The Advantages Of LED Grow Light In The Cultivation Of Medicinal Plants

Cultivation of medicinal plants is based on the domestication of wild performed a process for producing high-quality high-yield cultivation mode. Different medicinal plants on the ecological environment have different requirements, decisions of wild medicinal plants of its special growing environment, which the domesticated environmental control put forward higher requirements. Artificial light plant factory because of its excellent ability to control the environment, so that the rapid production and domestication of wild medicinal plants as possible.
Plant factory as a resource-intensive production model that can simulate the requirements of medicinal plants to maximize growth environment, while the introduction of multi-dimensional cultivation, can significantly improve the utilization rate per unit of land, productivity and economic efficiency. Light is the most important environmental plant growth factor, a suitable light environment is to achieve high yield and quality of medicinal plants in the most important prerequisite. Research and development of LED light source for optimal control of medicinal plants plant light environment possible.
For the cultivation of medicinal plants is, LED prominent advantages: First, can emit a half-wave width of ± 20 nm monochromatic light can provide a special environment needed for the plant; the second is illumination with a linear relationship between the duty cycle, easy adjustment of light intensity. The most commonly used artificial light, fluorescent lamps contain more blue light, incandescent and high-pressure sodium lamps contain more infrared light, its emission spectrum are fixed and can not effectively regulate light environment. Therefore, LED has obvious advantages in the domestication and cultivation of medicinal plants.
Plant Factory initial investment cost of the larger, high-value-added production of medicinal plants is an important direction for future development and trends. Use LED light source and gradually spread will make the plant medicinal plants in high-precision environmental control advantages into full play.

Dendrobium test
Dendrobium is a rare and ancient medicinal plants, first recorded in the year 2000, Liang, “Shen Nong’s Herbal Classic.” Pharmacological studies show that Dendrobium can significantly improve the SOD (superoxide dismutase) levels, reduce LPO (lipid peroxidation) and play a role in delaying aging. Modern pharmacological experiments discovered Dendrobium has anti-aging and enhance immunity, anti-tumor, treatment of cataract, dilation of blood vessels and anti-platelet aggregation, protection Qingyan throat and so on. In Dendrobium mainly formulated compound preparation widely used in clinical, can lower blood sugar, improve immunity, and safe non-toxic.
Dendrobium ecological environment of more stringent requirements, difficulties in natural reproduction, the survival rate is low and slow growth. Therefore, the use of Horticultural control methods, artificial propagation of Dendrobium become an important issue. This test is based on previous research on Dendrobium light environment on inquiry LED light quality and the proportion of Dendrobium plantlets transplanting survival rate and growth of the proposed plant Dendrobium closed plant growth light environment indicators provide theoretical and experimental basis for Dendrobium artificial breeding.

  1.  Test material
    The experiment was carried out from April to August, the plants in the greenhouse plants. Test material used with the one source of medicinal Dendrobium tissue culture seedlings (D. officinale), height of about 25 mm, fresh mass of about 400 mg, transplanted to plug 50 holes in. Plug in the selection of the matrix contains bark, bluestone, ceramic particles and special orchid potting nutrition, and use of EC 1.8 mS / cm nutrient solution manual sprinkler.
    Selection of Agricultural Environment Research Institute, Chinese Academy of Agricultural Sciences and Sustainable Development of self-developed LED lighting system (Figure 1, Figure 2). The light system is composed of a wavelength of 660 nm (half-wave width of ± 20 nm) of the red LED and 450 nm (half-wave width of ± 20 nm) blue LED Cross uniform composition, light intensity can be achieved at 0 ~ 288μmol / ( m2? s) freely adjust the irradiation distance between the light source and the plant can also be adjusted according to demand.
    Because LED is a cold light source, brachytherapy plants, can reduce unnecessary loss of light, space utilization can be improved plant factory, so the test LED light source from the plant just above 10 cm. Dendrobium plantlets transplanting stage environmental parameters are set as follows: day – temperature (25 ± 1) ℃, night temperature (15 ± 1) ℃, relative humidity 60% ~ 80%, CO2 concentration (1500 ± 30) μmol / mol, illumination time of 12 h / d. Test, depending on the settings and the red LED blue LED light quality ratio of 4 LED light quality test area (Table 1), each test area illumination are 70 μmol / (m2? S), in addition to light quality, the other test consistent conditions.
  2. Test Method
    Dendrobium plantlets 90 days after transplanting, randomly selected from each treatment 10 were measured plant fresh weight, height and stem diameter. The plants were then loaded into a paper envelope placed in a drying oven at 80 ℃ 72 h, remove the plants weighed dry weight; randomly selected from each of the five treatment using colorimetric measurements of chlorophyll and carotenoid content. Then the remaining 35 All 80 ℃ drying 72 h, then ground into powder drying plants, the use of sulfuric acid – phenol content measured Dendrobium polysaccharide in. Meanwhile, the ordinary civilian Metering respectively artificial light source power consumption.

