What are the key techniques for softwood cuttings of osmanthus in summer?

Osmanthus propagation methods include cuttings, layering and sowing, among which cuttings are the most widely used. Osmanthus cuttings are divided by season into spring cuttings and summer cuttings, and by branch maturity into hardwood cuttings and soft (softwood) cuttings. With softwood summer cuttings of osmanthus, callus tissue forms easily, rooting is fast and the survival rate is high. However, the following key techniques must be mastered:

1. Cutting time. For summer cuttings of osmanthus, May to July is more suitable, carried out at 6 to 9 in the morning and 4 to 7 in the afternoon, when the temperature is lower and evaporation is less.

2. Seedbed preparation. Osmanthus prefers warm, moist, fertile, well-aerated acidic soil. The bed soil should be deeply ploughed and finely harrowed, and formed into raised beds. Make the seedbed in a place with good drainage and convenient irrigation.

3. Cutting collection. For osmanthus cuttings, select a superior variety as the mother tree that grows vigorously, and cut strong, current-year, semi-lignified branches from the upper outer part of the canopy, remove the tender tip portion, and cut them into cuttings about 10 cm long. Leave 2 to 3 pairs of leaves at the top of each cutting, and cut off all the leaves at the base.

4. Root-promoting treatment. Soak the base of the cuttings in 500 ppm naphthalene acetic acid solution for 5 seconds, or soak the base of the cuttings in 40% ABT rooting powder solution for 2 hours, or soak in 0.01% aspirin for 4 to 5 hours; this can promote rooting and raise the survival rate.

5. Cutting method. Water the seedbed thoroughly before inserting, and insert after the water drains. Space plants 3 cm x 5 cm apart, insert the cuttings to a depth of about 6 cm, and water after inserting to make the soil bind closely to the cuttings.

6. Seedbed management. After cutting, promptly set up a shade shed to retain moisture and prevent high temperature and strong light. Keep the seedbed at 20°C to 28°C and relative humidity at 80% to 90%. If the temperature is high, ventilate and spray water to increase humidity, lower the temperature and prevent drought. Under suitable temperature and humidity, roots can form in about 1 month; gradually remove the shade shed, increase light, and water or spray at the right times to keep the soil moist and promote growth.

Key points for summer cuttings of osmanthus softwood

How do you take cuttings of osmanthus seedlings?

How do you take cuttings of osmanthus seedlings?

Cutting propagation makes use of the regenerative capacity and habit of forming adventitious roots of the vegetative organs of osmanthus. A portion of its semi-lignified branch is cut off and inserted into sand, perlite or vermiculite under certain environmental conditions so that it roots and sprouts to become a new plant. Plants produced by this method are called cutting seedlings. Cutting propagation is simple and easy to carry out, the material source is relatively abundant, seedlings form quickly, flowering time is early, a large number of seedlings can be raised in a short period, and the good traits of the mother plant can be maintained. This propagation method is widely used in osmanthus propagation.

Tools/materials

· Sharp knife, wire

· Land, osmanthus tree, water

· Rooting agent

· Shade net, plastic

Method/steps

1.Measures to promote rooting of cuttings

Mechanical treatment: during the plant's growing season, use a sharp knife, wire, etc. to girdle, notch or constrict the shoot, thereby preventing the photosynthates and growth hormones from the upper part of the cutting from being transported downward. Nutrients accumulate and concentrate at the wound, making the wound of the cutting swell, and at the dormant stage the cutting is cut off for insertion. Because of the ample nutrients, the rooting and survival rate of the cutting can be significantly improved.

Elution treatment: this uses solvents to remove some of the inhibitory substances in the plant body. Generally warm water treatment, running water treatment or alcohol treatment is used. These methods can not only reduce the content of inhibitory substances in the cutting but also increase the water content in the cutting.

Auxin treatment: Common growth hormones used for cuttings include cx naphthalene acetic acid (NAA), p-indoleacetic acid (IAA), p-indolebutyric acid (IBA), 1,4-D, etc. These auxins can promote rooting in the cuttings of most plants. When treating cuttings with an auxin aqueous solution, tie the already cut cuttings into a bundle in a certain number with the lower cuts on one plane, then soak the base of the cuttings 2 cm deep in the solution. For varieties that root with more difficulty and for hardwood cuttings, a slightly higher solution concentration may be used and the time may be correspondingly longer; conversely, for softwood and easily rooting varieties, the concentration may be slightly lower and the time slightly shorter.

