Sowing and propagation
　　1. Seed collection, selection and storage
　　When the seeds are mature, they should be collected in time. Select mother plants with typical varieties, excellent traits, lush branches and leaves, no diseases and pests, and in their prime to collect seeds. The harvesting of different types of flower seeds should grasp their maturity characteristics and harvest them in time. For example, the seeds of a string of red are dark brown, the seeds of dianthus are black, the skin of Tianmu Viburnum is red, and the seeds of peony are black. Some species, such as Impatiens, butterfly flower, delphinium, petunia, weigela, lilac, etc., are easy to crack. They need to be harvested in time before cracking to avoid seeds from scattering. Some seeds mature one after another, such as wolfberry, buddleja, a string of red, etc., which need to be observed at any time and harvested in time.
　　After the seeds are harvested, they should be classified and numbered to prevent the varieties from being mixed. Some species should be washed off the peel in time, the seeds should be taken out and dried. Some should be threshed, impurities should be removed, dried, and then selected, leaving seeds with full grains and discarding seeds with shrunken shells, broken and moldy seeds. Finally, the seeds are placed in special seed bags or envelopes for storage. Generally, flower seeds are suitable for dry storage. In a dry, sealed and low-temperature environment, their vitality can be maintained for a long time. Usually, the seed bags are stored in a refrigerator at 3-5℃, and the survival life of the seeds can be doubled. After the seeds of peony, peony, white magnolia, magnolia, and Michelia are harvested, the sand storage stratification method should be adopted, that is, a layer of sand and a layer of seeds are arranged at intervals, and the sand is kept moist to allow the seeds to pass the after-ripening period and be stored in the sand until sowing in the following spring. The seeds of water lilies and jade lotus must be stored in water after harvest.

　　2. Lifespan of flower seeds
　　Knowing the lifespan of flower seeds is of great significance in the cultivation of flowers and the use, storage, collection and exchange of flower seeds. The environmental conditions that affect the lifespan of seeds are mainly humidity, temperature and gas. Generally, flower seeds can maintain their lifespan for a long time after being fully dried and sealed in a bottle. Studies have shown that fully dried seeds can withstand extremely low temperatures as well as extremely high temperatures. Low temperatures can inhibit the respiration of seeds and extend their lifespan. Oxygen can promote the respiration of seeds, so excluding oxygen can extend the lifespan of seeds. There are physiological factors that affect the lifespan of seeds. One is the change in the nature of the seed coat, and the other is the decline in the vitality of the protoplasm. Usually,
the full seeds harvested after full maturity have a longer lifespan than those harvested before full maturity. The lifespan of the main flower seeds is shown in the table.

　　3. Pre-sowing treatment of flower seeds
　　Before sowing, flower seeds need to be treated in a certain way. The purpose is to eliminate the pathogens they carry, some to promote germination and growth, and some to break dormancy and make them germinate early. There are roughly the following methods:
　　① Seed disinfection
　　It can be soaked in 0.1% mercuric chloride or 0.3% copper sulfate solution, or 1% formalin solution for 5 minutes, then taken out and rinsed with sterile water, and then sowed.
　　② Cold water or warm water soaking seeds
　　Generally, seeds that are easier to germinate can be soaked in cold water or warm water (35-40℃) before sowing. After the seed coat becomes soft, it can be taken out for sowing.
　　③ File the seed coat The seed coat of
　　lotus, canna, yellow oleander and royal poinciana is relatively hard and not easy to absorb water. The seed coat can be worn or scratched with a file, and then soaked in warm water for 24 hours. The seeds will absorb water and swell, which can accelerate their germination.
　　④ Acid and alkali treatment
　　It is a method of using acid, alkali and other agents to corrode the seed coat to promote its germination. Treat the seeds with concentrated sulfuric acid for a few minutes to a few hours, and rinse off the agent with clean water after treatment.
　　⑤ Agent treatment:
　　Before sowing, soak the seeds of morning glory and broad-leaved Lathyrus in a 10-250 mg/L gibberellin solution, which can replace the effect of low temperature and promote germination.
　　⑥ Ultrasonic treatment:
　　After ultrasonic treatment of Siberian iris and night-falling money, it can not only promote early germination of seeds and increase germination rate, but also accelerate the growth of seedlings.
　　⑦ Freezing or low-temperature stratification method:
　　It has a significant effect on promoting germination for flower seeds that require low temperature and humid conditions to complete the dormant period, such as iris, water stachys, German gentian, delphinium, and long-haired primrose.

　　4. Sowing of flower seeds
　　The sowing period of open-field flowers is mainly in spring and autumn. Annual grass flowers have weak cold resistance, so they are usually sown after the late frost in spring. Open-field biennial flowers are cold-resistant flowers, and are generally sown in the cool autumn after the hot summer. Open-field biennial flowers are cold-resistant flowers, and are generally sown in the cool autumn after the hot summer. Due to the severe cold winter in the north, most types of biennial flowers need to overwinter in cold beds. The sowing period of perennial flowers varies with their cold resistance. Cold-resistant perennial flowers have strong cold resistance and can be sown in spring, summer or autumn. Generally speaking, it is better to sow them as soon as the seeds mature. The seeds of peony, iris, delphinium, etc. require low temperature and warmth to complete dormancy, so they must be sown in autumn.
　　There are roughly three ways to sow flowers:
　　① Broadcasting method
　　: Sow the seeds evenly on the soil surface. Due to the large amount of sowing, there are many seedlings, which are too crowded, which can easily cause leggy growth and the occurrence of diseases and insect pests. This method is often used when sowing in pots.
　　②Drill sowing method:
　　Seeds are sown in rows, and each row is kept at a certain distance. Because the row spacing is large and the sunlight is sufficient, the seedlings grow healthily. However, in a certain area, the number of seedlings is not as many as the broadcast sowing method. This method is mostly used for sowing in shallow boxes and hotbeds. It can also be used when there are many varieties and the number of each is small.
　　③Spot sowing method:
　　Also known as the hole sowing method, it is to sow in holes according to a certain row spacing. Generally, 2-4 seeds are sown in each hole. After germination, one healthy plant is left, and the rest can be moved to other places or removed. This method has the most sufficient sunlight exposure and air circulation, and the seedlings grow the most robustly. This method is divided into square, rectangular and triangular according to the form of row spacing.
　　When sowing, the sowing bed should be rich in humus, easy and fertile soil or sandy loam, with sufficient sunlight, air circulation and good drainage. When preparing the land, the soil should be appropriately moist, and fully decomposed and finely crushed compost or manure should be applied as base fertilizer. It is best to apply a moderate amount of superphosphate when sowing, which is conducive to the healthy growth of the root system. After the bed soil is leveled, it should be pressed down because the soil is too loose. When sowing, large seeds can be sown one by one, and fine seeds can be mixed with fine sand before sowing. The thickness of the soil after sowing depends on the size of the seeds. Generally, the thickness of the soil covering the large seeds is about 3 times the height of the seeds; the thickness of the soil covering the small seeds is not visible; the soil covering the small seeds should be sieved with a sieve with a pore size of 0.3 cm
. After sowing, cover the bed with straw and other materials, and then spray water with a fine-hole spray bottle. Keep the soil moist.

