Biology

Plant Growth and Hormones

695 Questions

Plant growth and hormones is a vital topic in biology that covers the physiological effects of different plant regulators like auxins, gibberellins, and cytokinins. These concepts are frequently tested in various general science sections of competitive exams. Practicing these questions helps clarify complex mechanisms like vernalisation, senescence, and tropism for test takers.

Abscisic acid effectsCytokinin functionsAuxins and tropismPlant tissue cultureSenescence in plantsNatural plant hormones

Plant Growth and Hormones Questions

Multiple choice senescence senescence and death plant growth plant growth and development biology

The induction of cell elongation by IAA is explained on the basis of ______________.

  1. The acid growth hypothesis

  2. Auxin-ethylene balance hypothesis

  3. Sodium-potassium pump hypothesis

  4. Osmotic pressure hypothesis
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The acid growth hypothesis explains that auxin (IAA) stimulates proton pumps to acidify the cell wall, activating enzymes that loosen the wall and allow for cell elongation.

Multiple choice senescence senescence and death plant growth plant growth and development biology

Senescence in plants leads into .......... of cells.

  1. Increase in size

  2. Increase in number

  3. Death

  4. Differentiation
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Senescence in plants is a process of aging. During process of senescence, cells undergo differentiation. It ultimately leads into the death of cells. 

Thus, the correct answer is option C.

Multiple choice biology living organisms and their surroundings living organism living vs nonliving living vs non living

Which one regulates plant growth?

  1. Commensalism

  2. Climate

  3. Hormones

  4. Both B and C
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

There are various plant hormones which regulate plant growth. Hormones like auxin, gibberellin, cytokinin promotes growth whereas hormones like ethylene and abscisic acid inhibits growth. Plant growth is also regulated by the climate or atmosphere. Various climatic factors like rainfall, light, temperature, humidity, etc regulates plant growth and development.

Thus, the correct answer is option D.

Multiple choice biology concept of life living organism living vs nonliving living vs non living

Plant response to environment is mainly through

  1. Induction of dormancy

  2. Abscission of parts

  3. Synthesis of pigments

  4. Growth
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Plants respond to their environment to ensure their survival. Plants response to environment is mainly through growth, either towards or away from stimuli. This type of response is called as tropism. It is brought about by hormones, which control plant growth and development.

Thus, the correct answer is option D.

Multiple choice mitosis structure of chromosome, cell cycle and cell division cell division biology cell division in embryo development division for growth and reproduction

Storage sprouting of potato can be prevented by 

  1. IAA

  2. Maleic hydrazide

  3. Cytokinins

  4. Gibberellins
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Maleic hydrazide : It is a growth retardant which checks cell division. So during seed storage this is applied for checking sprouting of potato tubers so that the importance of potato may not be lowered down.

Multiple choice botany mineral nutrition in plants deficiency diseases and symptoms deficiency symptoms macronutrients and micronutrients

Necrosis refers to 

  1. Inhibition of cell division

  2. Delay in flowering

  3. Death of tissues

  4. Falling of leaves
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When a living organism's cells or tissues die or degenerate, the condition is called necrosis. In a plant, necrosis causes leaves, stems and other parts to darken and wilt. Necrosis weakens the plant and makes it more susceptible to other diseases and pests. 

Thus, the correct answer is 'Death of tissues.'

Multiple choice biology respiration in plants amphibolic pathway living organisms and energy production life processes in living organisms- part 1

During amphibolic pathway, acetyl Co-A can perform the biosynthesis of 

  1. Amino acid

  2. Gibberellic acid

  3. Fatty acid

  4. All of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Fatty acid synthesis takes place in the cytoplasm of the cell. It is the creation of fatty acids from acetyl-CoA and NADPH through the action of enzymes called fatty acid synthases. Most of the acetyl-CoA which is converted into fatty acids is derived from carbohydrates via the glycolytic pathway. 

So, the correct option is 'Fatty acid'.

Multiple choice types of endosperms plant kingdom biology

Which one of the following phytochromones is associated with seed maturation?

  1. ABA

  2. Kinetin

  3. Ethylene

  4. IAA
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Abscisic acid (ABA) is the primary plant hormone associated with seed maturation, dormancy induction, and stress response. It prevents premature germination.

Multiple choice biology water absorption and ascent of sap in plants transport of water across plants habit of plants plant classifications

Assertion : Auxins promote apical dominance by suppressing the activity pf lateral buds.

Reason : In moriculture, periodic pruning of shoot tips is done to make mulberry plants bushy.

  1. If both the assertion and reason are true and the reason is a correct explanation of the assertion

  2. If both the assertion and reason are true but the reason is not a correct explanation of the assertion

  3. If the assertion is true but the reaon is false

  4. If both the assertion and reason are false

  5. If the assertion is false but reason is true
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Auxin is produced by shoot tip and acts as a growth promoter for apical bud and inhibit the growth of lateral buds. When a terminal bud is removed, the nearest axillary buds begin to grow and the plant branches rapidly. In case of mulberry plants, pruning is done to remove apical dominance and causes more branching of the main body of the plant.

Multiple choice chemistry water in our life how can we conserve water? droughts, floods and water conservation conservation of water and its importance and methods

Which hormone level increases during water scarcity condition?

  1. Auxin

  2. Cytokinine

  3. Abscisic acid

  4. Ethylene
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Abscisic acid (ABA) is known as a stress hormone in plants. Its levels increase significantly during water scarcity to induce stomatal closure, which helps the plant conserve water.

Multiple choice biology plant growth growth rates and conditions for growth population ecology growth and development

State whether the following statements are true or false.
Ethylene stimulates leaf release, while auxin keeps leaves from falling.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Ethylene is a gaseous hormone which stimulates the transverse growth but inhibits the longitudinal growth. Auxin delays the abscission of young leaves and provides nutrition to it so that they do not die down while ethylene increases the senescence of leaves and flowers and produces more gas which leads to loss of leaves.

So, the correct statement is 'True'.

Multiple choice evs seed becomes plant germination of seed seed germination journey of seed

Choose the correct answer from the alternatives given.
The ripening of fruits can be accelerated by:

  1. artificially adding ethylene gas to the atmosphere surrounding them

  2. warming the surroundings artificially

  3. keeping the fruits in a refrigerator

  4. reducing water supply to the plant when the fruits are maturing
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Ethylene is highly effective in fruit ripening. It enhances the respiration rate during ripening of the fruits. 

So, the correct option is 'artificially adding ethylene gas to the atmosphere surrounding them'.