SPECTRUM FOR PROMOTING GROWTH OF CANNABIS PLANTS

Abstract

A spectrum for promoting growth of cannabis plants. The spectrum comprises adding an irradiation of red light with peak wavelength at 655-690 nm into an indoor growing environment of cannabis to improve the levels of THC and CBD, the cannabinoid substances in cannabis. A ratio of photon number of the red light to the photon number of the entire light source is in a range from 40% to 70%. While maintaining the light intensity and other growth conditions, the yields and levels of THC and CBD, the cannabinoid substances in cannabis, can be increased by up to 32.48%.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation in part of PCT patent Application No. PCT/CN2019/106427, filed on Sep. 18, 2019, entitled “Light Regulation Method for Promoting Accumulation of Secondary Metabolites in Cannabis Plants”, which claims priority of U.S. patent application Ser. No. 16/446,602, filed on Jun. 19, 2019, in the USPTO, the entire content of which are hereby incorporated by reference in their entireties.

TECHNICAL FIELD

The subject matter herein relates to a technical filed of medicinal plants, and in particularly relates to a spectrum for promoting growth of cannabis plants.

BACKGROUND

Cannabis (Cannabis sativa L.) is an annual erect herb. The main active ingredient in cannabis plants is cannabinoids. Currently, over 70 kinds of natural cannabinoids are found, which are mainly used in some nervous system diseases, such as multiple sclerosis, motor neuropathy, chronic intractable pain, a drug-induced vomiting. Tetrahydrocannabinol (THC) and cannabidiol (CBD) are the main active ingredients. The level of CBD is a key medicinal quality indicator of industrial hemp mosaic. As a non-psychoactive compound, CBD has excellent tolerance and above-average safety, and is widely used in the field of medical research. CBD exerts analgesic and anti-inflammatory effects through dual inhibition of cyclooxygenase and lipoxygenase. It also has potential medical value in the treatment of schizophrenia, Alzheimer's disease and epilepsy. It also has a good intervention effect for drug-induced mental dependence such as morphine, cocaine, alcohol or the like. Tetrahydrocannabinol (THC) is a psychoactive cannabinoid. It is usually administered orally or inhaled. After being absorbed, it circulates through the blood to various organs and tissues, thereby exerting effects including analgesia, anti-inflammatory, immune regulation, anti-cancer, etc. The levels of THC and CBD are one of the important indicators of high-quality medicinal cannabis. Medicinal cannabis with high levels of THC and CBD has higher medicinal value and economic benefits in the cannabinoid extraction and processing industry. Therefore, the cannabis cultivation and regulation technology for obtaining high levels of medicinal ingredients has important application value. Accordingly, the cultivation technology of medicinal cannabis plants with high levels of CBD and THC has become a difficult point that needs to be solved urgently.

Indoor cultivation of cannabis can obtain plant raw materials with stable level and yield of medicinal ingredients in full years without being affected by seasons, because the indoor cultivation of cannabis has stable environmental factors including light, temperature, humidity, nutrition and the like required for growth. Light is one of the most relevant environmental factors influencing plant behavior. It is not only the basic energy source for photosynthesis, but also an important regulator of plant growth and development, which plays a significant role in plants' morphogenesis, reproductive development, and regulation of secondary metabolites. Cannabis is a light-loving and short-day plant, which is sensitive to light. It is an important technical means to improve the secondary metabolites for medicinal components by adjusting the light quality ratio of the light environment in the growth of cannabis. The way to adjust the light quality ratio of the light environment is feasible and simple for implementation. It will become an effective technology for producing medicinal cannabis with high levels of CBD and THC and provide a reliable way to provide high-quality raw materials for producing cannabinoid.

