Tag: plant growth and development

Questions Related to plant growth and development

It has been observed that after-effects of low temperature treatment are helpful in promoting the flowering in certain plants. Through this the vegetative period of plants becomes short and early flowering takes place. This phenomenon is known as

  1. Vernalisation

  2. Florignation

  3. Photoperiodism

  4. Heliotropism


Correct Option: A
Explanation:

Vernalization is the induction of a plant's flowering process by exposure to the prolonged cold of winter, or by an artificial equivalent. After vernalization, plants have acquired the ability to flower, but they may require additional seasonal cues or weeks of growth before they will actually flower. Vernalization is sometimes used to refer to herbal (non-woody) plants requiring a cold dormancy to produce new shoots and leaves but this usage is discouraged. Many plants grown in temperate climates require vernalization and must experience a period of low winter temperature to initiate or accelerate the flowering process. This ensures that reproductive development and seed production occurs in spring and winters, rather than in autumn. The needed cold is often expressed in chill hours. Typical vernalization temperatures are between 5 and 10 degrees Celsius (40 and 50 degrees Fahrenheit).

So the correct option is 'vernalisation'.

Which of the following hormones can replace vernalisation?

  1. Auxin

  2. Cytokinin

  3. Gibberellins

  4. Ethylene


Correct Option: C
Explanation:

Vernalization is the process by which plant can be induced to flower by exposing it to the prolonged period of low temperature or cold. After this, plants show quicker flowering. Gibberellic acid is a plant hormone which helps in growth of stem. It also brings about the rapid flowering in plants.

Thus, the correct answer is option C.

Low temperature is required in apple for a duration of

  1. 800 hours

  2. 400 hrs

  3. 200 hrs

  4. 100 hrs


Correct Option: A
Explanation:

Apple is able to grow in low temperature the earlier stages have less tolerance of lower temperature than the later stages and it requires around 800 hours for growth.

So the correct option is '800 hours'

The phenomenon which shortens vegetative period and hastens flowering is

  1. Etiolation

  2. Vernalisation

  3. Photoperiodism

  4. Parthenocarpy


Correct Option: B
Explanation:

Etiolation is a condition in which plant is grown in the partial or complete absence of light. The leaves are tiny and yellow in color. Vernalization is the process by which plant can be induced to flower by exposing it to the prolonged cold or winter. It shortens the vegetative period and hastens the flowering. Photoperiodism is the phenomenon in which various physiological reactions like flowering response to the relative length of day and night.

Thus, the correct answer is option B.

Nitrate reductase enzyme forms?

  1. $N _2$

  2. Amino acids

  3. $NCT _2$

  4. $NO^- _3$


Correct Option: A

Citrus canker is caused by.

  1. Alter aria citric

  2. Xanthamonas citric

  3. Diaporthe citric

  4. Phytophthora citrophthora


Correct Option: A

The compound pollen grain, massula is characteristic of ____________.

  1. Papilionaceae

  2. Caesalpiniaceae

  3. Mimosaceae

  4. Proteaceae


Correct Option: A

Pseudo-embryo sacs present in.

  1. Cyperaceae

  2. Poaceae

  3. Podostemonaceae

  4. Solanaceae


Correct Option: A

Fragrant flowers with well developed nectaries are an adaptation for _______.

  1. Hydrophily

  2. Anemophily

  3. Entomophily

  4. None of these


Correct Option: C
Explanation:

Entomophilous flowers produce an odour which many be pleasant (e.g., jasmine) or foul(e.g., Aristolochia, Arum Rafflesia). Smell and nectar attract flies and other insects.

Clay and humic acid particles hold tightly.

  1. Nitrate ions

  2. Ammonium ions

  3. Nitrite ions

  4. Molecular nitrogen


Correct Option: A