　　5. Management after sowing flower seeds After
　　the seedlings emerge from the soil, the temperature, humidity and light should be properly controlled, which is the key to whether the seedlings can grow healthily. If the air is not circulated, the temperature and humidity are too high, the seedlings will grow thin and weak, and they will be susceptible to damping-off. It is necessary to control the water content and increase the light. For box sowing and pot sowing, the glass or plastic film should be opened gradually, first opening a gap, and finally gradually removed to reduce the temperature and speed up air circulation. The seedlings of shade-loving flowers should also be exposed to light in the morning and evening, and shaded during the hot sun at noon. In short, the humidity should not be too high, the temperature should not be too high, the light should not be too weak, and attention
　　should be paid to gradual training, and not sudden cold or heat, dry or wet. Because the seeds are sown too densely during sowing (especially broadcast sowing), when the seedlings unfold their true leaves, there will be a phenomenon of seedlings crowding, competing for light and fertilizer, causing diseases, and timely seedling removal is required. All diseased seedlings and leggy seedlings with poor growth should be removed as soon as they are found. Thinning needs to be done several times. The first time, keep the seedlings at an equal distance according to a reasonable density, remove the overcrowded plants, and then combine it with transplanting. If the thinned seedlings are relatively strong and have 2-3 true leaves, they can be transplanted to the garden and pots for cultivation. The spacing between the rows and plants for each thinning should be such that the true leaves are not connected. Be careful not to involve the remaining seedlings when thinning.
　　After thinning, the seedlings grow rapidly. When the true leaves are fully expanded, they should be transplanted in time. Moisten the soil before transplanting. When lifting the seedlings, pay attention to less root damage and try to bring as much mud as possible to the root system. Transplanted seedlings can be planted in the garden or in pots. For transplanting in the open field, prepare the land in advance and apply light fertilizer once; for potted plants, choose mud pots, one or two or three plants per pot, and then add pots or separate pots after they grow up. Water thoroughly after planting to make the soil and the roots of the seedlings close. After transplanting, due to root injury, the seedlings often wilt temporarily, and management needs to be strengthened to slow down the spring as soon as possible. Therefore, it is best to transplant the seedlings on a cloudy and windless day or in the evening. Avoid direct sunlight for a week. After the seedlings are alive, they can be managed normally.

　　1. Characteristics of flower meristem propagation 　　Meristem
　　propagation is a method of using a part of a flower plant, such as a small plant, tiller or bulb sprouting at its rhizosphere, to split or cut it into several individual plants for planting. This is the simplest and most reliable propagation method. It is easy to operate and has a high survival rate, but the reproduction rate is low and the production quantity is limited, which cannot meet the needs of large-scale cultivation.
　　According to the different biological characteristics of flower plants, meristem propagation can be divided into two categories: one is the plant division method, which is mostly used for flower shrubs with strong clumping ability and perennial herbaceous flowers with strong tillering ability; the other is the bulb division method, which is mostly used for bulbous flowers with corms and bulbs.

　　2. Period for flower division:
　　The division and propagation of deciduous flowers should be carried out during the dormant period. In the south, it is carried out after the leaves fall in autumn, when the air humidity is high and the soil is not frozen. Some flowers can grow some new roots before winter, and the branches and shoots are not easy to dry out in winter, which is also conducive to easing the labor tension in spring. In the north, due to the severe cold in winter and the invasion of dry winds, division after autumn is easy to cause the branches to freeze and dry out, affecting the survival rate. Therefore, it is best to divide the plants in the spring before the soil thaws and before germination.
　　Evergreen flowers do not have an obvious dormant period, but whether in the south or the north, most of them stop growing and enter a dormant state during the season. At this time, the sap flows slowly, so they are mostly divided before the vigorous growth in spring. In the north, most of them are divided before moving out of the greenhouse or immediately after leaving the room.

　　3. The process of flower division
　　Flower division is to divide the small plants such as suckers, suckers, runners, stolons and rhizomes that arise from the mother plant, and plant them separately to form independent plants. Since these young plants have already produced more root systems, they are easy to survive after division.
　　Division of sprouts: For most perennial flowers such as chrysanthemums, orchids, and daylilies, many sprouts can occur at the base of the plant.
　　Division of runners: For most lawn plants such as dogtooth grass, buffalo grass, and zoysia grass, it is easy for runners to occur from the mother plant, and young plants will occur at each node and take root at the bottom.
　　Division of runners: For example, saxifrage and spider plants often use runners for reproduction. Runners are thin and above-ground stems with long internodes, and young plants will occur at the nodes.
　　Division of rhizomes: For example, zelan and aster have slender rhizomes (underground stems), which take root at the nodes to form young plants.
　　Sucker buds: such as aloe, tiger tail orchid, echeveria pseudo-Echeveria, water tower flower, etc., their fleshy or semi-fleshy leaves grow in clusters on very short twigs, and new roots grow out near the ground at the bottom. When the new roots grow, they can be separated from the mother plant and planted.
　　Before dividing the flowers and trees that need to be planted, most of them need to dig out the mother plant cluster from the field, with more roots, and then split the entire cluster into several clusters with a sharp knife or an axe, each cluster has more roots. There are also some flower shrubs and vines with strong sprouting ability, which often sprout many young clusters around the mother plant. When dividing the plants, there is no need to dig up the mother plant, just dig up the tiller seedlings and plant them separately. Because some ramet seedlings and plants are young and have few roots, they need to be cultivated in the flower garden for 1 year before they can be planted.
　　The division propagation of potted flowers is mostly used for perennial grass flowers. Before dividing the plants, remove the mother plant from the pot, shake off most of the soil, find out the extension direction of each tiller root system, and separate the clustered roots to minimize root damage. Then use a knife to separate the root neck connecting the tiller seedling and the mother plant, and immediately plant them in the pot. Some plants and flowers such as Crinum and Agave can often breed young plants from the root neck. At this time, you can first dig the nearby pot soil, then use a knife to cut off the connection with the mother plant, and then use the young plant to lift the tiller seedling and plant it separately.

