Overview

This topic covers how plants reproduce and develop, from pollination and fertilization to seed formation and germination. Understanding plant life cycles is essential to studying ecosystems, agriculture, and evolution.

Key Concepts and Structures

• Sexual Reproduction: Involves the fusion of male (pollen) and female (ovule) gametes in flowering plants to form a zygote that develops into a seed.
• Flower Anatomy: Key parts include sepals, petals, stamens (anther + filament), and carpels (stigma, style, ovary).
• Pollination: Transfer of pollen from anther to stigma, often aided by wind, insects, birds, or mammals.
• Fertilization: Once pollen reaches the stigma, it grows a pollen tube to deliver sperm to the ovule inside the ovary.
• Seed Development: Fertilized ovule becomes a seed. The seed contains the embryo, endosperm (nutrients), and a protective coat.
• Fruit Formation: The ovary develops into a fruit, which helps protect the seed and may aid in dispersal.
• Asexual Reproduction: Some plants reproduce without fertilization through mechanisms like runners, tubers, and cuttings.
• Germination: The process by which a seed sprouts and begins to grow, requiring water, oxygen, and suitable temperature.
• Hormonal Control: Plant hormones such as auxins and gibberellins regulate flowering, seed dormancy, and germination.
• Alternation of Generations: Plants alternate between diploid (sporophyte) and haploid (gametophyte) stages in their life cycles.

Quick Tip