1. Sexual reproduction: a reproductive mode in which fertilized eggs develop into new individuals. For example, seed propagation (reproduction of offspring from seeds in fruits through flowering, pollination and fruiting). ) (Egg cells in ovules combine with sperm in pollen to form fertilized eggs → embryos → seeds)

2. Asexual reproduction: Without the combination of hermaphroditic germ cells, new individuals are directly produced by the mother. Such as cutting, grafting, layering and tissue culture.

3. The key of grafting: the scion is closely combined with the cambium of the rootstock to ensure survival.

Chapter 14 biological reproduction and development

Asexual reproduction of organisms: Definition: It is a direct development from the mother to a new individual, without the combination of bisexual germ cells.

Reproductive model.

Common asexual reproduction: budding reproduction: hydra, yeast, etc.

Vegetative reproduction: Definition: Plants depend on the roots, stems and leaves of vegetative organs.

Asexual reproduction, also called vegetative reproduction. Advantages: the excellent characters of plant parents are maintained, and the process is accelerated.

Plant reproduction speed.

Methods: Grafting: Definition: To put the bud or belt of a plant.

Branches with buds are connected to another plant so that they can be integrated into a complete plant.

Grafted buds or branches are called scions, and grafted plants are called rootstocks.

High survival rate: when grafting, the scion must be well done.

Closely combined with the cambium of rhizome.

Bud grafting: peach, hawthorn, apple, etc.

Grafting: oranges, oranges, etc.

Cut: potatoes, grapes, roses and begonia.

Layers: oleander, osmanthus, etc.

Split reproduction and spore reproduction.

Plant tissue culture: definition: planting organs, tissues or cells.

Under aseptic conditions, it is cultured on a medium containing various nutrients and plant hormones, so that it gradually develops into a complete plant.

Has the advantages that a large number of plants can be produced in a short time,

And prevent the invasion of plant viruses.

Second, sexual reproduction of plants.

1. Definition: Generally speaking, it refers to the germ cells produced by parents, which become fertilized eggs through the combination of bisexual germ cells, and then

Develop into a reproductive model of a new individual.

Advantages: it can integrate the excellent characteristics of parents and improve the vitality of future generations. 4. Plant pollination

Definition: the process of pollen transfer from stamen anther to pistil stigma through different ways after flowering. Mode: self-pollination: the pollen in the stamen anther of the same flower is passed to the pistil, such as rice;

Cross pollination: the pollen in the stamen anther of one flower is transferred to the pistil of another flower.

Structural characteristics of fruits or seeds adapted to spread

(1) Fruits and seeds spread by wind, water, human and animal activities and their own power. Among them, pea seeds spread by their own strength, dandelion fruits and corn poppy seeds spread by wind, the thorns on the surface of Xanthium sibiricum fruits spread by people and animals, and water lilies spread by water.

13. The sexual reproduction process of angiosperms: flowering → pollination → fertilization → fruiting and seed formation.

Formation of fruits and seeds

Fertilized egg → fertilized egg → embryo seed

Ovary integument → seed coat → fruit ovary wall →→→→→ pericarp

Fertilization polar nucleus-endosperm

The number of fruit seeds is related to the number of ovules in each ovary.