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About Plant Lighting: 5 Species Of Monochromatic Light Affecting Plant Growth
- Dec 10, 2017 -

Small knowledge of plant lighting: 5 species of monochromatic light affecting plant growth

Light is the basic environmental factor of plant growth and development.

It is not only the basic energy of photosynthesis, but also an important regulator of plant growth and development.

The growth and development of plants is not only restricted by the amount of light or light (photon flux density, photonfluxdensity, PFD), but also affected by the light and radiation of different wavelengths and their different proportions.

Knowledge of plant illumination: 5 kinds of monochromatic light that affect plant growth

The solar spectrum can be divided into ultraviolet radiation (ultraviolet, UV< 400nm, including uv-320-400nm).

UV - B280 ~ 320 nm;

UV -c < 280 nm, 280 ~ 280 nm), visible or photosynthetic active radiation (photosyntheticallyactiveradiation, PAR. 400 ~ 700 nm, the blue light from 400 ~ 500 nm;

500 ~ 600 nm green;

Red light 600~700nm) and infrared radiation (700~ 800nm).

Because of the absorption of ozone in the stratosphere (stratosphere), uv-c and most uv-b cannot reach the surface of the earth.

Reach the UV B radiation intensity of the ground because of the geography (latitude and altitude), time (day time, seasonal change), weather (clouds, thickness, etc.) and other environmental factors such as air pollution and change.

Plants can detect changes in the physical and morphological structures necessary for survival in this environment by detecting the subtle changes in the light, intensity, duration and direction of light in a growing environment.

Blue, red, and far-red light play a key role in controlling the formation of plant light.

Phytochrome, Phy, cryptochrome, Cry, and photoreceptors (phototropin, phototropin, Phot) receive light signals and induce the growth and development of plants through signal transduction.

The monochromatic light here refers to the light within a given band range.

Different experiment USES the same kind of monochromatic light wavelength range is not completely consistent, and often close to the wavelength of monochromatic light have different degree of other band overlap, especially before good monochromaticity of LED light source appeared even more so.

Naturally, there will be different and even contradictory results.

Red light

Red light (R) inhibits internode elongation, promotes lateral branching and tillering, delay flower differentiation, and increases anthocyanin, chlorophyll, and carotenoids.

Red light can lead to a positive light movement in arabidopsis thaliana.

Red light has a positive effect on the resistance of plants to biological and non-biological stress.

Far red (FR) can counteract the red effect in many cases.

Low R/FR ratio results in lower photosynthetic capacity of vegetable beans.

In the growth of indoor fluorescent lamp with white as the main light source, with far red LEDs supplement radiation (734 nm) emission peak flower pigment glycosides, carotenoid and chlorophyll content decreased, and make the plant fresh weight, dry weight, stem length, Ye Changhe width increases.

The enhancement of the growth of the padded FR may be due to an increase in the absorption of light due to the increased leaf area.

Low R/FR under the condition of high R/FR, the plant leaves are large and abundant in biomass and cold adaptability.

Different ratios of R/FR can also alter the salinity of plants.


Generally speaking, increasing the proportion of blue light in white light can shorten the internode, reduce the leaf area, reduce the relative growth rate and increase the ratio of nitrogen/carbon (N/C).

Chlorophyll synthesis and chloroplast formation of higher plants and chlorophyll a/b with high chlorophyll a/b are required to be blue.

The photosynthetic rate of the cyanobacteria in red light gradually decreased, and the photosynthetic rate recovered rapidly under blue light or in a continuous red light.

When dark growing tobacco cells are transferred to a continuous blue light in 3d, the ribulose bisphosphate carboxylase/oxygenase (rubulose- 1, 5-bisphosphate

The amount of carboxylase/oxygenase, Rubisco and chlorophyll increased dramatically.

In accordance with this, the dry weight of cells in the volume of the unit's medium volume increased sharply, and in the continuous red light, it increased slowly and slightly.

Obviously, it is not enough for the photosynthesis and growth of plants to have just red light.

The wheat can complete the life cycle under the single red light LEDs, but for tall plants and a large number of seeds, it is necessary to supplement the appropriate amount of blue light (table 1).

Growing on a single red lettuce, spinach, and radish yield is lower than the combination of red and blue light plant, which grows and with adequate blu-ray combination of red and blue light production plant which grows better than cold white fluorescent grown plants.

Similarly, under a single red arabidopsis can produce seeds, but compared with the cold white fluorescent lamp plant which grows, with the percentage of blue light to reduce (10% ~ 1%), combination of red and blue light bolting, flowering plant which grows and the results are delayed.

However, the seed yield of a plant with 10 percent blue blue combined light was only half that of a plant with a cold white fluorescent lamp.

Excessive blue light inhibited plant growth, shortened internodes, reduced branches, decreased leaf area, and reduced total dry weight.

There are obvious species differences in the need for blue light.

Need to point out that while some research suggests that in a different type of source plant morphology and growth difference is related to the spectral blue proportion of different, but because of the different types of lamp of the blue light emission is different also, the conclusion is still problematic.

