Test: Pollination - NEET MCQ

The plant in the diagram:  A wind-pollinated plant showing compact inflorecence and well-exposed stamen: LABELLING UNDER DIAGRAM IN NCERT
Here's why:
- The plant has feathery structures resembling stigmas, which catch pollen.
- The lack of showy petals or nectar suggests a reliance on wind.
- Wind-pollinated plants typically have lightweight pollen that can be carried by ai
Therefore, based on its characteristics, wind is the most likely pollination method for this plant.
Topic in NCERT: Agents of Pollination
Line in NCERT:   Pollination by wind is more common amongst abiotic pollinations. Wind pollination also requires that the pollen grains are light and non-sticky so that they can be transported in wind currents. They often possess well-exposed stamens (so that the pollens are easily dispersed into wind currents, Figure 2.10) and large often-feathery stigma to easily trap air-borne pollen grains. Wind-pollinated flowers often have a single ovule in each ovary and numerous flowers packed into an inflorescence; a familiar example is the corn cob – the tassels you see are nothing but the stigma and style which wave in the wind to trap pollen grains. Wind-pollination is quite common in grasses.

The correct answer is: D: Statement I is correct; Statement II is correct and Statement II explains Statement I.
- Cleistogamous flowers have an advantage and a disadvantage over chasmogamous flowers.
- Seed set is assured even without pollinators, but genetic variations are less in cleistogamous compared to chasmogamous flowers.
- This means that cleistogamous flowers ensure seed production without external help, but with limited genetic diversity, which is explained by the second statement.
Topic in NCERT: Cleistogamous flowers
Line in NCERT: "Cleistogamous flowers produce assured seed-set even in the absence of pollinators."

To prevent both autogamy and geitonogamy, the correct choice is C:
Dioecious plant bearing only male or female flowers. Here's why:
- Dioecious plants have separate male and female individuals, reducing the likelihood of self-pollination.
- By having only male or female flowers on each plant, cross-pollination between different plants is necessary for fertilization, preventing both autogamy (self-pollination) and geitonogamy (pollination between different flowers of the same plant).
Topic in NCERT: Self-Incompatibility and Mechanisms Preventing Self-Pollination
Line in NCERT: Another device to prevent selfpollination is the production of unisexual flowers. If both male and female flowers are present on the same plant such as castor and maize (monoecious), it prevents autogamy but not geitonogamy. In several specissuch as papaya, male and female flowers are present on different plants, that is each plant is either male or female (dioecy). This condition prevents both autogamy and geitonogamy.

• Cleistogamy is autogamous pollination.
• Cleistogamous flowers are those that stay close together to avoid cross pollination and have adaptations to assist self pollination.
• Self-pollination Or Autogamy:
  
  Fig: Cleistogamous Flowers (inside unopened buds)
• Geitonogamy is the transfer of pollen grains from the anther to the stigma of another flower of the same plant.
•  Xenogamy is the transfer of pollen grains from anther to the stigma of a different plant.
• Chasmogamous flowers which are similar to flowers of other species with exposed anthers and stigma. It helps in both self and cross pollination of flowers.

Hence, the correct option is A

Topic in NCERT: Cleistogamous flowers

Line in NCERT: "Cleistogamous flowers are invariably autogamous as there is no chance of cross-pollen landing on the stigma."

Emasculation is the process of removing the anthers from the flower bud to prevent self-pollination. It is necessary in artificial hybridization to ensure that only the desired pollen is used for pollination and to avoid contamination with unwanted pollen.

Topic in NCERT: EMASCULATION AND BAGGING TECHNIQUES

Line in NCERT: "Emasculation is the removal of anthers to prevent self-pollination."

Correct Answer: D
- Autogamy refers to the process where a flower is self-pollinated, ensuring fertilization without needing another flower.
- Cleistogamous flowers are self-pollinating flowers that never open, ensuring autogamy.
- Therefore, it is accurate to say that cleistogamous flowers always exhibit autogamy as they are designed to self-pollinate without the need for external agents like insects or wind.
Topic in NCERT: Cleistogamous flowers
Line in NCERT: "Cleistogamous flowers are invariably autogamous as there is no chance of cross-pollen landing on the stigma."

