Climatic factors and cultivation techniques affecting the growth of Dendrobium candidum

Climatic factors and cultivation techniques affecting the growth of Dendrobium candidum

Yunnan Province is the best producing area of Dendrobium candidum, and temperature has the greatest effect on its quality, and it is easier to enrich lanolin in Dendrobium candidum at low altitude. The results showed that under the light transmittance of 50%, the growth phenotype of Dendrobium candidum was the best, and its polysaccharide content was the highest, up to 6.338%. However, the contents of total amino acid, cysteine, arginine, asparagine, lysine, total phenol and lanolin were the highest when the light transmittance was 10%. At the same time, when the light transmittance was more than 82%, the stem diameter and chlorophyll content of Dendrobium candidum increased negatively. It is not conducive to the growth of Dendrobium candidum, indicating that Dendrobium candidum can regulate the synthetic pathway of chlorophyll content in the plant under low light environment, maintain photosynthesis and meet the growth needs. therefore, in the period of high light intensity in July of that year, a high density sunshade net with 10% light transmittance was used. On the other hand, in the environment with weak light in winter, the low-density shading net with 50% light transmittance can give full play to the growth effect and effective components of Dendrobium candidum. Dendrobium is a temperature-loving plant. The germination of new tiller stem of Dendrobium candidum is related to temperature. Compared with wild drumstick Dendrobium, there are more phenomena of Dendrobium candidum with two bamboo shoots in one mother and another reserve bud dormant for many years on some old plants [Jishan Huayao]. The study shows that the number of sprouts increases under the condition of low temperature, but too low temperature will delay germination, resulting in delayed growth and development of new stems and poor maturity of pseudobulbs, and the interaction between light intensity and temperature affects each other. Dendrobium growth needs higher light intensity in a higher temperature range to supply plant growth.

Cultivation of Dendrobium candidum

For the large-scale artificial planting of Dendrobium candidum, its cultivation substrate needs to be studied. Select the cultivation substrate with good ventilation and maintenance of water and fertilizer, such as mature bark and moss differentiated from plants, which is rich in organic nutrients and mineral elements, loose texture, suitable for the attachment and growth of the root system of Dendrobium candidum, which accords with its most primitive habitat. it can obviously promote the growth of Dendrobium candidum [Jishan Huayao]. The study of Wang Yan and others found that Dendrobium candidum performed best in the mixed medium of orchid stone: bark 1 ∶ 1, and the maximum photosynthetic rate was 6 μ mol ·m-2 s-1, while water moss was not suitable to be used as the cultivation substrate of drumstick Dendrobium, because the water moss had high water absorption and kept moist all the time, which was easy to cause bacteria invasion, resulting in mildew and death of some plants. Therefore, the mixed substrate is the ideal substrate for the cultivation of Dendrobium. Pine bark is also used as the cultivation substrate of tissue culture plantlets, and the matrix composed of stone, gravel and broken brick is also a more suitable substrate for Dendrobium candidum in the tropics, while the stone bed is very suitable for root attachment and growth of Dendrobium candidum in hot summer, with large flowering quantity and high stem yield. Gao Yan et al used eucalyptus sawdust ∶ peat ∶ matured Artemisia argyi (7 ∶ 2 ∶ 1) in pot experiment, while cow dung was found to be a better fertilizer substrate in imitating wild cultivation.

At present, the yield of Dendrobium candidum is relatively small, which can not meet the needs of clinical and new drug development. the suitable cultivation method is an important way to improve the quality and yield of Dendrobium candidum. Its survival rate, growth and the content of medicinal components are related to the cultivation mode. Since Dendrobium candidum has been planted on a large scale for more than ten years, the cultivation methods are mainly greenhouse ground bed, forest ground bed, elevated seedling bed, tree sticking and flowerpot, and almost all of its cultivation provenance comes from wild seedlings. Sun Yongyu and others put forward a simple facility stone bed cultivation technique of Dendrobium candidum. In recent years, there are many explorations on the cultivation methods of Dendrobium candidum. In the experiments of trough cultivation, living cultivation and imitating wild cultivation, it is found that trough cultivation is easy to manage. Living cultivation has the limitations of the selection of host plants, and the management of imitating wild cultivation is simple, but it is limited by the original habitat suitable for the growth of Dendrobium candidum. According to the field-like standing wood, log three-dimensional and pot experiment, it is found that pot and original standing wood are most close to facility cultivation, which is simpler and easier to manage than imitation wild cultivation. in addition, the drumstick Dendrobium produced by log three-dimensional cultivation is more in line with the standard of green food. In the process of wild planting of Dendrobium candidum, the best host plant is evergreen tree species with lush crown, rough bark and many gullies, while mango and longan are common economic trees in Pu'er area. it has become a good host plant for Dendrobium candidum imitating wild planting.