　　4. The process of flower bulb division
　　Most of the underground parts of bulbous flowers have strong ability to divide, and they can grow some new bulbs every year. Using them for reproduction is simple and can bloom early. The bulb division method must be treated differently because of the different plant organs of the bulbous part.
　　Bulb division: For example, gladiolus, cyclamen and other bulbous plants, gladiolus has a strong ability to divide. After flowering, when the old bulbs dry up, it can divide 1-3 large bulbs and several small bulbs. The large bulbs can bloom after being divided in the second year, and the small bulbs can bloom after 1-2 years of cultivation. The bulbs with a diameter of less than 0.5 cm can be sown in furrows, which is the source of gladiolus for mass reproduction. The bulbs of cyclamen grow on the soil surface and rarely divide into small bulbs, so they are mostly propagated by sowing.
　　There are skin-scale sunflowers: such as daffodils, tulips, hyacinths and amaryllis, which are all autumn-planted bulbous flowers. Every year, several daughter bulbs are separated from the stem plate at the base of the old bulb. They are clasped on the mother bulb. These daughter bulbs are planted separately to cultivate large bulbs. Generally, it takes several years for them to bloom when they reach a diameter of 5-7 cm.
　　There are skin-free bulbs: lilies and other plants are skin-free bulbs. Each scale is quite large and clasped very loosely. When propagating, the scales can be peeled off and then inserted obliquely into the old pot soil. After rooting, 1-3 or more small bulbs can grow from the base of the old scales. They can be propagated by dividing and propagating again. It will take 3-4 years for them to bloom.
　　There are tubers: such as canna, etc., which have horizontal tubers in the underground part and have many branches. When dividing the tubers for propagation, each tuber branch must have a terminal bud to grow a new plant. After dividing and planting, no matter the size of the tuber, it can bloom in the same year.
　　Divide the root tuber: For example, dahlia, the underground part is the root tuber, and their leaf buds are all born on the root neck close to the surface, so each part must have the root neck part when divided. When propagating, the whole tuber should be planted in the soil for germination, and then the foot buds should be collected for cutting propagation.
　　Divide the rhizome: For example, the underground part of calla lily and Aspidistra is the rhizome, most of them are perennial evergreen plants, and the stem nodes of the rhizome can form lateral buds, which can grow new leaf clusters after they grow. The underground rhizome of the leaf cluster can be cut, and one plant can be divided into several plants, and potted together with the root system.

　　5. Management of flower division propagation
　　For woody flowers of the clump type and sprout type, some decomposed fertilizer can be applied to the hole when dividing. Usually, after watering the pot for division propagation, it is first placed in the shade or greenhouse for maintenance for a period of time. If there is a wilting phenomenon, water should be sprayed on the leaves and the surrounding area to increase the humidity. In Beijing, autumn division is developed. Before winter, it is advisable to cut the stem or prune it short and bury it in the soil to protect it from cold and overwinter. If it is divided before spring germination, it is only necessary to prune it appropriately to allow it to germinate and branch normally, but it is best to cut off all the flower buds and prevent them from blooming, so as to help the plant to resume growth as soon as possible.
　　For some perennial herbaceous flowers and bulbs, ground stems, and rhizome flowers, an appropriate amount of basal fertilizer can be applied to the bottom of the hole when dividing. The type of basal fertilizer should be more phosphorus and potassium fertilizer. After planting, water it thoroughly and loosen the soil in time to keep the soil appropriately moist. Do not water too much for the types transplanted and planted in autumn. Increase the number of watering in the spring of the following year and apply thin liquid fertilizer.

　　Layering propagation
　　1. Characteristics of layering propagation and the appropriate period for layering propagation
　　Layering propagation is to pile soil at the base of branches close to the ground or press the lower part of the base into the soil. For higher branches, high pressure method is used, that is, to surround the pressed part of the branch with moist soil or moss to provide environmental conditions for rooting. After rooting, it is cut off and planted to become an independent new plant. Layering propagation has a high survival rate. It can be used for species that are difficult to propagate by other methods, and it can maintain the excellent characteristics of the original variety; the disadvantage is that the position is fixed and cannot be moved, and it is not easy to propagate in large quantities in a short period of time. Among flowers, generally one- or two-year-old herbaceous flowers rarely use this method, and only some flowers and trees use it.
　　Because layering is a propagation method that does not separate from the mother plant, the period for layering is relatively long, which can be carried out throughout the growth period, but mostly in late April, when the temperature warms up and stabilizes. It can be continued to July-August, so that before winter, there is sufficient time to form a complete root system, so the seedlings grow quickly. Under the conditions of a medium or high temperature greenhouse, some potted flowers and trees can also be propagated by layering in winter.

　　2. The process of ordinary layering:
　　Bend the branches at the bottom of the mother plant and press them into the soil to a depth of about 10-20 cm. If the pressed branches are elastic and difficult to be pressed by the soil, you can use a thick lead wire to hook them and insert them into the soil, or add stones to the soil to suppress them. The branches pressed into the soil need to be cut or girdled with a knife. The branches should be exposed to the soil surface and exposed to light and dew. After the new roots grow well, they can be cut off and planted separately.
　　The ordinary layering method can be divided into 3 methods:
　　① Single branch layering method:
　　Most woody flowers or some species of perennial herbaceous flowers can be propagated by this method. When layering, use one or two years old branches close to the ground as layering materials, bend the branches and press them into the soil.
　　② Continuous layering method:
　　Mostly used for shrubs and flowers. First dig a longer longitudinal groove on one side of the mother plant, then slightly cut the nodes of the branches close to the ground, and then bury them shallowly in the soil groove, and expose the tips of the branches to the ground. After a period of time, new roots will sprout from the nodes buried in the soil, and soon the axillary buds on the nodes will also sprout and push out of the soil surface. When the newly sprouted seedlings mature, use a sharp knife to penetrate the soil layer to cut off the internodes of each section. After more than half a year of cultivation, the seedlings can be transplanted.
　　③ Wave layering method
　　For some flowers and trees with long branches that are easy to bend, such as wisteria, trumpet creeper, honeysuckle, etc., the long branches can be bent and pulled to the ground, and wounds can be made on multiple nodes. The wounds should be at least 30 cm apart, and then the wounds can be fixed and buried. After rooting and branching, they can be separated from the mother plant and planted separately.

　　3. The process of the soil layering method
　　The soil layering method is also called the pile soil layering method. It is suitable for clumping flowers and trees with many root tillers, such as pomegranate, campanula, rose, malus, magnolia, hydrangea, gardenia, azalea, peony, pearl bush, etc. This method can be used. Make a wound at the base of the branch, then pile up the soil, and transplant them separately after rooting.
　　Since the pressed branches do not need to be bent and buried in the soil, the soil layering propagation is more suitable for species whose branches are not easy to bend. It is carried out in the peak growth season in early summer. The lower part of the branch is ring-cut 20-30 cm above the ground, and then the base is piled up in a trowel shape to bury the lower half of the entire cluster. The soil pile should be kept moist. After a period of time, some of the hidden buds in the wound after ring cutting will regenerate and grow new roots. In the early spring of the following year, dig up the soil again, cut the new roots one by one from the bottom, and move them into the nursery after dividing them and cultivate them for another year, or they can be directly used for planting.

　　4. The process of high-branch layering
　　High-branch layering is also called aerial layering. It is mostly used for plants with upright branches, hard branches that are not easy to bend, and not easy to sprout. This method is also often used for some flowers and trees that are not easy to root by cuttings. A considerable number of them are precious flowers and trees, such as white orchid, camellia, bougainvillea, dracaena, magnolia, cordyline, croton, osmanthus, plum, Milan, Michelia, Indian rubber tree, etc. Most of the branches of high-branch layering should not exceed 1/3 of the mother plant branches, and the highest should not exceed 1/2, otherwise it will affect the normal growth and development of the mother plant.
　　High-pressure branches should choose strong branches. Use a sharp knife to cut twice about 5 cm above the branch, deep into the cambium, and remove the bark between the two knife marks. The ring cutting is completed, and the width of the ring cutting is 1-2 cm. The cortex should be removed after ring cutting, otherwise the ring cutting area is often filled with callus tissue and will not take root. After ring cutting, use leaf humus, dry moss, etc. to wrap the ring stripping area into a mud ball. In order to prevent rain erosion, cover the outside with a bamboo tube or flower pot. Nowadays, plastic film is often used, which is easy to obtain materials and simple to operate. Generally, it is wrapped with mud balls after ring cutting, and some are wrapped with mud balls after callus tissue grows. Keep the mud ball moist, and it will take root in about 2-3 months. When there are more roots, you can cut it with the mud ball, remove the wrapping, and plant it in a flower pot for maintenance.

