Tag: chemical coordination in plants

Questions Related to chemical coordination in plants

Identify the incorrectly matched pair.

biology life processes: control and coordination control and coordination in plants growth in plants chemical coordination in plants animal senses sense organs in animals sense organs in humans

  1. Auxin - Phototropism

  2. Gibberellins - Foolish seedling disease of rice

  3. Ethylene - Induces fruit ripening

  4. Cytokinin's - Promote apical dominance

Show answer
Correct Option: A

Match the names of the phytohormones with the roles listed. 

   List I    List II
 A  Auxin  p  Internodal elongation
 B  Gibberellin  q  Cell division
 C  Cytokinin  r  Ripening of fruits
 D  Ethylene  s  Abscission
     t  Apical dominance
biology life processes: control and coordination control and coordination in plants growth in plants chemical coordination in plants animal senses sense organs in animals sense organs in humans

  1. A- t, B- p, C- s, D- q

  2. A- t, B- p, C- q, D- s

  3. A- t, B- p, C- q, D- r

  4. A- t, B- s, C- p, D- q

Show answer
Correct Option: C
Explanation:
  • Auxin hormone causes apical dominance. Apical dominance is referred to the growth of plants attaining height. As a result of this, the plant will grow tall. Cytokinin is the phytohormone which is responsible for the multiplication if cells or cell division. 
  • In other words, cytokinin influences mitosis. Gibberellin is the hormone that induces internodal elongation. It is also called as bolting. This is commonly found in cabbage when this hormone is more in amount.
  •  The ethylene hormone is responsible for the ripening of fruits. Spraying of ethylene will promote early fruit ripening.

Match Column I with Column II and select the correct option from the codes given below.

Column I  Column II
 A. Auxin  1. Flowering
 B. Cytokinins  2. Phototropism
 C. Gibberellins  3. Stimulation of cell division
 D. Abscisic acid  4. Suppression of cell division
 E. Ethylene  5. Stomatal opening and closing
  6. Growth of lateral buds 
   7. Root growth
biology life processes: control and coordination control and coordination in plants growth in plants chemical coordination in plants animal senses sense organs in animals sense organs in humans

  1. A- 2, B- 7, C- 3, D- 5, E- 4

  2. A- 2, B- 3, C- 5, D- 7,E- 4

  3. A- 2, B- 5, C- 3, D- 4,E- 7

  4. A- 5, B- 2, C- 3, D- 7,E- 4

Show answer
Correct Option: A

Consider the statements A -D.
A. Ethephon is widely used in agriculture for the source of ethylene.
B. Auxin stimulates the stem to bent towards the source of light. 
C. Carbohydrates are produced in mature leaves and transported to other plants parts. 
D. Gibberellins promote the growth of plumule and radicle in seed germination.

Which of these statements are correct?

biology life processes: control and coordination control and coordination in plants growth in plants chemical coordination in plants animal senses sense organs in animals sense organs in humans

  1. A , B and C

  2. A, C and D

  3. A, B and D

  4. B, C and D

Show answer
Correct Option: A
Explanation:

Etheophon is the most widely used growth regulator for the source of ethylene, Auxins used to promote shoot elongation and carbohydrates are produced in mature leaves and will get transported to other parts of the plants. but gibberellins won't promote the growth of plumule and radicle in seed germination.

So the correct option is 'A, B and C.'

Auxin inhibits the growth of

biology life processes: control and coordination control and coordination in plants growth in plants chemical coordination in plants animal senses sense organs in animals sense organs in humans

  1. Apical buds

  2. Fruits

  3. Lateral auxillary buds

  4. Roots of cuttings

Show answer
Correct Option: C
Explanation:

Auxin induces shoot apical dominance. The axillary buds are inhibited by auxin, as a high concentration of auxin directly stimulates ethylene synthesis in lateral buds, causing inhibition of their growth and potentiation of apical dominance. When the apex of the plant is removed, the inhibitory effect is removed and the growth of lateral buds is enhanced. Auxin is sent to the part of the plant facing the light, and this promotes growth towards that direction. 

Therefore, the correct answer is option C.

