Reproduction In Plants Flashcards
Define reproduction
the process of producing offspring that are biologically or genetically similar to the parent organism.
Compare sexual and asexual reproduction
Asexual reproduction:
single parent involved
Offspring identical to parent
Offspring identical to each other
Type of cell division is only mitosis
Sexual reproduction:
Two parents involved
Offspring different from parents
Offspring different from each other
Type of cell division is only meiosis
Define perennation
The ability of organisms, particularly plants, to survive from one germinating season to another, especially under unfavorable conditions
Describe the life cycle of a typical flowering plant
Development of flowers
Pollination
Fertilization
Formation of seeds
Dispersal and f seeds
Germination
Growth of plant
Define pollination
The transfer of the pollen grains from the anther of one flower to the stigma of another flower.
Define fertilization
Fusion of the male and female gametes
What is the female gamete called?
Ovule
What is the male gamete called?
Pollen grain
What are the 5 main parts of a typical flower?
Gynaecium (carpel: stigma, style, ovary)
Androecium (stamen: anther, filament)
Corolla (petals)
Calyx (sepals)
Receptacle
Function of the gynaecium
Produces and contains the female gamete
Function of the androecium
Produces and contains the male gamete
Function of the Corolla
Attracts pollinators, such as insects to the flower
Function of the calyx
Protects the flower in the bud stage
Function of the receptacle
Bears the flower parts
Function of the petal
Provides colour and scent to attract pollinators
Function of the sepals
Protects the flower when in bud
Function of anther
Produces pollen grains containing male gametes
Function of filament
Holds the anther where it can best deliver pollen
Function of stigma
Catches pollen grains
Function of the style
Holds the stigma where it can best catch pollen
Function of the ovary
Contains ovules
Function of the ovules
Contains an ovum, the female gamete
Function of the embryo sac
Acts as the site for fertilization
What is self-pollination?
The transfer of pollen from the anther to the stigma of the same flower or flowers on the same plant
What is cross-pollination?
The transfer of pollen from an anther to a stigma of flowers on another plant of the same species
Examples of agents of pollination
Wind, insects, some birds
Why are agents of pollination necessary?
Plants are dependent on them to help bring their gametes together
Give an example of a wind-pollinated flower
Grass
Sugar cane
Corn
Give an example of an insect-pollinated flower
Pride of Barbados
Pea
Give characteristics of a wind pollinated flower
Don’t have bright petals, nectar or a scent
Pollen grains are very small and light
Large and feathery stigmas
Long filaments with anthers that hang out the flower
Describe how pollen is carried in water pollination
The pollen from the stamen of one plant will be carried across the surface of the water to the pistil of another flower
Characteristics of insect pollinated flowers
Flowers are large and bright
Petals are large and brightly colored with nectar and scented
Short stamen with anthers attached inside the flower
Sticky stigma that’s situated in the flower
Pollen grains are large, sticky or spiky
Describe what happens after pollination leading to successful fertilization
1) the pollen grains germinate
2) pollen tube grows down the style to the ovary
3) two male nuclei move down the pollen tube
4) pollen tube enters micropyle to reach female nucleus
Post fertilization changes in a flower
The ovule develops into a seed containing the embryo. The ovary grows into the fruit as th petals shrivel and drop off. The stigma, style and stamens also drop off. The sepals may remain.
Describe double fertilization
One sperm fuses with the central cell
One sperm fuses with the egg cell
Main function of the fruit
Protect the seeds during their development and aid in their dispersal
Why do plants disperse seeds?
Prevent overcrowding and competition for resources
Allow colonization of habitats
Reduce spread of diseases
The wall of the fruit is called
The pericarp
Define germination
The growth of a seed into a young plant or a seedling
Function of the micropyle
Water enters this opening during germination
Function of the testa
Seed coat which encloses and protects the seed
Define dormancy
The failure of seeds to germinate as soon as they are shed, even when conditions are ideal
2 types of germination
Epigeal germination - cotyledons carried above the soil Eg. Kidney bean, sunflower
Hypogeal germination - cotyledons remain below the surface of the soil Eg. Gungo pea
Conditions for Germination
Sufficient water
Adequate oxygen supply
Suitable temperature
Define dispersal
Process by which the offspring of a plant moves away from the parent plant.
