Plant Reproduction: Vegetative and Spore Methods

Study Notes

New plants can grow from parts of the parent plant thanks to meristem cells
Examples of vegetative reproduction methods: Cuttings, runners, suckers, tubers, bulbs
Fragmentation: a plant breaks into pieces, each piece can grow into a new plant
Some examples of vegetative reproduction are:
- Coleus plant (cuttings)
- Spider plants (runners)
- Strawberries (runners)
- Tulips (bulbs)
- Aspen (suckers)
- Potatoes (tubers)

Spores are similar to seeds but are produced by cell division, not the union of two cells
They are single-celled reproductive structures
They are easy to distribute over large areas because of their small size
Examples: Fungi (mushrooms)
One parent can produce many asexual spores, each growing into a new individual, identical to its parent
Many spores are produced to ensure at least one survives
Some fungi and algae produce zoospores which have flagella for movement

Alternation of generation: alternate between different forms (sporophyte & gametophyte)
- Sporophyte: diploid and produces spores from meiosis
- Gametophyte: haploid and produces gametes that combine to form a zygote

This is very similar to the fern life cycle in that it involves haploid spores and gametes, along with mitosis and meiosis in order to alternate between sporophyte and gametophyte generations.

Sexual reproduction relies on the union of two specialized sex cells called gametes
Male gamete (sperm), female gamete (egg cells or ova)
Fertilization: the union of two sex cells to produce a zygote

Angiosperms (flowering plants) and gymnosperms (conifers) reproduce sexually by forming seeds
Sexual reproduction in plants requires the joining of a male gamete with a female gamete to produce a zygote and an embryo
Most plants produce both male and female gametes, but some produce only one

Stamen: male part of a plant
- Filaments: support the anther
- Anthers: contains pollen, containing male gametes
Pistil: female part of a plant
- Stigma: site of pollination
- Style: connects the stigma to the ovules, pollen grows down this structure to the ovules
- Ovules: contain female gametes and are found in the ovary of the pistil
- Fertilization happens when the male and female gametes unite to form a zygote
- The zygote undergoes cell division to form a multicellular embryo, containing a miniature leaf, root, and stem
- The embryo is supplied with food by cotyledons
- These structures make up the developing seed

Many plants can self-pollinate, while others separate the male and female gametes
Cross-pollination: pollination from one plant to another by wind, water or animals (bees or butterflies)
Cross-fertilization: a pollen grain forms a long tube that grows down the style into the ovary, the gametes unite to produce a zygote, which then develops into an embryo

Embryo production usually happens inside a seed which protects the embryo and provides food (cotyledon)
Plants produced as a result of cross-fertilization show some characteristics of both plants, but are not identical to either plant

Asexual reproduction does not require specialized cells for reproduction
Can produce many organisms quickly
There is no partner required
Advantage in places where the environment doesn't change very much and can build a large population quickly
Disadvantage: when the environment changes, all the organisms will die if they do not have the ability to adapt to the change since there is limited diversity

Asexual reproduction: Requires one parent, produces an exact copy of itself, fast and easy but no genetic variation
Sexual reproduction: Requires two parents, provides genetic variation but is time-consuming