At present, high-pressure sodium lamps (HPS), metal halide lamps (MH), and light-emitting diode lights (LED) are mainly used to provide a light environment for indoor cannabis cultivation. HPS and MH are limited by their spectral design, and the achievable spectral energy distribution is limited. LED lights have the characteristics of narrow half-height and flexible spectral design, which have been widely studied. It has become an important research goal of high-quality and high-efficiency cultivation and production of medical cannabis to explore the cultivation methods for promoting accumulation of CBD and THC. However, in the LED light spectrum matching method that promotes accumulation of secondary metabolites in plants, it has not yet disclosed how to promote the indoor cultivation and growth of cannabis plants to achieve a better effect of promoting accumulation of levels of CBD and THC, secondary metabolites in cannabis.

SUMMARY

With respect to the background, one object of the present disclosure is to provide a spectrum for promoting growth of cannabis plants by regulating a growing environment of the cannabis.

Specifically, the object of the present disclosure is achieved by the following embodiments.

A spectrum for promoting growth of cannabis plants is provided. More specifically, an irradiation of red light is added into an indoor growing environment of cannabis to improving the levels and yields of THC and CBD, cannabinoid substances in the cannabis; wherein the red light has a peak wavelength at 655-690 nm.

In some embodiments, the step of adding the irradiation of red light having the peak wavelength at 655-690 nm comprises a combined irradiation with other wavelength bands or independent irradiation.

In some embodiments, in the combined irradiation with other wavelength bands, a ratio of the photon number of the red light to the photon number of the entire light source is 40-70%.

In some preferred embodiments, the ratio of the photon number of the red light to the photon number of the entire light source is 52-65%.

In some embodiments, the light source used in the indoor growing environment of cannabis is a LED light source.

In some embodiments, the LED light source is composed of 11.11-22.22% blue light, 40-70% red light, and 18.89-37.78% green light.

In some embodiments, the blue light has a peak wavelength at 440-460 nm, the red light has a peak wavelength at 660-685 nm, and the green light has a peak wavelength at 505-526 nm.

In some embodiments, the peak wavelength of the red light, preferably, lies at 680 nm.

In some embodiments, a ratio of the photon number of the blue light to the photon number of the red light is 1:4.

In some embodiments, the LED light source is realized directly by a LED chip or by using the LED chip to excite a phosphor material.

In some embodiments, an initial light intensity is 80 μmol/m² s, a maximum light intensity is 1000 μmol/m² s, and a photoperiod is 10-16 h/d.

Compared with the prior art, the present disclosure has the following advantages.

The present disclosure provides a method for promoting accumulation of THC and CBD, secondary metabolites in cannabis. By introducing an irradiation of red light into the indoor growing environment of the cannabis to improve the levels and yields of THC and CBD, secondary metabolites in cannabis; wherein the red light has a peak wavelength at 655-690 nm. While maintaining the light intensity and other growth conditions, the yields and/or levels of THC and CBD, secondary metabolites in cannabis, can be increased by at least to 32.48%.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a spectral distribution diagram from a LED light source which is realized directly by a LED chip according to the present disclosure.

FIG. 2 is a spectral distribution diagram from a LED light source which is realized by using the LED chip to excite a phosphor material according to the present disclosure.

FIG. 3 is a spectral distribution diagram of red-light waveband from a LED light source which is realized by using the LED chip.

DETAILED DESCRIPTION OF THE INVENTION

The present disclosure will be further described in detail below with reference to the drawings and specific embodiments, in order to better understand the objective, the technical solution and the advantage of the present disclosure. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of the disclosure.

