krit.club logo

Plant Life - Pollination and Fertilization

Grade 6ICSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

•

The flower is the reproductive organ of a plant. The male part is the androeciumandroecium (stamens) and the female part is the gynoeciumgynoecium (pistil/carpel).

•

Pollination is the process of transfer of pollen grainspollen \ grains from the antheranther to the stigmastigma of a flower.

•

Self-pollination occurs when pollen is transferred from the antheranther to the stigmastigma of the same flower or another flower on the same plant.

•

Cross-pollination involves the transfer of pollen from the antheranther of one flower to the stigmastigma of a flower on a different plant of the same species.

•

Agents of pollination include WindWind (Anemophily), WaterWater (Hydrophily), and Insects/AnimalsInsects/Animals (Zoophily).

•

Fertilization is the fusion of the male gametemale \ gamete (found in the pollen tube) with the female gametefemale \ gamete (egg cell) inside the ovuleovule.

•

After fertilization, the ovaryovary develops into the fruit and the ovulesovules develop into seeds.

•

The zygotezygote is the first cell of the new generation, formed by the union of male and female gametes.

📐Formulae

Male Gamete+Female Gamete→ZygoteMale \ Gamete + Female \ Gamete \rightarrow Zygote

Zygote→cell divisionEmbryoZygote \xrightarrow{cell \ division} Embryo

Ovary→post−fertilizationFruitOvary \xrightarrow{post-fertilization} Fruit

Ovule→post−fertilizationSeedOvule \xrightarrow{post-fertilization} Seed

💡Examples

Problem 1:

A flower has very light, smooth, and dry pollen grains produced in large quantities. Identify the most likely agent of pollination.

Solution:

WindWind (Anemophily)

Explanation:

Plants that use wind for pollination produce light and non-sticky pollen so they can be easily carried by air currents. They do not need to attract insects with nectarnectar or bright colors.

Problem 2:

What happens to the sepalssepals, petalspetals, and stamensstamens once fertilization is successfully completed?

Solution:

They usually witherwither and fall offfall \ off.

Explanation:

Once fertilization is achieved, the plant's energy is diverted to the development of the fruitfruit and seedseed. Therefore, non-essential parts like petals and stamens are no longer required and shed.

Problem 3:

Describe the path of the male gamete to reach the egg cell.

Solution:

Stigma→Pollen Tube→Style→Ovary→OvuleStigma \rightarrow Pollen \ Tube \rightarrow Style \rightarrow Ovary \rightarrow Ovule.

Explanation:

Upon landing on a compatible stigmastigma, the pollen grain germinates to form a pollen tubepollen \ tube that carries the male gametes through the stylestyle to reach the egg cellegg \ cell inside the ovuleovule.