Growing ConditionsFactors 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

Mineral Nutrients

N Nitrogen

K Potassium

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

• cheap and easy to obtain

• contains other nutrients needed by plants such as magnesium

• contains large quantities of known amounts of nutrients

• releases nutrients quickly

• easy to spread

Sepal

Protects the flower in bud

Anther

Produces pollen

(male gamete)

Stigma

Where the pollen lands

Style

Pollen travels down this Ovule

Egg

(female gamete)

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.

Does not require another plant of the same species near byAdvantage

Disadvantage 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

Nectar is produced

Small quantities of large, sticky pollen 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)

Tough, so water is needed to swell the seed and break the testa before the seed can germinate

Cotyledons (Food Store)

Glucose + Oxygen Energy

Plumule

Young shoot

Radicle

Young root

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

Phenotype: white

Genotype: rr

Red Rose

Phenotype:Red

Genotype: Rr

The allele for red flowers is dominant over the allele for white flowers

All the F1 generation are Red

rr

rr

b

b

R r

Inheritance of Flower Colour Using A Punnet Square

Rr

Rr

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

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

Sand

Silt

Clay

Humus

Water

Storing Crops

Ripening

Bruising

Pests Diseases