In the early stage of treatment to cannabis seedling, top branches of strong cannabis mother plant are selected as stem cuttings for plant cutting, or cannabis seeds are selected for sowing. The seedling stage is about 2 weeks. The cannabis seedlings with good rooting conditions are transplanted into the substrate or rock wool for the vegetative growth phase (the vegetative growth stage is about 4 weeks). Each rock wool block has 1 plant, and a density for the transplanted cannabis seedlings is 9 plants/m². The plant is topped when the plant is about 20 cm high for triggering the growth of side branches. After the vegetative growth stage is finished, the plant is moved to the flower promotion stage for flower promotion treatment. The planting density of the plant in the flower promotion stage is 4-6 plants/m². A distinguishment to the male and female flowers is required. The male flowers will be removed, and the female plants will be cultivated. The cultivation environment is set to have a day and night temperature at 24-26° C./21-22° C., humidity at 60-70%, CO₂ concentration at 10000 ppm. Throughout the growth process, the LED light source directly realized by the LED chip is an artificial light source. The spectrum distribution diagram directly realized by the LED chip is shown in FIG. 1. The LED light source as shown provides a light environment for the growth of cannabis. An initial light intensity is set to 80-100 μmol/m² s. As the plant height increases, the light intensity may reach 500-1000 μmol/m² s in the late stage, and the photoperiod is 10-16 h/d. After 7-9 weeks of growth at the flowering stage, the accumulation of levels and yields of THC and CBD, the cannabinoid substances in plants, would be promoted.

Embodiment 1

Top branches of strong cannabis mother plant are selected as stem cuttings for plant cutting. After the plant cutting is finished (the plant cutting stage is about 2 weeks), the cannabis seedlings with good rooting conditions are transplanted into the rock wool or the substrate for the vegetative growth phase (the vegetative growth stage is about 4 weeks). Each rock wool block has 1 plant, and a density for the transplanted cannabis seedlings is 9 plants/m². The plant is topped when the plant is about 20 cm high for triggering the growth of side branches. After the vegetative growth stage is finished, the plant is moved to the flower promotion stage for flower promotion treatment. The planting density of the plant in the flower promotion stage is 4 plants/m². A distinguishment to the male and female flowers is required. The male flowers are removed, and the female plants is cultivated as before. The cultivation environment is set to have a day and night temperature at 24-26° C./21-22° C., humidity at 60-70%, CO₂ concentration at 10000 ppm. Throughout the growth process, the LED light source is used to provide a light environment for the growth of the plant. An initial light intensity is set to 100 μmol/m² s. As the plant height increases, the light intensity reaches 550 μmol/m² s in the late stage, and the photoperiod is 12 h/d. Four control examples 1-4 are provided by using the blue LED light source having peak wavelength at 450 nm, the red LED light source having peak wavelength at 630 nm, the red LED light source having peak wavelength at 710 nm, and the red LED light source having peak wavelength at 730 nm, respectively. Six experimental examples 1-6 are provided by using the red LED light source having peak wavelength at 655 nm, 660 nm, 670 nm, 680 nm, 685 nm, 690 nm, respectively. When harvesting, the levels of CBD and THC in the cannabis plants are determined, and the dry weight of the inflorescence is collected at the same time to calculate the yields of CBD and THC per plant. The experimental results are shown in Table 1.

TABLE 1
	Peak	CBD	THC	Inflorescence	CBD	THC
Ind.	WL/	level	level	DW	yield	yield
Irradiation	nm	(%)	(%)	g/plant	g/plant	g/plant
Cont. Ex. 1	450	5.27	4.58	58.27	2.91	3.07
Cont. Ex. 2	630	5.42	4.60	83.14	4.51	3.82
Cont. Ex. 3	710	4.74	3.89	31.15	1.48	1.21
Cont. Ex. 4	730	4.52	3.57	24.84	1.12	0.89
Exptl. Ex. 1	655	5.69	4.80	83.09	4.74	3.98
Exptl. Ex. 2	660	5.77	4.87	82.45	4.76	4.02
Exptl. Ex. 3	670	6.05	5.04	83.02	5.02	4.18
Exptl. Ex. 4	680	6.14	5.24	83.78	5.14	4.39
Exptl. Ex. 5	685	6.06	5.11	84.67	5.13	4.33
Exptl. Ex. 6	690	5.80	4.86	79.57	4.62	3.87

The results suggest that, compared with control examples 1-4, the red light source in experimental examples 1-6 may greatly improve the levels of THC and CBD in the cannabis. Besides, compared with control example 1, the red light having peak wavelength at 680 nm is the most effective one which improves the levels of THC and CBD up to 16.51%. At the same time, the red light sources in experimental examples 1-6 are also good for the accumulation of inflorescence weight in the cannabis, and improving the yields of CBD and THC per plant.

