Presentation on theme: "9.3 Reproduction in angiospermophytes. 9.3.1 Draw and label a diagram showing the structure of a dicotyledonous animal- pollinated flower. *** Specifically:"— Presentation transcript:
9.3 Reproduction in angiospermophytes
9.3.1 Draw and label a diagram showing the structure of a dicotyledonous animal- pollinated flower. *** Specifically: Sepal, petal, anther, filament, stigma, style and ovary
9.3.2 Distinguish between pollination, fertilization and seed dispersal.
Pollination –first event to occur –movement of pollen onto the stigma of a carpel by a carrier. Fertilization –the union of haploid gametes to produce a diploid gamete. –happens within the ovary of the plant. –This gamete is now the seed produced by the plant. Seed dispersal –describes the action of the seed moving from its place of origin to another site where it will grow
9.3.3 Draw and label a diagram showing the external and internal structure of a named dicotyledonous seed. *** Specifically testa, microphyle, embryo root, embryo shoot, cotyledon
9.3.4 Explain the conditions needed for the germination of a typical seed.
Seeds are dormant which help the survival and conservation of plant species because seeds can wait for their optimal environment to grow. They are resistant to various factors and can stay dormant for many years until all factors around them are suitable to their individual needs. When they are provided with the right conditions their dormancy breaks and they start germinating and growing into the plant again. Terrestrial plants are generally stimulated to break dormancy when enough water is provided, however each seed requires different conditions.
9.3.5 Outline the metabolic processes during germination of a starchy seed.
Absorption of water precedes the formation of gibberellin in the cotyledon. This stimulates the production of amylase which catalyzes the breakdown of starch to maltose. This subsequently diffuses to the embryo for energy production and growth.
9.3.6 Explain how flowering is controlled in long-day and short-day plants, including the role of phytochrome.
Long day plants require a certain amount of daylight to initiate flowering, so these plants flower in the spring or summer. Short day plants will flower when the length of daylight falls below a certain amount. Short day plants typically flower in the fall of the year Phytochrome is a photoreceptor, a pigment that plants use to detect light. It is sensitive to light in the red and far-red region of the visible spectrum. –active form by red light (Pr) (660 nm), –inactive form by far-red light (Pfr) (730 nm). –Moonlight produces a greater percentage of far-red light than sunlight, so during the night the phytochrome is slowly converted to its inactive form. –More phytochrome is converted in a longer night, allowing the plant to measure the length of the night.
Circadian Rhythms in plants ology/bio_5_3_2_3.swf