3.3 - 3.7 biology : flowering plants

petal function

attracts pollinating insects

anther function

produces pollen

filament function

holds anther up

stigma function

female part - receive pollen

ovary function

contains ovules and ova. Turns into fruit after fertilization.

ovule function

contain the ova (egg cells) and turn into seeds after fertilization occurs

pollen

the male sex cell

nectary

contains sugary liquid to attract pollinating animals

sepal

tough outer leaves to protect the flower

differences between insect pollinated and wind pollinated flowers

describe process of fertilization after pollination

• pollen grain containing male nucleus lands on stigma

• pollen tube grows downwards through style

• it enters the ovule through the micropyle (small opening in surface)

• the male nucleus in the pollen meets the female nucleus within the ovum and they fuse

what is pollination

the transfer of pollen from the anther to a stigma by various means - including wind and insects

what is cross pollination

the transfer of pollen from the anther of one plant to the stigma of another plant

what happens to petals after fertilization

petals die and fall off

what happens to fertilized ovule

the ovule wall becomes the seed coat - called the testa

what happens to the ovary after fertilisation

Turns into fruit - the ovary wall becomes the fruit coat

germination

when a seed starts to develop into a new plant

what conditions needed for seed germination

• warm temperatures so optimum enzyme activity

• water to swell up seed and provide and environment for chemical reactions to occur in solution

• oxygen for respiration

what are cotyledons

they surround the embryo and store food for the seedling. most plants have one or two. they provide energy for the plant until it can photosynthesize

how do the plumule and radicle emerge

water absorption splits the seed coat known as the testa

definition of plumule

first emerging shoots

radicle

first emerging root

what does the cotyledon mainly comprise of

starch which is broken down by secrete amylase into maltose which is absorbed by embryo and proteins for growth

why do the radicle and plumule need a food source

so they can release enough energy during respiration to frow so that the plumule can develop leaves and start to photosynthesize and produce its own food

when does germination end

as soon as the plant is able to photosynthesize

how to set up germination experiment

4 testubes - one control with warmth from room temp, oxygen, wet cotton wool, one without water (dry wool), one without oxygen (oil on top of water), one without warmth (in fridge)

natural methods of asexual reproduction in plants

runners in strawberries. tubers in potatoes - new plants grow from the eyes, bulbs

artificial methods of asexual reproduction

cuttings - a piece of plants stem with a few leaves is cut off, dipped in rooting hormone, the cut piece is placed in damp soil or compost once roots have grown, the cutting grows into new plant

how do runners work

grow sideways from the stem with small plantlets. From the runners new genetically identical plants grow. once plantlets touch soil they grow roots and grow and become independent