Summary
In angiosperms one sperm fertilises the egg and the other forms the triploid endosperm.
In depth
One sperm nucleus fuses with the egg (2n zygote) and the other with two polar nuclei (3n endosperm), which feeds the embryo. Discovered by Nawaschin in 1898.
The two sperm in a pollen tube fuse with two different female cells, an event unique to flowering plants. The endosperm gives nutrition for the embryo, offering a reproductive efficiency since the nutritive tissue forms only if fertilisation occurs.
Remember: endosperm is triploid (3n).
Discovered in 1898 by Nawaschin and Guignard. The pollen grain has a generative cell that divides into two sperm; the tube nucleus guides growth. In the embryo sac, one sperm fertilises the egg, and the other fuses with the central cell with two polar nuclei to make triploid endosperm, which stores starch, oil or protein, such as in cereals. It ensures that food is only made when an embryo is present, which saves resources.
Endosperm is the main food source for humans: wheat, rice and maize grains are mostly endosperm. In some plants (orchids), little endosperm forms, and in beans the endosperm is absorbed by cotyledons. Evolution of endosperm may be a driver of angiosperm success.
Frequently asked questions
What is Double Fertilisation?
In angiosperms one sperm fertilises the egg and the other forms the triploid endosperm.
Which area of biology covers Double Fertilisation, and how advanced is it?
Double Fertilisation is one of the 56 topics in Plant Biology. It is rated Intermediate, so it suits learners who already know the core vocabulary. Related topics in this area include Monocots vs Dicots, Pollination, Plant Kingdom.
Why does Double Fertilisation matter?
This is a defining feature of flowering plants and the source of most of our calories.
Can you give an example of Double Fertilisation?
Cereal endosperm is the grain we eat.
What should I learn before Double Fertilisation?
Work through the Beginner topics in Plant Biology first, such as Plant Kingdom, Photosynthesis, Chlorophyll, then return to Double Fertilisation. Intermediate topics assume the Beginner vocabulary.
What topics are related to Double Fertilisation?
The closest topics to Double Fertilisation are Monocots vs Dicots, Pollination, Plant Kingdom, Seeds. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Double Fertilisation?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Double Fertilisation. To practise the whole of Plant Biology, use the Plant Biology quiz.
How is Double Fertilisation different from Monocots vs Dicots?
Double Fertilisation: In angiosperms one sperm fertilises the egg and the other forms the triploid endosperm. Monocots vs Dicots: Monocots have one cotyledon, parallel leaf veins and scattered bundles; dicots have two, netted veins and ringed bundles. Read both side by side and note what each one explains.
How should I study Double Fertilisation step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Monocots vs Dicots and explain the difference aloud. Finally, take the Plant Biology quiz and come back to this page for any question you miss.