Plant Reproduction
- Created by: Sophia Dowden
- Created on: 03-03-16 10:58
View mindmap
- Plant Reproduction (1)
- Structure of an insect pollinated flower e.g. primula/ primrose
- Collectively the SEPALS form the CALYX
- The PETALS form collectively the COROLLA.
- CARPEL: a flower's female sex organ. The ovary forms the fruit after fertilisation. The style joins the ovary to the stigma which has a sticky surface of which pollen grains adhere.
- OVULE: Contains the egg cell which develops into a seed after fertilisation.
- SEPAL: green - can photosynthesis. Function - to enclose the flower bud and protect it before it blossoms.
- RECEPTACLE: Supports the flower.
- NECTARY: Secretes nectar.
- STAMENS; Each one consists of a filament which supports anther which has four sacs containing pollen grains in which male gametes develop.
- Wind Pollination
- Small, insignificant petals, or no petals.
- Dull/green
- Not scented
- No nectar
- Large amounts of pollen
- Pollen is smooth/not sticky
- Pollen is light
- Anthers and Stigmas are outside the flower
- Large feathery stigmas.
- Insect pollination
- Large petals
- Brightly Coloured
- Scented
- Nectar
- Small amounts of pollen
- Pollen is sticky/ sculptured
- Pollen is heavy
- Anthers and Stigmas are inside the flower.
- Small smooth stigmas
- Pollination
- The transfer of pollen from the anther to the stigma.
- Self-pollination
- Self-pollination occurs when pollen from the stamen of a flower lands on its own stigma of the same plant.
- +++++ - plant can still reproduce if ISOLATED.
- - - - - = lack of genetic variation - if environment changes it may not be well suited and the plant will have some genes and same characteristics.
- Increased risk of genetic mutations (inbreeding)
- Self-pollination occurs when pollen from the stamen of a flower lands on its own stigma of the same plant.
- Cross Pollination
- Pollen from the stigma of one flower reaches/lands on the stigma of a different flower on a different flower but of the same species.
- - - - - = needs to be close to another plant of the same species
- +++++ = greater genetic variety
- Pollen from the stigma of one flower reaches/lands on the stigma of a different flower on a different flower but of the same species.
- Self-pollination
- The transfer of pollen from the anther to the stigma.
- Fertilisation
- Pollen grains land on the stigma. They then absorb water and germinate (pollen tube starts to grow)
- The pollen tube grows and this growth is CONTROLLED by the pollen tube nucleus
- Enzymes e.g. pectinase is SECRETED and digest a route along the ovary wall/ - through the style.
- The generative nucleus travels along the tube to the ovule
- Pollen tube passes through the micropyle
- Generative nucleus divides by mitosis = haploid nuclei
- Male gamete fuses with the polar nuclei to form a haploid endosperm
- The other male nucleus fuses with the polar nuclei to form a haploid endosperm
- Products/nutrients absorbed and used for growth
- Positively chemotrophic - pollen tube is attracted, chemicals released by the ovule. This is double fertilisation.
- Products/nutrients absorbed and used for growth
- The other male nucleus fuses with the polar nuclei to form a haploid endosperm
- Male gamete fuses with the polar nuclei to form a haploid endosperm
- Generative nucleus divides by mitosis = haploid nuclei
- Pollen tube passes through the micropyle
- The generative nucleus travels along the tube to the ovule
- Enzymes e.g. pectinase is SECRETED and digest a route along the ovary wall/ - through the style.
- The pollen tube grows and this growth is CONTROLLED by the pollen tube nucleus
- Pollen grains land on the stigma. They then absorb water and germinate (pollen tube starts to grow)
- Development of seeds
- Following fertilisation, the zygote divides rapidly by mitosis and develops into the embryo.
- The embryo differentiates into 3 parts - young shoot (PLUMULE) young root (RADICLE) and seed leaves (COTYLEDONS)
- The endosperm (triploid) divides by mitosis to give a mass of cells called the endosperm - food store which will support the seedling during germination.
- The number of cotyledons form the basis for the two major divisions and the flowering plants (angiosperm)
- Dicotyledons: Two seed leaves Non-endospermic food store is transferred from endosperm to the cotyledons. Broad beans.
- Monocotyledons: One seed leaf Endospermic Seeds Maize
- Dicotyledons: Two seed leaves Non-endospermic food store is transferred from endosperm to the cotyledons. Broad beans.
- The number of cotyledons form the basis for the two major divisions and the flowering plants (angiosperm)
- The endosperm (triploid) divides by mitosis to give a mass of cells called the endosperm - food store which will support the seedling during germination.
- The embryo differentiates into 3 parts - young shoot (PLUMULE) young root (RADICLE) and seed leaves (COTYLEDONS)
- Following fertilisation, the zygote divides rapidly by mitosis and develops into the embryo.
- Structure of an insect pollinated flower e.g. primula/ primrose
Comments
No comments have yet been made