plant reproduction Flashcards
1
Q
what is asexual reproduction in plants / list the types
A
- one diploid parent produces offspring, no fertilisation (do it on your own), formed from mitosis, genetically identical offspring
- vegetative propagation
- apomixis
2
Q
what is vegetative propagation
A
- part of parent plant becomes own individual, young is in close proximity to mother plant
- stolon (stem): plantlets grow off of stolon form along runners, strawberry plant
- tuber (root): new growth from ‘eyes’, underground system that can develop out new individuals (shoots that drop off), potato
- rhizome (stem): underground horizontal stem, formation of leaves, stems and roots, ginger
- reproductive leaves (budding): formation of new plants along margin of the leaf
3
Q
what is apomixis
A
- formation of a seed, mass production of a seed
- produce own young
- advantages: propagate / wide dispersal of seeds over large distances (citrus crops)
4
Q
what are the advantages and disadvantages of asexual reproduction
A
A:
- rapid (not chance)
- no fertilisation / pollinator
- formed by mitosis
- genetically identical offspring
- offshoots of mother plant (stronger than plant formed from seed)
D:
- no genetic diversity / variation, clones
- favourable characteristics thrive, catastrophic event = death
- no evolution or ability to adapt / change
5
Q
what is sexual reproduction in plants
A
- union of sperm and egg, involves fertilisation and meiosis, genetically different offspring, two diploid parents
- flower: advertises, attract pollinator (pollen from male to female = insect, bird)
- advantages: meiosis (genetic diversity within the population), evolution of community and adaption, survival of the fittest, formation of fruit (protective layer of seed)
- disadvantages: relies highly on chance, high affinity for pollen to leave anther and enter stigma (relies on timing, maturity, hormones)
6
Q
describe a summary of angiosperm fertilisation / growth
A
- germinated pollen grain (n, male gametophyte) on stigma
- fertilisation of female gametophyte (embryo sac, n)
- zygote (2n) to embryo (2n, sporophyte)
- fruit develops from ovary
- seed to germinating seed
- mature sporophyte plant (2n)
- waiting for germination to occur
7
Q
what are the different stages in sexual reproduction in an angiosperm
A
- alternation of generation:
- sporophyte: dominant stage of lifecycle, flower, asexual, zygote, embryo, sporophyte, micro / mega spore
- gametophyte: produces egg and sperm sexually, forms inside the sporophyte, mega / micro gametophyte and sperm / egg
- male: micro, smaller and dependent, microspore (2n) - micro-gametophyte (n) - sperm (n)
- female: mega, dominant, larger, megaspore (2n) - mega-gametophyte (n) - embryo sac / ovule / egg (n)
8
Q
describe the floral structure of a sporophyte
A
- 4 whorls (missing = incomplete)
1. sepal: green, hardened to form a capsule / operculum, base of petals
2. petal: brightly coloured, attract pollinators, tepal (no sepal / petal, fusion, undistinguished layer, white)
3. stamen: anther (produces pollen), filament (supports anther)
4. carpel: female reproductive organ, stigma (attracts / receives pollen), style (supports stigma), ovary (becomes fruit when fertilised), ovule (becomes seed when fertilised) - receptacle: joins all 4 whorls, tip of stem
- nectary: reward for pollinator, sugar / AA
9
Q
describe the location of a male sporophyte, how they are formed and how they fertilise an egg
A
- pollen grain on anther, formation of sperm in grains
- microspore (meiosis), produce pollen / micro-gametophyte (mitosis), becomes pollen grain (sperm, n)
- made up of vegetative cell (pollen tube) and generative cell (2 sperm)
- pollen lands on top of stigma, pollen tube forms (helps travel to egg which is enclosed and protected)
- sperm aren’t flagellated, 1 sperm (fertilises egg = zygote), 2 sperm (placenta)
10
Q
describe the location, structure and formation of a female sporophyte
A
- megaspore (4 cells = meiosis, 1 survives = egg, 3 = feeder, nutrition source), egg (mitosis) forms 7 cells with 8 nuclei (mega-gametophyte / embryo sac, no cytokinesis in one division), egg encased
- antipodal cells: feeder, before polar nuclei become placenta they feed egg, becomes endosperm
- polar nuclei: when fertilised become placenta, become endosperm
- egg: fertilised to form embryo
- synergic cells: guide pollen tube, release chemical messengers to do so
- micropyle: door way, entrance to seed, pollen tube enters through
11
Q
describe the process of pollination
A
- process leading up to fertilisation, promote cross pollination
1. pollen land on stigma, receptive for pollen tube to form
2. pollen tube germinates down style into micropyle / ovary becomes seed
12
Q
describe the process of double fertilisation
A
- two sperm were produced
- egg cell is fertilised to form zygote (2n, true fertilisation), forms new plant
- polar nuclei is fertilised to form endosperm (3n), support the growth of embryo (placenta), accessory fertilisation
13
Q
describe the development of an embryo and cotyledon
A
- undergoes mitosis forming cotyledons (embryonic cell leaf, stem, roots etc)
- mitosis = two or one cotyledon
- influences everything from germination, root structure, secondary growth
14
Q
what is sexual reproduction in an angiosperm
A
- flowering plant (two generations in lifecycle), alternation of generation, best of both worlds (spore and gamete producing worlds)
- advantages: dispersing over distance, no competition, spores migrate and move, migration / movement is possible over greater distance
- gametophyte stage: produces gametes, haploid
- sporophyte stage: produces spores, diploid
15
Q
describe a summary of the alternation of generation stages
A
- sporophyte (2n)
- differentiate to micro / mega sporangium
- become micro / mega spore (2n)
- mega / micro spore undergo meiosis (n)
- become mega / micro gametophyte
- become egg / sperm (n)
- gamete fusion, fertilisation, zygote (2n) and embryo (2n)
- develop into sporophyte (2n)
