Reproduction (Flowering Plants) Flashcards
What is the process called where plants transfer the male gametes (pollen) from the anther to the stigma?
Pollination
What are the two different methods of pollination flowers will use?
Insect pollination
Wind pollination
What is the function of the sepal?
To protect the flower when it was an unopened flower
The sepal is the green leaf looking structure near the base of the flower
What are the functions of the petals?
In insect pollinated plants, these are brightly coloured to attract insects
What is the male reproductive system in a flower called?
The stamen
What is the part of the male reproductive system in a flower called which produces and releases the male sex cell?
The anther
What is the structure which holds the anther up called?
The filament
What is the female reproductive system in a flower called?
The carpel
What is the funtion of the style?
To support and connect the stigma and the ovary, allowing for a pollen tube to grow between them inside of the style
What is the part of the female reproductive system in a flower called which collects the pollen grains?
The stigma
What is the function of the ovary?
It produces the female sex cell (the ovum)
What is the function of the ovule?
The ovules are found inside the ovary, and contain the female sex cells (the ova)
The ova will develop into seeds after fertilisation
How does the process of insect pollination work?
Insects visit the flowers attracted by the nectar, scent and petals
The insects body may brush with the anther when looking for nectar, and the pollen will stick to its body
When it then visits another flower (or the same one), it may brush up against the stigma in search for nectar, depositing pollen in the stigma, leading to fertilisation
How are insect pollinated flowers adapted for pollination?
Large and brightly coloured petals to attract insects
Nectar and scent to attract insects and make them brush past the anther and stigma in search of it
Large, sticky/spiky pollen grains in order to attach to insects
The stigma is inside the flower and is sticky so pollen grains stick to it when an insect brushes past
The anthers are inside the flower and are firmly attached to the flower as insects brush past them
The number of pollen grains produced are moderate as this type of pollination is efficient
How does the process of wind pollination work?
When ready, the anthers open and shed their pollen into the wind
It then, by chance, lands on the stigma of a plant of the same species
How are wind pollinated flowers adapted for pollination?
small and dull petals, often brown or green
no nectar, waste of energy, as insects aren’t necessary
Large amounts of pollen as most aren’t transferred so the more there are the better the chance of success
Small and light pollen so they’re blown easily
thin and loose, outside the flower to release pollen easily
Feathery stigma outside the flower to catch pollen
What triggers the growth of a pollen tube inside of a style?
A grain of pollen landing on the stigma of a plant of the same species
What happens following the growth of a pollen tube?
The nucleus inside the pollen grain moves down the tube as the tube grows down the style towards the ovary
Once the nucleus of the pollen grain and the nucleus of the ovum have fused (joined together), that particular ovule has been fertilised and a zygote has been formed
How are seeds and fruits formed following fertilisation?
After fertilisation, the ovule (that contains the zygote) develops into the seed
The wall of the ovule develops into the seed coat, known as the testa
The parts of the flower surrounding the ovule develop into the fruit, which contains the seeds
What are the factors required for seed germination?
Water - allows the seed to swell up, which causes the testa to burst, allowing the growing embryo plant to exit the seed
Oxygen - required for respiration, so that energy can be released for germination
Warmth - germination improves as temperature rises (up to a certain point) as the reactions which take place are controlled by enzymes
How do germinating seeds aquire nutrients and energy before they are able to grow their own leaves?
Structures known as cotyledons surround the embryo
The cotyledons contain food reserves that supply the young seedling with food (and, therefore, energy for growth) when the seed starts to germinate
What are the two methods of asexual reproduction in plants?
Natural
Human Controlled
How do runners work in plants?
Some plants grow side branches, known as runners, that have small plantlets at their ends
Once they touch the soil, these plantlets will grow roots and the new plantlets will grow and become independent from the parent plant
How are cuttings used for plant asexual reproduction?
Gardeners take cuttings from good parent plants
This cutting can either be placed into water until new roots grow or can sometimes be placed directly into soil
These cuttings are then planted and eventually grow into adult plants that are genetically identical to the original plant
