Grafting

Grafting method

Grafting is one of the artificial vegetative propagation methods of plants. That is, grafting the branches or buds of one plant to the stem or roots of another plant, so that the two connected parts grow into a complete plant. When grafting, the cambium layer of the scion and rootstock should be tightly combined to ensure the survival of the scion. The grafted branch or bud is called the scion, and the grafted plant is called the rootstock or platform. The scion usually uses a seedling with 2 to 4 buds, which becomes the upper part or top of the plant after grafting; the rootstock becomes the root part of the plant after grafting.

Grafting is carried out by taking advantage of the plant's ability to heal after being injured. During grafting, the cambium layers of the two injured surfaces are brought close to each other and tied together. As a result, due to cell proliferation, they heal each other and become a whole body connected by vascular tissue.

This is the principle of grafting.

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Grafting can show that the nucleus is the genetic control center.

Edit factors affecting this paragraph

The main factor affecting the survival of grafting is the affinity between the scion and the rootstock, followed by the grafting technology and post-grafting management. The so-called affinity refers to the ability of the scion and the rootstock to be the same or similar to each other in terms of internal tissue structure, physiology and genetics, so that they can combine with each other. High affinity and high grafting survival rate. On the contrary, the survival rate is low. Generally speaking, the closer the relationship between plants, the stronger the affinity. For example, apples are connected to Shaguo; pears are connected to Duli and Qiuzi pears; persimmons are connected to black dates; walnuts are connected to walnut trees, etc. The affinities are very good.

Edit the significance of this paragraph

Grafting is of great significance to the propagation of some fruit trees that do not produce seeds (such as persimmons and some varieties of citrus). Grafting can not only maintain the excellent traits of the scion variety, but also take advantage of the beneficial characteristics of the rootstock to achieve early fruiting, enhance cold resistance, drought resistance, and resistance to pests and diseases. It can also economically utilize propagation materials and increase the number of seedlings. It is often used in the propagation of fruit trees, forest trees, and flowers; it is also used in the cultivation of melon and vegetable seedlings. There are two types of grafting: branch grafting and bud grafting. The former is suitable to be carried out in spring and autumn, especially in spring when the survival rate is higher. The latter is best done in summer.

Edit the functions of this paragraph

1. Enhance plant disease resistance. Cucumbers grafted with black seed pumpkins can effectively prevent cucumber wilt and at the same time delay the onset of downy mildew. After grafting eggplants with CRP (Solanaceae) and tomatoes as rootstocks, the occurrence of Verticillium wilt can basically be controlled. .

2. Improve the plant’s ability to withstand low temperatures. Due to the well-developed root system and strong stress resistance of the rootstock, the grafted seedlings are obviously tolerant to low temperatures. For example, cucumbers grafted with black seed pumpkins have good root elongation at low temperatures. The roots can still grow normally when the ground temperature is 12-15°C and the air temperature is 6-10°C.

3. It is helpful to overcome the hazards of continuous cropping. The root system of cucumber is fragile and continuous cropping is prohibited. Solar greenhouse cultivation is very susceptible to damage from soil salt accumulation and harmful substances. After switching to black seed pumpkin roots, the damage from soil salt accumulation and harmful substances can be greatly reduced.

4. Expanded root absorption range and ability. The roots of grafted plants grow exponentially compared to self-rooted seedlings, and can absorb about 30% more nitrogen and potassium and 80% more phosphorus than self-rooted seedlings in the same area, and can utilize phosphorus in deep soil.

5. Helps increase production. The grafted seedlings have thick stems and large leaves, which can increase the yield by more than 40%. Late-maturing tomato varieties are used as rootstocks and early-maturing varieties are used as scions. This not only retains early maturity, but also greatly shortens the fruiting period and increases total yield.

Edit this paragraph location

Grafting is best carried out in a greenhouse. In high-temperature seasons, use sunshade nets or straw curtains to avoid direct sunlight, which may cause excessive wilting of the seedlings and affect their survival. For example, late-winter eggplant grafting in July is during the high-temperature period, so heatstroke prevention and cooling are key. In low-temperature seasons (such as the grafting of overwintering stubble of cucumbers and pumpkins at the end of September and early October), heat preservation should be the main focus. Low temperatures are not conducive to wound healing. The suitable temperature for grafting should be 24 to 28°C, with a relative air humidity of more than 75% and a humidity of more than 75%. If it is not enough, use a sprayer to spray water into the air or walls to increase the humidity.

Edit this section of tools

1. Blade: a double-sided blade for general shaving. Break it in half when grafting, which not only saves the blade, but also facilitates operation.

2. Bamboo sticks: One type is used for inserting holes in the rootstock. Its thickness is consistent with the thickness of the young stems of the scion seedlings, and one end is cut into a wedge shape.

On the other hand, the thickness is not strict. One end is cut into a single-sided wedge shape, and it is used to pick out the growing points of the pumpkin when it is connected.

