Tag: plant growth

Questions Related to plant growth

_______ is naturally occurring growth inhibitor.

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

  1. Ethylene

  2. Abscissic acid

  3. Cytokinin

  4. Gibberellins

Show answer
Correct Option: B
Explanation:

During drought and other unfavorable climatic conditions it is very important to maintain viability of the seeds. Abscissic acid is released during this condition and interacts with growth hormone in order to inhibit the growth of plant.

Which hormone is responsible for spoiling the whole barrel containing one bad apple?

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

  1. Ethylene gas

  2. Abscisic acid

  3. Auxin

  4. Gibberellins

  5. Cytokinins

Show answer
Correct Option: A
Explanation:

Ethylene is gaseous hormone promotes fruit ripening and abscission. It diffuses from the rotten apple to other apples in the barrel and thereby causing spoilage of the whole barrel. ABA, auxins, gibberellins and cytokines are not gaseous hormones and therefore can not diffuse from one fruit to other. Thus, the correct answer is A.

"One bad apple spoils the whole barrel" because of

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

  1. Ethylene gas

  2. Abscisic acid

  3. Auxin

  4. Gibberellins

  5. Cytokinins

Show answer
Correct Option: A
Explanation:

Ethylene gas is the plant hormone that promotes fruit ripening and rotting. It also controls flower wilting and leaf fall by stimulating the conversion of starch and acid to sugars. Therefore, it is said that one bad apple will spoil the whole barrel because of ethylene gas.

Therefore, the correct answer is option A.

Presence of ethylene gas causes fruits to ripen. As fruit ripens, it produces increasing amounts of ethylene.

This is an example of

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

  1. Positive feedback

  2. Negative feedback

  3. Homeostasis

  4. Endocrine regulation

Show answer
Correct Option: A
Explanation:

ethylene gas is an aging hormone used for fruit ripening but may also cause the plant to die. Ethylene gas is released when the plant is damaged mechanically or physically.

So the correct option is 'Positive feedback.'

In the fall, the leaves of deciduous trees change color, fall off and die. This shedding of leaves is Mated by which of the following plant hormones? 

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

  1. auxin

  2. gibberellin

  3. abscisic acid

  4. cytokinin

  5. ethylene

Show answer
Correct Option: C
Explanation:
A. Auxin plays role in cell elongation, apical dominance, root initiation, prevention of abscission, induction of parthenocarpy and also used as herbicide.
B. Gibberellin plays role in stem elongation, seed germination, breaking dormancy, elongation of internodes and inducing parthenocarpy.
C. Abscisic acid or ABA is known as stress hormone and induces stomatal closure, provides defence against salt and cold stress, induces dormancy, causes geotropism in roots and abscission of leaves, flowers and fruits.
D. Cytokinin plays role in promoting cell division and organ formation, delay in senescence, promoting lateral bud development in dicots, cell expansion in cotyledons leaves, promoting chloroplast development and chlorophyll synthesis.
E. Ethylene is a gaseous hormone and causes ripening of fruit.
So, the correct answer is 'Abscisic acid'.

Artificial ripening of which of the following fruits is useless ...............

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

  1. Mango

  2. Banana

  3. Guava

  4. Pomegranate or Coconut

Show answer
Correct Option: D
Explanation:

Artificial ripening of pomegranate and coconut is useless. It is not useful in these fruits because of their inner structure. In other fruits, calcium carbide is used for artificial ripening.

Which of the following hormone is produced during leaf fall?

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

  1. ABA

  2. Cytokinin

  3. Florigen

  4. All of the above

Show answer
Correct Option: A
Explanation:

ABA hormone is formed during leaf fall. It is a growth inhibiting hormone in plants which accelerates aging and inhibits germination and flowering. It also causes the closing of stomatal pore.

A characteristic feature of some fruit ripening is sudden increase in respiration. It is known as

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

  1. Climacteric

  2. Anthesis

  3. Climatic

  4. Photorespiration

Show answer
Correct Option: A
Explanation:

Certain fruits ripen with sudden rise in cellular respiration and ethylene production. Such fruits are called 'climacteric fruits'. Climacteric is considered final stage in fruit ripening process during which the fruit is maximum ripened with best taste for consumption. After that period, it starts to gradually deteriorate and the respiration returns to normal rate.

Hence the correct answer is 'Climacteric'.

Farmers of a particular region are concerned that premature yellowing of leaves of pulse crop might cause decrease in the yield. Which treatment could be beneficial to obtain maximum seed yield?

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

  1. Application of iron and magnesium to promote chlorophyll synthesis

  2. Frequent irrigation of crop

  3. Treatment of plants with cytokinins along with a small dose of nitrogen fertilizer

  4. Removal of all yellow leaves and spraying the remaining green leaves with $2, 4, 5-$T

Show answer
Correct Option: C

Leaf abscission is promoted by

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

  1. Ethylene

  2. Abscisic acid

  3. Cytokinin

  4. Tryptophan

Show answer
Correct Option: A
Explanation:

Leaf abscission is a detachment or fall of older leaves.It occurs at the base of the petiole. During abscission, high synthesize of ethylene is observed along with decrease in the concentration of auxin. Ethylene synthesizes enzymes like cellulase and pectinase which are involved in cell wall degradation. These enzymes loosens the cell wall and cells separate which ultimately leads to leaf abscission. 

Thus, the correct answer is option A.