Tag: cytokinins

Questions Related to cytokinins

Cytokinin is a hormone whose main function is ..................

  1. Induction of cell division and delay in senescence

  2. To take part in cell division

  3. Refers to cell movements

  4. To cause dormancy


Correct Option: A
Explanation:

Cytokinins are a class of plant growth substances that promote cell division, or cytokinesis, in plant roots and shoots. They are derivatives of pure adenine. It is a true cell division factor, promotes meristematic tissue regions. It prevents destruction of chlorophyll in leaves.

Which of the following causes delaying of senescence?

  1. Cytokinins

  2. Auxins

  3. IAA

  4. Ascorbic acid


Correct Option: A
Explanation:

Cytokinins retard the aging in plants. The effect is called as Richmond-Lang effect. Richmond-Lang effect is retardation of aging due to cytokinins which acts by retarding the rate of destruction of chlorophyll and yellowing of leaves.

Thus, the correct answer is option A.

Which of the following is a coconut milk factor?

  1. Auxin

  2. Cytokinin

  3. Morphactin

  4. None of the above


Correct Option: B
Explanation:

Kinetin is present in the coconut water, which is actually a liquid endosperm. Hence, the name coconut milk factor. It actually serves as the nourishment for the growth of embryo in coconut. Coconut water is also used as artificial blood plasma.

Guttman (1957) found a quick increase in the amount of RNA in the nuclei on onion root after .............

  1. Auxin treatment

  2. Kinetin treatment

  3. Gibberellin treatment

  4. All of the above


Correct Option: B
Explanation:

Kinetin promotes the synthesis of RNA, proteins, etc., which help in initiation of root, breaking of seed dormancy, etc. In the case of onion root, which underwent kinetin treatment more RNA could be spotted out because of this reason.

RNA formation is induced by .............

  1. Phyllocalins

  2. All calins

  3. Kinetins

  4. Florigens


Correct Option: C
Explanation:

Kinetins induce the synthesis of RNA. Kinetin is a type of cytokinin, a class of plant hormone that promotes cell division. It was originally isolated by Miller and Skoog et al. It was given the name kinetin because of its ability to induce cell division. Kinetin is often used in plant tissue culture for inducing formation of callus and to regenerate shoot tissues from callus. Florigen induces flowering.

Cytokinin was first synthesized by ...................

  1. Skoog and Miller

  2. Letham

  3. Bensan and Calvin

  4. Thimman and Went


Correct Option: B
Explanation:

Cytokinins are a class of plant growth substances that promote cell division or cytokinesis in plant roots and shoots. They are involved primarily in cell growth and differentiation, but also affect apical dominance, axillary bud growth and leaf senescence. Letham first synthesized it from corn milk.

An excised leaf does not turn yellow if it is induced to root. This is attributed to synthesis in root of ...................
or
Leaf ageing is retarded by ........................

  1. Ethylene

  2. Cytokinins

  3. Gibberellins

  4. Auxins


Correct Option: B
Explanation:

According to Richmond lang effect, cytokinin hormone in plants will cause retardation of chlorophyll and several other proteins. Thus, it helps in reducing the senescence.

The cut flowers and vegetables can be kept fresh a long period by this

plant hormone ...............

  1. Gibberellins

  2. Cytokinins

  3. Auxins

  4. Ethylene

  5. 2,4 - dichlorophenoxy acetic acid


Correct Option: B
Explanation:

Cytokinin is the plant hormone which is found to have profound effects in delaying the ageing of plant and thus increases the shelf life of vegtables and fruits. It acts by retarding the destruction and degeneration of chlorophyll and proteins. This is called as 'Richmond Lang effect'.

A plant hormone used for inducing morphogenesis in plant tissue culture

is ........................

  1. Abscisic acid

  2. Gibberellins

  3. Cytokinins

  4. Ethylene


Correct Option: C
Explanation:

Morphogenesis is the process of organ formation. Cytokinin is a plant hormone which plays a major role in organ formation or morphogenesis with the presence of auxin. It helps in rapid multiplication of cells by repeated cytokinesis and karyokinesis.

Cytokinesis refers to ................

  1. Division of chromosomes

  2. Division of cytoplasm

  3. Division of nucleus

  4. None of the above


Correct Option: B
Explanation:

Cytokinin is a plant hormone which is vital for the mitotic divisions taking place in plants. It thus enables cytokinesis and karyokinesis in the cells. This makes cytokinin an important constituent in callus culture.