3. Grafting clamp: Used to fix the scion and rootstock. There are currently two types of grafting clamps on the market, one is an eggplant grafting clamp, and the other is a melon grafting clamp.

Old grafting clips must be soaked in 200 times formaldehyde solution for 8 hours for disinfection in advance. The operator's fingers, blades, and bamboo sticks should be sterilized with 75% alcohol (medical alcohol), and disinfected every 1 to 2 hours to prevent miscellaneous bacteria from infecting the wound. However, blades and bamboo skewers wiped with alcohol cotton balls must wait until they are dry before use, otherwise the survival rate will be seriously affected.

4. Grafting machine: As the problem of obstacles to continuous melon cropping becomes more and more prominent, vegetable grafting technology has attracted people's attention. Specialized nursery households and nursery companies have also emerged. For professional nursery households and nursery companies, if they rely on manual grafting, the grafting timing will be easily delayed due to low work efficiency and low grafting technology level. They hope to use grafting machines. Small and semi-automatic grafting machines are popular in the market due to their low prices.

Among the current grafting tools, the Sono grafting machine imported from Taiwan is a semi-automatic grafting machine with a maximum productivity of about 310 plants/hour and a grafting success rate of 90%. Due to its simple structure, easy operation and low cost, It has a certain sales volume not only abroad but also in my country. It is suitable for semi-mechanized operations of fruit tree branches, watermelons, cucumbers and other melon vegetable seedlings.

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1. Docking method: The operation method is the same as the pumpkin docking method.

2. Split grafting method: Remove the growth point and core leaves of the rootstock, and cut an 8-10 mm long slit vertically downward between the two cotyledons; use a blade about 1 cm below the scion cotyledons on both sides of the young stem. Cut it into a double-sided wedge shape of 8 to 10 mm long. Align the double-sided wedges of the scion with the joint of the stock and gently insert it so that the two incisions fit closely together and secure the grafting clip.

3. Insertion method: First use a bamboo skewer to remove the true leaves and growth points of the gourd seedlings. At the same time, insert the bamboo skewer downwards from the growth point between the cotyledons of the rootstock to a depth of 0.5 to 0.7 cm, and then insert the bamboo skewer into the rootstock. Use a blade to cut the watermelon seedling into a wedge shape of about 0.5 cm from 1cm below the cotyledon. Pull out the bamboo stick and insert the watermelon seedling at the same time. This is the direct insertion method. Another method of insertion is the oblique insertion method. Use a single-sided wedge-shaped bamboo stick as thick as the scion. Place the plane of the bamboo stick downward and insert it obliquely from the base of the cotyledon on one side of the gourd seedling to the other side. The tip of the bamboo stick Push the skin of the young stem or pierce the skin, and then cut the watermelon seedling into a slanted stubble 1 cm below the cotyledon. While pulling out the bamboo stick, quickly insert the slanted stubble of the young stem of the watermelon seedling downward. After connecting, move it into the shed to strengthen management.

4. Machine implementation method: Using grafting machines, small and semi-automatic grafting machines are popular in the market due to their low prices.

Among the current grafting tools, the Sono grafting machine imported from Taiwan is a semi-automatic grafting machine with a maximum productivity of about 310 plants/hour and a grafting success rate of 90%. Due to its simple structure, easy operation and low cost, It has a certain sales volume not only abroad but also in my country. It is suitable for semi-mechanized operations of fruit tree branches, watermelons, cucumbers and other melon vegetable seedlings.

Edit this paragraph development overview

People have long discovered the natural grafting phenomenon in which tree branches in the forest are close to each other and connected after they are damaged by friction. In ancient China, it was called "Mulianli" ". Grafting is a production technology inspired by this natural phenomenon. In ancient Europe, Aristotle and the ancient Roman scholar Pliny both mentioned grafting. In the 5th century, grafting and bud grafting techniques were increasingly used in the Mediterranean region. In the 16th century, branch grafting methods such as cleft grafting, crown grafting, and tongue grafting were already available in England. Bud grafting technology was commonly used in Europe after the 17th century. At that time, it was mainly used to propagate peach, nectarine, apricot and other stone fruit trees.

The early records of grafting in China can be found in "The Book of Pan Sheng", which contains a method of grafting 10 gourd seedlings into one vine to form a large gourd. The Northern Wei Dynasty's "Qi Min Yaoshu" has detailed descriptions of the selection of rootstocks and scions in fruit tree grafting, the grafting period, how to ensure the survival of grafting and the impact of grafting. In the hundreds of years from the 6th to the 13th century, grafting technology developed greatly in ornamental plants and fruit trees such as peonies and chrysanthemums. In the Southern Song Dynasty, Han Yanzhi praised the wonders of citrus grafting technology in his book "Ju Lu" and said that "manpower is involved in nature." Due to the development of sericulture in the 13th century, mulberry grafting received attention. In the 17th century, Wang Xiangjin mentioned in "Qunfang Pu" that the combination of grafting and culture can promote plant variation. By the early Qing Dynasty, works such as "Huajing" further affirmed the effect of grafting in changing plant traits.