　　5. Management after layering of flowers After the layering takes
　　root, the time to cut off the mother plant can be determined according to its growth speed. Some species such as plum blossoms and wintersweets grow slowly and can only be cut off in the next year; while some species such as roses and honeysuckle grow faster and can be cut off in the same year. When transplanting, bring as much soil as possible to protect the new roots. During layering,
　　since it does not separate from the mother plant, the supply of water and nutrients is not a big problem, and there will inevitably be a process of transformation, adaptation, and independence after separation. Therefore, after separation, it should be placed in a shaded environment first, and avoid exposure to the sun, and then gradually increase the light. For newly separated plants, some branches and leaves should also be cut off to reduce transpiration, maintain water balance, and facilitate their survival. Pay attention to water supply after transplanting, spray water on the leaves and sprinkle water indoors when the air is dry, and keep the soil moist. Apply fertilizer appropriately to ensure growth needs.

　　Cutting propagation
　　1. Selection of cutting propagation period
　　The most suitable period for cutting propagation depends on the type, variety, and climate management method of the flowers. It is usually divided into two categories: soft branch cuttings during the growth period and hard branch cuttings during the dormant period. Because it is easy to obtain materials, has a large number of reproduction, quickly matures, blooms early, and can maintain the excellent characteristics of the original variety, it is widely used in production. Cuttings
　　during the growth period: It uses semi-hard branches or tender branches of some woody and herbaceous flowers as cuttings for cuttings. Most woody flowers generally have semi-hard branch cuttings after the first growth of new branches of the year ends, or about 1 month after flowering, about May-June. Herbaceous flowers have a strong adaptability to cutting propagation, and most of them can be cut in spring, summer, autumn and other seasons.
　　Dormant cuttings: For some deciduous woody flowers, hard branch cuttings should be taken during the period when the most nutrients are accumulated in the branches of the plants, which should be carried out from November to February or March of the following year after entering dormancy in autumn and winter or before germination in spring. If cuttings are taken in a greenhouse to accelerate reproduction, the cuttings should be placed in a low temperature treatment of about 5°C for 20-30 days before cuttings, which is conducive to germination through physiological dormancy. If dormancy is not broken, the cuttings may take root but are also easy to germinate.
　　Greenhouse flowers maintain their growth state all year round under the conditions of greenhouse growth. Therefore, whether herbaceous or woody flowers can be propagated by cuttings at any time in the four seasons, but in terms of their growth habits, spring is the best, followed by autumn, and then summer and winter. Of course, as long as all conditions and measures are met, ideal results can be achieved.

　　2. Methods of cutting propagation.
　　The methods of cutting propagation are determined by the different materials used for cuttings. Generally, they can be divided into several categories, such as branch cuttings, leaf cuttings, bud cuttings and root cuttings.
　　① Branch cuttings
　　. Use branches of flower plants as cuttings. Usually, according to the age of the branches, they are divided into two types: tender branch cuttings and hard branch cuttings: Tender
　　branch cuttings: also known as soft branch cuttings and green branch cuttings. Due to its strong vitality, as long as the conditions are right, it can quickly take root and sprout and grow into a new plant. Generally, strong and mature branches are cut, with or without stem tips. 2-3 nodes are a cutting, about 10 cm long. Cut off 1/3 of the leaves at the bottom of the cuttings, and keep the upper leaves. If the leaves are too large, 1/4-2/3 of each leaf can also be cut off. The incision at the bottom of the cuttings should be close to the bottom of the node, and the incision needs to be flattened with a sharp knife to facilitate wound healing and rooting. Chrysanthemum, carnation, begonia, and red safflower can all be propagated by softwood cuttings.
　　Hardwood cuttings: Use mature and lignified stems or branches as cuttings for cuttings. Select mature, short and sturdy annual branches, and cut them into cuttings about 10 cm long and with about 3-4 nodes. It is usually done during the dormant period from leaf fall to budding next year. Autumn cuttings are more common in the south; spring cuttings are more common in the north; winter cuttings are best in tropical and subtropical areas of South China; Rosaceae and other vines that are easy to root can also be propagated in the rainy season. Various millennium trees, cordyline, monstera, hand tree, golden plate, croton, rubber tree, etc. are propagated by hardwood cuttings.
　　② Leaf cuttings
　　: Use the leaves of flowers as cutting materials to propagate plants. It is often used for some perennial herbaceous flowers, especially some species with thicker leaves, thick petioles and veins, and adventitious teeth and adventitious roots are prone to occur on the leaves. It can be propagated by 4 different cutting methods.
　　Flat laying method: For example, for begonias, first cut off the petiole, then lay the leaves flat on the sand surface, fix them with iron needles or bamboo needles, and make the bottom of the leaves close to the sand surface. For young plants, they will grow from the veins or the base of the leaves.
　　Direct insertion method: For species such as Gloxinia, Tiger Skin Orchid, Northern Violet, Chrysanthemum, Gesneria, etc., this method of cutting is used. Insert the petiole directly into the sand. After a period of time, fibrous roots will appear in the wound at the base, and underground rhizomes will grow.
　　The apical buds will grow into new plants. Petiole insertion: The leaves and petioles of the rubber tree are soaked in water. New roots will grow from the wound at the base of the petiole. Then make a wound at the connection between the leaves and petioles and plant them in sand. After about 3 months, new seedlings can grow from the root zone.
　　Scale cutting: If you peel off the scales of lilies for cuttings, after the bulbs are harvested, dry them for several days, then peel off the scales and insert them in the bed. After about 6-8 weeks, small bulbs will be produced from the base of the scales.
　　③ Bud cutting
　　: This method can be used to save propagation materials and obtain more plants in a short period of time. This is to take advantage of the strong regeneration ability of axillary buds of some flowers. Chrysanthemums, geraniums, hydrangeas, etc. can all be used for bud cuttings.
　　④ Root cutting:
　　It is suitable for species that are easy to produce new shoots from the roots, such as peonies and trumpet creepers. You can choose thick roots, cut them into cuttings of about 5-10 cm, and insert them all in the bed. For perennial flowers with small fleshy roots such as sedge and perennial phlox, the roots can be cut into small sections of 2-5 cm, scattered on the sand surface of a shallow box or a large flowerpot, and then covered with 1 cm of sand or fine loose soil, and kept moist.

