Reproduction in Plants

Reproduction is a vital process for all living organisms, ensuring the continuation of species. This chapter explores how plants reproduce, both sexually and asexually.

8.1 Modes of Reproduction

Plants reproduce in two main ways: asexual and sexual reproduction.

Asexual Reproduction: New plants are produced without seeds.

Sexual Reproduction: New plants are produced from seeds.

Asexual Reproduction

Vegetative Propagation: New plants grow from parts of the parent plant such as roots, stems, leaves, or buds. This type of reproduction uses vegetative parts of the plant.

Activity 8.1: You can grow a new plant by cutting a branch (called a cutting) from a rose or champa plant. Bury it in soil and water it daily. Observe the growth of new roots and leaves.

Example Plants:

• Sugarcane, potato, and rose do not reproduce through seeds but through vegetative propagation.

• Ginger and turmeric can grow new plants from their roots.

• Bryophyllum can grow new plants from buds on the edges of its leaves.

Budding: Yeast, a single-celled organism, reproduces by forming a bud, which grows and eventually detaches to form a new cell.

Fragmentation: Algae reproduce by breaking into pieces (fragments), each of which grows into a new individual.

Spore Formation: Fungi and some plants like mosses and ferns produce spores, which are asexual reproductive bodies. Spores can survive harsh conditions and grow into new plants when favorable conditions return.

Sexual Reproduction

Structure of a Flower: Flowers are the reproductive parts of a plant. They have male parts (stamens) and female parts (pistils).

Pollination: The transfer of pollen from the anther (male part) to the stigma (female part) of a flower.

• Self-Pollination: Pollen from the same flower or another flower of the same plant lands on the stigma.

• Cross-Pollination: Pollen from one plant lands on the stigma of a flower on another plant of the same species.

Fertilisation: The fusion of male and female gametes to form a zygote, which develops into an embryo.

Fruits and Seed Formation

After fertilisation, the ovary grows into a fruit, and the ovules develop into seeds. The fruit protects the seeds, which contain the developing embryo.

Seed Dispersal

Seeds need to be spread out to grow into healthy plants without competing for resources. Dispersal methods include:

• Wind: Light seeds or seeds with wings or hairs are carried by wind (e.g., dandelion, maple).

• Water: Seeds that float are carried by water (e.g., coconut).

• Animals: Seeds with hooks or spines attach to animals and are carried to new locations (e.g., burdock).