Topic 9: Reproduction in Angiospermophytes 9.3

Draw and label a diagram showing the structure of a dicotyledonous animal- pollinated flower Limit the diagram to: sepals, petals, anther, filament, stigma, style and ovary

Distinguish between pollination, fertilization, and dispersal

Draw and label a diagram showing the external and internal structure of a named dicotyledonous seed Testa (seed coat), hypocotyl (embryonic shoot), radicle (embryonic root), cotyledons (seed leaves) Pisum sativum (common pea)

Explain the conditions needed for seed germination Water = rehydration of dry tissue Oxygen = aerobic cell respiration Suitable temperatures for enzymatic activity

Outline the metabolic events during the germination of a starchy seed Stage 1 – water absorption Stage 2 – gibberelin (growth hormone) produced by cotyledons = growth hormone Stage 3 – gibberelin stimulates amylase production = chem. breakdown of starch into maltose in food stores of the seed Stage 4 – maltose transported to radicle and plumulue Stage 5 – maltose converted to glucose = E or synthesis of materials for growth (e.g. cellulose) Stage 6 – cessation once leaves and sun connect

Explain how flowering is controlled in long-day and short-day plants, including the role of phytochrome Key points: –Phytochrome is a light absorbing pigment –Phytochrome exists in two interchangeable forms: phytochrome red (Pr) and far-red (Pfr). –Only Pfr is biologically active –****Pfr is a promoter of flowering in long-day plants and it inhibits flowering in short-day plants

Draw a similar presentation for Long-day (short-night) plants