4.2 - Sexual Reproduction in Plants Flashcards
What is the aleurone layer?
The protein-rich outermost layer of the endosperm that serves as an important enzyme store
What is the anther?
The pollen-bearing structure of the stamen
Define what a carpel is
The female part of the plant consisting of a stigma, a style and an ovary
What are cotyledons?
Embryonic seed leaves that emerge following germination
Explain what cross-pollination is
A type of pollination in which pollen is transferred from an anther of one plant to a stigma of a different plant. This results in plants with greater genetic diversity.
Define dehiscence
The splitting of an anther resulting in the release of pollen grains
What are dicotyledons?
Plants that produce seeds that contain two cotyledons; they have two primary leaves
What is double fertilisation?
Fertilisation of seed plants in which one male gamete fuses with a female gamete to form a diploid zygote and another fuses with two polar nuclei to form a triploid endosperm nucleus
Define what endosperm is
The food source surrounding the plant embryo
Explain what an endospermic seed is
A seed that contains an endosperm when mature e.g maize
What is germination?
The process by which a plant grows from a seed
What is gibberellin?
A plant hormone, which during germination, induces the synthesis of amylase by aleurone cells, hydrolysing stored nutrients in the endosperm
Explain what a hilum is
A scar on the testa as a result of separation from its funicle
What is an insect-pollinated flower?
A type of flower that relies on insects to transfer pollen grains between flowers
What is a micropyle?
A pore in the integument of an ovule through which the pollen tube enters the embryo sac. It remains as a pore in the testa.
Explain what a non-endospermic seed is
A seed that does not contain endosperm when mature e.g broad bean. Cotyledons serve as a food source.
Define the ovary of a plant
Part of the carpel that hold the ovules and following fertilisation, develops into the fruit
What is an ovule of a plant
The part of the ovary that gives rise to and contains the female germ cell. After fertilisation, the ovule becomes the seed
Define what petals are
Structures that surround the reproductive parts of a flower. They are often brightly coloured and fragrant to attract insects
What is a plumule?
The part of a plant embryo that develops into the primary shoot
What is a pollen grain?
A single granule of pollen that contains the male haploid gamete. Grains are small and produced in large numbers in wind-pollinated plants, whereas they are large and sticky in insect-pollinated plants
What is a pollen tube?
A hollow tube that grows from a pollen grain to the embryo sac in the ovule after pollination. It delivers two male gametes
Define what pollination is
The deposition of pollen onto a stigma from an anther
What is the radicle?
The part of a plant embryo that develops into the root
Explain what self-pollination is
A type of pollination in which pollen is transferred from an anther of a plant to a stigma of the same plant. This results in plants with less genetic diversity
What is the stamen?
The male part of the plant consisting of an anther and a filament that is involved in the production of male gametes in the form of pollen grains
Define what the stigma is
The sticky structure of the carpel that receives pollen grains
Explain what the tapetum is
A specialised layer of cells within the anther that provide nutrients to developing pollen grains
What is the testa?
The outer covering of a seed, commonly referred to as the seed coat
What is a wind-pollinated flower?
A type of flower that relies on wind to transfer pollen grains between flowers
