Plant Reproduction Flashcards
Describe factors of Asexual reproduction
- only one parent
- no gametes
- offspring are genetically identical to their parent
- quick Reproduction
- mitosis
Describe the factors of sexual reproduction
- two parents
- gametes are needed
- offspring are genetically varied
- offspring can cope with change in environment
- meiosis
What is an artificial asexual reproduction ?
Cuttings, where the stem or roots of the plant are cut off, and planted again and develop into a new plant
Describe fertilisation
• pollination occurs
• then the nucleus of the male gamete, the pollen grain, must fuse with the nucleus of the female gamete,
the ovum, which is inside the ovule in the ovary
• to transfer the nucleus to the ovum, The pollen grain grows a tube, the down through the style to the ovary
• here it passes through the gap in the ovary called the micropyle
• then it fertilises the ovums nucleus
• the then fertilised egg, called a zygote undergoes cell division by meiosis and develops into an embryo
What is pollination
The transfer of pollen grains from an anther to a stigma
What species is asexual reproduction useful for ?
If the species environment is stable
What are Natural methods of asexual reproduction ?
Runners
What part of the flower is the stamen ?
Male part
What part of the flower is the carpel ?
Female part
What is the male sex cell ?
Pollen grain
What is the female sex cell ?
The Ova
Where are pollen grains formed ?
At the anthers
Where is the ova produced ?
In the ovules
What is self-pollination ?
when the pollen grains are transferred from the anthers of a flower to the stigma of the same flower
What is cross-pollination ?
When pollen grains are transferred from the anthers of a flower to the stigma of another flower
Features of an insect pollinated flowers
- Large and brightly coloured petals to attract insects
- presence of nectaries to give nectar award to insects
- small and sticky pollen grains
- position of stamen and stigma are inclosed within the flower so that insect must make contact
- sticky stigma so pollen grains attached to insects
Features of a wind pollinated flower ?
- small and dull petals
- large inflated pollen grains to carry in the wind
- stamen and stigma are exposed so that wind can easily blow pollen away and to catch pollen blowing in the wind
- they have a feathery stigma to catch pollen blowing in the wind
- no nectaries
What occurs after fertilisation
• the ovule turns into the seed and the ovary will become a fruit
Describe the process that occurs after fertilisation
- Zygote develops into an embryonic plant with a small root called a radicle and a shoot called a plumule
- The other contents of the ovule develop into cotyledons which will be food store for the young plant when the seed germinates
- the ovule wall becomes the seed coat called a testa
- the ovary wall becomes the fruit coat
What are cotyledons made of ?
Starch and protein
Why are seeds dispersed ?
If all the seeds produced germinate in the same place, there would be too much competition for the available resources such as water and mineral irons
How are seeds dispersed ?
By wind or animals
Features of a wind dispersed seed
- Wings
* Parchute
Features of an animal dispersed seed
- hairs
* hooks
What does a seed containing a plant embryo consist of ?
- radicle (root)
- plumule (shoot)
- cotyledons
What is the root called in a plant embryo ?
Radicle
What is a shoot called in a plant embryo ?
Plumule
When is germination over ?
Once the seed is able to photosynthesise
What do cotyledons help the plant do ?
They provide food for the plant embryo to grow allowing the radicle to grow down on the plumule to grown upwards, until the plant can photosynthesis
Why may a seed become dormant ?
If there are not the right conditions for germination
What conditions are needed for germination ?
- warm temperatures : so the enzymes can act efficiently
- water : for chemical reactions to take place in solution
- oxygen : for aerobic respiration
How is dormancy broken when a seed germinates ?
The seeds food store is broken down by enzymes and respired aerobically