　　3. Operation of cutting propagation
　　The equipment for cutting propagation can be selected according to the scale and requirements. When propagating in large quantities, it is advisable to carry out the propagation in a greenhouse so as to adjust the room temperature and facilitate the survival of cuttings. The cutting bed is generally about 70-80 cm high, about 100 cm wide, and about 20-30 cm deep. It faces the glass window or plastic film, and drainage holes must be set at the bottom of the bed. The cutting box is a more ideal cutting equipment. There are many types. Generally, there is a glass cover to maintain air humidity and an automatic temperature regulator. The open-air cutting bed is the most widely used. It is advisable to choose sandy and well-drained soil, preferably semi-shaded. For small-scale propagation, shallow pots, shallow boxes or general flower pots are used.
　　The cutting medium requires ventilation, easy to keep moist and good drainage. Commonly used are river sand, peat, vermiculite, perlite, etc. River sand is the most widely used, and coarse quartz sand without organic matter is the best. It has good ventilation and drainage, but weak water retention. Peat has strong water retention and can remain moist for a long time. Its equal mixture with river sand is ideal for cuttings of most flowers. Vermiculite has strong water and nutrient retention. Perlite has more pores than vermiculite, so its water retention is relatively poor. Other cutting substrates include sphagnum moss, humus, clay, charcoal powder, brick chips, coal slag, coconut fiber, etc.
　　When propagating by cuttings, you must first choose the cuttings. No matter which method is used for cuttings, you must choose a part with vigorous growth and no pests and diseases, which is conducive to rooting, survival, and cultivating excellent seedlings. When cutting branches, cut the selected branches into cuttings with a length of 10-15 cm and 3-4 nodes. The lower end of the cut is cut flat near the node, because the meristem in this part is active and easy to root. The upper end of the cut is cut into a 45-50 degree slope 1 cm above the top bud to prevent water accumulation on the top and cause rot. For cuttings during the growing season, especially leaf cuttings, cuttings should be cut before cuttings are taken. For roses, hibiscus, trumpet creepers, etc., cuttings can be taken in a closed plastic shed, or the cuttings can be tied into bundles, buried in the soil or
buried in a flower pot with wet sand, and placed in a place of 0-5℃ (if the amount is small, it can also be wrapped with plastic film and placed in a refrigerator at 5℃), and then cuttings can be taken in early spring of the following year. For herbaceous flower cuttings such as hydrangeas that contain more water, dip some plant ash at the bottom of the cuttings before cutting to prevent rot after cutting. For some varieties such as lilac and roses that are difficult to root, the bottom of the cuttings can be dipped in a rooting agent before cutting, which has a significant effect in promoting rooting.

　　4. Management in cutting propagation
　　In order to promote the rooting of cuttings as soon as possible after cutting, it is necessary to strengthen the management of cuttings after cutting, which is mainly to maintain the appropriate temperature, humidity, light and air conditions in the cutting bed.
　　Temperature conditions play an important role in the rooting of cuttings. The suitable rooting temperature for most soft branch cuttings of flowers is 20-25℃; the suitable temperature for semi-hard branch and hard branch cuttings is 22-28℃; the suitable temperature for leaf cuttings and bud cuttings varies according to the species, and the suitable temperature is within the range of 20-28℃. If the cuttings have a device to increase the bottom temperature, it is conducive to hard branch cuttings in early spring. If the temperature of the cutting bed is lower than 20℃, the cuttings are not easy to root; if it is higher than 28℃, the cuttings will easily wilt and affect rooting. For this reason, the appropriate temperature should be maintained as much as possible, especially in summer to prevent high temperature hazards, open the cover, and spray the leaves to cool down.
　　Temperature is also an important condition necessary for the survival of cuttings. The substrate is required to continuously provide sufficient moisture to maintain the normal freshness of the branches and leaves, to facilitate the formation of the callus tissue of the cuttings, and finally to produce the root system. Generally, a soil moisture content of 50%-60% is appropriate. Excessive moisture often causes the cuttings to rot. In order to avoid excessive evaporation of the cuttings and leaves, the cutting bed is required to maintain a high air humidity, usually 80%-90% relative humidity. For this reason, leaf spraying and adjusting the covering should be used in time to control and master it.
　　Light is also an important condition for the rooting and survival of the cuttings. The terminal buds and leaves of the cuttings can only photosynthesize and produce auxins to promote rooting under sunlight, but since they have been separated from the mother plant, they should be properly shaded, and the general shade degree is 70%. After rooting, the light can be gradually increased to facilitate growth.
　　Oxygen is also necessary for the rooting of the cuttings. Therefore, in addition to the loose substrate, attention should also be paid to the ventilation of the cutting bed.

　　5. The process of water-cut propagation of flowers
　　Water-cut propagation of flowers requires simple conditions and easy operation. Some flowers suitable for water-cut propagation, such as Begonia, Impatiens, Oleander, Rose, Camellia, Azalea, Hibiscus, Gardenia, Trumpet Creeper, White Orchid, Magnolia, Pomegranate, Carnation, Lucky Bamboo, Dahlia, etc., can be propagated by soaking cuttings in water and rooting. For
　　water-cut propagation, woody flowers should choose semi-lignified branches, and herbaceous flowers should choose mature and strong branches. Cut the strong and sturdy branches of the current year or two years old into 6-10 cm long cuttings, leaving 2-5 leaves on the upper part, and cut the lower end of the branch into a horseshoe shape with a knife. Soak in 0.1% potassium permanganate solution for 6-24 hours before inserting. You can also soak the base with a mixture of 100 mg/L indolebutyric acid and 100 mg/L naphthaleneacetic acid for 6-24 hours, or soak it quickly with 1000 mg/L indolebutyric acid for 3-5 seconds, then insert it into a glass bottle, change the water every 1-2 days, place it in a culture room at 20-25℃, and it will take root in about 10-30 days. When the root system is fully developed, the rooted cuttings can be taken out and potted, and then placed in a shaded place
to slow down the seedlings. This method is particularly suitable for herbaceous flowers, which can greatly reduce the rot phenomenon in sandy cuttings and increase the rooting rate.

　　Grafting propagation
　　1. Selection and cultivation of rootstocks
　　The selection of rootstocks is very important in grafting propagation. The rootstock should be selected from species that are closely related to the scion and have strong affinity. If the relationship between the rootstock and the scion is distant or the affinity is poor, even if the graft survives, it is easy to break at the interface. Therefore, the correct selection of the rootstock is not only easy to heal, but also can improve the adaptability of the grafted seedlings, prolong life or bloom early. The rootstock must be selected from species with strong resistance, strong growth, and adaptability to the woodland environment.
　　The cultivation of rootstock seedlings usually uses the method of sowing, not only because the seedlings have strong resistance to adverse external environmental conditions and long life, but also because of their young age, it is impossible to change the inherent characteristics of the scion of excellent varieties. The diameter of the main branch of the seedlings used as rootstocks should be thicker than the scion and fully lignified, so most of them need to be cultivated in the nursery for more than 2 years. After sowing, the seedlings need to be transplanted or potted. The time for transplanting is after the autumn of the sowing year or the early spring of the following year. The purpose of doing this is, on the one hand, to cut off the main root of the stock, promote the development of its lateral roots or fibrous roots, and increase the root absorption area; on the other hand, to increase the spacing between plants and rows, which is convenient for manual operation during grafting and for lifting the seedlings with soil balls in the future. The stock seedlings should also be pruned and the overly dense side branches should be removed to facilitate the grafting operation.