Rooting agent treatment, ABT rooting powder can supplement the exogenous auxin needed for rooting of cuttings and can also promote the synthesis of endogenous auxin. Cuttings treated with rooting powder root quickly, shorten the rooting time and have a relatively high rooting rate. When treating cuttings with ABT rooting powder, generally a quick dip of 500-2000 mg/L; a slow soak of 50-2000 mg/L. Generally 1 g of ABT rooting powder can treat 4000-6000 cuttings.

Whether a cutting survives also depends on where the nutrient consumption goes. Generally, when the air temperature is higher than the soil temperature, the cutting sprouts and unfolds leaves first and roots later, easily consuming the limited nutrients in the body and leading to a low cutting survival rate. When the soil temperature is higher than the air temperature, the cutting roots first and grows leaves later, which helps raise the survival rate. Artificial means can be used to create an environment where the soil temperature is higher than the air temperature, so that the cutting roots first and sprouts later. Commonly used methods include burying heating wires in the cutting bed, or burying heating pipes and putting in fresh horse manure, etc., all of which can raise the soil temperature and promote rooting.

2. 2

3. Cutting period

Spring cuttings: suitable for most osmanthus varieties. Spring cuttings use the dormant branches of the previous year directly; at this time the nutrients in the cuttings are abundant, and some rooting-inhibiting substances have already been converted. Spring cuttings should be done early; if inserted after the buds sprout, the survival rate will be correspondingly lower.

Summer cuttings: summer cuttings use the vigorously growing semi-lignified cuttings of the current year of osmanthus for insertion, but summer temperatures are relatively high, which easily causes the softwood to lose water and die. The relative air humidity should be raised to reduce transpiration of the cuttings, maintain the water metabolism balance in the body, and raise the cutting survival rate.

Autumn cuttings: autumn cuttings are made at the time when the cuttings have stopped growing but have not yet entered dormancy, when the nutrients in the cuttings are abundant. First, because the inhibitory substances in the cuttings have not yet reached their peak, this can promote the early formation of callus tissue and thus facilitate rooting; second, because in autumn the soil temperature cools later than the air temperature, this helps the root primordia form early. In winter, cold-protection measures are needed, such as covering with plastic film. Rooting is fast the following spring, and some cuttings can be used the same year.

4. 3

5.Collection of cuttings

That is, cutting the cuttings. The quality of a cutting depends on the genetic characteristics and growth condition of the mother plant, and the time of collection and the part collected vary by species. The survival rate of cuttings from different parts differs; for osmanthus, it is best to use well-developed 1- to 2-year-old branches located at the roots or the base of the trunk as cuttings. The length of the cutting is preferably 10-15 cm. The upper cut should be flat, preferably 1 cm from the topmost bud; too short affects sprouting, too long makes the cut hard to heal. The position of the lower cut should be 0.5-1 cm below a bud node; this part has many parenchyma cells and easily forms healing tissue and roots. A flat cut heals quickly and roots evenly in a ring-shaped distribution, and the small wound can reduce rot at the cut. For varieties that root with more difficulty, oblique cuts and double-sided oblique cuts are used, so that the cut has a large contact surface with the soil and the callus tissue formed is larger, which facilitates the absorption of water and nutrients but easily forms one-sided roots.

In the process of osmanthus cutting propagation, depending on the part of the cutting used, it can be divided into:

Cutting with a partly semi-lignified softwood branch: the method of using a softwood base with a portion of semi-lignified branch as the cutting.

Hardwood cutting, also called semi-lignified cutting, long-branch cutting, ordinary cutting: the method of selecting 1- to 2-year-old semi-lignified branches, cutting them into sections and inserting them.

Heel cutting: the method of using a semi-lignified branched shoot, cutting it off and then breaking off the branch by hand to use as the cutting.

Mallet cutting: the method of girdling or constricting a branch to produce callus tissue, then cutting off the cutting with the callus body from the callus site.

Short-branch cutting (single-bud cutting): the method of cutting from a semi-lignified branch a section with 1 leaf and 1 sprouting or latent bud to use as the cutting.

Management after cutting: to raise the cutting survival rate, relatively high humidity should be maintained in the substrate and the air; softwood cuttings have even higher requirements for air humidity. Immediately after inserting, give the first watering generously so that the cuttings are in close contact with the soil, and do a good job of moisture conservation and loosening the soil. After the cuttings survive, gradually move them to the cultivation site for growing on. In the growing season with relatively high air temperature and sufficient sunlight, a full-light automatic intermittent misting cutting bed can be used for cutting; after inserting, make full use of the daytime sunlight for photosynthesis, and use an automatic control device for intermittent misting to meet the cuttings' requirement for air humidity, ensuring the cuttings do not wilt and also favoring rooting.