Line in NCERT : Some examples of water pollinated plants are Vallisneria and Hydrilla which grow in fresh water and several marine sea-grasses such as Zostera. Not all aquatic plants use water for pollination. In a majority of aquatic plants such as water hyacinth and water lily, the flowers emerge above the level of water and are pollinated by insects or wind as in most of the land plants.

• Wind pollination is common in grasses.
• Grasses produce a large amount of pollen which by the help of wind reach to the stigma for reproduction.

Hence, the correct option is C
NCERT Reference: Topic “Agents of Pollination” of chapter Sexual Reproduction in Flowering Plants of NCERT

Topic in NCERT: Wind Pollination

Line in NCERT: "Wind-pollination is quite common in grasses."

• In self-pollinating plants, there is less dependence on external factors to cause pollination.
• These plants depend on wind or other smaller insects that visit the flower regularly.
• In self- pollinating flowers, the anthers, and stigma are of similar lengths to facilitate the transfer of pollen.

Self -pollination can be further divided into two types:

1. Autogamy– In this type of self-pollination, the pollen is transferred from the anthers of one flower to the stigma of the same flower.
2. Geitonogamy– In this type of self- pollination, the anthers are transferred from the anthers of one flower to the stigma of another flower but on the same plant.

Self Pollination:

Hence, the correct option is A

Topic in NCERT: Kinds of Pollination

Line in NCERT: "Geitonogamy - Transfer of pollen grains from the anther to the stigma of another flower of the same plant."

1. Geitonogamy is a type of self pollination in which pollen is transferred from the anther of one flower to the stigma of another flower of the same plant.
2. Xenogamy is the cross-pollination between the flowers of different plants. It produces hererozygosity because two genetically different parents are involved.
   Cross-pollination is the transfer of pollen grains from anther to stigma of different flower
3. Chasmogamy is the condition in which bisexual flowers have exposed anthers and stigma. Both self-pollination and cross pollination can occur in these flowers.
4. Autogamy is a type of self-pollination in which pollen is transferred from the anther to the stigma of the same flower.

Thus, it's xenogamy that can bring genetically different pollen grains to the stigma of a plant.

Hence, the correct option is B
NCERT Reference: Topic “Pollination” of chapter "Sexual Reproduction in Flowering Plants" of NCERT

Topic in NCERT: Kinds of Pollination

Line in NCERT: "Xenogamy - Transfer of pollen grains from anther to the stigma of a different plant (Figure 1.9b). This is the only type of pollination which during pollination brings genetically different types of pollen grains to the stigma."

Wind-pollinated flowers are characterized by traits facilitating pollination by wind.
The exception is D: Many ovules in each ovary. its actually Wind pollinated flowers often have a single ovule in each ovary and numerous flowers packed into an inflorescence; a familiar example is the corn cob – the tassels you see are nothing but the stigma and style which wave in the wind to trap pollen grains.Here's why:
- Wind-pollinated flowers typically have:
- Large, often-feathery stigma to catch airborne pollen effectively.
- Light and non-sticky pollen grains that can be carried by the wind.
- Well-exposed stamens for easy dispersal of pollen.
- Having many ovules in each ovary is not a characteristic related to wind pollination; it's more about seed development after pollination.
Topic in NCERT: Wind Pollination in Flowering Plants
Line in NCERT: "Wind-pollinated flowers often have a single ovule in each ovary and numerous flowers packed into an inflorescence."

The correct answer is D: Pollination by water in Vallisneria.
- Vallisneria is a submerged aquatic plant that relies on water for pollination.
- It has separate male and female flowers on different plants.
- Male flowers detach and float on the water surface, releasing pollen.
- The pollen is then carried by water currents to reach the female flowers for pollination.
- This method ensures successful fertilization in underwater environments.
Topic in NCERT: Pollination by Water
Line in NCERT: "Some examples of water pollinated plants are Vallisneria and Hydrilla which grow in fresh water and several marine sea-grasses such as Zostera."

Pollination can be categorized into three types based on the source of pollen: autogamy (pollination within the same flower), geitonogamy (pollination between flowers of the same plant), and xenogamy (pollination between flowers of different plants).

Topic in NCERT: Kinds of Pollination

Line in NCERT: "Depending on the source of pollen, pollination can be divided into three types."