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asexual reproduction
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Asexual reproduction refers to the reproductive mode in which new individuals are directly produced by the mother without the combination of bisexual reproductive cells. It can be divided into fission propagation (bacteria and protozoa) and budding propagation (yeast, hydra, etc.). ), spore propagation (ferns, etc. ) and vegetative propagation (strawberry stolons, etc. ), it can shorten the growth cycle of plants and keep the excellent characteristics of the mother.
Chinese name: asexual reproduction
Explanation: The mother directly produces the reproductive model of new individuals.
Nature: science
Category: biology
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brief introduction
definition
Without the combination of hermaphroditic germ cells (gametes), new individuals with unchanged genetic traits are directly produced by the mother.
classify
Asexual reproduction is divided into fission reproduction, budding reproduction, spore reproduction, fracture reproduction and vegetative reproduction.
superiority
Shorten the plant growth cycle;
2. Keep the excellent characters of crops and add some new advantages; ? Asexual reproduction atlas? 2 sheets
3. Increase crop yield.
disadvantaged
Many people have sexual reproduction and are prone to death due to bacterial invasion.
Breeding mode
divide
Schizogenesis, also known as schizogenesis, is a reproductive mode in which organisms split from their mothers into new offspring. The new individuals produced by division and reproduction are roughly the same in size and shape. In single-celled organisms, this mode of reproduction is more common. For example, paramecium, amoeba, euglena and bacteria all divide and reproduce. ? The division and reproduction process of paramecium
Germination propagation
Bud propagation, also called bud propagation, is a kind of propagation method in which the mother gives birth to buds in a certain part. The bud grows up gradually, forms the same individual as the mother, falls off from the mother and becomes a complete new individual? The germination and reproduction process of hydra. Yeast and hydra (when the environment is bad, hydra also has sexual reproduction. ) often bud and reproduce.
spore reproduction
(including only asexual spores)
Some creatures, when their bodies grow up, can produce a kind of cell, which can directly form a new individual without going through two two combination. This cell is called spore, and this reproduction is called spore reproduction. For example, Rhizopus forms sporangia at the top of its upright mycelium, producing spores. Spores can develop into new rhizopus when they fall in a humid and warm environment rich in organic matter. Generally speaking, lower plants and fungi reproduce in this way. Such as Adiantum, Penicillium and Aspergillus.
vegetative propagation
The reproductive mode in which vegetative organs (roots, leaves and stems) of plants produce new individuals is called vegetative reproduction. For example, the tubers of potatoes, the roots of thistles, the creeping branches of strawberries and the leaves of begonia can all germinate, and these buds can form new individuals.
Nutritional reproduction can make offspring keep their parents' traits, so people often use artificial methods such as rooting, cutting, grafting, layering and high pressure to propagate flowering fruit trees.
The vegetative propagation in the natural state is called natural vegetative propagation. Such as strawberry creeping branches, begonia leaves and potato tubers; Artificial assisted vegetative propagation is called artificial vegetative propagation. Such as cutting and grafting.
Potato, sweet potato and yam (propagated by tuber)
Poplar, willow, rose, rose (cutting)
Cultivation (grafting) of excellent varieties such as apples, pears and walnuts.
Plants that can produce aerial roots can be layered, such as banyan and oleander.
Plant tissue culture also belongs to asexual reproduction, such as the cultivation of many new crop varieties (rice, tobacco, corn and wheat), the reproduction of precious plants (excellent orchids and precious medicinal materials) and the reproduction of plants with low seed survival rate, which is widely used.