Tag: pollination and its types

Questions Related to pollination and its types

Lever or turn - pipe mechanism of pollination occurs in.

biology pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

  1. Salvia

  2. Antirrhinum

  3. Phlox

  4. Gloriosa

Show answer
Correct Option: A
Explanation:

In Salvia, pollination is entomophilous, which means it occurs by insects. Pollination occurs by the lever or turns pipe mechanism. The petals of the Salvia are bifurcated. When the insect visits some flower and sits on the petals, then the stamens are brought down to the touch the back of insect and pollen are laden on it.

When the insect visits another flower, cross-pollination occurs.

 Thus, the correct answer is A.

Continued self pollination results in

biology pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

  1. Self incompatibility

  2. Gametes lose vigour

  3. Inbreeding depression

  4. Formation of unisexual flowers.

Show answer
Correct Option: C

Identify the correct pair of statements.
(i) White kernel of Coconut is a free nuclear endosperm
(ii) In dioecious plants, autogamy is prevented but geitonogamy occurs
(iii) Cleistogamous flowers are always self pollinated
(iv) Castor is an endospermic seed.

biology pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

  1. i, ii

  2. iii, iv

  3. ii, iv

  4. ii, iii

Show answer
Correct Option: B
Explanation:
•Coconut has free nuclear endosperm. During the development of a nuclear type of endosperm, the primary endosperm mother cell divides by free nuclear divisions, and these divisions are not followed by cell wall formation. Thus, the free nuclei remain in the cytoplasm of the embryo sac. These nuclei now arrange themselves towards the periphery of the embryo sac and centripetal wall formation occurs that finally leads to a cellular type of endosperm. Thus, the kernel of coconut is cellular endosperm.
•Dioecious plants have unisexual male and female flowers on different plants i.e. a plant may have either male flowers or female flowers but not both. Dioecious plants prevent Autogamy which is the transfer of pollen from the anther to the stigma of the same flower, as only unisexual flowers are there. Also, Geitonogamy which is the transfer of pollen from the anther to the stigma of another flower on the same plant is prevented because male and female flowers are not present on the same plant.
•Cleistogamy is the phenomenon, where flowers never open and in such flowers, only self-pollination occurs within the bud (unopened flower). Bisexual flowers which do not open at all are called cleistogamous. In such flowers, anthers and stigma lie close to each other. When the anthers dehisce in the flower buds, pollen grains come in contact with the stigma and pollination occurs.
•Castor is an endospermic seed in which endosperm is not fully consumed by the growing embryo and it is persistent in the seed.
Hence, from all the statements given in the question, statements (iii) and (iv) are correct.
So, the correct answer is B.

Above ground cleistogamous flowers are formed late in the season in

biology pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

  1. Balsam

  2. Viola

  3. Oxalis

  4. All the above

Show answer
Correct Option: B
Explanation:
Cleistogamy is the phenomenon, where flowers never open and in such flowers, only self-pollination occurs within the bud (unopened flower). Bisexual flowers which do not open at all are called cleistogamous. In such flowers, anthers and stigma lie close to each other. When the anthers dehisce in the flower buds, pollen grains come in contact with the stigma and pollination occurs. Example of Cleistogamous flowers is Viola. Viola has two kinds of flowers, Chasmogamous flowers that are formed on the upper branches in early season, which are pollinated by insects and Cleistogamous flowers that are formed above the ground late in the season.
So, the correct answer is B.
Cleistogamy does not require anthesis because
biology pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

  1. No pollination agent is required

  2. It assures heterozygosity

  3. It allows xenogamy

  4. It favours insect pollination

Show answer
Correct Option: A
Explanation:
Anthesis is the flowering period in which flowers are fully opened.
Cleistogamy is the phenomenon, where flowers never open and in such flowers, only self-pollination occurs within the bud (unopened flower). Bisexual flowers which do not open at all are called cleistogamous. In such flowers, anthers and stigma lie close to each other. When the anthers dehisce in the flower buds, pollen grains come in contact with the stigma and pollination occurs. Cleistogamous flowers are not dependent on external agencies for pollination.  Since, Cleistogamous flowers have self pollination and don't depend on pollination agents, anthesis is required in them as these flowers do not open at all.
So, the correct answer is A.

Both autogamy and geitonogamy cannot occur in

biology pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

  1. Papaya

  2. Cucumber

  3. Castor

  4. Maize

Show answer
Correct Option: A
Explanation:
Autogamy is the kind of self pollination in which pollens are transferred from the anther to the stigma of the same flower. Geitonogamy is the kind of self pollination in which pollens are transferred from the anther of one flower to the stigma of another flower on the same plant.
Papaya is a dioecious plant i.e. it has male and female flowers on separate plants. Hence, neither Autogamy nor Geitonogamy can occur. So, the correct answer is A.

Match the columns and choose the correct combination.

I II
(a) Cleistogamy (m) Insect pollination
(b) Geitonogamy (n) Bud pollination
(c) Entomophily (o) Pollination between flower of the same plant
(d) Xenogamy (p) Wind pollination
(q) Cross pollination
biology pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

  1. a-m, b-q, c-n, d-o

  2. a-n, b-o, c-m, d-q

  3. a-q, b-p, c-o, d-n

  4. a-o, b-m, c-q, d-n

Show answer
Correct Option: B
Explanation:
•Cleistogamy is the phenomenon, where flowers never open and in such flowers, only self-pollination occurs within the bud (unopened flower).
•Geitonogamy is a type of self pollination in which pollen are transferred from the anther of one flower to the stigma of another flower of the same plant.
•Entomophily is the pollination of flowers by means of insects.
•Xenogamy is the cross pollination between the flowers of different plants.
Hence, the correct match is:
a-n, b-o, c-m, d-q
So, the correct answer is B.

Which one of the following is one of the characteristics of self-pollinated flowers ?

biology pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

  1. Flowers are large and showy

  2. Flowers remain closed and do not open

  3. Stigma and anthers mature at the same time

  4. Pollen is produced in very large quantities

Show answer
Correct Option: B
Explanation:

Self-pollinated flowers remain closed and don't open allowing maximum time for the mature stamens and pistils to exchange and receive the gametes. 

So, the correct option is 'Flowers remain closed and do not open'.

Which of the following features are mostly observed in self pollinating flowers?

biology pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

  1. Inconspicuous flowers

  2. Presence of nectaries

  3. No fragrance

  4. Short style

  5. Versatile anthers

Show answer
Correct Option: A
Explanation:

The inconspicuous flower is a flower that is small, not showy and difficult to see. They are observed in self-pollinating flowers.

So, the correct option is 'Inconspicuous flowers'.

Which of the following statement is NOT correct?

biology pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

  1. Pollen germination and pollen tube growth are regulated by chemical components of pollen interacting with those of the pistil.

  2. Some reptiles have have also been reported as pollinators in some plant species.

  3. Pollen grains of many species can germinate on the stigma of a flower, but only one pollen tube of the same species grows into the style.

  4. Insects that consume pollen or nectar without bringing about pollination are called pollen/nectar robbers.

Show answer
Correct Option: C
Explanation:

Pollen grains of other species are not compactable and do not germinate on the stigma of the flower of different species.

So, the correct option is 'Pollen grains of many species can germinate on the stigma of a flower, but one pollen tube of the same species grow into the style'.