A brief introduction to the grafting technique of bonsai plants

What is grafting?

Grafting is to attach some organs of one plant, such as buds or branches, to the stem or root of another plant, so that the two parts can heal each other and grow into a complete plant. The buds or branches grafted are called scions (commonly known as yards), and the plants that accept scions are called rootstocks (commonly known as mother and son, Taiwan wood, foot wood). Rootstocks mainly absorb water and inorganic salts. The seedlings obtained by grafting are called grafted seedlings.

What is the principle of graft survival?

Grafting is a reproductive method that makes use of the ability of plant regeneration. The most powerful place of regenerative energy of plants is the forming layer. It is located between the xylem and phloem of plants. It can absorb water and minerals from the outer phloem and the inner xylem to divide itself and produce xylem inward and phloem outward, making the branches of the plant thicker and thicker. Grafting is to make the scion and the rootstock respectively cut to form a layer.

They are closely connected with each other, differentiate calli because of trauma, and the developed calli combine with each other to fill the gap between scion and rootstock, communicate and dredge the tissue, so that nutrients can transmit to each other enough to form a new plant.

What are the internal factors that affect the survival of grafting?

The affinity of rootstock and scion refers to the similarity of internal tissue structure, genetic and physiological characteristics between rootstock and scion, and the ability to grow normally by grafting. Affinity mainly depends on the genetic relationship between rootstock and scion. Generally speaking, the closer the kinship is, the stronger the affinity is. The genetic relationship between the same genus and the same species is close, and the grafting is easy to survive. For example, double peony grafted on double peony, walnut grafted on walnut, rose grafted on rose, and peach grafted on mountain peach are the easiest to survive. This grafting combination is called "common rootstock".

The grafting affinity between different genera of the same family is small, and the grafting is not easy to succeed. There is less affinity between different families, so it is difficult for grafting to succeed.

What are the external factors that affect the survival of grafting?

1. Temperature

The optimum temperature for callus growth is about 20-25 degrees Celsius.

two。 Interface humidity

Keeping high humidity is beneficial to the growth of callus. Generally, plastic bags and wax seals are used to maintain the humidity of scions and rootstocks.

3. Light

Light has an obvious inhibitory effect on callus, and the callus grows well under dark conditions, so it is necessary to shade the callus after grafting. It is generally covered with soil or opaque materials to create dark conditions.

4. Rootstock quality

Rootstocks and scions have strong ability to live. Generally choose the Lignified crown, do not choose the growing branch, because the growing branch is easy to lose water.

5. The living habits of rootstocks

The living habits of rootstock and scion should be suitable. Generally, the survival rate of first germination of rootstock is high, while that of scion is low, because the scion is easy to lose water when it germinates first. For example, when the top bud of persimmon is grafted on Junqianzi (round jujube), the survival rate is high, regardless of whether Junqianzi sprouts or not.

6. Grafting period

Grafting is closely related to air temperature, soil temperature and the active state of rootstocks. Therefore, the grafting period should be selected according to the characteristics of flower species.

7. Grafting technique

The interface cutting is required to be smooth, fast and skilled.

When is it suitable for grafting?

Branch grafting is mainly carried out before the germination of early spring flowers and trees. At this time, the tissue of rootstock and scion is full, and the temperature and humidity are also beneficial to the formation of layer division and callus growth. It is better for shoot grafting in summer plum rain season.

Budding is mainly carried out in summer and autumn, when the cambium cells are still very active, the tissue of bud grafting is abundant, the grafting is healed in the same year, and it is very suitable to sprout in the following spring after overwintering.

Appropriate.

Generally, branch grafting is carried out in February-March, lean grafting in May-June, and bud grafting in July-September. In cold areas, the time of budding should be advanced to avoid freezing injury.

How to carry out grafting

1. Splice

Cutting is the basic technique of grafting, which is suitable for ground grafting of rootstocks with 1 cm to 2 cm root neck. The specific steps are as follows:

(1) choose anvil and scion. The young shoots with full tissue development were used as scions, and the annual branches with sunny and short internodes were the best, without disease and insect branches, flower bud branches, secondary branches and weak branches. Deciduous trees can be collected and stored after dormancy (sand storage, refrigerator storage or wax seal storage). Roses (rose) are not easy to survive and should be picked up as they are picked. Evergreen trees are generally not stored and can be picked up as they are picked. The rootstock should be strong, well-developed root system, no diseases and insect pests, more nutrient accumulation, and pay attention to the affinity with the scion.

