Understand seed structure, fruit classification, and the mechanisms of asexual seed production (apomixis/polyembryony).
Preview · progress not saved — Chapter 1 is free
Maturation of the ovule into seed and ovary into fruit.
Fertilised ovules naturally develop into seeds. Depending on how they utilize their food reserves, seeds are broadly classified into two main types based on endosperm retention.
Structure of an apple showing thalamus contribution.
Structure of some seeds
In false fruits like the apple, the thalamus forms the main fleshy edible portion, rather than just the ovary.
Cloning via seeds.
While seeds are generally the products of fertilisation, a few flowering plants—such as some species of Asteraceae and grasses—have evolved a special mechanism to produce seeds without it. This is called apomixis.
Apomixis is essentially a form of asexual reproduction that mimics sexual reproduction. In some apomictic species, a diploid egg cell is formed without reduction division (meiosis) and develops directly into an embryo without needing to be fertilised.
Test understanding of fruit types and seed terminology.
Mature seeds can be classified based on whether they retain endosperm. Seeds that completely consume their endosperm during development are called seeds, with examples being pea and groundnut. In a few species like black pepper and beet, the remnant nucellus persists and is referred to as the . As ovules mature into seeds, the ovary develops into a fruit, and its wall becomes the pericarp. While most fruits develop solely from the ovary, fruits that develop from the ovary along with the thalamus are called fruits, such as apples and strawberries. Occasionally, fruits develop without any fertilisation process occurring. Fruits that develop without fertilisation are called fruits, and they can be induced using growth hormones to be seedless.