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

http://www.learner.org/jnorth/images/graphics/t/flower_parts.gif

• 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.

http://www.click4biology.info/c4b/9/plant9.3.htm#1

• Circadian Rhythms in plants

http://www.ucopenaccess.org/courses/CPBiology/bio_5_3_2_3.swf