15 | Reproduction in Plants Flashcards
Definition of reproduction?
Reproduction is the process of producing new organisms.
Definition of asexual reproduction?
Asexual reproduction is the process resulting in the production of genetically identical offspring from one parent, without the fusion of nuclei of haploid gametes.
Definition of sexual reproduction?
Sexual reproduction is the process involving the fusion of nuclei of the haploid female gamete and the haploid male gamete to form a diploid zygote and the production of genetically dissimilar offspring.
Differences between asexual and sexual reproduction?
SPOF
What is the sepal?
- Modified leaf which enclose and protect the other parts of the flower in the bud stage
- All sepals together make up the calyx
What is the petal?
- Brightly coloured and conspicuous modified leaves to attract insects for pollination and provide a platform for insects to land
- All petals together make up the corolla
What is the receptacle?
Enlarged end of the flower stalk
What is the pedicel
Flower stalk
What is the stamen
male part of the flower
consists of
- filament
- anther
What is the filament
Holds anther in a suitable position to disperse pollen grain
What is the anther
- produces pollen grain
- has 2 lobes
– each contain 2 pollen sacs, which produces pollen.
— pollen grains are haploid as they are produced by meiosis
— the nucleus in the pollen grain is the male gamete (?)
What is the carpel?
- Female part of the flower
- Consists of one or more stigmas - consists of a style
- consists of an ovary
Function of the stigma?
Capture pollen grains
Function of the style?
Holds stigma at a suitable position to trap pollen grains and through which pollen tube grows
Function of ovary?
- Produces and protects 1 or more ovules
- Ovary will develop into a seed after fertilisation. It produces the haploid female gamete or ovum by meiosis
- The ovum is in the ovule.
Define pollination
Pollination is the transfer of pollen grains from the anther to the stigma
Define self-pollination
Self pollination is the process whereby the pollen grains from the anther are transferred to the stigma of the same flower or a different flower on the same plant.
Advantages of self-pollination?
WELPQ
- less pollen and energy is Wasted (W)
- not dependent on External factors for pollination (E)
- more Likely to take place since stigmas are closer to anthers (L)
- only one Parent is required (P)
- beneficial Qualities are passed down from parent plant to offspring (Q)
Disadvantages of self-pollination?
GPD
- offspring produced are Genetically similar to parents causing fewer varieties of offspring, less adapted to changes in the environment (G)
- Probability of harmful recessive alleles being expressed in the offspring is higher as compared with cross-pollination (P)
- species may become weaker, smaller and less resistant to Disease (D)
Ways to prevent self pollination?
MUAF
- stamen and pistil Mature at different times (M)
- Unisexual plant [plant producing either male of female flowers] (U)
- stigma of the flower is Above the anther (A)
- stigma and anther are situated Far apart from each other (F)
Define cross-pollination
Cross-pollination is the process of pollination whereby the pollen grains from the anther are transferred to the stigma of another flower on another plant of the same species.
Advantages of cross-pollination?
QVSPH
- offspring can inherit beneficial qualities from both parents (Q)
- more varieties of offspring are produced which leads to greater genetic variation (V)
- Seeds produced are capable of surviving longer before germination takes place (S)
- probability of harmful recessive alleles being expressed in offspring is lower as compared with self-pollination (P)
- increased probability of offspring being heterozygous (H)
Disadvantages of cross-pollination
PEWL
- Two different plants of the same species are required (P)
- Dependent on external factors for pollination (E)
- More pollen and energy wasted (W)
- Less likely to occur as compared to self-pollination (L)
What occurs during insect pollination?
notes
an example of an insect pollinated flower?
clitoria flower
describe the example of the insect pollinated flower?
notes
what occurs during wind pollination
- the long pendulous filaments expose the anthers to the wind
- when the wind blows, pollen grains are released and carried away by the wind
- the pollen grains land on large and feathery stigma, which has a large SA to trap the pollen grain
an example of a wind pollinated flower
Ischaemum muticum
describe the example of the wind pollinated flower
notes
things to compare for insect-pollinated and wind-pollinated flowers
PPNNSSS
- petals
- pollen
- nectar guide
- nectar
- stigma
- stamen
- scent
comparison in notes
process of fertilisation
notes
