| What does flowering involve? | change in gene expression in shoot apex |
| when does flowering begin? | response to length of light and dark periods |
| What are 3 ways in which plants reproduce? | vegetative propagation: from plant cutting
spore formations: moulds and ferns
pollen transfer: flowering plants |
| What is sexual reproduction in flowering plants? | pollen transfer (M gamete) to an ova (F gamete) |
| What are the 3 phases of sexual reproduction in flowering plants? | pollination
fertilization
seed dispersal |
| What happens during pollination? (2) | pollen grains are transferred from anther = stigma
most plants have both structures (monoecious) = self pollination |
| Why is cross pollination better than self pollination? | improves genetic diversity |
| What happens during fertilisation? (3) | M gamete nuclei and f gamete nuclei forms a zygote
m gamete = pollen grain
f gamete = in ovule |
| What happens during seed dispersal? | fertilisation of gametes = forms seeds = moves away from prental plant |
| What is the purpose of seed dispersal? | reduces comeptition bw germinating seed and parental plant |
| What are diff methods of seed dispersal? | wind
water
fruits
animals |
| What is cross pollination? | transferring pollen grains from 1 plant to the ovule of a diff plant |
| What is a mutualistic relationship? | both species benefit from the interaction |
| How are pollinators involved in a mutualistic relationship? (2) | flowering plant = sexual reproduction w/ pollen transfer
animals = nutrition source (nectar) |
| What are some examples of pollinators? | birds
bats
insects (bees butterflies) |
| Where is the pollen located? | pollen grain= stamen = anther |
| Where is the ova located? | ova = ovule = stigma = pistil |
| How does flowering occur? (3) | develop from shoot apex by changes in gene expression
= enlargement of shoot apical meristem
differentiates into sepals, petals, stamen and pistil |
| How are the genes responsible for flowering activated? (3) | abiotic factors - seasons
blooms when a suitable pollinator is available
day/ night length (photoperiodism) |
| What is photoperiodism? | response to lengths of light and dark in plants |
| What are flowers? | reproductive organs of angiospermophytes that contain male and female structures |
| What is the male part of the flower called? and what does it consist of? (3) | stamen
anther - produces pollen (m gamete)
filament- stalk to hold up anther for pollinators |
| What is the female part of the flower called? and what does it consist of? (3) | pistil /carpel
stigma - sticky tip to catch pollen
style - tube to connect stigma and ovule
ovule = contains female gametes forms seed after fertilisation |
| What are the support structures in the flower? | petals - brightly colored to attract pollinators
sepal - outer covering to protect flower when in a bud
peduncle - stalk |
| Draw and label a flower structure (10) | petal
anther
filament
stamen
sepal
peduncle
ovule
style
stigma
pistil |
| What is the difference between long day and short day conditions? | long day = blooms in summer
short day = blooms in winter/ autumn |
| What detects the lengths of light and dark periods? | phytochromes |
| What are phytochromes? | leaf pigments to detect light and dark |
| What are the 2 forms of phytochromes? | inactive form (Pr) = converted into active form when it absorbs red light (660 nm)
active form (Pfr) = broken down into inactive form when it absorbs far red light (725nm)
= gradually goes into inactive form without light |
| When is the active form of phytochromes predominant? | during the day |
| When is the inactive form of phytochromes predominant? | during the night |
| Which type of phytochrome causes flowering? | active form (Pfr) |
| How does Pfr differ for short day plants? (4) SID the LAD | flower when days are short
night period = exceeds a critical length
Pfr inhibits flowering = needs low levels of Pfr
= long nights
SID = short day inhibit flowering |
| How does Pfr differ for long day plants? (4) SID the LAD | night period less than critical length
PFR activates flowering
high levels of Pfr needed
short nights
long day activate flowering |
| How can long day plants be induced to flower out of season? | exposing plant to light source during night
eg: carnations |
| How can short day plants be induced to flower out of season? | covering plant with an opaque black cloth for 12 hours a day
eg: crysanthemums |
| What are the features of a seed? (5) | testa - outer seed coat that protects embryonic plant
micropyle - small pore in outer covering for water
cotyledon - food store for seed = embryonic leaves
plumule - embryonic shoot (epicotyl)
radicle - embryonic root |
| draw and label a seed (5) | cotyledon
testa
micropyle
radicle
epicotyl / plumule |
| What is germination? | seed emerges from a period of dormancy and sprouts |
| What is needed for germination? (4) | oxygen - aerobic respiration (needs lot of ATP to develop)
water - metabolically activates seed (triggers gibberellin production)
temp - optimal temp for enzyme function
pH - optimal pH for enzyme function |
| How can germination be measured? | by the rate of seed growth over a set period of time |
