Introduction to plant reproduction

Question 1

Vegetative Reproduction:

Answer 1

The plants that result from vegative reproduction are clones of the original plant because their genetic make ups are identical to the original plant.

Question 2

Advantages of Vegetative Reproduction:

Answer 2

It is faster to grow new plants than from a spore or a seed.
The resultant plants are more uniform in their characteristics.
The only way to produce some fruits that do not produce seeds.

Question 3

Natural Vegetative Reproduction

Answer 3

When conditions are dry, some mosses dry out, break apart, and are scattered by the wind.
When conditions improve, some of theses pieces are able to resume growth in a new location.

Question 4

Humans use vegetative reproduction:

Answer 4

Farmers, horticulurists, and scientists can use buds, leaves, stems, or root pieces from certain plants to grow new plants.
A few cells of plant tissues can be placed on nutrients agar in sterile conditions to produce hundreds of identical plants.

Question 5

Alternation of Generations:

Answer 5

The life cycle of most plants includes a diploid (2n) sporophyte stage and a haploid (n) gametophyte stage.

Question 6

Gametophyte Stage:

Answer 6

The gametophyte stage produces gametes–egg and sperm. In nonvascular plants, the sperm must have a small amount of water to get to the egg.

Question 7

Sporophyte Stage

Answer 7

In vascular plants, the sperm may be carried by the wind, or another vector such as an insect. Fertilization of the egg by the sperm forms a cell that is first cell of the sporophyte stage.

Question 8

Moss reproduction and the Life cycle

Answer 8

The life cycle of the mosses begins with the dominant stage, the gametophyte.

Question 9

Male & Female Structures.

Answer 9

There are both male and female forms of the gametophyte.
Eggs are produced in the female structure, called the archegonium.
Sperm are produced in the male structure, called the Antheridium.

Question 10

Fertilization:

Answer 10

Sperm require water to swim to the egg. The chemical that allows sperm to find the egg is called, Chemotaxis.

Question 11

Mature Sporophyte

Answer 11

The mature sporophyte consists of a stalk that grows in the gametophyte stage.

Question 12

Spore Development

Answer 12

At the tip of the stalk is a capsule where up to 50 million spores may form by meiosis. The spores produce a protonema that can develop into the gametophyte plant and start a new cycle.

Question 13

Fern Reproduction & Life cyle

Answer 13

Another life cycle that has alternation of generations and produces spores is that of the fern.

Question 14

Spore Production:

Answer 14

Spores are produced from the sori, on the underside of a frond. If a fern spore lands on damp, rich soil, it can grow and form a tiny, heart-shaped gametophyte called a prothallus.

Question 15

Fern Fertilization:

Answer 15

Fertilization produces a sporophyte that grows from the prothallus.
The young sporophyte develops into a frond to start the cycle over again.

Question 16

Conifer Reproduction & Life Cycle:

Answer 16

Conifers are heterosporus–they produce two types of spores that develop into male and female groups.

Question 17

Female Cones

Answer 17

At the base of each scale on a female cone are two ovules.
Each ovule has a megasporangium that produces megaspores.
One of the megaspores develops into the female gametophyte.

Question 18

Male Cones:

Answer 18

Each scale on the male cone contains hundreds of sporangia produce microspores, which produce the male gametophyte, or pollen grain.

Question 19

Pollination:

Answer 19

Pollination occurs when the pollen grain from the species of a plant lands on the female reproductive structure of a plant of the same species. The pollen grain is trapped in a sticky substance called the pollen drop which is located near the micropyle.

Question 20

Seed Development

Answer 20

Seed development within the cone may take as long as three years.
The seed embryo will use the cotyledons for photosynthesis upon sprouting.