35. Plant Reproduction Flashcards
Sexual reproduction def.
Involves 2 sex cells/gametes joining together
5 stages of plant reproduction
(Pretty Flowers For Dreamy Girls)
- Pollination
- Fertilisation
- Fruit and Seed Formation
- Dispersal
- Germination
Function of
Sepal
Petal
Sepal: Green leaf like structure, protects flower whan it is a bud.
Petal: Protects inner parts of flower.
Function of Carpel Stigma Style Ovary
Carpel: Produce female gamete: egg
Stigma: Catches pollen
Style: Pollen transported to ovary
Ovary: Produces egg (female gamete)
Function of
Anther
Filament
Stamen
Anther: Produces pollen (male gamete)
Filament: Supports anther and ensures that anther is located up high so pollen can leave easily.
Stamen: Produces pollen grain which contains pollen
Pollination def.
Is the transfer of pollen from the anther to the stigma
Self pollination
Transfer of pollen from an anther to the stigma of the same plant.
Cross pollination
Transfer of pollen from an anther to the stigma of a different plant
Methods of pollination
Wind and Animal
Characteristics of Wind pollinators
and examples
Small green petals
Large amounts of pollen
Stamens and carpels hang outside in wind
Examples: Grass, oak, hazel
Pollen sac structure
Outside - In
Fibrous layer-protection
Tapetum- provides energy for dividing of pollen sac to produce pollen grains
Pollen mother cells: produce pollen grains
Pollen grains
How many pollen sacs in an anther
4
How a pollen grain develops
from start to before pollination
1 Microspore mother cell *Divides by meiosis* 4 Haploid cells-cluster called tetrad *seperate* Pollen grains with n nuclei *mitosis* Generative nucleus and Tube nucleus
Structure of pollen grain
Exine: Outer spikey coat
Intine: Smooth inner coat
Function of tube nucleus and generative nucleus
Tube: Forms pollen tube
Generative: Forms male gamete
What happens to pollen grain after pollination
Generative nucleus (n) divides by mitosis to form 2 pollen/male nuclei (n) Tube nucleus doesn't divide but forms pollen tube. Pollen nuclei travel down tube
Female gamete formation- where
Ovule in ovary
Ovary structure and function
Microphyle: where pollen tube enters
Nucellus: provides nutrients for growth
2n Nucleus: Megaspore mother cell divides to produce egg
Female gamete formation-what happens
1. Megaspore mother cell (2n) divides by Meiosis to form 4 haploid cells. 3 haploid cells degenerate Remaining cell called embryo sac (n) 2. Nucleus of embryo sac divides by mitosis 3 times = 8 haploid nuclei 5 of these nuclei disintegrate remaining 3 are gametes 1 = egg cell 2 = polar nuclei
Fertilisation def.
The fusion of the male and female gametes (n) to produce a zygote (2n)
Plants carry out double fertilisation
Where does fertilisation take place
In the ovule of the ovary in the carpel