R2101 - Structure & function of flowers fruits & seeds Flashcards
3.1 State the function of flowers.
- purely reproduction
- aid pollination
- give rise to seeds and fruits
3.1 State the meaning of monoecious with two examples.
Monoecious plants have separate male and female parts on the same plant.
- Cucumis spp. (Cucumbers)
- Alnus spp. (Alders)
3.1 State the meaning of dioecious with two examples.
Dioecious plants have male and female flowers on separate plants – so the individual plants are effectively either male or female.
- Ilex spp. (hollies)
- Salix spp. (willows)
3.1 State the meaning of the term pollination.
The transfer of pollen from the stamen (male) to the stigma (female) of a flower - enabling the ovules to be fertilised.
3.1 Describe the characteristics of wind pollinated plants - include flower structure and pollen
- Flowers - small, inconspicuous, green petals, reduced in size or absent
- Flower structure - often dangles loosely, stamens hang out of the flower.
- No scent or nectar
- Pollen - large quantities made, light and smooth and easily carried by wind
- Anthers - larger, loosely attached to long filaments, to release pollen more easily
- Stigmas - feathery, hang outside flower to catch passing pollen grains
- Grasses are wind-pollinated, as are many trees
- Catkins produced by trees produce are an example of wind pollination
3.1 Give two examples of wind pollinated plants.
- Grasses are wind-pollinated e.g. zea mays (corn)
- Catkins produced by trees produce are an example of wind pollination e.g. Corylus avellana (hazel with catkins)
3.1 Describe the characteristics of bee pollinated plants (8) - include flower structure and pollen.
- Shallow flowers with short floral tubes to match the length of the bee’s tongue
- Bright white, yellow or blue flowers
- Nectar guides sometime only visible to bees
- Sugar-rich nectar
- Sticky scented pollen
- Sweet, mild scent
- A landing stage, e.g. Antirrhinum, Digitalis
- Sometimes highly adapted to particular bee species
3.1 Give two examples of bee pollinated plants.
Limnanthes douglasii (poached egg plant)
Borago officinalis (borage)
3.2 State the meaning of the term fertilisation.
The fusion of a male gamete from pollen with a female gamete in the ovule to produce the embryo.
3.2 State the meaning of the term fruit.
A fruit is formed from the ovary after fertilisation.
3.2 State the term of the meaning seed.
A seed is formed from the ovule after fertilisation.
3.2 State the function of fruits.
- distribution and protection of the seed
- may impose dormancy until conditions are favourable
3.2 State the function of seeds.
- distribution and protection of the embryo
- may impose dormancy until conditions are favourable for germination
- gives rise to new plants
3.2 Describe the means by which seeds are dispersed - wind with named examples.
wings - wing-like structures that spin in the wind as it falls from the plant e.g. Fraxinus excelsior (Ash)
parachutes - feathery parachutes attached that carry seeds long distances e.g. Taraxacum officinale (Dandelion)
censer - shaken from small pores in the fruit as the plant sways like a church censer e.g. Papaver rhoeas (poppy)
3.2 Describe the means by which seeds are dispersed - water with named examples.
- fruits of plants growing in or near water are adapted to float for dispersal
- Cocus nucifera (coconut)
- Nymphaea alba (White waterlily)
3.2 Describe the means by which seeds are dispersed - explosive with named examples.
- seed is distributed explosively by the fruit forming a spring mechanism as it dries
- Lathyrus odoratus (sweet pea)
- Lupinus perennis (Lupin)
3.2 Describe the means by which seeds are dispersed - animals with named examples.
attachment - seed have tiny hooks to attach to fur or feathers: Gallium aparine (Goose grass)
scatter hoarding - seed is taken and buried by squirrels: Quercus robur (Common oak)
frugivory - fruit is eaten and the seeds then excreted far from the parent plant: Rubus fruticosus (blackberry)
3.2 Describe the internal and external structure of the seed and state the function of the various parts: (10)
- Embryo = radicle, plumule, cotyledon, hypocotyl, epicotyl
- Testa = the seed coat
- Cotyledon = the seed leaves and food store (remember, monocots only have one of these, whilst dicots have two)
- Endosperm (in monocots) provides food for the embryo
- Plumule = forms the first shoot
- Radicle = forms the first root
- Epicotyl = elongates to grow the shoot and attaches the plumule to the cotyledon
- Hypocotyl = elongates to grow the root and attaches the radicle to the cotyledon
- Hilum = the scar showing where the seed was attached to the ovary
- Micropyle = a small gap where the pollen entered the ovule and often the place where water enters the seed to begin germination
3.2 Describe ONE example of epigeal germination.
Epigeal germination is where the cotyledons emerge above ground. E.g Phaseolus vulgaris (french bean)
3.2 Describe ONE example of hypogeal germination.
Hypogeal germination is where the cotyledons remain below ground. E.g. Vicia faba (broad bean)