Embodiment 2

Top branches of strong cannabis mother plant are selected as stem cuttings for plant cutting. After the plant cutting is finished (the plant cutting stage is about 2 weeks), the cannabis seedlings with good rooting conditions are transplanted into the rock wool or the substrate for the vegetative growth phase (the vegetative growth stage is about 4 weeks). Each rock wool block has 1 plant, and a density for the transplanted cannabis seedlings is 9 plants/m². The plant is topped when the plant is about 20 cm high for triggering the growth of side branches. After the vegetative growth stage is finished, the plant is moved to the flower promotion stage for flower promotion treatment. The planting density of the plant in the flower promotion stage is 4 plants/m². A distinguishment to the male and female flowers is required. The male flowers are removed, and the female plants is cultivated as before. The cultivation environment is set to have a day and night temperature at 24-26° C./21-22° C., humidity at 60-70%, CO₂ concentration at 10000 ppm. Throughout the growth process, the LED light source is used to provide a light environment for the growth of the plant. An initial light intensity is set to 100 μmol/m² s. As the plant height increases, the light intensity reaches 750 μmol/m² s in the late stage, and the photoperiod is 12 h/d. Spectrum of combined light source are used in four control examples (Cont. Ex. 5-8 as shown in Table 2) and five experimental examples (Exptl. Ex. 7-11 as shown in Table 2). The peak wavelength of blue lights in the spectrum in both control examples and experimental examples lie at 450 nm, while the green light at 526 nm and the red light at 660 nm. A ratio of the green light to the blue light is fixed at 1.7. Different ratios of red light are provided in control examples 5-8 and experimental examples 7-11. When harvesting, the levels of THC and CBD in the cannabis are determined, and the dry weight of the inflorescence is collected at the same time to calculate the yields of THC and CBD per single plant. The experimental results are shown in Table 2.

TABLE 2
	Spectral composition and
	Peak characteristics
	X1,	X2,	X3,
	Ratio of	Ratio of	Ratio of
	400-499	500-599	600-780
	nm	nm	nm
	photons	photons	photons
	to	to	to	Biological indicators
	380-780	380-780	380-780			Inflores-
	nm light	nm light	nm light	CBD	THC	cence	CBD	THC
	source	source	source	level	level	DW	yield	yield
SN	(%)	(%)	(%)	(%)	(%)	g/plant	g/plant	g/plant
Cont.	31.48	53.52	15	9.42	3.19	120.37	11.34	3.84
Ex. 5
Cont.	25.92	44.08	30	9.65	3.30	124.49	12.01	4.11
Ex. 6
Cont.	7.41	12.59	80	9.56	3.26	123.58	11.81	4.03
Ex. 7
Cont.	3.70	6.30	90	9.03	3.08	118.35	10.69	3.65
Ex. 8
Exptl.	22.22	37.78	40	10.89	3.61	138.26	15.06	4.99
Ex. 7
Exptl.	17.78	30.22	52	11.21	3.74	139.12	15.60	5.20
Ex. 8
Exptl.	15.56	26.44	58	11.41	3.82	143.25	16.34	5.47
Ex. 9
Exptl.	12.95	22.05	65	11.23	3.72	145.69	16.36	5.42
Ex. 10
Exptl.	11.11	18.89	70	10.72	3.56	140.21	15.03	4.99
Ex. 11

The results suggest that, compared with control examples 5-8, the experimental examples 7-11, which regulates the ratio of red light to the light source in a range of 40-70%, may greatly increase the levels of THC and CBD in the cannabis. Compared with control example 5, the levels of CBD and THC in experimental example 9 have been increased by 21.13% and 19.75%, respectively. At the same time, it is beneficial to improve the accumulation of inflorescence weight of cannabis and increase the yields of CBD and THC per plant by adding into the combination of blue light and green light with different ratios of red light.

