Tag: plant hormones

Questions Related to plant hormones

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.

Cytokinins are mostly produced in

  1. Shoot apex

  2. Root apex

  3. Young leaves

  4. Lateral buds


Correct Option: B
Explanation:

Cytokinin is a plant hormone. It promotes cell division. It also delays the destruction of chlorophyll and protein. It shows delay of senescence in leaves.  It is mostly produced in the root apex. When an excised leaf is induced to root, it does not turn yellow because root apex synthesizes cytokinin hormone.

Thus, the correct answer is option B.

Delay in senescence is caused by the spray of 

  1. IBA

  2. GA

  3. Cytokinin

  4. ABA


Correct Option: C
Explanation:

Senescence means aging. Cytokinin is a plant hormone. It plays major role in cell proliferation and cell division. During senescence, cytokinin levels are low. It delays in senescence of leaves when sprayed externally by delaying the destruction of chlorophyll and proteins in leaves. 

Thus, the correct answer is option C.