Tag: plant hormones

Questions Related to plant hormones

Which is not the effect of ethylene?

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

  1. Promotes senescence and abscission of plant organs

  2. Breaks seed and bud dormancy

  3. Brings about horizontal growth of seedlings

  4. Hastens fruit ripening

  5. Helps to overcome apical dominance

Show answer
Correct Option: E
Explanation:

Ethylene is a plant hormone. It is also called as ripening hormone as it hastens fruit ripening in plants. In certain plants, it breaks seed and bud dormancy and induces germination. It also causes flowers to fall from the plant and hence, promotes senescence and abscission of plant hormones. It also causes the triple response in etiolated seedlings. It inhibits stem elongation and brings about the horizontal growth of seedlings. 

Thus, the correct answer is option E.

Ethylene promotes water absorption by increasing the root's absorption surface. It promotes:

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

  1. Premability of cell membrane

  2. Rormation of root hairs

  3. Concentration of cell sap

  4. All of these

Show answer
Correct Option: D
Explanation:
Ethylene promotes water absorption by increasing the root's absorption surface. It promotes the elongation of the root hairs and the root itself and it is also responsible for increasing the cell permeability in some cases. It has also been observed to increase the osmotic pressure and the concentration of cell sap.

So, the correct answer is 'all of these'.

Artificial ripening of fruit is carried out by

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

  1. Auxin

  2. Gibberellin

  3. Abscisic acid

  4. Ethylene

Show answer
Correct Option: D
Explanation:

Ethylene is sprayed on fruits to promote artificial ripening, which is very commonly seen in fruit shops.
Ethylene is applied on fruits in the form of a spray. It acts to the fruit cell wall made of pectin or cellulose and promotes ripening.

How many of the following are true regarding secondary growth in root?
A. All cambium are secondary in orgin
B. Lenticels are not formed
C. Bark is formed
D. Cork cambium is originated from outer layer of cortex

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

  1. Two

  2. Three

  3. One

  4. Four

Show answer
Correct Option: B
Explanation:

In dicotyledonous plants, roots undergo secondary growth to increase in thickness by the formation of the secondary meristem. In roots, vascular bundles are radial, primary cambium is absent. During secondary growth, some of the parenchyma cells beneath each phloem group become meristematic and thus form cambium strips, which is secondary in origin. 

Lenticels can be developed by the activity of phellogen or cork cambium as transversely elongated outer cortex regions. 
In stems and roots of the woody dicots, all the cork layers together with cortical and dry secondary phloem tissue external to the innermost phellogen are called outer bark; while all the tissues external to the vascular cambium (secondary phloem, primary phloem, cortex, periderm, and tissues outside the periderm are termed bark. 
In dicot roots, cork cambium or phellogen arises in the outer cells of the pericycle. 
Hence, the except D all other options are correct. 
So, the correct answer is option B, Three. 

Gibberellic acid is known to carry out all these functions except?

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

  1. Increase in yield in grapes and apple

  2. Speed up malting process

  3. Activation of $\alpha$-amylase

  4. Nutrient immobilisation in aleurone layer

Show answer
Correct Option: A

Which would do maximum harm to a tree?

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

  1. The loss of half of its leaves

  2. The loss of all of its leaves

  3. The loss of half of its branches

  4. The loss of its bank

Show answer
Correct Option: A

Cycocel is a .............

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

  1. Wound hormone

  2. Growth hormone

  3. Rhizocaline necessary for root formation

  4. Growth retardant

Show answer
Correct Option: D
Explanation:

 Cycocel is among the most reliable and widely used plant growth regulators on the market. Cycocel may be used on any crop in the green house or nursery including but not limited to, poinsettias, hibiscus, azzaleas and geraniums to reduce stem elongation, induce early flowering, and to produce compact plants with multiple buds per shoots.

Acid deposition weakens plants by damaging their

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

  1. Leaves

  2. Roots

  3. Stems

  4. All of them

Show answer
Correct Option: A

Elongation of internodes is inhibited by ..............

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

  1. Gibberellins

  2. Morphactins

  3. Both (A) and (B)

  4. None of the above

Show answer
Correct Option: B
Explanation:

Morphactins have inhibitory effect on the stem elongation. Increases concentration produced dwarfing in the plants. Morphactins are a group of substances which act on morphogenesis and modulate the expression of plants. Chemically, they are the derivatives of fluorene compounds.

Wound hormone is called as ..................

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

  1. Traumatin

  2. Hormone only

  3. Auxins

  4. Phyllocaline

Show answer
Correct Option: A
Explanation:

Traumatic acid is a monounsaturated dicarboxylic acid naturally occurring in plants. The compound was first isolated from wounded bean plants. Wound hormone is also called as necrohormone.