Plant Reproduction 1
A plant that completes its life cycle in one growing season.
annual
This does not involve the manufacture or union of sex cells or
gametes, e.g. binary fission, fragmentation, spore formation and
budding. It involves only one parent and the offspring are genetically
identical to or have the same genetic content as pa
asexual
reproduction
Modified bud. Swollen, underground, overlapping fleshy leaves and
reduced stem, e.g. onion, tulip.
bulb
The union of haploid male and female gametes produced by
different members of the same species, or from a member of a
different species.
cross-fertilise
Slip removed from a plant and rooted, e.g. busy lizzie, geranium.
cutting
The carrying of seed or fruit away from the parent plant, necessary
to avoid overcrowding, minimise competition and encourage
colonisation. This increases the chances of survival of the seed.
Agents include wind, water, animal and self.
dispersal
Inactive, resting or non-vegetative state before growth, e.g. buds,
seeds, and spores.
dormant
Immature plant contained in a seed.
embryo
Nutritive tissue found within the embryo sac of a seed plant. Arises
from the union of a generative nucleus (a sperm cell) and two polar
nuclei to form a triploid endosperm nucleus (3n). This nucleus
divides repeatedly by mitosis and forms the endosperm, which acts
as a food store.
endosperm
Plant that produces a number of generations in one growing season,
e.g. Shepherd’s purse.
ephemeral
Cotyledons brought above ground. Hypocotyl elongates, e.g.
sunflower seed (fruit).
epigeal
germination
The union of a haploid male gamete nucleus with a haploid female
gamete nucleus resulting in the formation of a diploid zygote.
fertilisation
Reproductive shoot of plant, containing sepals, petals, stamens and
carpel.
flower
A mature ripened ovary or modified part of a flower (e.g. the
receptacle), usually containing seeds. Its role is reproduction and
seed dispersal. It is also a source of food for animals.
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fruit
That part (stage/generation) of the life cycle of a plant that produces
the gametes – usually haploid.
gametophyte
Is the beginning of the growth of seeds, spores or pollen grains after
a period of dormancy. Certain conditions must be available, i.e.
water, oxygen and a suitable temperature.
germination
Scar or mark on a seed where it was attached by a stalk to the
placenta.
hilum
Cotyledons remain below ground, epicotyl elongates, e.g. broad
bean.
hypogeal
germination
Thin inner wall of a pollen grain.
intine
Two nuclei found in pollen tube as it approaches the micropyle of
the ovule. One will fertilise the egg and the other will join with the
two polar nuclei to form the triploid (3n) endosperm nucleus.
These are four haploid cells produced by meiosis in the ovule of a
flower. Three of these cells will degenerate and the remaining cell
nucleus divides three times by mitosis to produce eight haploid
nuclei. These arrange themselves as follows: three at the top, three
at the bottom and two polar nuclei in the centre. The one in the
middle on the bottom is the egg cell (n).
A small opening found between the integuments of an ovule
through which a pollen tube can gain access to the embryo sac to
deliver its nuclei and effect fertilisation and through which water
enters seeds to begin germination.
male gamete
nuclei
megaspores
micropyle
Main food store for developing embryo is in cotyledons, e.g. broad
bean.
non-endospermic
seed
A structure in which eggs are stored.
ovisac
Structures used by plants to store food, made by the plant during
the growing season, and help them survive the adverse conditions of
winter, e.g. tap roots.
perennating
organs
Plant that lives for many years and produces seed each year.
perennial
One of two nuclei in the centre of the embryo sac which, when
fertilised by the male gamete nucleus from the pollen grain, will
develop into the triploid endosperm nucleus.
polar nucleus
Elongated or tubular containers found in the anther at the top of the
stamen in which pollen grains are produced.
pollen sacs
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The transfer of pollen from the anther of the stamen of one flower,
to the stigma of the carpel of (a) the same flower or another flower
on the same plant or (b) another flower on a different plant of the
same species. Wind and insects are agents.
The ability of an organism to produce new individuals of its own kind
by either sexual or asexual means and pass on genetic information
to the next generation.
pollination
reproduction
Shoot of a plant specially cut for grafting onto stock.
scion
A young plant that has been grown/raised from a seed.
seedling(s)
The union of haploid male and female gametes produced by the
same plant.
self-fertilise
Part of a flower, usually green in colour. Protects the flower when it
is a bud.
sepal
That part (stage/generation) of the life cycle of a plant that produces
the spores. Usually diploid.
sporophyte
That part of the carpel on which the pollen grains must land if
pollination is to be successful.
stigma
The ‘neck’ of a carpel on top of which is the stigma and below is the
ovary. Upon germination of the pollen grain the pollen tube grows
down through here.
style
Having three times the haploid number of chromosomes (3n).
triploid
A type of reproduction in plants that does not involve the
production of seed, e.g. rhizomes, corms, tubers, bulbs, cuttings,
layering, grafting, budding and tissue culturing. Cloning.
vegetative
propagation
Method used to scatter/spread seed from the parent plant using
water, e.g. water lily.
water dispersal
The transfer of pollen from the anther of one flower to the stigma of
another by wind.
wind pollination
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