Flowers, Fruit and Seeds Flashcards
3.11 State the function of flowers
Primary purpose of flowers is to to aid pollination; to give rise to seeds and fruits
3.12 Draw a vertical section of a monocotyledon flower (not grass) to show where appropriate:
- receptacle,
- tepal,
- sepal,
- petal,
- calyx,
- corolla,
- nectary,
- anther,
- filament,
- stamen,
- stigma,
- style,
- ovary,
- ovule
picture
3.12 Draw a vertical section of a dicotyledon flower to show where appropriate:
- receptacle,
- tepal,
- sepal,
- petal,
- calyx,
- corolla,
- nectary,
- anther,
- filament,
- stamen,
- stigma,
- style,
- ovary,
- ovule
picture
3.12a Describe the structure and state the function of receptacle
Description: receptacle the thickened part at the end of the flower stalk on which the organs of a flower grow
Fuction: receptacle holds all the floral parts together, it may keeps the flower in an elevated position to attract pollinating insects
3.12b Describe the structure and state the function of tepal
Description: tepal is a division of the perianth, i.e. a sepal or petal (perianth is a collective term used to descibe external flower parts: the petals and sepals), used especially when it is unclear which is which
Function: tepal
3.12c Describe the structure and state the function of sepal
Decription: sepal a single part of the outermost whorl of floral organs, the calyx, usually green
Fuction: sepal protect the the unopened developing flower and prevents dessication
3.12d Describe the structure and state the function of petal
Decription: petal a single, usually free, unit of a completely divided corolla, or second floral whorl. Often brightly coloured and or unsually shaped
Function: petal to attract pollinating insects thereby increasing the chance of pollination
3.12e Describe the structure and state the function of calyx
Descrption: calyx the outermost whorl of floral organs, often divided into sepals
Function: calyx protects the developing flower and prevents dessication
3.12f Describe the structure and state the function of corolla
Description: corolla (ring of petals) may be small and insignificant in wind-polinated flowers, or large and colourful in insect-pollinated species
Function: corolla to attract pollinating insects thereby increasing the chance of pollination
3.12g Describe the structure and state the function of nectary
Description: nectary organs in which nectar is formed
Function: nectary produce nectar which attracts pollinating insects thereby increasing the chance of pollination
3.12h Describe the structure and state the function of anther
Description: anther the part of the stament containing the pollen
Function: anther produce male sex cells (pollen grains) needed for sexual reproduction
3.12i Describe the structure and state the function of filament
Description: filament a slender stalk that attaches to the base of the flower and bears an anther (pollen)
Function: fillament to support the anther
3.12j Describe the structure and state the function of stamen
Description: stamen the male organ of the flower, consisting of a filament bearing the anthers that hold the pollen
Function: stamen to prduce the pollen grains which house the male sex cells
3.12k Describe the structure and state the function of stigma
Description: stigma often sticky it is adapted to catch and trap pollen
Function: stigma the recieves pollen on the female organ of a flower
3.12l Describe the structure and state the function of style
Description: style is part of the female organ, between the ovary and the stigma, often long and slender and sometimes lacking when the stigma sits on the ovary
Function: style assists pollination by delivering pollen grains to the egg
3.12m Describe the structure and state the function of ovary
Description: ovary the ovule-bearing part of the female organ, often enlarged, that contains the ovules and may eventually become fruit
Function: ovary the place where ovules are formed and produced and may eventaully become the fruit
3.12n Describe the structure and state the function of ovule
Description: ovule the immature seed in the ovary before fertilisation
Function: ovule produce male sex cells (eggs) needed for sexual reproduction
3.13 State the meaning of ‘monoecious’ and dioecious’ in relation to plants. Know 2 examples of each
Monoecious: plants with male and females flowers on the same plant or a plant where all flowers produce both functional male and female organs, are described as hermaphrodite or bisexual.
- e.g. Cornus alba
- e.g. Musa basjoo
Dioecious: plants with male and female flowers on different plants can be describes as unisexual
- e.g. Skimmia japonica
- e.g. Ginko biloba
3.14 State the meaning of ‘pollination’
pollination: the transfer of pollen from anther to stigma of a flower is the essential first step in the process leading to fetilization.
3.15 Describe the characteristics of wind and bee pollinated plants -variations in flower structure and pollen
Wind pollinated plant characteristics:
- inconspicuous often green colour,
- small size flowers with exposed anthers and stigmas
- scentless
- necterless
- proportionally larger, feathery very sticky stigmas
- small, smooth light pollen grains in very large quantities
Bee pollinated plant characteristics:
- showy colourful flowers
- often scented to attract polinators
- nectar to entice reward visiting pollinators
- petals may have nectar guide markings
- stigma and stamen tend to be shorter and sturdy
- larger, heavier pollen grains produced in smaller quantities
3.21 State the meaning of the term ‘fertilisation’
Fertilisation: the result of one male gamete, from pollen, reaching a female gamete, an egg cell, in the ovule leading to the fusion of gamets to produce a new embryo of the same species
3.22a State the meaning of the term fruit
Fruit is formed from the ovary wall usually following fertilisation and encloses the seed
3.22b State the meaning of the term seed
Seed is the structure that develops from the ovule after fetilisation.
