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Reproduction in Plants - Sexual Reproduction and Parts of a Flower

Grade 7CBSE

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

🔑Concepts

Sexual reproduction involves the fusion of male and female gametes to produce a new individual, ensuring genetic variation.

The flower is the reproductive organ of the plant. A flower may be unisexual (e.g., papaya, corn) or bisexual (e.g., rose, mustard).

The male reproductive part is the Stamen, which consists of the anther and the filament. The anther contains pollen grains that produce male gametes.

The female reproductive part is the Pistil (or carpel), consisting of the stigma, style, and ovary. The ovary contains ovules, where the female gamete or egg is formed.

Pollination is the transfer of pollen grains from the anther to the stigma. It can be self-pollination (within the same flower) or cross-pollination (between different flowers of the same kind).

Fertilization is the process where the male gamete fuses with the female gamete to form a single-celled ZygoteZygote.

After fertilization, the ovary grows into a fruit, and the ovules develop into seeds. The seeds contain the embryo, which is a result of the ZygoteZygote dividing.

📐Formulae

Male Gamete+Female GameteFertilizationZygoteMale\ Gamete + Female\ Gamete \xrightarrow{Fertilization} Zygote

OvaryPostfertilizationFruitOvary \xrightarrow{Post-fertilization} Fruit

OvulePostfertilizationSeedOvule \xrightarrow{Post-fertilization} Seed

💡Examples

Problem 1:

A pollen grain lands on the stigma of a flower. Describe the process that leads to the formation of a ZygoteZygote.

Solution:

  1. Pollen grain germinates on the stigma. 2. A pollen tube grows through the style to reach the ovary. 3. The male gamete travels through the tube. 4. Fusion of male and female gametes occurs in the ovule: Male Gamete+Female Gamete=ZygoteMale\ Gamete + Female\ Gamete = Zygote.

Explanation:

This process is called fertilization. The pollen tube acts as a conduit for the male gamete to reach the egg inside the ovule.

Problem 2:

Identify the biological 'product' and 'container' in a mango after the process of sexual reproduction.

Solution:

The 'container' is the ripened ovary, which becomes the Fruit (MangoMango). The 'product' inside is the developed ovule, which becomes the SeedSeed.

Explanation:

In angiosperms (flowering plants), the ovary walls thicken and ripen to protect the seeds, which contain the embryo for the next generation.