Tag: plants: structure and function

Questions Related to plants: structure and function

Which of the following is not the example of escape in time?

biology plant growth seed dormancy fruit plants: structure and function

  1. Seed dormancy

  2. Arctic tern

  3. Diapause

  4. Hibernation

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Correct Option: B

Dormancy is absent in seeds of ______________.

biology plant growth seed dormancy fruit plants: structure and function

  1. Wheat

  2. Maize

  3. Rhizophora

  4. Cycas

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Correct Option: A

Which of the following action makes a seed coat becomes permeable to water?

biology plant growth seed dormancy fruit plants: structure and function

  1. Scarification

  2. Stratification

  3. Vernalization

  4. All of the above

Show answer
Correct Option: A
Explanation:

Scarification involves weakening, opening or altering the coat of a seed to encourage the germination. It can be done mechanically, thermally and chemically. This will make the seed coat permeable for water and air, which will help in germination of seeds.

Stratification is the process of pretreating the seed to stimulate natural condition that a seed must endure before germination. It involves soaking and chilling of seeds prior to sowing.
Vernalisation is the induction of plant's flowering process by exposure to the prolonged cold of winter. It literally has to be chilled in order to reproduce.
Somewhere, all these processes are used to break the dormancy the seeds naturally as well as artificially
So, the correct answer is 'Scarification'

Which of the following conditions is needed by almost all seeds to break dormancy?

biology plant growth seed dormancy fruit plants: structure and function

  1. Exposure to light

  2. lmbibition

  3. Abrasion of the seed coat

  4. Exposure to cold temperatures

Show answer
Correct Option: B
Explanation:

Seed dormancy allows seeds to overcome periods that are unfavourable for seedling established and is therefore important for plant ecology and agriculture. Several processes are known to be involved in the induction of dormancy and in the switch from the dormant to the terminating state. Imbibition is a special type of diffusion when water is absorbed by solids-colloids causing an enormous increase in volume. If it were not for the pressure due to imbibition, seedlings would not have been able to emerge out of the soil into the open; they probably would not have been able to establish.

So the correct option is 'Imbibition'.

State whether the following statements are true or false.
In a plant seedling exposed to light on only one side, auxin produced in the tip moves to the lighted side and inhibits growth of cells there.

biology plant growth seed dormancy fruit plants: structure and function

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

When the light is exposed to only one side of the seedling, the auxin will move and grow towards the side of the light. This phenomenon is termed as phototropism (Movement of plant growth towards the source of light). Thus only one seed of the seedling will be able to grow and the other where light is unable to reach will not grow.

So, the correct statement is 'False'.

Seed dormancy is associated with

biology plant growth seed dormancy fruit plants: structure and function

  1. Hard seed coat

  2. Immature embryo

  3. Presence of germination inhibitors

  4. All of these

Show answer
Correct Option: D
Explanation:
Seed dormancy is defined as a state in which seeds are prevented from germinating even under environmental conditions normally favourable for germination. There are a few main causes of seed dormancy, such as hard seed coat, which are impermeable to water and gases so restrict water uptake and oxygen exchange. The immature embryo that is seeded with small and undeveloped embryos do not germinate. Germination inhibitors that is Seeds contain some chemical plant growth regulators, which inhibit seed germination.
So, the correct option is, 'all of these'.

Seed dormancy can be broken by the following combination of chemicals

biology plant growth seed dormancy fruit plants: structure and function

  1. ${GA} _{3}$, IAA, ABA

  2. $KN{O} _{3}$, ${GA} _{3}$ and ethylene chlorohydrin

  3. NAA, 2, 4, 5-T and IAA

  4. ABA, BAP and ${GA} _{3}$

Show answer
Correct Option: B
Explanation:

Seed dormancy is induced in plants under unfavorable condition due to growth inhibitor hormone-like abscisic acid. Gibberellin is most commonly used to breaks the seed dormancy and induce flowering under normal condition. Apart from this, other chemicals are used to break the seed dormancy. These chemicals include potassium nitrate (KNO$ _3$), thiourea and ethylene chlorhydrin.

Thus, the correct answer is option B.

An example of false fruit is

biology fruit and seed morphology of the fruit fruit plants: structure and function

  1. Apple

  2. Banana

  3. Grapes

  4. Mango

Show answer
Correct Option: A
Explanation:

A false fruit or pseudo-carp is derived from the floral parts other than ovary, e.g., peduncle in cashew-nut, thalamus in apple, pear, gourd and cucumber; fused perianth in mulberry and calyx in Dillenia.

Thus, the correct answer is option A.

A fruit without seed is not useful in case of

biology fruit and seed morphology of the fruit fruit plants: structure and function

  1. Grape

  2. Pomegranate

  3. Orange

  4. Lemon.

Show answer
Correct Option: B
Explanation:

Pomegranate is a fruit with outer hard layer formed of exocarp and partially mesocarp, which also forms septa in the fruit. The endocarp covers the seeds as a papery structure and the seeds have modified fleshy testa which can be eaten. So, if seed is removed, the rest is not useful.

In grape, the pericarp is eaten and seed is not eaten.
In orange and lemon, the endocarp is edible/usefull and  seed is not eaten.
So, the correct answer is 'Pomegranate'.

The fruit developed from single ovary is

biology fruit and seed morphology of the fruit fruit plants: structure and function

  1. Composite

  2. Simple fruit

  3. Aggregate fruit

  4. None of the above

Show answer
Correct Option: B
Explanation:

A simple fruit is one which develops from a single ovary of a single flower.

Composite fruit develops from an inflorescence.
Aggregate fruits develop from multicarpellary apocarpous ovary.
So, the correct answer is 'Simple fruit'.