Reproduction in Plants

Topic 9.4: Reproduction in Plants

Essential Idea: Reproduction in flowering plants is influenced by the biotic and abiotic environments.

At SHS, Topic 9.4 is taught in the following class unit(s):

Communities and Ecosystems (unit 24)
Angiosperm Reproduction (unit 38)

Statements & Objectives:

9.4.U1 Flowering involves a change in gene expression in the shoot apex.

Compare the vegetative and reproductive phases of the angiospermatophyta life cycle.
State that flowers are produced from a shoot apical meristem.
State two abiotic factors that may trigger flowering.
Compare the timing of flowering in short-day plants and long-day plants.
Outline the process by which changes in gene expression trigger flowering.

9.4.U2 The switch to flowering is a response to the length of light and dark periods in many plants.

State the role of the pigment phytochrome.
Describe the conversions between the two forms of phytochrome.
Describe role of phytochrome in controlling flowering in long and short day plants.

9.4.U3 Success in plant reproduction depends on pollination, fertilization and seed dispersal.

Define pollination, fertilization and seed dispersal.
State the changes to the ovule and ovary that result from fertilization.
List mechanisms of seed dispersal.

9.4.U4 Most flowering plants use mutualistic relationships with pollinators in sexual reproduction.

Define mutualism.
Explain an example of mutualism between a flowering plant and its pollinator.

9.4.A1 Methods used to induce short-day plants to flower out of season.

State how plants can be manipulated to force flowering out of season.

9.4.S1 Drawing internal structure of seeds.

Draw and label the structure of seeds, including:
- Embryo root
- Embryo shoot
- Cotykedons
- Testa
- Micropyle
- Hilum
State the function of the different parts of the seed.

9.4.S2 Drawing of half-views of animal-pollinated flowers.

Draw and label an animal pollinated flower, including:
- Nectar-secreting glands
- Petals
- Sepals
- Anthers
- Filaments
- Carpel
- Stigma
- Style
- Ovary
- Ovule
State the function of the different parts of the animal-pollinated flower.

9.4.S3 Design of experiments to test hypothesis about factors affecting germination.

Define germination.
Outline why water, oxygen and warmth are required for germination.
Outline the role of gibberellin during germination.
Write five example problem questions for experiments that could test factors affecting germination.

9.4.NOS Paradigm shift-more than 85% of the world’s 250,000 species of flowering plant depend on pollinators for reproduction. This knowledge has led to protecting entire ecosystems rather than individual species.

Contrast traditional conservation efforts with newer strategies of conservation.

In the News:

Lizards, mice, bats and other vertebrates are important pollinators, too (2018-04-04)
Duck faeces shed light on plant seed dispersal (2018-02-05)
When did flowers originate? (2018-02-05)
Flower petals have ‘blue halos’ to attract bees (2017-10-18)
Tree hitched a ride to island (2014-06-18)
Calcium and reproduction go together like the birds and the bees (2014-08-22)
Solving Crimes With Pollen, One Grain Of Evidence At A Time (2015-04-25)
Hips, haws and drupes: when is a nut not a nut? (2016-11-10)
‘This is amazing!’ African elephants may transport seeds farther than any other land animal (2017-04-10)
Watching their Dust: Photographing Players in Pollination (2017-04-24)
Nocturnal pollinators go dark under street lamps (2017-08-02)
Headbanging Aussie bee takes a heavy metal approach to pollination (2015-12-14)
Sweet success: how bees choose which pollen to collect (2016-07-12)
The Beautiful Tricks of Flowers (TED, 2011)
What's In It For The Corpse Flower To Smell Like Death? (2016-10-25)
Biggest producer of coffee could see bean-growing land shrink nearly 90% by 2050 (2017-09-11)
WE CAN SAVE INDIVIDUAL SPECIES — BUT CAN WE SAVE ENTIRE ECOSYSTEMS? (2016-02-23)
A stinging report: Climate change a major threat to bumble bees (2017-09-29)