Tag: plant hormones

Questions Related to plant hormones

Which one of the following triggers the ripening of fruits?

biology plant growth other plant hormones cytokinins, ethylene and abscisic acid plant hormones

  1. Ethylene

  2. Indoleacetic acid

  3. Gibberellic acid

  4. Kinetin

Show answer
Correct Option: A
Explanation:

Ethylene is a simple gaseous plant growth regulator (PGR). It is synthesised in large amounts by tissues undergoing senescence and ripening fruits. the hormone enhances the respiration rate during ripening of the fruits. Ethylene helps fruits ripen by making them softer, through the breakdown components of the cell walls, and sweeter, through the conversion of starches to sugars.

Thus, the correct answer is option A.  

Test Group 1 Test Group 2 Test Group 3
Pair of ripe apples One ripe apple, one unripe apple Pair of unripe apples

Presence of ethylene gas causes fruits to ripen. As fruit ripens, it produces increasing amounts of ethylene. An investigator placed fruit samples sealed containers as shown in the image, and left them for three days. At the end of the time period, the investigator used iodine to test for the presence of starch.

List these in order from highest to lowest starch content.

biology plant growth other plant hormones cytokinins, ethylene and abscisic acid plant hormones

  1. Group 1, Group 2, Group 3

  2. Group 3, Group 2, Group 1

  3. Group 1, Group 3, Group 2

  4. Group 3, Group 1, Group 2

Show answer
Correct Option: B
Explanation:

The iodine test is used to test Starch content. The solution of iodine contains, an aqueous solution of 1.8% iodine and 3.0% potassium iodide, binds with starch, producing a dark color. The fruits which show more stain the fruit shows, the more starch it contains and the less ripe it is.

So the correct option is 'Group 3, Group 2, Group 1.'

One hormone stimulates the closure of stomata and another one influences the swelling of the axis in dicot plants. They are 

biology plant growth other plant hormones cytokinins, ethylene and abscisic acid plant hormones

  1. Gibberellins and ethylene

  2. Abscisic acid and cytokinins

  3. Gibberellins and cytokinins

  4. Auxins and cytokinins

  5. Abscisic acid and ethylene

Show answer
Correct Option: E
Explanation:

Abscisic acid is a plant hormone. It is also called as a stress hormone. During adverse environmental conditions, it's concentration increases. During water stress condition, it stimulates closure of stomata and hence decreases transpiration rate. Ethylene is also a plant hormone. It shows the triple response. It influences the horizontal growth of seedlings, swelling of the axis and apical hook formation in dicot plants.

Thus, the correct answer is option E. 

Parthenocarpic fruit cannot be produced by application of

biology plant growth other plant hormones cytokinins, ethylene and abscisic acid plant hormones

  1. IAA

  2. 2, 4-D

  3. ABA

  4. IBA

Show answer
Correct Option: C
Explanation:

Parthenocarpy is the process of producing seedless fruits without fertilization. Various phytohormones are used to produce parthenocarpic fruit. Auxin hormone like IAA, IBA, 2, 4 -D are most widely used to induce parthenocarpy. It can also be induced by application of gibberellin hormone.

Thus, the correct answer is option C. 

Find out correct options.

   I      II      III
a Foolish plant p Volatile hormone x Induces dormancy
b Induces senescence q Abscisic acid y Ripens fruit
r Gibberella z Usually sterile plant
biology plant growth other plant hormones cytokinins, ethylene and abscisic acid plant hormones

  1. a- p- y, b- r- x

  2. a- r- z, b- q- z

  3. a- r- z, b- p- y

  4. a- q- x, b- r- y

Show answer
Correct Option: B
Explanation:

The foolish seedling disease affects the rice plant through the roots or crowns. It is caused by the fungus Gibberella fujikuroi. It is the source of gibberellin hormone. The plant is usually sterile. Abscisic acid is a plant hormone that induces senescence in plants. Under stress environmental condition, it induces seed dormancy.

Thus, the correct answer is option B.

The primary and secondary growth of a shoot is inhibited by

biology plant growth other plant hormones cytokinins, ethylene and abscisic acid plant hormones

  1. Auxin

  2. Gibberellin

  3. Cytokinin

  4. Abscisic acid

Show answer
Correct Option: D
Explanation:

Abscisic acid is a plant hormone. It is growth inhibitor hormone. Its primary role is inhibition of growth of root, shoot, leaf, etc. It inhibits primary and secondary growth of shoot. During stress condition, its concentration increases.

Thus, the correct answer is option D.

Which one is derivative of a carotenoid?

biology plant growth other plant hormones cytokinins, ethylene and abscisic acid plant hormones

  1. IAA

  2. ABA

  3. IBA

  4. GA

Show answer
Correct Option: B
Explanation:

Abscisic acid is plant hormone. It is terpenoid chemically, that is derivative of carotenoid. It stimulates seed dormancy in plants. Carotenoids are also called as tetraterpenoids.

Thus, the correct answer is option B.

State whether the following statements are true or false.
A cut woody stem exposed to a cytokinin solution will be induced to grow roots rapidly.

biology plant growth other plant hormones cytokinins, ethylene and abscisic acid plant hormones

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

cytokinins are the plant growth regulators that promote cell division, they function similar to auxin and helps in cell elongation and are majorly present in the roots and then passes through the xylem. They perform many functions like cell division, embryo and endosperm formation, and growth of root cells etc.

So, the correct statement is 'True'.

Kinetin, a modified form of adenine was discovered from

biology plant growth other plant hormones cytokinins, ethylene and abscisic acid plant hormones

  1. Autoclaved herring sperm DNA

  2. Coconut milk

  3. Corn kernel

  4. Fungus

Show answer
Correct Option: A
Explanation:

Kinetin is a modified form of adenine which is discovered by Miller and Skoog as a compound from autoclaved herring sperm DNA. Herring is a fish. From it's sperm, DNA is isolated which is sterilized using steam at high pressure which is called autoclaved herring sperm DNA. From this, kinetin was isolated which has ability to induce cell division.

Thus, the correct answer is 'Autoclaved herring sperm DNA.'

Horizontal growth of seedlings, swelling of axis and apical hook formation in dicot seedlings is brought about by

biology plant growth other plant hormones cytokinins, ethylene and abscisic acid plant hormones

  1. Auxins

  2. Gibberellins

  3. Ethylene

  4. Kinetin

  5. Abscisic acid

Show answer
Correct Option: C
Explanation:
Ethylene is a gaseous plant hormone. It is also called as ripening hormone as it stimulates ripening of fruits. It also promotes the horizontal growth of seedlings, swelling of the axis and increase curvature by apical hook formation in dicot seedlings. It inhibits stem elongation. This is called as triple response shown by ethylene.
Thus, the correct answer is option C.