Which of the following plant hormones is incorrectly paired with its function?

biology life processes: control and coordination control and coordination in plants growth in plants chemical coordination in plants animal senses sense organs in animals sense organs in humans

  1. Auxins- Responsible for apical dominance

  2. Abscisic acid- Regulates the rate of transpiration

  3. Gibberellins- Promotes bud and seed dormancy

  4. Ethylene- Promotes ripening

Show answer
Correct Option: C
Explanation:

Gibberellins regulate the cell growth and influence various developmental processes, including stem elongation, germination, dormancy, flowering, sex expression, enzyme induction, and leaf and fruit senescence. Ethylene promotes ripening. Auxins are responsible for apical dominance. Abscisic acid regulates the rate of transpiration. 

Therefore, the correct answer is option C.

Abscisic acid regulates

biology life processes: control and coordination control and coordination in plants growth in plants chemical coordination in plants animal senses sense organs in animals sense organs in humans

  1. Shoot elongation

  2. Cell elongation and cell wall formation

  3. Cell division

  4. Leaf fall and dormancy

Show answer
Correct Option: D
Explanation:

Abscisic acid regulates leaf fall and dormancy.

Other functions of abscisic acid includes:
  1. It induces bud dormancy in a number of plants. In perennial plants, ABA causes the active axillary buds to become dormant.
  2. It maintains dormancy in many seeds.
  3. It inhibits mitosis in vascular cambium.
  4. It accelerates senescence in leaves.
  5. It functions as a stress hormone by inducing a temporary closure of stomata, to tide over adverse environmental conditions.
  6. It promotes abscission of leaves, flowers and fruits in most of the plants.
  7. It inhibits seed germination.
  8. It delays cell division and cell elongation.
  9. It promotes rooting of stem cuttings in some plants like ivy and bean.
  10. It inhibits flowering except in some short day plants where it promotes flowering.

Plant hormone is also known as___________________

biology life processes: control and coordination control and coordination in plants growth in plants chemical coordination in plants animal senses sense organs in animals sense organs in humans

  1. Planktohormone

  2. Phytohormone

  3. Photohormone

  4. All of the above

Show answer
Correct Option: B
Explanation:

  • Plant hormones are also known as phytohormones, they are chemicals that regulate plant growth. 
  • Plant hormones are signal molecules produced within the plant and occur in extremely low concentrations. 
  • Hormones regulate cellular processes in targeted cells locally and, moved to other locations, in another functional part of the plant. 
Hormones also determine the formation of flowers, stems, leaves, the shedding of leaves, and the development and ripening of fruit. The term 'Phytohormone' was coined by Thimann in 1948. 

Therefore, the correct answer is option B.

Hormone which initiates mobilization of storage materials is_________________ 

biology life processes: control and coordination control and coordination in plants growth in plants chemical coordination in plants animal senses sense organs in animals sense organs in humans

  1. Gibberellins

  2. Abscisic acid

  3. Cytokinin

  4. Auxin

Show answer
Correct Option: A
Explanation:

  • Gibberellins are phytohormones that initiate mobilization of storage materials in seeds during germination. 
  • They also cause elongation of stems, stimulate bolting in biennials stimulate pollen tube growth. 
  • Gibberellins include a large range of chemicals that are produced naturally within plants and by fungi. 
  • Gibberellins are important in seed germination, affecting enzyme production that mobilizes food production used for the growth of new cells. 

Therefore, the correct answer is option A.

Plants do not have glands, then how do they secrete hormones?

biology life processes: control and coordination control and coordination in plants growth in plants chemical coordination in plants animal senses sense organs in animals sense organs in humans

  1. Each cell is capable of producing hormones

  2. One cell produces hormone and then is transferred to others

  3. Hormones are produced by soil and taken up by the roots

  4. None of these

Show answer
Correct Option: A
Explanation:

  • In animals, there are various glands that produce different hormones but such glands are absent in the plants. Instead, each cell is capable of producing hormones. 
  • Plant hormones shape the plant, affecting seed growth, time of flowering, the sex of flowers, senescence of leaves, and fruits. 
  • They affect which tissues grow upward and which grow downward, leaf formation and stem growth, fruit development and ripening, plant longevity and even plant death. 
  • Hormones are vital to plant growth and lacking them, plants would be mostly a mass of undifferentiated cells. So, they are also known as growth factors or growth hormones.

Therefore, the correct answer is option A.