6. END

Notes

· Pay attention to the choice of cutting period

· Pay attention to the control of water and the surrounding environmental temperature

· For collection of cuttings, choose mother plants in good growing condition

Osmanthus tree seedling raising:

Knowledge on softwood cutting seedling raising of osmanthus trees. Osmanthus belongs to the Oleaceae family and is an evergreen tree. Its branches and leaves are deep green, its form is graceful, and when it blooms the fragrance fills the air and drifts for miles. The flowers can be eaten and used to extract essence, and it is an important ornamental and economic tree species in China, with very high ornamental and economic value. Because osmanthus has few seeds and they are hard to obtain, and grafting is also not ideal, cutting propagation is mostly used, among which

softwood cutting seedling raising has the advantages of convenient material collection, simple operation and a high survival rate. Its key techniques are introduced here for reference.

1 Cutting time. It is suitable to carry out from mid-May to mid-July and from mid-September to mid-October. At this time the new shoots have stopped growing, the branches contain relatively many nutrients, their meristematic tissue has a relatively strong meristematic capacity, and the temperature is suitable, so rooting after cutting is easy. Osmanthus tree picture

2 Cutting bed preparation. It is suitable to choose light loamy cultivated land whose previous crop was rice as the nursery site. Plough deeply to make the bed; the bed should be 120 cm wide, 25 cm high and the ditch 40 cm wide, and the soil should be fine and crumbly, the bed surface level and the ditches unobstructed. Above the cutting bed, build a plastic film arch shed 50 cm above the bed surface, and above that build a shade shed 180 cm above the bed surface with a light transmittance of about 35%.

3 Cutting collection. Select vigorous, pest- and disease-free superior plants as mother trees for cutting collection, and cut current-year semi-lignified softwood shoots from the upper outer part of the canopy as scions. The scions should be tied into small bundles by diameter class, and the base wrapped in moist toilet paper and brought back indoors for processing.

4 Cutting treatment. Cut the shoots into 8-10 cm lengths, retaining 2 leaves that have been half cut off; cut the upper end into a flat opening and sharpen the base into a slant, tie into small bundles, and soak the portion below 3 cm of the base in 5×100000 naphthalene acetic acid or 1×10-4 No. 1 ABT rooting powder solution for 1 hour, then take them out for insertion.

5 Cutting operation. The cuttings should be inserted in separate beds (sections) by diameter class. With a plant spacing of 5×10 cm, first use a wooden peg as thick as the cutting to make holes in the cutting bed, then insert the lower 2/3 of the cutting into the holes and press the soil tightly around the cuttings. Finally, water the cutting bed thoroughly once with 0.01% carbendazim aqueous solution for soil disinfection and to supply water and retain moisture.

6 Management after cutting

6.1 Water spraying and shading. When there are no water droplets in the shed film and the bed soil is dry, spray water to retain moisture. The high-level shade shed should be covered in the morning and uncovered in the evening; the relative humidity inside the film shed should be kept above 85%, and the temperature controlled at 18-30°C. If the temperature is on the high side and the humidity too low, this can be regulated by removing the covering and increasing water spraying; if the temperature is on the low side and the humidity too high, this can be controlled by sealing the shed film and reducing water spraying.

6.2 Spraying and loosening the soil. Along with water spraying, spray 5×10-4 carbendazim aqueous solution once every 7 days to prevent the cuttings from being infected by bacteria and causing cortex rot. The cutting bed should be loosened frequently to maintain good soil permeability and prevent the young roots of the cuttings from rotting due to lack of oxygen.

6.3 Bud removal and fertilization. The sprouts at the base of the cuttings must be removed in time to reduce nutrient consumption. Along with water spraying, spray 0.2% urea or potassium dihydrogen phosphate solution once every 10 days to promote the growth of the cutting root system and new shoots.

6.4 Dismantling the shed and transplanting. Summer cuttings can have the shade shed removed in October and can be transplanted to the field nursery the following spring; autumn cuttings can have the shade shed removed the following spring and be transplanted to the field nursery in early summer. Both summer and autumn cuttings can remain in the bed for 1 year; the following winter the seedlings reach 30-50 cm in height and can be released from the nursery for planting out or moved to a nursery for growing on.