3.22a State the function of fruits
The function of fruit is:
- dispersal
- protection of the seed against extream conditions
- may impose dormancy
3.23b State the function of seeds
The function of seeds are:
- distribution and protection of the embryo against extream conditions
- may impose dormancy until favourable condiotns arise
- gives rise to new plants
3.24a Describe the means by which seeds are dispersed: wind. Name two plant examples for the above
Seeds are dispersed by wind in the following ways:
- wing some woody species produced winged fruits e.g. Acer saccharum
- parachute some fruits have tiny feathry parachutes Cirsium arvense (creeping thistle)
- censer seeds of poppy capsules are shaken from small pores in the fruit as the plant sways in the wind e.g. Papaver somniferum
3.24b Describe the means by which seeds are dispersed: water. Name one plant examples for the above
Seeds are dispersed by water in the following ways:
- aquatic plants or those growing close to rivers and seashores use the moving water to aid seed dispersal. The boyant fruit or seed being carried away by the moving water e.g. Lysichiton americanus (yellow skunk cabbage)
3.24c Describe the means by which seeds are dispersed explosive. Name two plant examples for the above
Seeds are dispersed by explosive (Self-dispersal) in the following ways:
fruit splits open propelling the seeds into the air, may be caused by a build up of water pressure or due to tension caused by uneven seed pod dessication
- e.g. Cytisus ‘Burkwoodii’
- e.g. Lupinus ‘Red Rum’ PBR
3.24d Describe the means by which seeds are dispersed: animals. Name two plant examples for the above
Seeds are dispersed by animals in the following ways:
- attachement hooked fruits become attached to animal fur when the plant is brushed against e.g. Arctium lappa (burdock)
- scatter hoarding birds or mamals may collect and disperse fruits, such as squirrels collecting acorns from oak trees e.g. Quercus robur
- frugivory fruits are eaten by animals, the seeds pass though the animals digstive system to be deposited elsewhere e.g. Sambucus nigra (elderberry)
3.25a Describe the internal structures of the seed and state the function of the various parts. Examples to be studied include: French bean Phaseolus vulgaris and broad bean Vicia faba:
- testa
- cotyledon
- embryo
- radicle
- plumule
- hypocotyl
- epicotyl
- endosperm
- hilum
- micropyle
11.
internal structures
3.25b Describe the external structures of the seed and state the function of the various parts. Examples to be studied include: French bean Phaseolus vulgaris and broad bean Vicia faba:
- testa
- cotyledon
- embryo
- radicle
- plumule
- hypocotyl
- epicotyl
- endosperm
- hilum
- micropyle
external seed structures
3.25c Describe and state the function of the testa
Description: testa (seed coat) encloses the embryo. It is formed from the outer layer of the ovule after fertilization. Waterproof and air tight and may contain germination inhibitors enabling dormancy until favourable conditions
Function: testa protection of the embryo against physical damage and desication, through adverse environmental conditions
3.25d Describe and state the function of the cotyledon
Description: cotyledon (seed leaf) is part of the embryo.may be one or two depending on whether it is a moncotyledon or dicotyledon. Cotyledon become the first leaf / leaves of a seedling when germination occurs. Cotyledon may coccupy a large part of the seed.
Function: cotyledon site of photosynthesis, may also act as a food store for the embryo
3.25f Describe and state the function of the embryo
Description: embryo is a rudimetry plant contained in a seed. Consisting of cotyledon/s (seed leaves), radicle (root) and plumule (stem). Once the embryo begins to germinate (grow out from the seed) it is called a seedling.
Function: embryo an imature plant waiting for favourable growing conditions
3.25g Describe and state the function of the radicle
Description: radicle part of the embryo which develops into the first root arising from the germinating seed
Function: radicle embryonic root system which will take up water and nutrients from the growing medium
3.25h Describe and state the function of the plumule
Description: plumule part of the embryo which develops into the shoot system arising from the germinating seed.
Function: plumule ebryonic shoot system, (translocation of water, mineral nutrients, plant hormones and food) bearing leaves for photosysnthesis and flowers for seed and fruit production.
3.25i Describe and state the function of the hypocotyl
Description: hypocotyl the region of stem below the cotyledon/s and above the radicle, it links the root system to the shoot system
Function: hypocotyl embryonic stem that bears the cotyledon/s
3.25j Describe and state the function of the epicotyl
Description: epicotyl embryonic stem above the cotyledons and below the plumule
Function: epicotyl to bear the plumule ?
3.25k Describe and state the function of the endosperm
Description: endosperm surrounds the embryo. It is a food store, of starch, within seeds which is not part of the embryo.
Function: endosperm the food store of the seed which fules the early stages of development
3.25l Describe and state the function of the hilum
Description: hilum scar often present where the seed was once attached to the ovary wall
Function: hilum an indication that the seed is mature and therefore viable
3.25m Describe and state the function of the micropyle
Description: micropyle a weakness in the testa where water uptake occurs triggering germination
Function: micropyle to allow the embryo to imbibe water and start germination
3.26a Describe epigeal germination, give one example
Description: epigeal germination meaning ‘above ground’. The cotyledons are pushed above ground. The hypocotyl elongates while the epicotyl remains the same. The hypocotyl pushes the cotyledon upwards. Typically plants with epigeal germination have littel food stored in the cotyledon, leaves are quickly produced and photosynthesis occurs rapidly.
e.g. Phaseolus vulgaris
3.26b Describe hypogeal germination to include one example
Description: hypogeal germination means below ground. The cotyledons stay below ground level. The epicotyl grows while the hypocotyl stays the same size. Plants with hypofeal germination typically need little in the way of external nutrients to grow.
e.g. Pisum sativum