Embodiment 3

Top branches of strong cannabis mother plant are selected as stem cuttings for plant cutting. After the plant cutting is finished (the plant cutting stage is about 2 weeks), the cannabis seedlings with good rooting conditions are transplanted into the rock wool or the substrate for the vegetative growth phase (the vegetative growth stage is about 4 weeks). Each rock wool block has 1 plant, and a density for the transplanted cannabis seedlings is 9 plants/m². The plant is topped when the plant is about 20 cm high for triggering the growth of side branches. After the vegetative growth stage is finished, the plant is moved to the flower promotion stage for flower promotion treatment. The planting density of the plant in the flower promotion stage is 4 plants/m². A distinguishment to the male and female flowers is required. The male flowers are removed, and the female plants is cultivated as before. The cultivation environment is set to have a day and night temperature at 24-26° C./21-22° C., humidity at 60-70%, CO₂ concentration at 10000 ppm. Throughout the growth process, the LED light source is used to provide a light environment for the growth of the plant. An initial light intensity is set to 100 μmol/m² s. As the plant height increases, the light intensity reaches 800 μmol/m² s in the late stage, and the photoperiod is 12 h/d. A light source composed of 15% blue light, 25% green light and 60% red light is provided as the experimental light source. The blue light has a peak wavelength at 450 nm, the green light has a peak wavelength at 520 nm. On this basis, same ratio of red lights having different peak wavelengths are introduced to form control examples 9-11 and experimental examples 12-17 (as shown in Table 3). Additionally, the ratio of photon numbers between the red light (600-780 nm) and the blue light (400-499 nm) is 4:1. When harvesting, the levels of CBD and THC in the cannabis are determined, and the dry weight of the inflorescence is collected at the same time to calculate the yields of CBD and THC per plant. The experimental results are shown in Table 3.

TABLE 3
	Spectral composition and
	Peak characteristics
	X1,	X2,	X3,
	Ratio of	Ratio of	Ratio of
	400-499	500-599	600-780
	nm	nm	nm
	photons	photons	photons
	to	to	to		Biological indicators
	380-780	380-780	380-780				Inflores-
	nm light	nm light	nm light	Red	CBD	THC	cence	CBD	THC
	source	source	source	peak	level	level	DW	yield	yield
SN	(%)	(%)	(%)	WL	(%)	(%)	g/plant	g/plant	g/plant
Cont.	15	25	60	630	10.65	3.65	136.49	14.54	4.98
Ex. 9
Cont.	15	25	60	710	9.12	3.15	119.46	10.89	3.76
Ex. 10
Cont.	15	25	60	730	8.56	3.04	112.58	9.64	3.42
Ex. 11
Cont.	15	25	60	655	10.93	3.76	137.56	15.04	5.17
Ex. 12
Exptl.	15	25	60	660	11.01	3.80	136.25	15.00	5.18
Ex. 13
Exptl.	15	25	60	670	11.15	3.83	138.65	15.46	5.31
Ex. 14
Exptl.	15	25	60	680	11.34	3.91	139.24	15.79	5.44
Ex. 15
Exptl.	15	25	60	685	11.28	3.84	138.62	15.64	5.32
Ex. 16
Exptl.	15	25	60	690	10.98	3.78	139.57	15.32	5.28
Ex. 17

The results suggest that the obtained CBD and THC levels will be verified when the wavelength of red light is changed in the combined irradiation of red-blue-green light. Compared with control examples 9-11, the light sources in experimental examples 12-17 will improve, in a certain, the levels of THC and CBD in cannabis. Compared with control example 11, the light source in experimental example 15 improves the levels of CBD and THC up to 32.48% and 28.62%, respectively. At the same time, the addition of different ratios of red light will be beneficial to improve the accumulation of inflorescence weight of cannabis and increase the yields of CBD and THC per plant.