　　2. Operation of branch grafting
　　Branch grafting is a grafting method that uses branches of flowers and trees as scions. It is usually carried out during the dormant period, and only the approach grafting is carried out during the growth period. It can be divided into the following types:
　　① Cut grafting It
　　is mostly used for open-field woody flowers such as plum blossoms and peach trees. It is often carried out in spring when the top buds have just sprouted and the branch shoots have not yet grown. At this time, the sap in the branches has begun to flow, the interface is easy to heal, and the survival rate of the graft is high. It is better to choose one-year-old branches as scions. The scion is 5-7 cm long, with 2-3 buds left on each section, and the lower end is cut into an inclined surface. The rootstock is cut 5 cm above the ground, and then cut longitudinally. The size of the incision is similar to that of the scion. Then align the cambium of the scion and the rootstock and tie them tightly to prevent rain from entering.
　　② Cleft grafting
　　: Also known as cutting grafting, it is mostly used for grafting thicker rootstocks or flowering trees. First, cut off the upper part of the rootstock about 10 cm above the ground, and then cut a 3-5 cm deep incision vertically in the center of the cross section of the rootstock. The scion is selected with a full bud segment, leaving 2-4 buds as a scion, about 5-10 cm long; the two sides of the base are cut into wedges, inserted into the incision of the rootstock, and the cambium is aligned, and then tied with a film strip.
　　③ Approach grafting:
　　It is often used for some flowers and trees that are difficult to root by cuttings and difficult to survive by other grafting methods. For flowers and trees propagated by approach grafting, the mother plant should be planted next to the rootstock, or planted in the same flowerpot. The rootstock can also be hung on the scion mother tree or placed next to it. Cut off a part of the rootstock and scion, and the wound surface cambium is close to each other, and then tied with plastic film. After grafting, cut off the scion under the interface, and cut off the upper rootstock in batches to become an independent plant. Generally, the crown of the scion mother tree is required to be larger, and the crown of the rootstock is smaller. It is also possible to graft 4-5 branches at a time.
　　④ Twig grafting method:
　　The technology is the same as the cleft grafting method, except that the rootstock and scion are made of the tender branches of the current year. It is usually
　carried out in the first 2-3 months of the growth of flowers and trees, which is conducive to the later growth, development and maturity of the grafted seedlings and easy to overwinter. The rootstock is selected as the thick branches of the current year, and the scion is selected as the strong tender branches sprouted in the current year. The grafting technology refers to the cleft grafting method.
　　⑤ Root grafting method
　　: It is a grafting method that uses the root as the rootstock. It is commonly used for peony, rose, magnolia, trumpet creeper, hibiscus, wisteria, etc. Most of them are carried out in the dormant period in winter or early spring. Generally, the roots of 1-2 year-old seedlings are used as rootstocks, and the root thickness is 1-1.5 cm. At 4-5 cm from the thicker end of the rootstock, select a smooth and straight part and make a small inclined cut. The inclined surface is about 30 degrees to the longitudinal axis of the root, and the depth of the cut is about 1/3-1/2 of the thickness of the connecting part. After the rootstock is cut, insert the scion into the rootstock so that the cambium layers of both sides are closely connected, then tie it with plastic film strips and bury the interface with wet sand.

　　3. Bud grafting operation
　　Bud grafting saves scion materials, is simple, has a high survival rate, and a long grafting time. It can check the survival status early, and can be re-grafted if it does not survive. For flowers and trees used for tooth grafting, the cortex and wood must be easy to peel off. The time for bud grafting is mostly in mid-to-late August in the north and early September in various parts of the south. It can be divided into the following types.
　　① T-shaped bud grafting
　　It is also called shield bud grafting because the rootstock is cut in a T shape and the bud piece is shield-shaped. This method is the most widely used. During the operation, the grafted bud is cut into a shield-shaped bud piece of about 2 cm with the bud as the center. When cutting the bud, cut into the wood. Then choose a smooth place on the rootstock and cut it into a T-shaped interface, and also cut into the wood. Then pry open the bark, insert the cut bud piece tightly, and the upper part of the bud piece should be in close contact with the cut horizontal knife, and then tie it tightly with a plastic film strip. About one week after grafting, if the petiole falls off, it means that it has survived, and if it does not fall off, it means that it has not survived. The binding material can be removed 2-3 weeks after grafting. After survival, the buds do not germinate in the same year. The rootstock can be cut off 10 cm above the interface, and the grafted buds are planted facing south. Pay attention to removing the rootstock's suckers in the next spring.
　　② Bud chip grafting:
　　When the stock and scion are not much different in thickness (at most twice as large), bud chip grafting, referred to as chip grafting, is suitable. No need to peel the bark, the operation is simple, the survival rate is high, and the growth and development are good. The bud chip and the rootstock cut are roughly the same, both are inverted shield shape. The lower end of the bud chip is embedded in the wood at the lower end of the rootstock, and the interface is close. Other methods are basically the same as the shape bud grafting.
　　③ Bud tube grafting:
　　Also known as tube bud grafting and bud grafting, it is easy to operate and has a high survival rate. The grafted bud is cut with a width of 1.5-2 cm with the bud as the center, and the branch skin is cut once on the upper and lower rings, and then a longitudinal cut is made on the back of the bud, and the bud tube is gently removed. The rootstock is girdled once, cut several times longitudinally, and the bark is peeled down to the same length as the tube bud. If the rootstock is thicker than the bud tube, a part of the rootstock can be left unpeeled, and then the bud is covered with the rootstock bark. The upper and lower ends of the bud tube should be tied with cotton thread. In the early stage of grafting, the interface should be protected from light and wrapped with opaque plastic tape to block light, which is conducive to callus survival. In the early stage of survival, it is necessary to avoid exposure to the sun and do a good job of watering and other management. When cutting the rootstock, wax should be applied to the fracture to prevent rot.

　　4. Factors affecting graft survival
　　The factors affecting graft survival are mainly the affinity between the stock and the scion, the internal conditions of the stock and the scion, the environmental conditions during grafting and the grafting technology.
　　In terms of the affinity between the stock and the scion, the grafting survival rate is high when the stock and the scion are of the same species and genus in plant taxonomy, while it is difficult for different species and different genera to survive, and even if they survive, they will grow poorly in the future. In flower grafting, single-petal plants of the same species are often used as stock, and scions are taken from double-petal plants, which takes into account the affinity between the stock and the scion.
　　The degree of development and storage and accumulation of nutrients of the stock and the scion are also very important. Therefore, in grafting, the stock and the scion must be selected very strictly. Only when the stock and the scion contain sufficient nutrients can the differentiation of the cambium be promoted, the formation of callus tissue can be promoted, and the grafting survival rate will be high. If the tissues of either the stock or the scion are not substantial and the development is not sound, the success of the grafting will be affected.
　　The scion should be taken from the sunny side of a healthy plant. It requires annual or current year branches with full growth and short internodes. The survival rate of branches over two years old is low. The scion of evergreen tree species is generally grafted immediately after harvesting, and no storage is required. The rootstock is required to be in the vigorous growth period or after the sap begins to flow when grafting. In this way, after grafting, during the healing of the scion and the rootstock, and the growth of the scion bud, sufficient nutrients and water can be obtained from the rootstock, which is beneficial to improve the survival rate.
　　In terms of environmental conditions, the most suitable temperature for grafting is 20℃. Below 15℃ or above 30℃ will affect the healthy growth of callus tissue. Therefore, when the temperature is low during grafting in spring, it is necessary to cover with plastic film or bagging for insulation. It is very necessary to maintain high humidity after grafting. Generally, flowers and trees need to maintain a temperature of more than 90%. To this end, avoid strong light exposure to reduce leaf evaporation, and plastic tape should also be tied to the grafting site to keep it moist. Generally, dark conditions can promote wound healing.

