Plant growth and development

Maryland mammoth tobacco is a short day plant. Its critical duration of darkness is 10 hours. Under which of the following conditions will it not flower?

• A

• B

• C

• D

Four potted plants (I, II, III, and IV) of a short day plant, which has the critical period of 14 hours; are taken and exposed to light for different time periods. The light periods given are listed in the table.

Which potted plant will show flowering after exposure to light?

• I

• II

• III

• IV

Sedum is a long day plant. Its critical duration of light is 13 hours. Under which of the following conditions would it flower?

• A

• B

• C

• D

Select the incorrect statement.

• Impermeable and hard seed-coat causes seed dormancy.

• Effect of inhibitory substances can be removed by subjecting the seeds to gibberellic acid and nitrates.

• Immature embryos causes seed dormancy.

• None of these

A farmer while growing grape plants in his garden, observes the following:

(i) Fruit size normally remained small

(ii) Natural seed abortion.

(iii)Reduced stem and leaf growth.

Which problems could be solved by application of gibberellic acid during the development of fruits?

• (i) and (ii)

• (i) and (iii)

• (i), (ii) and (iii)

• None of these

Assertion : The constantly dividing cells both at the root apex and the shoot apex, show the mersitematic phase of growth.

Reason : The cells of this region are rich in protoplasm and are without nuclei.

• Both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.

• Both Assertion and Reason are true but the Reason is not the correct explanation of the Assertion.

• Assertion is true but Reason is false.

• Both Assertion and Reason are false

Assertion : Nutrients are required by plants for the synthesis of protoplasm and act as source of energy.

Reason : Water provides the medium for enzymatic activities needed for growth.

• Both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.

• Both Assertion and Reason are true but the Reason is not the correct explanation of the Assertion.

• Assertion is true but Reason is false.

• Both Assertion and Reason are false

Match the following:

• A-I, B-II, C-III, D-IV

• A-II, B-III, C-IV, D-I

• A-III, B-IV, C-I, D-II

• A-IV, B-I, C-II, D-III

Statement I: Difference in shape of leaves in air and those in water in buttercup is example of plasticity.

Statement II: Nutrients are required by plants for releasing the metabolic energy essential for plant growth activities.

Statement III: Increased vacuolation, increase in cell size and new cell wall deposition are characteristic of cells in phase of elongation.

• Statement I and II are correct

• Statement II and III are correct

• Statement I and III are correct.

• All the above are correct.

Which amongst the following is a natural auxin?

• 2,4-D

• IAA

• NAA

• GA3