Tag: plant growth and development

Questions Related to plant growth and development

The ability of the callus cells to differentiate into a plant organ is

development of plants plant growth growth and development plant growth and development biology

  1. Differentiation

  2. Dedifferentiation

  3. Redifferentiation

  4. None of the above

Show answer
Correct Option: C
Explanation:

The phenomenon of generation of whole plant by single cell is totipotency.

This is the characteristic of plants mostly. When a plant of differentiated tissue is cultured in a nutrient medium  it gain the property of division get specialized and form and organ.
So the correct option is "Redifferentiation".

Which of the following set is not natural plant growth regulator?

development of plants plant growth growth and development plant growth and development biology

  1. $GA _3, IAA, 2IP$

  2. $IAA, 2IP, Zn$

  3. $ABA, IBA, GA _3$

  4. $ABA, GA _3, IAA$

Show answer
Correct Option: B
Explanation:
  • Plant growth regulators function as chemical messengers for intercellular communication. There are currently five recognized groups of plant hormones: auxins, gibberellins, cytokinins, abscisic acid ($ABA$) and ethylene.
  • Indole-3-acetic acid ($IAA$, $3-IAA$) is the most common, naturally occurring plant growth regulator of the auxin class. 
  • $2IP$ (Isopentenyl adenine) is a naturally occurring cytokinin that regulates cell division, development, and nutrient processing in plants.
  • Zinc ($Zn$) is not a plant growth regulator. It is one of the eight essential micronutrients. It is needed by plants in small amounts, but yet crucial to plant development.
  • So, the correct answer is '$IAA, 2IP, Zn$'.

The process in which a simple permanent tissue like parenchyma and collenchyma regain their power of cell division and becomes lateral meristems. It helps in the formation of secondary tissues known as

development of plants plant growth growth and development plant growth and development biology

  1. Dedifferentiation

  2. Cell division

  3. Autolysis

  4. Totipotency

Show answer
Correct Option: A
Explanation:

The cells derived from root apical and shoot-apical meristems and cambium differentiate and mature to perform specific functions. This act leading to maturation is termed as differentiation. During differentiation, cells undergo few to major structural changes both in their cell walls and protoplasm. The living differentiated cells, that by now have lost the capacity to divide can regain the capacity of division under certain conditions. This phenomenon is termed as dedifferentiation. For example, formation of meristems – interfascicular cambium and cork cambium from fully differentiated parenchyma cells. While doing so, such meristems / tissues are able to divide and produce cells that once again lose the capacity to divide but mature to perform specific functions, i.e., get redifferentiated. 

How many of the following are true regarding secondary growth in root?
A. All cambium are secondary in orgin
B. Lenticels are not formed
C. Bark is formed
D. Cork cambium is originated from outer layer of cortex

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

  1. Two

  2. Three

  3. One

  4. Four

Show answer
Correct Option: B
Explanation:

In dicotyledonous plants, roots undergo secondary growth to increase in thickness by the formation of the secondary meristem. In roots, vascular bundles are radial, primary cambium is absent. During secondary growth, some of the parenchyma cells beneath each phloem group become meristematic and thus form cambium strips, which is secondary in origin. 

Lenticels can be developed by the activity of phellogen or cork cambium as transversely elongated outer cortex regions. 
In stems and roots of the woody dicots, all the cork layers together with cortical and dry secondary phloem tissue external to the innermost phellogen are called outer bark; while all the tissues external to the vascular cambium (secondary phloem, primary phloem, cortex, periderm, and tissues outside the periderm are termed bark. 
In dicot roots, cork cambium or phellogen arises in the outer cells of the pericycle. 
Hence, the except D all other options are correct. 
So, the correct answer is option B, Three. 

Gibberellic acid is known to carry out all these functions except?

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

  1. Increase in yield in grapes and apple

  2. Speed up malting process

  3. Activation of $\alpha$-amylase

  4. Nutrient immobilisation in aleurone layer

Show answer
Correct Option: A

Which would do maximum harm to a tree?

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

  1. The loss of half of its leaves

  2. The loss of all of its leaves

  3. The loss of half of its branches

  4. The loss of its bank

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Correct Option: A

Cycocel is a .............

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

  1. Wound hormone

  2. Growth hormone

  3. Rhizocaline necessary for root formation

  4. Growth retardant

Show answer
Correct Option: D
Explanation:

 Cycocel is among the most reliable and widely used plant growth regulators on the market. Cycocel may be used on any crop in the green house or nursery including but not limited to, poinsettias, hibiscus, azzaleas and geraniums to reduce stem elongation, induce early flowering, and to produce compact plants with multiple buds per shoots.

Acid deposition weakens plants by damaging their

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

  1. Leaves

  2. Roots

  3. Stems

  4. All of them

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Correct Option: A

Elongation of internodes is inhibited by ..............

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

  1. Gibberellins

  2. Morphactins

  3. Both (A) and (B)

  4. None of the above

Show answer
Correct Option: B
Explanation:

Morphactins have inhibitory effect on the stem elongation. Increases concentration produced dwarfing in the plants. Morphactins are a group of substances which act on morphogenesis and modulate the expression of plants. Chemically, they are the derivatives of fluorene compounds.

Wound hormone is called as ..................

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

  1. Traumatin

  2. Hormone only

  3. Auxins

  4. Phyllocaline

Show answer
Correct Option: A
Explanation:

Traumatic acid is a monounsaturated dicarboxylic acid naturally occurring in plants. The compound was first isolated from wounded bean plants. Wound hormone is also called as necrohormone.