First, the preparation of Dendrobium candidum before transplanting
1. Select seedlings
Bottle seedlings grow well, with normal leaf color, root length of more than 3cm, fleshy stems with 3-4 internodes and 4-5 leaves, normal leaf color, root length of more than 3cm, 4-5 roots, white-green root skin, no black roots, no deformity and no variation.
Get out of the bottle
When the tissue culture seedlings come out of the bottle, gently take out the culture medium together with the seedlings, put them neatly into a basin to be cleaned, and put the contaminated seedlings, bare-rooted seedlings or few-rooted seedlings into it respectively. Normal tissue culture seedlings should be washed with clear water first, especially agar, so as to avoid mildew and rotten roots of agar, and then washed with clear water again. After the above cleaning, the roots of bare roots or few tissue culture seedlings should be soaked in 100mg/L ABT rooting powder 15 minutes for rooting induction. After cleaning the contaminated seedlings, soak the whole seedlings in carbendazim 1000 times solution 10 minute. Proper management in the later stage can effectively control the occurrence of pollution.
3. Preparation of matrix
Suitable substrates should be selected for transplanting tissue culture seedlings of Dendrobium candidum. The roots of Dendrobium candidum are aerial roots, with obvious aerobic and shallow roots. Therefore, it is advisable to require the substrate to be loose and breathable, well drained, not easy to be moldy, free from germs and hidden pests. Weeds, limestone, broken bricks, bark, shavings, fern roots, board edges, fungus chaff and wood chaff can be selected as transplanting substrates.
4. Selection of cultivation sites
Dendrobium candidum likes warm, foggy, breezy, clean and scattered environment, avoiding direct sunlight and exposure. In the process of transplanting, conditions should be created to create the best growth environment for Dendrobium candidum. The origin of Dendrobium candidum is mostly in temperate zone and subtropical zone, and the climate is warm and humid all the year round, with the temperature above 0℃ in winter. According to the growth habit of Dendrobium candidum, natural factors such as light, temperature, humidity and ventilation should be considered. The author thinks that it is best to transplant it in greenhouse and elevated border, which is easy to meet the best environmental requirements for Dendrobium candidum growth and many natural factors are easy to control. The construction of seedling greenhouse should meet the following three conditions:
(1) The seedling greenhouse needs electricity, water and access. The greenhouse is required to have a width of 6m, a length of 30m, a shoulder height of more than 107m, and a roof height of more than 2.8m The roof of the greenhouse is covered with plastic drip-free film and a sunshade net with 70% shading degree. A tap water pipe is installed in the greenhouse, and a 40-mesh insect net is installed around and at the entrance of the greenhouse. If conditions permit, the shed should be equipped with an automatic or manually controlled spraying system (preferably spraying drugs, fertilizing and spraying drugs), which can not only prevent sun, rain and insects, but also keep warm, moisturize and ventilate, and greatly reduce the labor.
(2) An elevated planting bed is set in the shed, and the bottom of the bed is overhead. Angle steel, bricks, wooden strips or square strips can be used as the frame of planting border, and then a plastic flat plate with an aperture of 0.3~0.5cm can be laid as the supporting surface of cultivation substrate. It is required that the width of the frame is 1~ 1.2m, the length of the frame can be determined, and the overhead height at the bottom of the frame is 30~50cm. Above the planting bed, there is a nozzle that can be sprayed at any time. It is best to control the spraying time. If there are no conditions, you can also use a sprayer instead. The purpose of setting up the elevated planting bed is to make the moisture and ventilation easy to control, provide the best moisture for the growth of tissue culture seedlings, ensure ventilation and ventilation, and spray fertilizers and drugs at the same time, so that the transplanting survival rate is high and the labor force can be greatly saved when transplanting in a large area.
(3) spreading a layer of substrate with a thickness of 5-8 cm on the planting bed, and paving. Before transplanting, the substrate was sprayed with 0.3% potassium permanganate or 1000 times carbendazim solution for disinfection.
Second, Dendrobium candidum transplantation
1. transplant time
The best transplanting season should be when the daily average temperature is 15~30℃, and the temperature is too low or too high to be transplanted out of the bottle.
2. Transplantation method
Carefully take out the tissue culture seedlings with tweezers, wash off the culture medium, and then transplant them to the planting bed. When transplanting, dig a hole 2~3cm deep in the substrate with your fingers, gently put the roots of Dendrobium into the hole, be careful not to break the fleshy roots of Dendrobium, and then cover them with the substrate. Bare-rooted seedlings or few-rooted seedlings are best planted separately for easy management.
Third, the management of Dendrobium candidum after transplantation
1. Temperature management
Artificial transplantation of tissue culture seedlings of Dendrobium candidum should meet the requirements of warm in winter and cool in summer. The suitable temperature for the growth of tissue culture seedlings is 20~30℃. When the temperature is high in summer, the greenhouse should be ventilated and cooled, and it should be sprayed frequently to cool down and moisturize, 3~5 times a day for 2~5 minutes each time; When the temperature is low in winter, the greenhouse should be sealed around to prevent tissue culture seedlings from frostbite.
2. Humidity management
Newly transplanted tissue culture seedlings are very sensitive to water, but without water, they grow slowly, dry up and have low survival rate. However, excessive spraying will lead to waterlogging and root rot, which is easy to cause large-scale soft rot in the case of high temperature and high humidity. The air humidity should be kept at about 90% within one week after transplanting (the seedlings have not yet grown new roots), and it can be kept at 70%~80% after one week. The cross potential of planting border between dry and wet is beneficial to rooting and germination.
3. Fertilizer and water management
Foliage fertilizer is the main fertilizer for greenhouse transplanting. Because Dendrobium is aerial rooting, it is necessary to spray suitable foliar fertilizer as nutrient solution to provide sufficient nutrients for plants, which is conducive to early rooting and long buds. Foliage fertilizer can be selected from potassium nitrate, potassium dihydrogen phosphate, humic acid, imported ternary compound fertilizer and diluted MS medium. Generally, one week after transplanting, one thousandth of potassium nitrate or potassium dihydrogen phosphate is sprayed every 7~ 10 day for three times in a row. Spraying 3‰ ternary compound fertilizer every 10- 15 days after new buds grow. In general, watering is stopped two days after fertilization. If the air convection is too large, water should be sprayed appropriately according to the dry humidity of the substrate.
Fourth, iron sheet