In summary, plants experience different light qualities through photoreceptors such as phytochromes and cryptochromes. The light absorbed by plants is concentrated in the visible part of the wavelength range of 380 to 780 nm. Red light accounts for about 85% of the absorbed physiological radiation light energy, and blue light accounts for about 12%. Therefore, the red light and blue light are essential light qualities for plant growth. The red light is mainly used to generate assimilate and accumulate biomass, and the blue light is a necessary condition for chlorophyll synthesis and chloroplast formation. The blue light affects the morphology of plants by controlling the stomata shape. At the same time, the blue light can also promote the accumulation of secondary metabolites in plants. Green light has always been a controversial light quality. Some scholars believe that it will inhibit the growth of plants, cause the plants to be short and reduce the yield of leafy vegetables. In the present disclosure, under the proof of the above-mentioned embodiments, it is beneficial for promoting accumulation of levels and yields of CBD and THC, the cannabinoid substances in cannabis, by adding an irradiation of red light with peak wavelength at 655-590 nm into the indoor growing environment of cannabis and maintaining the ratio of photon number of the red light (600-780 nm) to the photon number of the entire light source (380-780 nm) in a range of 40-70%. Therefore, different plants may have different optimal spectral formula during growth. The special spectral formula for cannabis as provided may enable the cannabis to accumulate and synthesize more THC and CBD, secondary metabolites in the cannabis, during the industrial cultivation.

It should be noted that the aforementioned embodiments are merely preferred embodiments of the present disclosure, and those embodiments are not to be deemed as limiting the scope of the invention. The scope of the disclosure should be limited by the by the scope of the claims. It will be apparent to those skilled in the art that other modifications and changes may be made without departing from the spirit and scope of the disclosure.

Claims

1. A spectrum for promoting growth of cannabis plants, comprising:

adding an irradiation of red light into an indoor growing environment of cannabis to improve accumulation of levels and yields of tetrahydrocannabinol (THC) and cannabidiol (CBD) in the cannabis; wherein the red light has a peak wavelength at 655-690 nm.

2. The spectrum of claim 1, the step of adding the irradiation of red light having the peak wavelength at 655-690 nm into an indoor growing environment of cannabis comprises a combined irradiation with other wavelength bands or an independent irradiation.

3. The spectrum of claim 2, wherein the in the combined irradiation with other wavelength bands, a ratio of the photon number of the red light to the photon number of the entire light source is 40-70%.

4. The spectrum of claim 3, wherein the ratio of the photon number of the red light to the photon number of the entire light source is 52-65%.

5. The spectrum of claim 2, wherein the light source used in the indoor growing environment of cannabis is a LED light source.

6. The spectrum of claim 4, wherein the LED light source is composed of 11.11-22.22% blue light, 40-70% red light, and 18.89-37.78% green light.

7. The spectrum of claim 4, wherein the blue light has a peak wavelength at 440-460 nm, the red light has a peak wavelength at 660-685 nm, and the green light has a peak wavelength at 505-526 nm.

8. The spectrum of claim 7, wherein the peak wavelength of the red light lies at 680 nm.

9. The spectrum of claim 6, wherein a ratio of the photon number of the blue light to the photon number of the red light is 1:4.

10. The spectrum of claim 3, wherein the LED light source is realized directly by a LED chip or by using the LED chip to excite a phosphor material.

11. The spectrum of claim 3, wherein an initial light intensity is 80 μmol/m2 s, a maximum light intensity is 1000 μmol/m2 s, and a photoperiod is 10-16 h/d.

12. The spectrum of claim 1, wherein the light source used in the indoor growing environment of cannabis is a LED light source.

13. The spectrum of claim 5, wherein a ratio of the red light in the LED light source is 52-65%.

14. The spectrum of claim 6, wherein a ratio of the red light in the LED light source is 52-65%.