Reproduction in plants

Topic 9.4

Essential idea: Reproduction in flowering plants is influenced by the biotic and abiotic environment.

Understandings

9.4.U1 Flowering involves changes in gene expression in the shoot apex

Florigens and gene expression in the shoot apex

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

Florigen, light and dark periods

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

The figure below shows the process of pollination, which is the delivery of pollen from the anther to the stigma. The transfer of pollen can occur from the anther to the stigma on the same plant or between different plants. Placing the mouse pointer on the figure will produce a new figure outlining fertilization and seed dispersal.

Pollination, fertilization and seed dispersal

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

Sexual reproduction in plants requires pollinators

Applications

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

Importance of CRITICAL NIGHT LENGTH in flowering of plants

Importance of critical night length in flowering plants
How to induce short-day plants to flower out of season

Skills

9.4.S1 Drawing internal structure of seeds

Seed Germination

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

Animal-pollinated flower

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

Information: Metabolic activities of a germinating starchy seed

The figure outlines the metabolic processes carried out by a germinating starchy seed. The process starts with the absorption of water and the formation of gibberellin in the embryo's cotyledons. This stimulates the production of amylase, which catalyzes the breakdown of starch to maltose. The maltose diffuses to the embryo for energy and growth. Note that seeds vary in their oxygen, water, and temperature requirements.

Seed Metabolism

Conditions necessary for seed germination

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