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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 GameteZygoteMale \ Gamete + Female \ Gamete \rightarrow Zygote

Zygotecell divisionEmbryoZygote \xrightarrow{cell \ division} Embryo

OvarypostfertilizationFruitOvary \xrightarrow{post-fertilization} Fruit

OvulepostfertilizationSeedOvule \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:

StigmaPollen TubeStyleOvaryOvuleStigma \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.

Pollination and Fertilization - Revision Notes & Key Formulas | ICSE Class 6 Science