Tag: plants: structure and function

Quizzes (27) Questions (150)

Questions Related to plants: structure and function

Multiple choice biology plant growth seed dormancy fruit plants: structure and function

Which of the following is used to break the seed dormancy?

  1. ABA

  2. Cytokinin

  3. Auxin

  4. Ethylene
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

ABA, abscisic acid was discovered for its role in regulating abscission and dormancy. It acts as a general plant growth inhibitor and an inhibitor of plant metabolism. It inhibits seed germination, stimulates the closure of stomata in the epidermis and increases the tolerance of the plant to various kind of stresses. 

Gibberellins cause fruits like apple to elongate and improve its shape. They also delay senescence.
Auxins promote stem elongation, inhibit the growth of lateral buds (maintains apical dominance). They are produced in the stem, buds, and root tips. Ethylene is highly effective in fruit-ripening, it promotes senescence and abscission of plant organs especially leaves and flowers. Ethylene breaks the seed and bud dormancy and initiates seed germination.

Multiple choice biology plant growth seed dormancy fruit plants: structure and function

Dormancy of seed is broken by 

  1. Auxin

  2. Gibberellin

  3. Abscisic acid

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

Gibberellin are involved in seed germination in certain plants. They break seed dormancy by promoting mobilisation of reserve food material. In a classic experiment involving barley seed germination, researchers showed that the release of gibberellin from the embryo triggers the synthesis of $\alpha$-amylase, an enzyme that digests starch in the endosperm. As a result, glucose becomes available for absorption by the embryo. Although enzymes mobilize starch reserves in many types of seeds, gibberellin control of seed enzymes appears restricted to cereals and other grasses. 

Thus, the correct answer is option B.

Multiple choice biology plant growth seed dormancy fruit plants: structure and function

Type of seed dormancy is

  1. Physiological

  2. Morphological

  3. Mechanical

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The conditions present outside the embryo causes Exogenous dormancy and are grouped into physiological, morphological and mechanical dormancy.

So the correct option is 'All of the above.'

Multiple choice biology plants: structure and function seed dormancy fruit plant growth

Seed dormancy is an adaptation to ensure its germination during

  1. Unfavourable period

  2. Favourable period

  3. Stress condition

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

Seed dormancy is an adaptation to ensure its germination during favourable period. One important function of most seeds is delayed germination, which allows time for dispersal and prevents germination of all the seeds at the same time. The staggering of germination safeguards some seeds and seedlings from suffering damage or death from short periods of bad weather or from transient herbivores; it also allows some seeds to germinate when competition from other plants for light and water might be less intense. Seed dormancy can be caused by all the factors mentioned. A dormant seed is one that is unable to germinate in a specified period of time under a combination of environmental factors that are normally suitable for the germination of the non-dormant seed. Dormancy is a mechanism to prevent germination during unsuitable ecological conditions, when the probability of seedling survival is low. 
Thus, the correct answer is option B.

Multiple choice biology plant growth seed dormancy fruit plants: structure and function

Select the correct reason for seed dormancy.

  1. Immature embryo

  2. Hard seed coat

  3. Presence of germinating inhibitors

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Dormancy is the condition of a seed when it fails to germinate even when environmental conditions considered necessary for germination are available. The following are some main causes of seed dormancy:

1) Immature embryo: some seeds fail to germinate due to the partial development of the embryo at the time of their dissemination.
2) Hard seed coat: the presence of hard seed coat causes dormancy as it is impermeable to water and gases and mechanically restrict the growth of the embryo.
3) The presence of germinating inhibitors: Some plants produce certain chemical compounds which inhibit seed germination.
Thus option D is the correct answer. 

Multiple choice biology plant growth seed dormancy fruit plants: structure and function

Treatment of seed at low temperature under moist conditions to break its dormancy is called as 

  1. Chelation

  2. Scarification

  3. Vernalization

  4. Stratification
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Stratification involves the treatment of seeds at low temperature (5-10 degree C) under sufficiently moist conditions to break its dormancy and to induce germination.

Scarification involves damage or breakage of seed coat by physical methods or chemical methods to break seed dormancy.
Vernalization and Chelation are the methods of cooling of seed during germination in order to accelerate flowering when it is planted. Hence option D is correct.

Multiple choice biology plant growth seed dormancy fruit plants: structure and function

Common cause of seed and bud dormancy is the presence of

  1. Ethylene

  2. Cytokinins

  3. Abscisic acid

  4. Both B and C
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Dormancy is defined as the condition of seed when it fails to germinate even though the envoirnment condtions, usually considered favourable for active growth, are present.

A. Ethylene serves as a hormone in plants. It acts at trace levels throughout the life of the plant by stimulating or regulating the ripening of fruit, the opening of flowers, and the abscission (or shedding) of leaves.

B. Cytokinins are plant hormones that cause increased celldivision by stimulating the process of mitosis. 

C. Abscisic acid owes its names to its role in the abscission of plant leaves. In preparation for winter, ABA is produced in terminal buds. This slows plant growth and directs leaf primordia to develop scales to protect the dormant buds during the cold season.

So, the correct answer is 'Abscisic acid'.

Multiple choice biology plant growth seed dormancy fruit plants: structure and function

The pant in which hypocotyl store food is

  1. <p>Bertholettia</p>

  2. <p>Nymphae</p>

  3. Cotton

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

A. The storage function  of Lecythis and (Brazil nut) Bertholletia is neither endosperm nor cotyledon, but hypocotyl.

B. Nymphae- Food stored in perisperm.

C. Cotton- Food stored in cotyledons.

D. Rice- Food stored in endosperm.

So, the correct answer is 'Bertholettia'.

Multiple choice biology plant growth seed dormancy fruit plants: structure and function

Which of the following is associated with dormancy of seeds?

  1. IBA

  2. GA

  3. Ethylene

  4. Ferulic acid
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Germination Inhibitors: They occur in the seed coats and cotyledons of the embryos. The important germination inhibitors causing seed dormancy are abscisic acid, phenolic acid, ferulic acid, coumarin, short fatty acids and cyanogenic chemicals, e.g., Apple, Peach, Ash, Cucurbita, Iris, Xanthium. Counteracting Inhibitors: Inhibitors are destroyed by dipping seeds in KNO$ _3$, thiourea, ethylene chlorohydrin and gibberellin. IBA, GA, ethylene are counteracting inhibitors of seed dormancy while ferulic acid is a germination inhibitor. So, the correct answer is 'Ferulic acid'.