Plant Reproduction - Teacher Notes
Introduction to Plant Reproduction
Moss Reproduction and Life Cycle (typical of non-vascular plants)
Exhibit alteration of generations - spores produced by a moss sporophyte grow into moss
gametophyte plants.
1. Mature sporophyte releases spores
2. If spores find favourable conditions they form a protonema that develops into the
gametophyte plant.
3. The gametophyte stage produces archegonia (creates eggs) and antheridia (creates
sperm). These structures can be on the same or separate plants.
4. If water is present, the sperm swims to the archegonia to fertilize the egg. This forms
the first cell of the sporophyte stage called the zygote. The zygote develops into a
mature sporophyte. The cycle repeats.
The gametophyte stage is dominant. It is needed for nutrition and support because
sporophytes cannot photosynthesize.
Plant Reproduction - Teacher Notes
Fern Reproduction and Life Cycle (typical of seedless vascular plants)
Exhibit alteration of generations - spores produced by a fern sporophyte grow into fern
gametophyte plants.
1. Mature sporophyte, known as a frond(lacy leaf-like structure), releases spores
2. If spores find favourable conditions they form a gametophyte prothallus.
3. The prothallus develop both archegonia (creates eggs) and antheridia (creates
sperm).
4. If water is present, the sperm swims to the archegonia to fertilize the egg. This forms
the first cell of the sporophyte stage called the zygote. The zygote develops into a
mature sporophyte. The cycle repeats.
The sporophyte stage is dominant.
Plant Reproduction - Teacher Notes
Conifer Reproduction and Life Cycle (typical of gymnosperms)
1. Mature sporophyte releases spores. Conifers are heterosporous, meaning they
produce two types of spores that develop into male or female gametophytes.
Male cones produce microspores, which develop into pollen grains. Pollen grains are
transported by wind.
Female cones produce megaspores, which develop into the archegonia.
2. When a pollen grain lands on the archegonia, pollination occurs.
3. Following pollination, the pollen grain generates a pollen tube which grows into the
ovule. The sperm travel through the pollen tube to fertilize an egg and produce a
zygote.
4. With cell division, the zygote forms an embryo with one or more cotyledons. These
undergo photosynthesis and provide nutrition for the embryo when the seed sprouts.
5. When seeds mature, the female cone opens and releases seeds to the air. If the
seed lands in favourable conditions, it develops into the sporophyte. The cycle
repeats.
Plant Reproduction - Teacher Notes
Life Cycle of a Flowering Plant
Plant Reproduction - Teacher Notes
Parts of the Plant
Roots
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water and minerals are absorbed (taproots vs fibrous roots)
also used to anchor the plant
movement of water up to leaves is influenced by TRANSPIRATION
Stems
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Support plant
transport water through xylem
transport nutrients through phloem
a celery stalk soaked in food coloring will absorb the food coloring, you can
see the xylem
Two types of stems: herbacious and woody
Leaves
 Photosynthetic organ of the plant, used to convert sunlight into food
 Photosynthesis Equation:
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Stomata: pores within the leaf that open to let CO2 in and O2 out. Guard
cells open and close.
Cuticle: waxy covering on leaf that prevents water loss
Flower
 Reproductive organ of the plant
 Flowers are usually both male and female
 The male part of the flower is the STAMEN
 The female part of the flower is the PISTIL
 See your coloring sheet for more detail on flower anatomy
Plant Reproduction - Teacher Notes
Plant Reproduction
 Pollen is produced by the stamen.
 Pollen moves away from the plant via the wind or other pollinators (birds &
bees)
 The pollen lands on the pistil of another plant and fertilizes the eggs within
the ovary
 The flower petals fall off, the ovary develops into a FRUIT that encloses the
seeds
 Fruits are dispersed in a variety of ways (wind, animals)
 Fruits are not always edible, anything with a seed inside can be considered a
fruit (helicopters, acorns, dandelions)
Asexual Reproduction in Plants
 Many plants can clone themselves, a process called VEGETATIVE
PROPAGATION
 strawberry plants and other vine like plants send out runners, which grow
into new plants
 some plant clippings will grow into new plants
 a Potato will grow into a new plant
How Plants Grow
 Germination occurs when a seed sprouts (usually caused by changes of
temperature and moisture)
 Monocots have 1 seed leaf (cotyledon), Dicots have 2 seed leaves
Plant Reproduction - Teacher Notes
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Perennials - live serval years, and reproduce many times, woody plants are
perennials
Annuals - a plant that completes its life cycle in one growing season (grows,
flowers, reproduces and then dies)
Biennials - takes two growing seasons to complete, it reproduces in the
second growing season
Plants grow only at their tips in regions called MERISTEMS
PRIMARY GROWTH makes a plant taller at roots and stems
SECONDARY GROWTH makes a plant wider, or adds woody tissue
Tree Rings tell the age of a tree, each ring represents a growing season. The
photo shows a tree which has been through four growing seasons. The
lighter thinner rings are winter periods.
VASCULAR CAMBIUM: area of the tree that makes more xylem and phloem
and forms the annual rings
Read in the text pages 447-454.