Transcript Plant Cultivation Revision

Growing Conditions
Factors that a gardener needs to consider to
maximise plant growth:
• Water
• Light – motorised screens, shading
• Suitable temperature – greenhouses,
polytunnels, cloches, ventilators, fans,
fleece
• Growing medium (soil, compost etc)
• Humidity
Photosynthesis
Carbon Dioxide + water
Oxygen + glucose
Unhealthy Plant
•
•
•
•
Wilting – under watering
Pest Damage – aphids, slugs
Poor Growth
Fungal Disease – damping off, potato
blight
Biological Pest Control
• Predator of the pest used to eat the pest
• Example: Ladybird is a predator to an
aphid
• Advantage – No pesticides
• Disadvantage – Can change predator-prey
relationships, changing the ecosystems
K Potassium
Mineral Nutrients
N
Nitrogen
P Phosphorus
Too much
Nitrogen
Stem grows too tall and thin and crop falls over
Burns the roots
N,P,K,Mg
• Too much Nitrogen – excess growth, lot of
green leaves, not many flowers
• Not enough Phosphorous – stunts growth
(particularly roots), grow slowly, less
resistant to disease or drought
• Not enough potassium – edge of leaves
yellow/brown, fewer flowers/fruit
• Not enough Magnesium – yellow leaves,
less healthy, yield lower
Fertilisers – absorbed by the roots
Organic
Inorganic
• adds humus and so improves
crumb structure
• decays slowly so releases nitrogen
over a long time
• contains large quantities of
known amounts of nutrients
• cheap and easy to obtain
• releases nutrients quickly
• contains other nutrients needed
by plants such as magnesium
• easy to spread
Anther
Stigma
Where the pollen lands
Produces pollen
(male gamete)
Style
Pollen travels down this
Ovule
Egg
(female gamete)
Sepal
Protects the flower in bud
Ovary
Develops into the fruit
Cross Pollination
The transfer of pollen from the anther of one flower to the stigma of another
flower of the same species
This increases genetic variation so plants are able to adapt to their surroundings
Self Pollination
The transfer of pollen from the anther of one flower to the stigma of the same
flower.
Advantage
Disadvantage
Does not require another plant of the same species near by
Little genetic variation in offspring
Wind Pollinated Plants
Feathery Stigma
hanging outside the
flower to increase
surface area to catch
pollen
Anthers hanging outside
the flower so wind will
blow pollen away
Lots of small, light pollen produced so it can be carried by the wind
Flower small and green and not scented since it does not need to
attract insects
Insect Pollinated Plants
Brightly coloured,
scented flowers to
attract insects
Anthers and stigma inside
flower in the best position for
the insect
Small quantities of
large, sticky pollen
is produced
Nectar is produced
A word of caution
Make sure that there are insects or wind in glass houses and polytunnels
Vegetative Reproduction
• This is asexual
• All offspring are genetically identical to the
parents
• Growers know what they will produce
• If one plant gets a disease they will all get
the disease
Runners eg. Strawberry
plants
An above ground stem
Rhizomes eg. Ginger
An underground stem
Bulbs eg. Onion
Leaves become swollen with food
stores.
Seed Germination
Testa (Seed Coat)
Plumule
Tough, so water is needed
to swell the seed and break
the testa before the seed
can germinate
Young shoot
Radicle
Cotyledons (Food Store)
Glucose + Oxygen
Young root
Energy
Enzymes are needed for respiration
therefore seeds only germinate in the
warmth
Light is not usually needed for germination except in
certain seeds such as lettuce
Raising Plants from Seed
Growing from seed
• Thinning out: weak seedlings removed to
give others more room
• Pricking out: Lift the seedlings out carefully
holding their cotyledons (seed leaves) and
re-plant in a new tray to allow seedlings to
grow well.
• Potting on – give seedlings more room to
grow
• light sensors
• temperature probes
• carbon dioxide sensors
• pH meters
• humidity sensors
White Rose
Red Rose
Phenotype: white
Phenotype:Red
Genotype: rr
Genotype: Rr
The allele for red flowers is dominant over the allele for white flowers
All the F1 generation
are Red
Inheritance of Flower Colour Using A Punnet Square
A red flowered plant was crossed with a white flowered plant. What is the ratio of
phenotypes and genotypes in their offspring?
R
r
R
r
b
r
Rr
rr
b
r
Rr
rr
Percentage Genotypes: 1:1 Rr:rr
Percentage Phenotypes: 1:1 Red : white
Single Digging
• aerates the soil
• removes weeds
• improves drainage
• FYM can be added to improve
crumb structure
• raked to produce a good tilth
Clay
Water
Humus
Sand
Silt
Storing Crops
Ripening
Bruising
Pests
Diseases