　　5. Management after grafting
　　In order to promote the healing of the interface, it is necessary to maintain a high relative humidity at the interface. For this purpose, in addition to wrapping the interface with plastic film strips to keep it moist, the interface can also be covered by burying fine soil, especially for dormant grafting. Plastic bags or small plastic sheds should also be placed on the grafting site to maintain relative humidity, increase soil temperature, and promote healing. The covering should be removed after the temperature rises to prevent the buds from not being able to see the light in time or from being yellow and weak due to insufficient light. The binding should also be removed in time to avoid affecting the normal growth of the stock and scion.
　　After the bud grafting survives, the top of the stock can be cut off before the budding in early spring of the following year. The scion buds can grow into seedlings in the same year after germination. The binding can be removed in the autumn of the same year when the grafted plants are close to each other. If the interface has healed, the scion can be cut off from the mother plant from the bottom of the interface to become a new seedling; if the grafting does not survive, the stock and scion should be separated and grafted again next year. After the grafting is successful, the new shoots should be protected by a support in the first year, especially in the windy season, to prevent the scion from breaking off from the rootstock. Pay attention to the water and fertilizer management of the grafted seedlings, and keep them moist. The suckers that emerge from the rootstock should be cut off in time.

Tissue culture technology　

　　1. Application value of flower tissue culture
　　Flower tissue culture is to separate part of the flower plant body, such as stems, stem segments, leaves, flowers, young embryos, etc., in a sterile test tube, and with certain nutrition, hormones, temperature, light and other conditions, to produce a complete plant. Because its conditions can be strictly controlled, it grows rapidly, and a cycle is 1-2 months, so it has important application value in the production of flower plants.
　　Rapid mass reproduction: It is widely used for some rare varieties of flowers that are difficult to reproduce and some flowers that need to be produced in large quantities in a short period of time. Orchids, chrysanthemums, gladiolus and other flowers use axillary buds to proliferate, and a large number of plants can be obtained in a short period of time. African violets can induce adventitious buds through leaves, and daffodils can induce adventitious buds through ground scales to achieve the purpose of mass reproduction.
　　In terms of flower breeding: many flowers such as lilies and irises can be used for distant hybridization. Due to physiological metabolism and other reasons, hybrid embryos are often aborted early, so hybrid plants cannot be obtained. Embryo culture in test tubes can make them grow smoothly and obtain distant hybrids. In addition, callus mutagenesis, pollen culture and other methods can be used to breed flowers.
　　In terms of cultivating virus-free seedlings: a large number of flowers such as chrysanthemums, gladiolus, daffodils, tulips, dahlias, etc. are propagated by asexual reproduction, and viruses are passed on and accumulated from generation to generation, causing more and more serious damage. By separating the growth points of flower plants with a size of 0.1-0.5 mm, the seedlings obtained are basically virus-free. Therefore, this technology has been widely used in the cultivation of virus-free seedlings of flowers.

　　2. Requirements for laboratories and equipment for flower tissue culture
　　Flower tissue culture is to cultivate flowers under artificial control conditions. It is a new technology for modern factory production of flowers, so it has certain requirements for laboratories and equipment.
　　Laboratory
　　① Chemical laboratory: mainly responsible for the task of preparing culture medium. It is required to have various chemical reagents, various glassware, weighing balance, etc.
　　② Washing room: mainly for washing glassware, requiring running water device, and oven for drying after washing.
　　③ Sterilization room: mainly for sterilizing culture medium and utensils. There must be a high-pressure sterilizer, water source and power supply. ④ Inoculation room
　　: It is a place for separation, sterilization, inoculation and transfer of flower materials. It is required to be closed, clean, tidy, equipped with ultraviolet lamps, and can be sterilized at any time. Some can also be replaced by inoculation boxes or clean workbenches.
　　⑤ Culture room: It is the place where flower materials are cultivated and grown. It is required to be clean, well-insulated, with uniform room temperature, and have insulation and fireproof properties.
　　Equipment
　　① Balance: for weighing drugs and hormones when preparing culture medium. Use ordinary balance for macroelements; use analytical balance for trace elements and hormones.
　　② Acidometer: used to measure pH of culture medium.
　　③ Autoclave: used to sterilize culture medium and instruments.
　　④ Oven: used to dry and sterilize clean glassware.
　　⑤ Distilled water production device: used to obtain pure water for culture.
　　⑥ Refrigerator: used to store mother liquid and plant materials.
　　⑦ Inoculation box or clean bench: used for inoculation or transfer of plant materials.
　　⑧ Air conditioner: used to control room temperature.

　　3. Requirements of flower tissue culture on culture medium
　　Culture medium is a very important matrix in flower plant tissue culture. There are many kinds of
　　culture medium currently used, but their main components are roughly the same, the main component is water, and other macroelements, trace elements, vitamins, growth regulators, sucrose and agar. At present, the most widely used culture medium in flower tissue culture is MS culture medium. Its composition is to add 1.65g ammonium nitrate, 1.9g potassium nitrate, 0.44g calcium chloride, 0.37g magnesium sulfate, 0.17g potassium dihydrogen phosphate, 0.83mg potassium iodide, 5.2mg boric acid, 22.3mg magnesium sulfate, 3.6mg zinc sulfate, 0.25mg sodium molybdate, 0.025mg copper sulfate, 0.025mg cobalt chloride, 27.8mg iron sulfate, 30g sucrose and 7g agar when preparing 1L (1000ml) culture medium. The concentration of macroelements in MS culture medium is too high, so 1/2 or 1/4 of the concentration of macroelements is often used for culture, so that the growth effect is good.
　　Before preparing the culture medium, you should prepare glassware such as Erlenmeyer flasks, test tubes, beakers, measuring cylinders, and pipettes, and weigh the medicines in advance. When preparing, first dissolve the agar, then add various nutrient elements and sucrose dissolved in water, and then use sodium hydroxide or hydrochloric acid to adjust the pH of the culture medium, generally around 5.7. Later, it can be dispensed into the culture bottle and the bottle cap is covered. The culture medium must be sterilized by high pressure after preparation. After cooling, put it in the culture room for pre-culture for 3 days. If there is no contamination by miscellaneous bacteria, the flower material can be inoculated.

