1.Flowers, Fruit and Seeds Flashcards
3.11 State the function of flowers
- Aid pollination and reproduction
3.12 Label these key parts of a monocotyledon flower:
- receptacle,
- tepal,
- sepal,
- petal,
- calyx,
- corolla,
- nectary,
- anther,
- filament,
- stamen,
- stigma,
- style,
- ovary,
- ovule
- Perianth
3.12a Describe the structure and the function of Perianth
- Collective term for calyx and corolla (sepals and petals)
- Easy to see on Diocots - sepals are clearly distinct - often visable from behind
- Harder to see on Monocots - nearly indistinguishable
3.12a Describe the structure and the function of receptacle
- Thickened part at the end of the flower stalk on which the organs of a flower grow
- Holds all the floral parts together
- May keep the flower in an elevated position to attract pollinating insects
3.12b Describe the structure of tepal
- Describes the sepal or petal when the two can not be easily told apart
3.12c Describe the structure and the function of sepal
- A single part of the outermost whorl, the calyx, usually green
- Protect the the unopened developing flower
3.12d Describe the structure and state the function of petal
- Single unit of the corolla, or second floral whorl
- Often brightly coloured
- Attract pollinating insects thereby increasing the chance of pollination
3.12e Describe the structure and the function of calyx
- Collective term for sepals
- Protects the developing flower
3.12f Describe the structure and the function of corolla
- Collective term for petals
- Attract pollinating insects thereby increasing the chance of pollination
3.12g Describe the structure and the function of nectary
- Organ in which nectar is formed and stored
- Produce nectar which attracts pollinating insects thereby increasing the chance of pollination
3.12h Describe the structure and the function of anther
- Part of the stamen containing the pollen
- Produce male sex cells needed for reproduction
3.12i Describe the structure and the function of filament
- Slender stalk that attaches to the base of the flower
- Supports the anther
3.12j Describe the structure and state the function of stamen
- Combination of the filament and anther
- Produce the pollen grains which house the male sex cells
3.12k Describe the structure and the function of stigma
- Often sticky
- Adapted to catch and trap pollen
- Receives pollen on the female organ of a flower
3.12l Describe the structure and the function of style
- Part of the female organ
- Between the ovary and the stigma
- Often long and slender
- Assists pollination by transporting pollen grains to the egg
3.12m Describe the structure and the function of ovary
- Ovule-bearing part of the female organ
- Often enlarged
- Contains and produces ovules which may eventually become the fruit
3.12n Describe the structure and the function of ovule
- Immature seed in the ovary before fertilization
- Produce female sex cells (eggs) needed for sexual reproduction
3.13 State the meaning of ‘monoecious’ and dioecious’ in relation to plants.
State 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
- Described as hermaphrodite
- Majority of plants
- e.g. Cedrus atlantica
- e.g. Quercus robur
Dioecious
- Plants with male and female flowers on different plants
- Individual plants are effectively male or female
- Can be describes as unisexual
- e.g. Juniperus communis
- e.g. Ilex aquifolium
3.14 State the meaning of ‘pollination’
- Transfer of pollen from anther to stigma of a flower
- First step in the process leading to fertilization.
