1. Propagation Techniques of Dendrobium candidum
The reproductive modes of Dendrobium can be divided into two categories: sexual reproduction and asexual reproduction. At present, asexual reproduction is mainly used in production.
1, sexual reproduction is seed reproduction. Dendrobium seeds are very small, each capsule is about 20 thousand, yellow powder, usually does not germinate. It can germinate and grow only under the conditions of sufficient nutrients, appropriate humidity and moderate light, and generally needs to be cultured in a tissue culture room. However, although the reproductive coefficient of Dendrobium is extremely high, the success rate of its sexual reproduction is extremely low.
2. Asexual reproduction
(1) ramet propagation: It should be carried out in spring or autumn, preferably before Dendrobium germinates in late March or early April. Select 1 ~ 2-year-old plants with good growth, no pests and diseases, developed roots and many buds as seed plants, uproot them, remove dead branches and cut off redundant fibrous roots, keep the old roots about 3 cm, and divide them into several clusters according to the number of stems, each cluster must have 4 ~ 5 stems, which can be used as seed stems.
(2) Cutting propagation: in spring or summer, preferably in May-June. Choose a three-year-old plant with strong growth, take its complete and round stem segments, each segment has 4-5 nodes, and the length is about 15-25 cm. Insert it into vermiculite or river sand, and the stem depth will not fall. It can be transplanted when the axillary buds on the stem germinate and grow white aerial roots. Generally, when selecting materials, the upper stem segment is the main one, because it has great advantages at the top, high survival rate, many buds and fast growth and development.
(3) High bud propagation: mostly in spring or summer, mainly in summer. Dendrobium plants over three years old germinate axillary buds on their stems every year, also called high buds, and grow aerial roots to become seedlings. When they grow to 5 ~ 7 cm, they can be cut and transplanted.
(4) In vitro tissue culture and propagation: Dendrobium nobile can adopt the following methods for tissue culture and rapid propagation of test-tube seedlings. After routine disinfection, leaves, tender stems and roots of Dendrobium nobile were cut into 0.5 ~ 1 cm as explants, and ms and B5 were used as basic media, and NAA (0.05 ~ 1.5 mg/L), IAA (0.2 ~ 1.0 mg/L) and IAA were added respectively. Tissue culture was carried out under the conditions of medium pH 5.6 ~ 6.0, culture temperature 25℃ ~ 28℃, illumination 9 ~ 10 hour per day and illumination intensity 1800 ~ 1900lx. After 19 days, small buds appeared on the stems and leaves. After about 1 month, the buds are elongated and the tips are bifurcated. After 2 months, the shoots grew into 4-8 leaves and 2.0-2.7 cm high test-tube seedlings. However, the fragments of leaves and roots remain unchanged. In the combination of different medium formulations, MS has obvious advantages over B5 basic medium.
Second, how to plant Dendrobium candidum and how to plant Dendrobium candidum.
1, time The cultivation time of Dendrobium candidum is generally spring and autumn every year, and spring is better than autumn. In Zhejiang, the best cultivation time of Dendrobium candidum is from mid-April to late June every year, during which the temperature is 65438 02 ~ 25℃, the air humidity is high, and the survival rate of transplanted test-tube seedlings is high and the growth time is long. Followed by mid-September to 10. In the meantime, it is especially necessary to do a good job in cold and antifreeze.
2. Water, humidity and water management are one of the key links in the cultivation process of Dendrobium candidum. Newly transplanted Dendrobium seedlings are most sensitive to water, and it is generally appropriate to control the water content of the substrate at 60%~70%, and it is appropriate to grasp the substrate without dripping water. Within 7 days after transplanting (the seedlings have not yet grown new roots), the air humidity is kept at about 90%, and after 7 days, the plants begin to grow new roots, and the air humidity is kept at 70%~80%.
3. Temperature and illumination The suitable growth temperature of Dendrobium candidum is 15~28℃. Therefore, in order to create a temperature environment suitable for its growth, it is necessary to strengthen the ventilation and heat dissipation in the greenhouse when the temperature is high in summer, and control the temperature in the greenhouse within a suitable range by means of shading, spraying and ventilation. When the temperature is low in winter, the greenhouse should be closed, and if necessary, the temperature in the facility can be increased by various heating methods to prevent plant frostbite.
Dendrobium candidum likes shade, so shading measures should be taken to reduce light. The suitable shading degree of Dendrobium candidum in the growth period is about 60%. When the seedlings are just planted, the greenhouse must be covered with a shading net with shading degree above 70% to prevent the seedlings from wilting due to strong light irradiation and affect the survival rate. In summer and autumn with high temperature and strong light, the sunshade net in the greenhouse must be covered tightly, because strong light is easy to make the plants top in advance and affect the yield. In winter, the shade shed should be properly opened to facilitate light transmission and prolong the growth period. In the case of attached tree cultivation (attached to the main plant), the branches that are too dense with the main plant should be appropriately cut off in winter and spring every year.
4. Precautions: Try to control the water content in summer and autumn, and the water content of the substrate should be 40%~50%; In winter after 1 1 month, the temperature gradually decreases. When the temperature is lower than 10℃, Dendrobium candidum basically stops growing and enters a dormant state. At this time, the requirement for water content is very low, and the water content of the matrix should be controlled within 30%.