Reproduction in Plants Flashcards
Male parts of a plant
- Stamen consists of anther and filament
Female parts of a plant
- Carpel consists of stigma, style and ovary
State the functions of the sepals, petals, anthers,
stigmas and ovaries
- Sepals: protect flower when it’s a bud
- Petals: bright-coloured and scented, have nectary at base to attract insects
- Anthers: where pollen is made
- Stigma: for pollen grains to reach to the ovaries
- Ovaries: contain ovules. Each ovule has an egg cell
Characteristics of insect-pollinated flowers
- Petals: large and colourful to attract insects
- Nectary: sweet sugary fluids to attract insects
- Scent: strong, sweet and attractive
- Stigma: sticky and fury for insects to rub against
- Pollen: large and heavier
- Anther: sometimes enclosed
Characteristics of wind-pollinated flowers
- Absent of petals, nectary and scent
- Stigma: feathered => large surface area to increase pollination. feathered to catch pollen grains in air
- Pollen: light and in large quantities
- Anther: exposed
- Filament: for anther to be exposed
Define pollination
the transfer of pollen grains from the male part of the plant (anther of stamen) to the female part of the plant (stigma)
Distinguish between self-pollination and
cross-pollination
- Self pollination: pollen is transferred from the anther to the stigma of the same flower or to a different flower but on the same plant
- Cross pollination: pollen is transferred from the anther to the stigma of another plant of the same species
Discuss the implications to a species of selfpollination and cross-pollination
- Cross pollination ensures exchange in genetic material => greater variation
- Self pollination => advantageous features can be passed down. Also an advantage where there’s no insects
Advantages of asexual reproduction
- Can reproduce rapidly
- Advantageous features can be passed down through alleles
Disadvantages of asexual reproduction
- Little/ no variation
- Diseases from parent cell can be passed down
Describe the growth of the pollen tube
- Pollen grains land on ripe stigma => start to grow => each grow a pollen tube which grows down the style to the ovary
- As it grows, get nutrients from the tissues of the style and carry male gamete nucleus with it
- First pollen tube to reach the ovary, enters the ovule through micropyle => male and female gametes fuse => fertilisation
Outline the formation of a seed and fruit
- Zygote divides and grows into an embryo. Ovule forms seed with embryo inside it
- Ovary forms fruit with seeds in it
Seed and fruit dispersal by wind and by animals provide what
a means of colonising areas. Without dispersal, new plants would be too crowded, competing for space, light, water and nutrients
Define dormancy
a period in which a plant does not grow as it awaits necessary environmental conditions such as temp, moisture
How seeds grow
- Stage 1: testa splits and radicle emerges
- Stage 2: epicotyl elongates, radicle grows into soil
- Stage 3: epicotyl pulls plumule out from the cotyledons
- Stage 4: epicotyl pulls plumule backwards through soils so leaves aren’t damaged, lateral roots develop
- Stage 5: once above soil, epicotyl straightens and leaves are opened, roots develop rapidly