The application of modern scientific methods to study grafting has a history of less than 100 years, but it has developed very rapidly.

Edit the application and pictures of this section

In addition to maintaining the excellent characteristics of the variety, grafting is also used in fruit tree production to achieve early fruiting, overcome the difficulties of some varieties that are difficult to reproduce, and resist disease. Immunity and prevention of insect pests; in addition, the terroir adaptability of rootstocks can be used to expand the cultivation area, improve yield and quality; and dwarf or arbor the fruit trees (Figure 3). In the production of ornamental plants, the root grafting method (Figure 3a) is commonly used to restore tree vigor and preserve ancient and famous trees; the bridging method (Figure 3b) is used to save large trees with damaged trunks (see tree protection); The grafting method is used to replace the original inferior species of the big tree, make up for the incomplete canopy, etc. The use of high-inoculation replanting can also solve the problem of pollination of self-pollinated fruit trees that are not fruitful or dioecious, as well as the reproductive shape of special ornamental tree species such as Sophora japonica, Weeping peach, and Weeping plum.

Application effect of grafting machine

In terms of genetic breeding, grafting can be used to create asexual hybrids, and use the early nutritional proximity method to overcome distant hybrid sterility. In forest tree breeding, grafting technology is often used to dwarf the mother plant to facilitate cross-breeding operations and the establishment of seed orchards and ear-picking orchards. The use of special rootstocks to promote plant flowering, such as grafting sweet potatoes onto water spinach or moonflowers for hybrid purposes, is a common method used by breeders.

In addition, grafting is often used as a means to study plant physiology, plant pathology, plant virology and plant histogenesis. Many scholars often use grafting in order to clarify the local synthesis process and stage development of certain substances in individual organs.

Applications of grafting machines:

Grafting machines

As the problem of obstacles to continuous melon cropping becomes more and more prominent, vegetable grafting technology has attracted people's attention. Specialized nursery households and nursery companies have also emerged. For professional nursery households and nursery companies, if they rely on manual grafting, the grafting timing will be easily delayed due to low work efficiency and low grafting technology level. They hope to use grafting machines. Small and semi-automatic grafting machines are popular in the market due to their low prices.

Among the current grafting tools, the Sono grafting machine imported from Taiwan is a semi-automatic grafting machine with a maximum productivity of about 310 plants/hour and a grafting success rate of 90%. Due to its simple structure, easy operation and low cost, It has a certain sales volume not only abroad but also in my country. It is suitable for semi-mechanized operations of fruit tree branches, watermelons, cucumbers and other melon vegetable seedlings.

Edit this paragraph Development Trend

The application scope of grafting technology is still expanding. In addition to fruit trees and ornamental trees, grafting is increasingly used on herbaceous plants such as vegetables, forest trees and other economic plants such as rubber trees and cocoa trees. In terms of grafting materials, they have developed from ordinary branch grafting and bud grafting to twig grafting, leaf grafting, germ grafting, growing point grafting, bud eye grafting of bulbs and tubers, and even grafting of inflorescences, stigmas, ovaries and fruits. Almost all plants All parts can be used for grafting. Since 1980, microbody propagation and microbody grafting have been developed based on tissue culture technology. In sterilized tissue culture, virus-free seedlings of citrus, apple and other fruit trees can be cultivated using 0.10-0.14 mm isolated stem tip micro-grafts, which have been used in China, the United States, and Spain. In addition to the continuous improvement of grafting technology, further exploration of the nature of grafting affinity and the mechanism of rootstock influence will be the focus of future research.

Notes when editing this paragraph

1. Choose rootstocks and scions with strong affinity

Affinity refers to the ability of the rootstock and scion to heal after grafting. In general, The closer the genetic relationship, the stronger the affinity, and the higher the grafting survival rate.

2. Choose rootstocks and scions with strong vitality

Viability is related to the nutrients accumulated in the vegetative organs of the rootstock and scion. The more nutrients accumulated in the vegetative organs, the more substantial the development will be. Therefore, before grafting, water and fertilizer management of the rootstock should be strengthened to allow it to accumulate more nutrients, and mature branches with full buds should be selected as scions.

3. Choose the best grafting time

Generally, branch grafting should be carried out in early spring before the fruit tree germinates, because at this time, the rootstock and scion tissues are full, and the temperature and humidity are also conducive to the formation of Vigorous division of layers accelerates wound healing. Bud grafting should be carried out during the slow growth period. It is best to survive the grafting this year and germinate into seedlings next spring.

4. Use plant hormones to promote healing

The scion should be treated with plant hormones before grafting. For example, soaking with 200-300PPM naphthylacetic acid for 6-8 hours can promote the formation of cambium layer. activity, thereby promoting wound healing and improving the survival rate of grafting.

5. Standardized technical operations When grafting, the action should be rapid, and the rootstock and scion should be trimmed strictly according to the technology. The joint surface should be smooth so that the cambium layers of the rootstock and scion are closely connected. The binding should be moderately tight and untied in a timely manner. tie.

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