Whats Pollination?
• Transfer of pollen grains from anther to stigma of a flower

Types of pollination
• Self pollination takes place when mature pollen grains of a flower fall on the stigma of the same flower
• Cross pollination takes place when pollen grains of a flower fall on the stigma of another flower of the same species

Advantages of pollination
• Healthy offspring
• Leads to variation
• Greater chances of dispersal

Agents of pollination
• Wind
• Insects

Adaptations of flowers to wind and insect pollination

Insect pollinated flowers (entomophilus)
• Are scented to attract insects
• Have stick stigma for pollen grains to stick on
• Are brightly coloured to attract insects
• Presence of nectar to attract insects
• Have nectar guides to guide insects to the nectarines
• Have nectarines to secrete nectar
• Stigma/ anthers located inside the flower/tubal/funnel shaped corolla to increase chances of contact by insects
• Sticky/spiny/spiky pollen grains which stick on the body of insects and on stigma
• Large/conspicuous flowers easily seen by/attract insects
• Anthers firmly attached to the filament for insects to brush against them
• Landing platform to ensure contact with anthers and stigma
• Mimicry to attract (male) insects.



Wind pollinated flower (anemophilus)
• Anthers/stigma hang outside the flower to increase chances of pollination
• The style/filament is long to expose stigma/anthers
• Stigma is hairy/feathery/branched to increase surface area over which pollen grains land/to trap pollen grains
• Pollen grains are smooth/dry/light/small to be easily carried by wind
• Large amount of pollen grains to increase chances of pollination
• Anthers loosely attached to filaments to enable them to sway to release pollen grains
• Pollen grains may have structures which contain air to increase buoyancy
• Flowers have long stalks holding them out in the wind


Ways in which plants prevent(Hinder) self-pollination
• Protandry(anthers/stamens mature first)
• Protagyny (pistils mature first)
• Monoecism (where male and female parts are on same plant but different parts)
• Dioecism(where male and female parts are on different plants)
• Incompatibility (self sterility)
• Heterostyly (styles at different heights)

Characteristics that ensure cross pollination takes place in flowering plants
• Presence of special structures that attract agents of pollination
• Protandry/dichogamy
• Protagyny/dichogamy
• Monoecism
• Self sterility
• Heterostyly

Advantages of cross pollination
• hybrid vigour
• less prone to diseases
• promotes genetic variation
• greater evolutionary potential