Download
1 / 14
200 likes | 400 Vues
Plant Reproduction. How do plants reproduce. There are two kinds of ways that plants reproduce. Do you know what they are??? The two ways are sexual reproduction and asexual reproduction. What is the difference between the two????. Sexual Reproduction in Plants.
E N D
How do plants reproduce • There are two kinds of ways that plants reproduce. Do you know what they are??? • The two ways are sexual reproduction and asexual reproduction. • What is the difference between the two????
Sexual Reproduction in Plants • Sexual reproduction in plants is the production of seeds. • Producing seeds requires combining a pollen grain and ovum (egg). • This combines genes from 2 different parents and causes the plants to be genetically different. • What are some benefits of genetic variation???? • Sexual reproduction in seed plants usually involves flowers. • What function do the flowers serve????? • There are other ways that plants reproduce sexually that don’t involve flowers but they work in similar ways. • Pine trees use cones to reproduce. The cones are both male and female and serve the same purpose as flowers. Did you know??? That most flowers have both male and female parts on the same flower, and often they are capable of fertilizing themselves.
Plant life cycle: Sexual reproduction • A plant starts out as a pollen grain and an unfertilized egg. • This produces a seed through the process of fertilization. • When the seed settles it grows into a seedling. • The seedling grows into a mature plant which is capable of producing more pollen and eggs, which grow new plants.
Parts of a Flower • The Stamen is the male reproductive part of the flower. It contains the pollen. • Pollen is responsible for fertilizing the ovum (egg). • The Pistil is the female reproductive organ. • At the base of the pistil is the ovary, which contains the ovum. • Pollen travels down the stigma where it meets the ovum (egg) and fertilizes it. • Once the ovum is fertilized the plant concentrates its energy on producing a seed. • The seed must have high energy stores so that the embryo inside it can grow until it is developed enough to produce its own food. • That is why nuts are so high in energy. Question: What is the function of the petals on the flower???? Answer: The petals may have more than one function, but the most common function is to attract insects and animals that will move pollen and fertilize the plants.
Pollen and pollination • As we said before pollen is what fertilizes the ovum. • Pollination is the process of fertilization. • Pollinators are the organisms (birds/insects) that help in the process of fertilization. • Hummingbirds, bees, and other insects get pollen stuck to them when they are collecting nectar. When the move to the next flower some of the pollen will fall off and fertilize the that flower.
Seed distribution • Seeds are dispersed in a number of different ways. How many can you think of???? • Some seeds are dispersed by the wind, like dandelions. • Some fall to the ground and grow only where they fall. • Some are eaten by animals and when the animals pass them they are dropped in the soil. • Some seeds stick to the fur of animals and are dropped in other places. You’ve probably had these types of seeds stuck to your shoelaces when you walk through the forest.
What is Asexual reproduction??? • Asexual reproduction is the process of reproduction which only one parent is required • Asexual reproduction in plants is also known as vegetative reproduction. • Asexual reproduction creates plants that are genetically identical to one another. Questions: What are the advantages and disadvantages of creating genetically identical plants??? What ways do you know of that plants reproduce asexually????
Types of Vegetative reproduction • Runners: Runners are long stems that grow along the surface of the soil. Eventually they will grow into a new plant. • Rhizomes: Stems that run underground and sprout new plants. • Suckers: Roots from the parent plant that produce new plants. • Cuttings: When you cut the stem of a plant and put the stem into a good growing medium (soil, water) the cutting can produce new roots and continue to grow.
Grafting • Grafting is another form of asexual reproduction. • Grafting is when a cutting from one plant is inserted into the stem of a different plant. • The cutting uses the other plants root systems to grow the cutting. • This means that you could potentially have and apple tree that grows three different types of apples.
