Biology

Plant Growth and Hormones

727 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 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

Which of the following are synthetic phytohormone?

  1. IBA, IAA, BAP
  2. $2, 4$-D, NAA, BAP

  3. Zeatin, IBA, IAA
  4. NAA, IAA, $2, 4$-D
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • The plant growth regulators (PGRs) or phytohormones are small, simple molecules of diverse chemical composition. For example, auxins, gibberellins, cytokinins, abscisic acid, and ethylene.
  • NAA (naphthalene acetic acid) and 2, 4-D (2, 4-dichlorophenoxyacetic)are synthetic auxins.
  • 6-Benzylaminopurine, benzyl adenine, BAP  is a first-generation synthetic cytokinin that elicits plant growth and development responses, setting blossoms and stimulating fruit richness by stimulating cell division.
  • Hence 2,4-D, NAA, BAP  are synthetic phytohormone.
  • So, the correct answer is '2,4-D, NAA, BAP '.
Multiple choice 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

Phytohormone which promotes nutrient mobilisation, also help in?

  1. Induce flowering in mango

  2. Fruit thinning of cotton

  3. Production of new leaves and chloroplasts

  4. Seed development and dormancy
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Pytohormone which causes mobalization of nutrients is cytokinin and  it also helps in the formation of new leaves and chloroplast. 

Multiple choice 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

In plants, the chemical control is brought about by 

  1. Phytohormones

  2. Hormones

  3. Enzymes

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A- Phytohormones are plant hormones. These are organic substances which are produced in the plants. They bring about total control over growth and other physiological functions in the organism.

Multiple choice 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

Organic substances which regulates the growth of plants are called

  1. Plant hormones / Phytohormones

  2. Plant enzymes

  3. Plasma membrane

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  •  Plant hormones/phytohormones are numerous organic chemical substances that control the growth and differentiation of plant cells, tissues, and organs.
  • Plant enzymes are both organic and inorganic nature. They are not involved in the regulation of growth directly.
  • The plasma membrane regulates the transport of materials entering and exiting the cell. so option A is the correct answer.
Multiple choice 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

Phytohormones are 

  1. Hormones regulating growth from seed to adulthood

  2. Growth regulators synthesised by plants that influence physiological processes

  3. Hormones regulating flowering

  4. Hormones regulating secondary growth
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Phytohormones are produced by plants, that regulate germination, growth, metabolism, or other physiological activities.

So the correct option is 'Growth regulators synthesized by plants that influence physiological processes.'

Multiple choice 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

How does chemical coordination occur in plants?

  1. Phytohormones

  2. Blood

  3. Water

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

Plants do not have a nervous system or blood; they use chemical messengers called phytohormones to coordinate growth and physiological responses.

Multiple choice 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

Phytohormones are

  1. Chemicals regulating flowering

  2. Chemicals regulating secondary growth

  3. Hormones regulating growth from seed to adulthood

  4. Regulators synthesised by plants and influencing physiological processes
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Phytohormones are chemical substances synthesized by plants. 
These chemical substances regulate various physiological processes in plants.
So, the correct answer is 'Regulators synthesised by plants and influencing physiological processes'
Multiple choice 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

Chemicals having profound effect on growth and development are

  1. Enzymes

  2. Phytohormones

  3. Catalytic agents

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

Phytohormones are also called as plant hormones. These are chemicals which play important role in growth and development of plants. These are involved in various physiological processes of plants like growth, flowering, fruiting, shoot and root development, etc. Phytohormones liks auxin, cytokinin act as growth promoter whereas hormones like abscisic acid, ethylene act as growth inhibitor. 

Thus, the correct answer is option B.

Multiple choice 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

Through their effect on phytohormones, temperature and light control

  1. Stomatal closure

  2. Apical dominance

  3. Flowering

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

Phytohormone is the plant hormone that is involved in various processes of plants. Hormones like gibberellin induce flowering and abscisic acid inhibits flowering in plants. In plants, flowering is controlled by light and dark periods (photoperiod) and temperature in specific environments. Plant generally requires either long day or cold condition for flowering.

Thus, the correct answer is option C.

Multiple choice 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

Phytohormone is a naturally produced organic substance in ________________.

  1. Higher plants which controls growth and development in general

  2. Plants to control growth and physiological functions at the site of its production

  3. Higher plants controlling growth and development at a site for removed from the site of its production and is effectively only when present in large quantities

  4. Higher plant controlling physiological and growth functions at a site quite removed form the site of its production and is effective when present when in minute quantities
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice 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

High concentration of hormone will

  1. Kill the plant

  2. Cause chlorosis in leaves

  3. Cause stunting in plants

  4. Show no effect on the plant
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When concentration of hormones in the plant body increases, growth of the plants decreases.

So, the correct option is cause stunting in plants’.

Multiple choice 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

Identify the physiological process induced by two phytohormones having a common precursor which is formed due to catalytic activity of pyruvic dehydrogenase complex
(a) More female flowers in Cucumber
(b) $\alpha$-amylase production in Barley grains
(c) Acceleration of fruit ripening in Tomato
(d) Delay in sprouting of Potato tubers.

  1. a, b

  2. a, c

  3. c, d

  4. b, d
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Ethylene is a plant hormone. It accelerates fruit ripening in tomato. Maleic hydrazide is a type of auxin, plant hormone. It delays sprouting of potato tubers. Both these hormones have common precursor that is formed due to the catalytic activity of pyruvic dehydrogenase complex.

Thus, the correct answer is option C.

Multiple choice biology chemical coordination and integration hormones coordination in human beings- chemical control endocrine system in humans

Which hormone inhibit morphogenesis?

  1. ABA

  2. 2, 4-D

  3. Jasmonic acid

  4. IBA
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • The plant hormone abscisic acid (ABA) has been shown to promote abscission and dormancy, to inhibit cell elongation and to be involved in several hormones mediated plant responses
  • ABA inhibits seed germination.It also inhibits morphogenesis(It is the biological process that causes an organism to develop its shape).
  • So, the correct answer is 'ABA'.
Multiple choice botany reproduction in angiospermic plants artificial vegetative propagation common modes of vegetative propagation vegetative propagation asexual modes of reproduction

Which of the following defines phytotron?

  1. Fish culture facility

  2. Plant hormone

  3. Secondary metabolite

  4. Controlled plant culture facility
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A phytotron is an enclosed research greenhouse used for studying interactions between plants and the environment. It was a product of the disciplines of plant physiology and botany. The first phytotron was built under the direction of Frits Warmolt Went at the California institute of Technology in 1949. It was funded by the Harry B. Earhart Foundation and was officially known as the Earhart plant research Laboratory.