(2) cutting scion. Cut off a section in the middle of the branch, about 10 to 12 centimeters long as a scion. Keep 3-4 buds on the scion, the upper mouth slightly higher than the top bud, to protect the bud from bruising, the lower mouth should be 3-4 cm below the lowest bud. The ear is 5-8 cm long with 3-4 buds. Cut the scion into two sides, one long and the other short. The long face cuts off more than 3 of the xylem, showing a 30-degree slope, the length of the cutting surface is 2.3 to 2.5 cm, and the last bud remains on both sides of the cutting surface; cut a small horseshoe-shaped slope on the opposite side of the long face, cutting it to 45 degrees and 0. 5% long. About five centimeters. These two cut faces should be flat and smooth.

(3) cutting rootstocks. Cut off the branches of the rootstock and cut the rootstock 3 to 4 centimeters above the ground. Cut the end of the anvil flat, then make a light cut on one side of the cut of the rootstock, then cut down vertically, with a length of about 2 to 3 centimeters, and strive to be smooth. Such a section has a large area and is easy to align and closely connect with the scion cambium.

(4) combination. Cut the scion and cut the rootstock. The scion is long facing inward and short facing outward. When inserting people, the scion just touched the lower end of the cut of the rootstock, do not use force to press down, the upper end should expose a line (commonly known as "blank", about 0.3 cm), so that there is room for callus growth.

(5) binding. The combination of rootstock and scion should pay attention to binding. When binding, do not move the scion to form a layer alignment position, loose and tight moderately. You can tie it up from the top down or from the bottom up. Commonly used 0.5 cm wide plastic belt as binding material, good moisturizing performance, difficult to survive flowers and trees should also be coated with wax.

(6) Management. General flowers and trees can be grafted and planted in the open field, as long as the cut part is covered with fine soil, the soil should be 1 cm higher than the scion, exposing only the terminal bud. Camellia can be bagged and planted. However, hotbed cultivation can promote healing and improve the survival rate. In the future, keep watering from the base to keep the mound moist until after budding. After the cutting seedlings survive and spread their leaves, do not rush to release the binding material, but keep it for one or two months.

After 1-2 months of grafting, the shoots can sprout. After the buds are unearthed, the sealing soil is gradually removed and the interface is exposed.

two。 Split joint

When the rootstock is thick and the scion is small, split grafting is used.

(1) rootstock treatment. Cut off the branches of the rootstock, cut the rootstock at the grafting site, and flatten the end of the rootstock. It is required that there should be no nodal scar within 6 cm below the cut. Cut vertically and longitudinally from the center of the cross section of the rootstock. The knife should be sharp and slightly thick. When it is about to split the rootstock,

It's wedge-shaped. The split is 3cm to 4cm deep.

(2) scion cutting method. The scion is also cut into a wedge, the two cutting faces are symmetrical, and the cutting surface is 3-5 cm long.

(3) combination. Pry open the split of the rootstock with a split knife, insert the scion, gently remove the split knife, so that the two sides form a layer of close connection. When the rootstock is thick, it can only aim at one side of the cambium, or one ear can be grafted on the left and right side of the split of the rootstock, and the well-developed branch can be selected after survival. When inserting a scion, the cutting surface of the scion is exposed to 0.5 cm.

(4) binding. After that, it is bound with wool or hemp rope and choked with dirt. Camellia, pine and other twigs can be bagged and moisturized (twigs are often used for splicing).

(5) other operating essentials are basically the same as splicing.

3. Lean on the connection

The grafting method is mostly used for other kinds of flowers and trees that are difficult to survive by grafting, but precious and difficult to live, such as sweet-scented osmanthus, maple, camellia, bergamot and other citrus. This is because when relying on grafting, the rootstock and scion are pulled together without leaving the mother plant, and the scion is cut off from the mother plant only after survival, so propagation by grafting is the most sure.

The pick-up time is mostly carried out in the period of exuberant flower growth in summer.

For flowers and trees propagated by grafting, the mother plant should be planted next to the rootstock or in the same flowerpot, or the rootstock can be hung from the scion mother tree or placed next to it. The rootstock should choose more than 2-year-old branches with a diameter of 1-1.5 cm, and the scion should choose 1-2-year-old branches with branches on adult plants, with a diameter of 0.6 cm and a length of 15 cm.

Both sides of the rootstock and scion go forward to align the cambium of the rootstock and scion without exposing gaps, so that the cambium of the injured surface is close to each other, and then fasten it with plastic tape or hemp rope to prevent Rain Water from pouring in. Cut off the scion at the lower part of the interface after living, and cut off the upper rootstock in batches to become independent plants. It is generally required that the crown of the scion mother tree is larger, and the crown of the rootstock is smaller, which can be connected with four or five branches at a time.