3.15 Describe the characteristics of wind pollinated plants
- Inconspicuous often green colour
- Minimal or no flowers
- Scentless
- Necterless
- They have vast amounts of very light pollen
- Stigma is proportionally larger, feathery and very sticky adapted to attract pollen
- E.g Grasses and many Trees (Oaks, wheat, rice, barley)
3.15 Describe the characteristics of bee (insect) pollinated plants
- Bright colourful flowers
- Often scented to attract pollinators
- Contain nectar to entice reward visiting pollinators
- Stigma and stamen tend to be shorter and sturdy
- Larger, heavier pollen grains produced in smaller quantities
- Not all plants can be pollinated by all bees, some need larger bee’s or other insects and may have specialised petals to attract a specific species
- Not just bees/ insects, may also be bats, birds)
- E.g Tomatoes, apples, beans
3.21 State the meaning of the term ‘fertilisation’
- The result of one male gamete, from pollen, reaching a female gamete, an egg cell, in the ovule which produce a new embryo of the same species
- The pollen must be deposited on the right female part of the flower - Stigma
3.22a State the meaning of the term fruit
- Formed from the ovary wall usually following fertilisation and encloses the seed
3.22b State the meaning of the term seed
- The structure that develops from the ovule after fetilisation, it contains the plant embryo
- Contains nutrients to survive
3.22a State the function of fruits
- Seed distribution
- Protection of the seed against extreme conditions
- May impose dormancy / inhibit germination
3.23b State the function of seeds
- Protection of the embryo against extreme conditions
- In annuals they allow seed to survive unfavorable conditions
- May impose dormancy until favorable conditions arise
- Gives rise to new plants
- Transmit genetic diversity
- Shape and size have developed to aid distribution
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
- Parachute some fruits have tiny feathery parachutes
- E.g Acer sp
3.24b Describe the means by which seeds are dispersed: water.
- Aquatic plants or those growing close to rivers and seashores use the moving water to aid seed dispersal
- Buoyant fruit or seed is carried away by the moving water
- E.g Nymphaea spp (water lilies)
3.24c Describe the means by which seeds are dispersed explosive.
- Fruit splits open propelling the seeds into the air
- Can be caused by a build up of water pressure
- Or due to tension caused as the seed dries
- E.g Geranium sp
3.24d Describe the means by which seeds are dispersed: animals.
- Attachement hooked fruits become attached to animal fur when the plant is brushed against
- 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 digestive system to be deposited elsewhere
3.25c Describe and state the function of the testa
- Seed coat
- Encloses the embryo
- Waterproof and air tight
- May contain germination inhibitors enabling dormancy until favourable conditions (after cold winter, or fire)
- Protects the embryo against physical damage and desication
3.25d Describe and state the function of the cotyledon
- Seed leaf
- Part of the embryo
- May be one or two depending on whether it is a moncotyledon or dicotyledon
- Becomes the first leaf / leaves of a seedling when germination occurs
- May occupy a large part of the seed
- Once grown is the first site of photosynthesis
- May also act as a food store for the embryo
3.25f Describe and state the function of the embryo
- Contained in a seed
- Immature plant waiting for favorable growing conditions
- Consisting of cotyledon/s (seed leaves), radicle (root) and plumule (stem)
- Once the embryo begins to germinate it is called a seedling
3.25g Describe and state the function of the radicle
- Part of the embryo which develops into the first root arising from the germinating seed
- Embryonic root system which will take up water and nutrients from the earth
3.26a Describe Epigeal germination
- Meaning ‘above ground’
- The epicotal lengthens pushing seed above ground
- The cotyledons then emerge above ground
- E.g Brassica spp (Cabbage)
3.26b Describe Hypogeal germination
- Means ‘below ground’
- The cotyledons stay below ground level
- The plume pushes through the earth to the light
- E.g Phaseolus vulgaris (French bean)
State the differences between sexual and vegetative reproduction in plants
Sexual
- Usually involves flowers
- Fusion of male and female gametes
- Produces seed
- Genetic diversity is possible
- Therefore adaption to changing environments
- e.g Calendula officinalis
Vegetative
- Non-sexual
- Can be natural (Rhizomes, suckers)
- Nursery production (Division, cuttings)
- Offspring are genetically identical
- Not able to adapt
- e.g Ranunculus repens
State the difference between Indehiscent and dehiscent fruit/seed
Indehiscent
- Fruit and seed are combined
- May need decay to separate
- E.g nuts, Hazel
- E.g Maple fruit
Dehiscent
- Fruit forms a casing to protect seed
- Casing needs to be broken for seeds to disperse
- E.g Poppy
