Co-evolution: flowers & pollinators How a bee sees a flower…insects see UV light = a bulls-eye to the nectar

Angiosperm: fruiting plants

Other fruits…

Seed & Plant embryo Seed offers… protection for embryo (new plant) stored nutrients for growth of new plant seed coat food for new plant seed leaves embryo (new plant) Cotyledon (“seed” leaves) = first leaves of new plant Cotyledon (“seed” leaves) = first leaves of new plant

Seed dispersal 4 types Wind Water Animal Explosive

Plant Hormones (how plant cells talk) Hormone = chemical messages between cells; regulate cellular processes Formation of flowers, stems, leaves Shedding of leaves Formation/ripening of fruit Growth – up or down Sex of flower Plant length of life; death

Plant hormone groups Auxins Growth direction Flower formation Fruit set and growth Formation of adventitious roots (fibrous) Gibberellins Stimulate cell division Break seed dormancy; speed germination

Plant hormone groups Cytokins Aging and senescence (death) Used to delay these processes Ethylene Gaseous form only Induces fruit ripening Cause leaves to droop (epinasty) and drop (abscission) Produced in response to stress Promotes senescence

Tropism Directional movement responses that occur in response to a directional stimulus Phototropism = response to light Thigmotropism = response to touch Hydrotropism = response to water Gravitropism/geotropism = response to gravity Chemotropism = response to chemicals

Tropisms can be positive or negative Positive = towards stimulus Negative = away from stimulus Positive: with gravity Negative: against gravity

Nastic Movement Plant movement that occurs in response to environment Not dependent on the direction of the stimulus Examples: Venus fly trap, mimosa leaf Nastic movementNastic movement VIDEO