is promoted by

  1. GA

  2. IAA

  3. Ethylene

  4. Both B and C


Correct Option: D
Explanation:

Flowering in pineapple is not only based on external factors like temperature, daylength but also is based on internal factors like phytohormones. Pineapple flowering can be artificially induced by activity of the ethylene and IAA (indoleacetic acid). During flowering of pineapple, low temperature stimulates ethylene biosynthesis. Other hormones which are involved in initiating pineapple flowering are a-naphthalene acetic acid (NAA), indolbutiric acid (IBA), 2,4-dichlorofenoxiacetic acid (2,4-D). 

Thus, the correct answer is option D.

Ethylene is connected with

  1. Aerobic respiration

  2. Climacteric respiration

  3. Anaerobic respiration

  4. Fermentation


Correct Option: B
Explanation:

Ethylene is a plant hormone. It is also called as ripening hormone as it is responsible for ripening of fruits. Fruit ripening is accompanied by increase rate of respiration. The climacteric respiration occurs during fruit ripening which is associated with increased ethylene production. Due to increased respiration, complex carbohydrates are broken down into simpler sugars and cell wall becomes soft. 

Thus, the correct answer is option B.

Ethylene is metabolic product of

  1. Valine

  2. Serine

  3. Methionine

  4. Glutamic acid


Correct Option: C
Explanation:

Ethylene is a metabolic product of methionine. It is synthesized from methionine amino acid by methionine cycle or yang cycle. Methionine is first converted to adenosylmethionine. It is then converted to Aminocyclopropane carboxylic acid. It is then oxidized to form ethylene. It is a gaseous plant hormone which stimulates ripening of fruits in plants.

Thus, the correct answer is option C.

State whether the following statements are true or false.
Ethylene evolution is highest when the fruit is unripe but diminishes as the fruit matures.

  1. True

  2. False


Correct Option: A
Explanation:

Ethylene is a gaseous hormone that promotes transverse growth but inhibits lateral growth. They are produced by the amino acid methionine. It was found that ripened fruits produce this hormone, so when the ripened fruits are placed together with unripe fruits, the unripe fruits will get ripened due to the release of this gas. Ethylene evolution is highest at the time of ripening but it diminishes when the fruit matures and the evolution of gas got reduced.

So, the correct statement is 'True'.

Choose the correct answer from the alternatives given.
Which of the following plant hormones stimulates the ripening of fruit and inhibits plant growth?

  1. Abscisic acid

  2. Cytokinin

  3. Ethylene

  4. Gibberellin


Correct Option: C
Explanation:
  • Ethylene is a simple gaseous 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
  • So, the correct option is 'Ethylene'.

Which one of the following responses of plants to growth hormones is true for ethylene?

  1. Increase in cell elongation

  2. Decrease in the formation of female flowers

  3. Increase in ripening of fruits

  4. Decrease in abscission of flowers


Correct Option: C
Explanation:

Ethylene affects fruit - ripening. Normally, when the seeds are mature, ethylene production increases and builds - up within the fruit, resulting in a climacteric event just before seed dispersal. The nuclear protein 'Ethylene Insensitive 2' is regulated by ethylene production, and in turn, regulates other hormones including ABA and stress hormones.