Science 7–10 · Year 9

Flower dissection: male and female parts and the ovules inside

Science understanding: Biological sciences (ACARA Year 9 reproduction, AC9S9U02; on the NSW side flower structure sits in Stage 4 Living systems, whose plant systems content point carries the example of a plant dissection to observe the roots, flowers, stems and leaves of plants, and the Stage 5 content point on how genetic information is passed on to offspring by sexual and asexual reproduction is cited here as SC5-GEV-02, as it is for the two asexual reproduction entries in this bucket; pollination is named nowhere in the Stage 4 or Stage 5 content)

PracticalLow risk

The idea

A flower is a reproductive organ whose parts are arranged for pollen transfer and fertilisation, and its structure can be read from the outside in.

Safety card

Low riskAn adult supervises

Hazards

Blade
Lily pollen stains fabric and is toxic to cats

Controls

Cut on a board away from the hand
Keep flowers away from pets; wash hands

Note

No hazardous chemicals; record a RiskAssess risk assessment for the activity as school procedure requires.

What you need

One flower per learner, chosen for the season and what is available as the SAPS flower dissection notes advise; large simple flowers such as lily (Lilium) or alstroemeria from a florist, or a brassica flower from the garden, are easy to dissect
Forceps, scalpel or single-edged blade on a board, hand lens, white card, clear sticky tape
A slide, coverslip and microscope for pollen

How to do it

Working from the outside in, remove the outer whorl (sepals, or tepals in a lily) and tape each part to the card in a row; count them.
Remove the second whorl and tape it in a second row; count it. A lily and an alstroemeria have no petals: both whorls are tepals, which is why the two rows together come to six, while a brassica has four petals inside its four sepals.
Remove the stamens; count them, and with the hand lens find the anther and filament. Dust some pollen onto a slide and view it at 100x and 400x.
Leave the pistil. Identify stigma, style and ovary; cut the ovary across with the blade and view the cut face under the hand lens to see the ovules in their chambers.
Tape the pistil sections to the card and label every part.
Compare counts with another species and note which parts are in threes and which in fours or fives.

What you should see

A lily gives 6 tepals, 6 stamens and 1 pistil whose ovary cross-section shows three chambers with rows of ovules; a brassica gives 4 sepals, 4 petals, 6 stamens (4 long, 2 short) and a two-chambered ovary. Pollen grains are visible as many small rounded or oval bodies at 400x. The learner knows it worked when every whorl is counted, the ovules are seen in the cut ovary, and the labelled card matches the SAPS flower structure diagram.

What changes

This activity lists no variables to change, measure and keep the same.

Common misconceptions

Each of these ideas is wrong, and the activity is a chance to test it.

Petals are the reproductive parts.
Pollen is the plant's seed.
Every flower has both male and female parts; some species separate them.

Curriculum references

The NSW syllabus outcomes and Australian Curriculum v9 codes this activity supports. They are references, not a verified or complete curriculum alignment.

Science 7–10 Syllabus (2023)SC5-GEV-02 SC5-WS-01 SC5-WS-08
Australian Curriculum v9AC9S9U02AC9S9I03AC9S9I08

Sources

The pages the author read to write this activity.

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