No fertilizer is applied after grafting, but the basin soil should always be kept moist. The incision can be healed in 1 to 2 months, and then cut off between the scion and the mother plant to become an independent plant.

4. Ventral graft

Ventral grafting, also known as root grafting, is a branch grafting method without cutting the anvil crown. It is generally grafted at the root edge of the rootstock, which is suitable for the grafting and propagation of Pinus elliottii and Pinus elliottii. It is also used in Sabina vulgaris, Sabina vulgaris and Sabina vulgaris, and has been used in social rhododendron and camellia in recent years.

There are many specific methods of abdominal grafting, among which abdominal grafting, skin insertion and subcutaneous ventral grafting are the most widely used in flower and tree production.

(1) abdominal incision. This is the traditional abdominal connection method, which is the most commonly used and is generally carried out in early spring. The specific steps are as follows (take five-needle pine as an example):

Scion cutting: choose 1-2-year-old five-needle pine branches without disease and insect pests as scions, 5 cm in length, remove the needles in the lower part 2 cm in length, obliquely cut a knife, about 2 cm in length, and cut a small slope on the reverse side, with a length of 0. About 5 cm, the cutting method is the same as the cutting joint.

Cut rootstock: choose 2-3-year-old black pine as rootstock (Pinus massoniana can also, but the survival rate is lower than black pine). After digging up with mud, cut off part of the branches and leaves, repair the root system, in the straight and smooth part of the rhizosphere stem, oblique cut, 2.5 cm long, deep to the xylem, showing a shield-shaped mouth, can also be cut vertically with slightly xylem, the incision should be slightly longer than the cutting surface of the scion, otherwise it is not easy to close.

Binding and binding: after cutting the rootstock, the scion should be quickly cut into the rootstock, aim at the cambium, and then bind with plastic film tape. Put a small plastic bag on the scion and joint to prevent dehydration, and remove the plastic bag after the ear bud sprouts.

Management: the five-needle pine connected by the abdomen should be planted in the high and dry place, and the interface should be covered with soil to moisturize in the north. In the early stage of healing (about [month), it is best to shade the light, see sparse light later, shade in the hot summer, and avoid exposure when you just put the needle.

(2) subcutaneous abdominal connection. It is an improved abdominal grafting method, which is suitable for grafting in the growing period (June to September). The scion takes the semi-lignified branches of the year, so it is also called ventral grafting of twigs. The survival rate of this method is high. Ear cutting and operation are the same as abdominal grafting. Cut the rootstock into T-shape: first cut a knife horizontally, then cut it longitudinally in the middle of the horizontal line, open the cortex, expose the layer, and finally bind it.

5. Water branch grafting

Water branch connection is also called water plug connection and hanging bottle connection. Used in camellia and rhododendron. In the process of callus survival, the scion replenishes water from the bottle and is not easy to wither.

(1) carve the anvil. The water-grafted rootstock is a perennial old stem or curved thick root, which is first planted in a pot, cut into a tree stump, and sprouted into sparse lateral branches. the upper end of the rootstock is carved into grooves with a round blade, and the upper end is slightly to the xylem. 5 cm left and right.

(2) cutting ears. The scion is about 25 cm long, with 3-4 leaves at the upper end. The middle is cut into a convex V-shaped, about 3 cm long. The cutting should be as deep as the xylem. Otherwise, it will not grow well.

(3) binding. The cutting surface of the scion should reveal 0.5 cm of the cross section of the rootstock, which is beneficial to the formation of callus. The scion at the junction should be slightly higher than the rootstock (about 3-4 mm) and should not be sunken into the groove. Use binding material to cover all the rootstocks.

(4) hanging bottle. Finally, hang a vial, fill it with water, and fix it at the base of the scion. When the callus survived, remove the hanging bottle, cut off the scion below the interface, and keep it under the shade shed. The binding material can be removed after 1 month. The seedlings grafted with water branches grow rapidly.

Why trim the tillering buds in time?

The "tillering bud" mostly refers to the branches that grow from the rootstock base of the grafted seedling, such as rose grafted on the rose rootstock, and those growing from the rose rootstock are called tillering buds. Such as clove grafting in privet, red maple grafting in green maple and so on, this situation will occur. If the tillering buds on the rootstock are not repaired in time, it is bound to seize the nutrition of the scion, affect its growth and development, and seriously cause the scion to wither and die.

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