Biological reproductive variety of ways, mainly divided into two types of asexual and sexual reproduction, some plants can not only reproduce sexually, but also reproduce asexually.
Sexual reproduction refers to a cell binding amphoteric form a fertilized egg, and then the fertilized egg into a new individual mode of reproduction and sexual reproduction allows greater variation progeny, offspring that the new trait, strong viability, and more conducive to adapt to the environment is conducive to breeding race. As long as the development of a fertilized egg into a new individual mode of reproduction is sexual reproduction. Corn is propagated by seeds, fertilized embryo is formed by the development of this mode of reproduction corn belongs to sexual reproduction. IVF is sexual reproduction. IVF is a special technique, is to get the egg and sperm have in vitro and let them complete the process of in vitro fertilization artificial controlled environment, then the early embryo into a woman's womb, a child conceived in the womb become . It produced using in vitro fertilization techniques referred IVF baby. IVF is characterized by sexual reproduction, in vitro fertilization, in vivo development.
Without binding is asexual reproductive cells from the parent to produce a new individual directly. In essence, that is, asexual reproduction is carried out by the body cells. The advantage is asexual propagation speed, is conducive to maintaining parental traits disadvantage because of parent-offspring and genetic characteristics, after all, no change, reduce variability, ability to adapt to changes in the environment will be reduced. The main types of asexual reproduction include: reproductive division, spore, budding, vegetative reproduction (grafting, layering, cuttings, etc.), tissue culture and cloning. Way of breeding plants with roots, stems, leaves and other vegetative organs is called vegetative propagation. Poplar, willow, grapes, Roses, roses and other plants used for breeding methods cuttings; pomegranate, laurel, oleander and other plants commonly used method of layering breed; methods apples, pears, peaches and many other commonly used grafting fruit trees to breed improved varieties . Grafting refers to a branched or buds of plants, plant connected to the other, so that two portions joined together grow into a complete plant body. When grafting, Jieshangqu buds or branches called the scion, then the plant is called the rootstock. Grafting and budding branches take two types of grafting is when scion branches, budding is when scion bud. To improve the survival rate of grafting, the grafting success, cambium of the rootstock and scion closely is the key.
Most single-celled organisms divide germ, protozoa can also reproduce sexually. "Budding" in the "bud" refers to the buds grow on the mother, rather than the structure of the real buds on higher plants. For example: the use of potato tubers sprout for breeding is the use for breeding, it is not the budding vegetative reproduction. In essence, the "buds" and the mother is the same, but the buds smaller. Asexual reproductive spores in the "Spore" is asexual spores, and somatic cells have the same number of chromosomes or DNA. Therefore, asexual spores can only be through mitosis or no mitosis to produce, and can not be produced by meiosis. Vegetative reproduction is the use of vegetative organs of plants to reproduce, only higher plants differentiate root, stem, and therefore, it is a way of asexual reproduction of higher plants, low plant cells vegetative reproduction impossible. In 1997 British scientists cloning of Dolly the sheep bred is one example. Our research on cloning technology, but also made great achievements. For example, shortly after the birth of Dolly, cloned goat cloning success rate is 10-20 times that of the sheep Dolly.
Whether the essential difference between asexual and sexual reproduction are combined with gender germ cells. Many plants can not only reproduce sexually, but also reproduce asexually. A variety of ways to enhance the reproductive ability of plants to adapt to environmental change, expanding their distribution range, the plant is widely distributed in a wide variety of ecological environment.
Cutting process material: the good development of the branches is about 15 cm cut stem segments, each segment generally retained two sections. Upper horizontal cutout is to reduce water loss, the cutout is inclined downward advantageous in increasing the area of the absorbent. Removing a top portion of the blade section reduced transpiration, following a section of the entire blade is removed from the petiole facilitate rooting. The following sections will need a cuttings buried in the soil, pay attention to shade, timely watering. 25-30 days after the general to give birth to a new root cuttings, we shall survive to see the new shoots grow.
Plant tissue culture is the use of the principle of asexual reproduction of plants, the plants quickly develop into new tissue in vitro plant biotechnology. With this technique, it can be cut into small pieces of plant leaves, shoot tip, stem or anthers, pollen, etc. placed under sterile conditions, cultured in a medium, so that they develop into a complete plant. The advantage of this method is that, propagation speed, little affected by the seasons; induced mutation easier; virus also can be effectively removed.