Reproduction in Flowering Plants

flowers are the

reproductive organs of plants

male parts of the flower

stamen = anther and filament

female parts of the flower

carpel = stigma, style and ovary

plants produce

pollen

pollen contains

a nucleus - which is the male gamete

pollen is produced in the

anther

pollination is the

transfer of pollen grains from the anther to the stigma

2 types of pollination are called

wind and insect

insects are

pollinating agents

insects collect

nectar from flowers

when an insect enters the flower

it brushes against the anther, which deposits its sticky pollen onto

when an insect visits another flower,

it brushes against the stigma, depositing the pollen from the first flower, resulting in pollination

inside the ovary are the

ovules, containing the ova = female gamete

petals:

large and bright to attract insect

scent and nectar:

entice the insect to push parts of the stamen, to get to the sweetness

anther:

inside the flower and contains the pollen grains, stiff and firm to brush against insects

stigma:

inside the flower, where pollen grains stick to it when an insect brushes past

stamen:

enclosed within a flower so that insect must make contact with it

pollination in wind pollinated plants

the anther opens and sheds its pollen into open air. the pollen is blown by the wind and lands on the stigma

wind petals:

small and dull

wind scent and nectar:

absent

wind anthers:

swing loosely so that pollen grains fall easily

wind stigma:

outside the flower, large and feathery in order to catch pollen grains

wind stamen:

exposed so that wind can easily blow away pollen

cross vs self pollination:

pollen grains are transferred from a plants anther to another plants stigma vs pollen grains are transferred from the same flower’s

flowers have parts that are both

male and female

self pollination negatives

it decreases genetic variation of offspring as gametes come from the same parent, thus genetically identical. lack of variation is disadvantageous as it means that if the environment changes, it is less likely that any of the plants will have adaptations that suit the new conditions well

cross pollination increases

genetic variation of offspring

fertilisation in flowers leads to

fruit and seed formation

fertilisation in flowers is when

the nucleus of the pollen grain and nucleus of the ovum fuse

what develops into the fruit?

the ovary wall

what develops into the seed?

the ovule

the seed coat is known as

the testa

a mechanism for seed dispersal: fruit

fruit are eaten by animals and dispersed through their droppings

a mechanism for seed dispersal: outer material

some fruit have sticky hooks that get caught in animals fur walking past and are eventually dispersed by dropping off

when a seed has the right conditions, it may begin to

germinate

germination is the

beginning of the growth in a seed

when seeds germinate, the

embryo begins to grow into a young seedling

what surrounds the embryo as it begins to grow into a young seedling?

cotyledons

what do cotyledons contain?

food reserves and energy for the seed to start germinating

plants can reproduce both

sexually and asexually

asexual reproduction in plants involves

a parent who is genetically identical to their offspring

example of plants that reproduce asexually by natural methods

runners

example of plants that reproduce asexually by artificial methods

cuttings

how do runners reproduce asexually by natural methods?

the grow horizontally so that once they touch the soil, plant will grow roots and new plantlets will grow and become independent from their parents

how do cuttings reproduce asexually by artificial methods?

humans cut a section of the parent plant with a new bud and place it into water, then directly into the soil. cuttings eventually grow, becoming genetically identical to their parents

sometimes, what happens to the stem of a cutting?

it may be dipped into “rooting powder” which contains plant growth regulators, encouraging new root growth