Test results and analysis

At the end of cultivation, Dendrobium morphological indicators were measured. Table 2 shows Dendrobium plantlets transplanting 90 days, compared with the original weight of 400 mg, plant fresh weight has increased in different lighting conditions, the fresh weight of each treatment room has a clear trend, expressed as then decreases to the test area LED3 fresh weight of the most significant increase, compared with the original weight increased by about 130%, significantly higher than other test area; LED4 test area smallest increase in more than just the original weight increased by about 22.5%. Height Dendrobium plants under different light conditions LED treatment also increased, with fresh quality also showed the same trend, up to a maximum height of the test area LED3 growth, significantly higher than the test area LED4, two other experimental treatment zone There was no significant difference between. Dry mass between each test plant, stem diameter and the number of no significant difference.

But also on the content of Dendrobium photosynthetic pigments and polysaccharide content were measured. From Table 3, it found that chlorophyll a content showed a trend of first increases and then decreases, there is a significant difference between (1 and 3 was no significant difference) among the treatments, chlorophyll a content LED2 handle the highest ratio of processing 31% LED4 high, significantly higher than other treatments, indicating that R / B = 2 helpful Dendrobium accumulation of chlorophyll a. Change of chlorophyll b content of chlorophyll a change in the same trend, but also to deal with LED2 maximum for (0.40 ± 0.050) mg / g, but not with the other treatments showed significant differences. Carotenoid content also showed the same trend, but the maximum in the process LED3, is (0.33 ± 0.022) mg / g, and the other treatments did not show significant differences.
Dendrobium polysaccharide to characterize the quality of an important feature, there are significant differences in the polysaccharide content in different pilot areas. With the increase of R / B ratio of polysaccharide content increased first and then decreased, indicating that R / B ratio of Dendrobium polysaccharide content has a regulatory role. Processing LED2 polysaccharide content of 2.16%, significantly higher than other treatments, indicating that R / B = 2 in favor of transplanting stage the Plants Dendrobium polysaccharide content accumulation.
Measuring the power consumption of the light source device discovery, different R / B ratio Dendrobium transplanting seedlings influential power plant, the overall power consumption with increasing R / B ratio is reduced, the consumption of processed LED4 minimum charge, 90 days after the end of the culture, plant seedlings Dendrobium power consumption of 1.15 kW? h, which is due to less power than the red LED blue LED power, with the increase of light quality ratio, more red, overall power becomes small, so power consumption is decreased.
In conclusion
These studies show that plant medicinal plants can provide a suitable environment for the growth of Dendrobium, Dendrobium growth conditions showed that transplanting seedlings, the plants used for medicinal plant domestication plant is entirely feasible. Meanwhile, data analysis, a wavelength of 660 nm and 450 nm LED combination light source, when the R / B = 2, Dendrobium transplanting seedlings grew well integrated, the highest content of chlorophyll b, chlorophyll a content and polysaccharide were significantly higher than other treatments, light environmental parameters for transplanting seedlings of Dendrobium.
Dendrobium is a growth cycle is longer, higher environmental requirements of medicinal plants, the study found that the LED light source can provide suitable optical environmental parameters, Dendrobium conducive to growth and development. With the increasing popularity of the plant factory, cultivation of high-value precious medicinal plants will be an important direction of development, LED light source is considered to be able to provide suitable optical environmental parameters for high-quality source of medicinal plants.