Cultivation techniques of Dendrobium candidum

Dendrobium candidum, also known as Dendrobium nigra, belongs to the genus Dendrobium of Orchidaceae and is a precious wild medicinal plant. Its active components are mainly Dendrobium polysaccharides, Dendrobium alkaloids, amino acids, etc., in which the content of Dendrobium polysaccharides is as high as 21.7%, which can significantly improve the immune function of the body, and has the effects of nourishing stomach and fluid, tonifying kidney, nourishing yin and clearing heat, anti-hypoxia, anti-fatigue, anti-tumor and so on.

The artificial cultivation of Dendrobium candidum can be divided into two categories: "imitation wild cultivation" and "facility cultivation". According to the different carriers of cultivation, the cultivation methods can be subdivided into stone cultivation, tree cultivation, stone wall cultivation, rock wall cultivation, three-dimensional cultivation, pot, three-dimensional pot, seedling bed and so on. Now the most widely used, efficient and high-yield is "facility cultivation". The models of "facility cultivation" are: shade greenhouse cultivation, solar greenhouse, balcony three-dimensional cultivation, indoor three-dimensional pot cultivation and so on.

In the place to the south of the Yangtze River, Dendrobium candidum can be cultivated directly on the trunk of the forest, but without "facility cultivation", construction or the use of facilities, the cost will be very low; in the cold places in the north, you can use the balcony of the house, waste vegetable greenhouse and other suitable adjustment or transformation of "facility cultivation", the use of three-dimensional potted Dendrobium candidum, do not need to build a greenhouse, the cost is also very low.

Environmental requirements for planting Dendrobium candidum

"protected cultivation" is aimed at the small environment within the cultivation facilities, and "imitating wild cultivation" is aimed at the local climate environment, rather than requiring the climate of the whole province or region. There are the following main conditions:

1. Temperature: the survival temperature is-2-41 ℃, the growth temperature is 10-35 ℃, and the optimum growth temperature is 20-32 ℃. When high temperature, such as summer, the greenhouse should be shaded and ventilated, and often sprayed to cool and moisturize; when low temperature, such as winter, heat preservation is needed.

2. Humidity: humidity needs to be adjusted accordingly with the level of temperature. When the growth is exuberant, it is best to keep the air humidity of the small environment inside the plant at 60%-90%. High temperature requires high humidity, low temperature requires low humidity, high temperature and high humidity should strengthen ventilation to prevent the occurrence of bacterial and fungal diseases.

3. Substrate: cultivation requires the use of substrate, and the substrate is required to keep the root environment easy to leak, breathable and multi-void.

4. Water quality: the water quality used for pouring Dendrobium candidum requires the use of weak acid or neutral water.

5. Lighting: adjust shading with temperature and light, and control the shading degree at 50-80% when it is suitable for growth.

6. Ventilation: the cultivation site requires good ventilation. To put it simply, there are two major requirements: first, the cultivation environment requires "warm, moist, weak light"; second, the cultivation substrate requires "empty pine, air permeability, water leakage".

Artificial cultivation method of Dendrobium candidum

The site or carrier for cultivation can choose flat land, hillside, wall, rock wall, tree trunk, balcony and flowerpot, which requires no stagnant water and easy to filter water. When planting, you can first lay 3mur5cm of cultivation substrate, and then plant the washed seedlings on the substrate like planting seedlings. The substrate for cultivation can be selected: pebbles, limestone, bark, sawdust, waste materials of bacteria, etc., which can be mixed according to a certain proportion; the rotten soil formed by leaves and branches under the forest can also be mixed with stones according to a certain proportion; or part of the crop shell is used as the cultivation substrate.

Transplanting of Dendrobium candidum

The natural reproduction rate of Dendrobium candidum is very low, so rapid mass propagation of tissue culture seedlings of Dendrobium candidum has become an effective way to solve the problem of seedlings. The tissue culture seedlings of Dendrobium candidum planted on the elevated border can be sprayed and watered at any time, removing excess water at any time, will not cause rotting roots and dead seedlings because of too much water, and can ensure that the roots are ventilated, so the survival rate of transplanting can be greatly improved, reaching more than 95%.

