Reproduction in Flowering Plants Emphasis on Pollinators Mrs. Zemcik Living Environment Expanded by Joe Naumann, UMSL

Flower Sexual reproductive structure Produces egg and sperm Fertilization takes place inside the flower

Pistil *Stigma –top of the pistil, Sticky surface for pollen to stick to *Style – connects the stigma to the ovary *Ovary –contains ovules ( eggs) Stamen *Anther – produces sperm nuclei by meiosis. Sperm nuclei are enclosed by pollen grains. *Filament – holds the anther up Female reproductive organ Male reproductive organ

Pollination Transfer of mature pollen grains from the anther to the stigma -wind -insects -birds & other animals

Important (endangered?) Pollinators Bees Butterflies Moths Wasps Bombyliid flies syrphid flies Beetles Midges Thrips Ants Green bottle flies Bactrocera fruit flies Bats Birds –Hummingbirds –Honeyeaters –Sunbirds monkeys, lemurs, possums, rodents and lizards

Scopa (pollen holder) of a Megachilid bee

Halictid bee, showing adhering pollen

Syrphid fly, showing some adhering pollen

Halictid bee

Pollinator population declines and conservation In 1999 the Convention on Biological Diversity issued the São Paulo Declaration on Pollinators, recognizing the critical role that these species play in supporting and maintaining terrestrial productivity as well as the survival challenges they face due to anthropogenic change. Today pollinators are considered to be in a state of decline; some species, such as Franklin’s bumble bee (Bombus franklini) have been red-listed and are in danger of extinction.

Serious Problem Declines in the health and population of pollinators pose what could be a significant threat to the integrity of biodiversity, to global food webs, and to human health. At least 80% of our world's crop species require pollination to set seed. An estimated one out of every three bites of food comes to us through the work of animal pollinators.

When a pollen grain lands on the stigma, it germinates and a pollen tube grows down through the style to an ovule (egg)

Fertilization The sperm travels through the pollen tube to the ovule. The sperm & egg fuse forming the zygote (fertilized egg) –this grows into the plant embryo (cells grow by mitosis)

* Self pollination –pollen from same flower *Cross pollination – pollen from a different flower - more variation

The ovary and zygote (fertilized ovule) develop and ripen. *The ovule forms the seed and the ovary forms the fruit. A fruit is a ripened ovary

The plant embryo uses food stored in the cotyledon of the seed until it develops leaves for photosynthesis

micropyle –opening in ovule where pollen tube attached, sperm entered hilum –scar where ovule attached to ovary radicle –embryonic root Seedling

Epicotyl – grows above the cotyledons and gives rise to the leaves. Hypocotyl –below the point of attachment of the cotyledon, develops into the stem.

Parts of a seed Dicot Monocot Seed coat Epicotyl Cotyledons Hypocotyl Seed coatEndosperm Epicotyl Hypocotyl Radicle Cotyledon

Seed Germination MonocotDicot Hypogeous Epigeous Radicle

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