　　4. The process of flower tissue culture
　　Flower plant tissue culture is sterile culture, which means that the cultured materials are required to be free of bacteria. When cutting flower materials from fields or greenhouses, you should choose healthy and disease-free mother plants, and take young and tender parts with strong division ability to facilitate growth.
　　Although the materials have been selected, there are always many bacteria on the outside. For this reason, surface sterilization should be carried out before inoculation. Usually, rinse with tap water for more than ten minutes, and the mud should be brushed off. After rinsing, soak in 70% alcohol for 10-15 seconds for disinfection. Then rinse twice with sterile water (autoclaved distilled water), then soak in 10% bleaching powder clarified solution for 20 minutes for disinfection, and finally rinse with sterile water 3-4 times. Materials with hairs that are not easy to moisten and disinfect can be added with some washing powder. The above operations should be carried out in sterile environmental conditions such as inoculation boxes or ultra-clean workbenches. For materials that have been surface sterilized, use sterile filter paper to absorb water. Then use a scalpel to cut the required part, usually a few millimeters in size, and less than 1 mm
for virus-free seedlings, and then use a dissecting needle or gun-type tweezers to inoculate the material into a culture bottle for culture. After using the tools, dip them in 95% alcohol or use flame sterilization to avoid cross contamination caused by bacteria in the tools. When operating, you should wear work clothes and a work hat, wash your hands in advance, and then wipe them with alcohol cotton.

　　5. Cultivation and transplantation of flower tissue culture materials
　　After inoculation, the flower materials are placed in the culture room for cultivation. The culture room is a place for the cultivation and growth of flower materials, generally from a few to more than ten square meters. The height is about 2 meters, the space is small, and the temperature control energy can be saved. The culture materials are placed on the culture rack for cultivation. The culture rack can be made of wood or metal, with 4-5 layers, each layer is 40-50 cm high, and the fluorescent lamp is installed on the top. The rack is about 1.2 meters long, the same as the length of a 40-watt fluorescent lamp, and 80-90 cm wide. Two fluorescent lamps can be installed on each layer, so the illumination during cultivation is about 3000 lux. The temperature of the culture room is mostly maintained at a constant temperature day and night, maintained at 25℃±2℃, and there are also day and night temperature changes. The temperature can be lower at night, which should be determined according to
the needs . Fluorescent lamps are illuminated for 12-16 hours a day.
　　Flower test tube seedlings generally grow well and have many roots due to artificially provided superior conditions in all aspects, but often due to the lack of mastery of their characteristics, the survival rate is not high during transplantation. This is because the test tube seedlings are cultured in the bottle under very high humidity conditions, and carbon sources such as sucrose are artificially provided. The flower materials are in a heterotrophic state, which can be said to be much more delicate than flowers grown in a greenhouse. If they are suddenly moved from the bottle to the soil to live an autotrophic life, they will often be damaged or even die due to the drastic change. For this reason, when the flower test tube seedlings are first moved out, they should still be covered with glass bottles or film bags (with a few small holes on them), and then removed after 1 week. Spraying conditions are even more ideal. Shade for the first 7-10 days, and then gradually expose to sunlight. The transplanting substrate should be half sand and half vermiculite. It should be well drained and ventilated, and nutrient solution should be poured every other day. In this way, they are gradually trained to adapt to the environment. After 2-3 weeks, the acclimated and trained seedlings can be moved to the culture soil for planting.

Grafting technology of trees and shrubs
　　When asexual reproduction of trees and shrubs is carried out, it is not easy to take root and survive by using cuttings and whole strips. Seedlings propagated by sowing often have variation in characteristics and cannot maintain the characteristics of the original variety. Therefore, trees and shrubs are mostly propagated by grafting.

　　Grafting refers to cutting a part of the branches or leaves of a plant body and grafting it onto another plant body, so that the two become a new plant. The branches or buds on the cut plant are called scions, and the grafted plants are called stock.

　　1. Advantages of grafting The growth, development, flowering and fruiting of grafted plants can maintain the original variety characteristics unchanged. Grafted seedlings grow and develop faster than cutting seedlings and seedlings. Enhance the ability to adapt to adverse environments. Plants have strong resistance to diseases and insects.

　　2. Difficulty of grafting survival From the perspective of plant taxonomy, the closer the relationship between plants, the easier it is to survive after grafting, which is caused by the different plant tissue structures. Whether the graft survives depends first on the degree of healing of the callus tissue formed between the cut surface of the stock and the scion. After grafting, plants with fast callus formation on the cut surfaces of the stock and scion and large callus formation are easy to survive, otherwise it is difficult to survive. Graft survival refers to the close contact between the cambium of the cut surfaces of the stock and scion, and callus differentiation from the cut surfaces of both sides. This is the regeneration ability of the plant itself. The developed callus combines to fill the gap, and the nutrients absorbed by the stock are transported to the scion through the callus. During the formation of callus, the scion sprouts and begins to grow. Of course, the difficulty of graft survival is also affected by the morphology of the stock and scion at the time, external factors and operation techniques.

　　3. Grafting affinity Grafting affinity refers to the long-term normal growth and development from a seedling to an adult tree after the graft survives. If the tree gradually weakens and dies after the graft survives, or the grafted part is poorly developed and easily broken by the wind, it is considered incompatible. However, some incompatibility phenomena are manifested as dwarfing of the tree, yellowing of leaves, thick upper and thin lower joints or thin upper and thick lower joints, etc. But from the perspective of cultivation, if the tree can develop normally after these phenomena, it can be used in garden cultivation or potted plants.

　　4. Selection of rootstocks Different flower and tree species use different rootstocks. For example, roses can use various roses as rootstocks; peach or various peach blossoms can use longevity peach, mountain peach, hairy peach as rootstocks; osmanthus can use privet as rootstock; plum blossoms can use peach, apricot or plum as rootstocks; azalea can use hairy azalea as rootstock; cherry can use hairy cherry as rootstock; white orchid can use magnolia as rootstock; camellia can use wild camellia as rootstock; wintersweet can use dog bud wintersweet as rootstock; papaya can use stalked crabapple as rootstock.

　　Some flower and tree seeds must be treated with low-humidity sand storage to break the dormancy period before they can germinate, such as roses, roses, stalked crabapple, mountain peach, hairy peach, plum, elm leaf plum, crabapple fruit, mountain thorn fruit, longevity peach, hairy cherry, etc. Low-humidity sand storage refers to washing and drying the harvested seeds in the shade, burying them in a flower pot with a layer of wet sand or a combination of wet sand and seeds, and placing the flower pot in a cold room at 0-5℃. The sand storage time should be prepared in advance according to the sowing period.

　　5. Grafting technology The grafting time is generally when the top buds begin to sprout in early spring. The scion is a full and plump annual branch cut off during pruning last autumn, cut into 6-10 cm long sections, with at least 2 plump buds on each section. In order to keep moisture, the cut is often cut with paraffin. When grafting, use a cutter to cut two symmetrical bevels of different sizes on the scion, one bevel is 1.5-2.0 cm long and the other is 0.8-1.0 cm long. The cut surface must be flat, and it is best to cut it with one knife. At the same time, cut the rootstock about 20 cm from the natural ground of the rootstock, and cut a crack downward on the north side of the cross section of the rootstock, 2.0-2.4 cm deep. Then insert the long cut surface of the scion into the cut of the rootstock with the long cut surface facing inward. The cambium on one side must be aligned with the cambium on the rootstock side. If the rootstock and scion are of similar thickness, it is better to align the cambium on both sides. It is best to tie it with plastic strips. It is better to tie it with a small plastic bag at the grafting site to prevent moisture evaporation.

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