1. Refining seedlings: before transplanting, the bottle seedlings were refined to the seedling refining room for 2 or 3 weeks, so that the bottle seedlings made a transition from a closed and stable environment to an open and changing environment, and slowly adapted to the natural environment. The bottle seedlings grew healthily, the leaf color was normal, the root length was above 3cm, the fleshy stem had 3-4 internodes, 4-5 leaves, the leaf color was normal, the root length was above 3cm, there were 4-5 roots, the root bark was white and greenish, no black root, no deformity, no variation.

2. Out of the bottle: when the tissue culture seedlings come out of the bottle, open the bottle cork and gently take out the culture medium with the seedlings, place them neatly in the basin to be cleaned, and place the contaminated seedlings, bare-root seedlings or few-root seedlings respectively. The normal tissue culture seedlings should first wash the culture medium in tap water, especially to wash off the Agar, so as not to cause rotten roots caused by Agar mildew, and then wash it with tap water. After the bare root or few root tissue culture seedlings were washed, the roots of the seedlings should be soaked in ABT rooting powder of 100mg/L for 15 minutes for rooting induction. After washing the contaminated seedlings, soak the whole seedlings with 1000 times carbendazim for 10 minutes. Proper management in the later stage can effectively control the occurrence of pollution.

3. Preparation of substrate: suitable substrate should be selected for transplanting tissue culture seedlings of Dendrobium candidum. The root of Dendrobium candidum is aerial root, which has obvious aeration and shallow root. therefore, it is appropriate for the matrix to be loose and permeable, good drainage, not easy to mildew, no pathogens and insect pests. Water moss, limestone, broken brick, bark, shavings, fern root, plate edge, fungus bran and wood chaff can be selected as transplanting substrates.

Field Management of Dendrobium candidum

1. Watering: the air humidity in the later stage of Dendrobium planting is too small to often water and moisturize, and a sprayer can be used to water it in the form of spray.

2. Topdressing: Dendrobium should pay attention to topdressing during the growing season. Mature peanut drums, rapeseed cakes, calcium superphosphate and other mixtures such as river mud can be sprinkled on the roots. In addition, 0.05 color 0.1% potassium dihydrogen phosphate can be used for extra-root topdressing.

3. Pruning: before sprouting new buds in spring every year, the withered stems in the clump will be cut off combined with the old stems harvested, and the diseased stems, weak stems and diseased roots will be removed. After 8 years of planting, they will be rebranched and propagated according to the growth situation of the clumps.

Control of Diseases and insect pests of Dendrobium candidum

1. Black spot of Dendrobium: it occurs from March to May in order to wither the leaves. The control method can be sprayed twice with 50% carbendazim 1000 times solution.

2. Dendrobium anthracnose: in order to damage leaves and stems and branches, brown or gray disease spots appeared in damaged leaves, which occurred from January to May. The prevention and treatment method was sprayed with 1000 times of thiophanate methyl solution for 3 times.

3. Dendrobium phenanthrene shield scale: parasitic on the edge or back of plant leaves, sucking sap, the peak incubation period is in late May. The method of prevention and control can be killed by spraying 4000 times of the biological pesticide Haizheng Chongling liquid or concentrated burning of the old branches of the shield shell.

Harvesting and processing of Dendrobium candidum

1. Harvest. Harvest before sprouting at the end of spring every year, cut off more than three-year-old stems and branches, leaving tender stems to continue to grow.

2. Processing. Depending on the variety and commercial medicinal materials, there are two ways:

① washed all the sand from the collected stems, removed the leaves and fibrous roots, divided them into single stems, scalded them in hot water of 85 ℃ for 2 minutes, picked them up, spread them out on a bamboo mat or cement field and exposed them to the sun. When they were 50% dry, rub the sheath membrane with their hands and spread it out again, and pay attention to turning it frequently until the feet are dry.

② can also soak the washed Dendrobium in boiling water for 5 minutes, remove it to dry, place it on the bamboo mat and expose it to the sun, turn it 3 times a day until the body is soft, rub it while drying, repeatedly to remove the remaining leaf sheath, and then dry it to the feet.