For example, although in the same light intensity fluorescent lamp soybeans and sorghum crops grown in the plant dry weight and net photosynthetic rate in unit leaf area were significantly higher than those of low pressure sodium lamp plant which grows, but these results cannot be completely attributed to the lack of the blu-ray under low pressure sodium lamp, I am afraid, and low pressure sodium lamp under the yellow, green and orange light too little about too much.

Green light

In white light (red, blue and green light), the seedling of tomato seedling is significantly lower than that of red and blue light.

The spectra of growth inhibition in tissue culture showed that the most harmful photoplasm was green light, which peaked at 550nm.

The marigold plants with green light were increased by 30%~50 %.

The whole spectrum of green light causes the plants to be small and dry, and the fresh weight decreases.

The green light is removed to enhance the flowering of marigold, while the green light inhibits the flowering of the bamboo and lettuce.

However, there are also reports of green light promoting growth.

Kim et al. (2006) summed up the results of green light (LEDs) supplementation of green light, and concluded that plant growth was inhibited when green light was more than 50%, while the proportion of green light was less than 24%.

While on the background in the combination of red and blue light leds offer by green fluorescent adding green lettuce above ground dry weight increased, but adding green light to strengthen growth, more than the cold white light to produce biomass conclusion is problematic: (1) their observations of the dry weight is only the dry weight of aboveground biomass, if including underground root dry weight, the result could be different;

(2) red, blue and green colors light lettuce aboveground dry major crops grown in the cool white fluorescent lamp plant which grows is likely to be the three color light with green light (24%) is far less than the cold white fluorescent lamp (51%) as a result, namely the cold white fluorescent green inhibition is greater than the results of the three color lamp;

(3) the photosynthetic rate of the plants with red and blue combined light was significantly higher than that of the plants with green light.

The green light effect is usually contrasted with red and blue effect.

The green light can reverse the opening of the blue light.

However, using a green laser to process the seeds can make radishes and carrots twice as large as the control.

A dim green pulse can accelerate the elongation of the seedlings that grow in the dark.

Using a single green light from LED source (525nm + 16 nm) pulse (11.1 mu mol·m-2· s-1, 9s) to treat arabidopsis seedling, resulting in the decrease of the plasmid transcriptional material and the increase of the growth rate of the stem.

Plant lighting knowledge: affect plant growth of 5 kinds of monochromatic light (2007) according to the past 50 years plant biology research materials, light green is discussed in the plant, flowering, stomatal opening, stem growth and development, the condition of chloroplast gene expression and plant growth regulating effect on, think green light perception system harmonious with red and blue light sensors to regulate the growth and development of plant.

Note that in this review, the green light (500-600nm) is extended to include the yellow part of the spectrum (580~ 600nm).

Yellow light

Yellow light (580~600nm) inhibits the growth of lettuce.

, each in chlorophyll content and dry weight of different proportion far red, red, blue, and yellow light uv mapping results showed that only the yellow light (580 ~ 600 nm) can explain high pressure sodium lamp and metal halide lamp the differences of two light growth effect, namely yellow inhibit growth.

Moreover, the yellow light (peak at 595nm) is stronger than green light (at 520nm).

Some of the conflicting conclusions about the effects of yellow/green light may be due to the inconsistency of the wavelength ranges used in those studies.

Moreover, since some researchers classify the light of 500-600nm as green light, the literature on the effects of yellow light (580~600nm) on plant growth and development is rare.

Ultraviolet radiation

Ultraviolet radiation reduces the leaf area of plants, inhibits the elongation of the endoderm, reduces photosynthesis and productivity, makes plants vulnerable to pathogens, but can induce the synthesis and defense mechanism of flavonoids.

Uv-b can reduce the content of ascorbic acid and beta-carotene, but can effectively promote anthocyanin synthesis.

Uv-b radiation results in small plant phenotype, small and thick leaves, short petioles, and changes in roots/crowns.

On greenhouse endogenous long from China, India, the Philippines, burr, Thailand, Vietnam and Sri Lanka, seven different areas of rice cultivated in 16 investigation results show that adding UV - B, which could lead to an increase in total biomass quantity has four varieties (including reached significant level of only 1, from Sri Lanka), less cultivated with 12 (of which reached significant level 6);

The area of leaf area and tiller number of those sensitive to uv-b were significantly reduced.

The content of chlorophyll increased by 6 cultivars (2 of which reached a significant level);

The photosynthetic rate of leaf was significantly reduced with 5 cultivars, and 1 cultivated species obviously increased (its total biomass increased significantly).

The proportion of uv-b/PAR is an important determinant of the plant's response to uv-b.

For example, uv-b and PAR jointly affect the form and oil yield of mint, and high quality oil production requires high levels of unfiltered natural light.

Need to point out that the influence of UV - B laboratory studies, although in the identification of transcription factors and other molecular and physiological factors on is A role, but due to the use of A higher level of UV - B, is not accompanied by uv-a, easy-going, is often very low background PAR, the results usually cannot be mechanically extrapolation to the natural environment.

Field studies usually use UV lamps to raise or use filters to reduce uv-b levels.