Method for promoting accumulation of secondary metabolites in cannabis

Abstract

A method for promoting the accumulation of secondary metabolites of cannabis is disclosed. The method comprises the step of adding an irradiation of green-yellow light, which has a peak wavelength at 505-590 nm, into the indoor growing environment of cannabis to improve the level of cannabidiol (CBD), secondary metabolites in cannabis. While maintaining the light intensity and other growth conditions, the yield and/or level of CBD, secondary metabolites in cannabis, can be increased by up to 11.04%.

Claims

1. A method for promoting accumulation of cannabidiol (CBD) in cannabis, comprising: adding an irradiation of a green-yellow light into an indoor growing environment of cannabis to improve the accumulation of level and yield of CBD in cannabis, wherein the green-yellow light has a peak wavelength at 505-590 nm; wherein the step of adding the irradiation of green-yellow light having a peak wavelength at 505-590 nm comprises a combined irradiation with other wavelength bands or independent irradiation; wherein the combined irradiation or the independent irradiation used in the indoor growing environment of cannabis is a LED light source; wherein the LED light source consists of 13.2% blue light, 52.8% red light, and 34.0% green-yellow light; wherein in the combined irradiation with other wavelength bands, a ratio of the photon number of the green-yellow light to the photon number of the combined irradiation does not exceed 50%; wherein a ratio of a number of the photons of the blue light to a number of the photons of the red light is 1:4; wherein an initial light intensity of the combined irradiation or the independent irradiation is 80 μmol/m.sup.2s, a maximum light intensity of the combine irradiation or the independent irradiation is 1000 μmol/m.sup.2s, and a photoperiod is 10-16 h/d; wherein the blue light has a peak wavelength at 445 nm, the red light has a peak wavelength at 660 nm, and the green-yellow light has a peak wavelength at 526 nm.

2. The method of claim 1, wherein the LED light source is realized directly by a LED chip or by using the LED chip to excite a phosphor material.

3. The method of claim 1, wherein the peak wavelength of the green-yellow light lies at 515 nm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) 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.

(2) 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.

(3) FIG. 3 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.

DETAILED DESCRIPTION OF THE INVENTION

(4) 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.

(5) 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/m.sup.2. 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/m.sup.2. 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%, CO.sub.2 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/m.sup.2s. As the plant height increases, the light intensity may reach 500-1000 μmol/m.sup.2s 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 of CBD, the secondary metabolites in the inflorescence of cannabis plants, would be promoted.

Embodiment 1

(6) 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/m.sup.2. 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/m.sup.2. 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%, CO.sub.2 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/m.sup.2s. As the plant height increases, the light intensity reaches 550 μmol/m.sup.2s in the late stage, and the photoperiod is 12 h/d. A blue LED light source with a peak wavelength at 445 nm is provided as a control example, and green-yellow light sources with peak wavelengths at 505 nm, 515 nm, 526 nm, 571 nm are provided as 4 experimental examples. When harvesting, the CBD level in the cannabis is determined, and the dry weight of the inflorescence is collected at the same time to calculate the CBD yield of single plant. The experimental results are shown in Table 1.

(7) TABLE-US-00001 TABLE 1 CBD Inflorescence CBD Ind. Peak level DW yield Irradiation WL/nm (%) g/plant g/plant Cont. Ex. 1 445 5.08 62.35 3.17 Exptl. Ex. 1 505 5.29 73.65 3.89 Exptl. Ex. 2 515 5.63 80.76 4.55 Exptl. Ex. 3 526 5.34 79.68 4.25 Exptl. Ex. 4 571 5.18 72.15 3.73

(8) The results suggest that the green-yellow light is more effective than the blue light in improving the CBD level. Besides, the green-yellow light with peak wavelength at 515 nm is the most effective one which improves the CBD level up to 10.83%. The green-yellow light is also good for the accumulation of inflorescence weight in cannabis, and improving the CBD yield per plant.

Embodiment 2

(9) 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/m.sup.2. 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/m.sup.2. 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%, CO.sub.2 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/m.sup.2s. As the plant height increases, the light intensity reaches 700 μmol/m.sup.2s in the late stage, and the photoperiod is 12 h/d. A light source composed of 20% blue light and 80% red light is provided as the control example 2, wherein the blue light has a peak wavelength at 445 nm, the red light has a peak wavelength at 660 nm. On this basis, light sources having different ratio of green light with peak wavelength at 526 nm added in the control example 2 are provided as experimental examples 5-10 (Table 2). The experimental examples 5-10 also satisfy that a ratio of photon numbers between the red light and the blue light is 4:1. When harvesting, the CBD level in the cannabis is determined, and the dry weight of the inflorescence is collected at the same time to calculate the CBD yield per plant. The experimental results are shown in Table 2.

(10) TABLE-US-00002 TABLE 2 Ratio of Ratio of Ratio of Peak 400-499 nm 600-780 nm 500-599 nm WL photons in photons in photons in of Inflores- 380-780 nm 380-780 nm 380-780 nm green CBD cence CBD Comb. light light light light/ level DW yield Irradiation source (%) source (%) source (%) nm (%) g/plant g/plant Cont. Ex. 2 20.0 80.0 0 — 7.41 74.52 5.52 Exptl. Ex. 5 18.4 73.6 8.0 526 7.69 73.45 5.65 Exptl. Ex 6 16.8 67.2 16.0 526 7.85 78.24 6.14 Exptl. Ex 7 15.0 60.0 25.0 526 8.02 77.21 6.19 Exptl. Ex 8 13.2 52.8 34.0 526 8.16 79.12 6.46 Exptl. Ex 9 11.6 46.4 42.0 526 7.96 77.43 6.16 Exptl. Ex 10 10.0 40.0 50.0 526 7.59 74.64 5.67

(11) The results suggest that it is possible to improve the CBD level, up to 10.12%, by adding into the combination of red light and blue light with different ratio of green-yellow light. At the same time, it is beneficial to improve the accumulation of inflorescence weight of cannabis and increase the CBD yield per plant by adding into the combination of red light and blue light with different ratio of green-yellow light.

Embodiment 3

(12) 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/m.sup.2. 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/m.sup.2. 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%, CO.sub.2 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/m.sup.2s. As the plant height increases, the light intensity reaches 800 μmol/m.sup.2s in the late stage, and the photoperiod is 12 h/d. A light source composed of 20% blue light and 80% red light is provided as the control example 3, wherein the blue light has a peak wavelength at 445 nm, the red light has a peak wavelength at 660 nm. On this basis, same ratio of green lights having different peak wavelengths being added in the control example 3 are provided as experimental examples 11-20 (Table 3). The experimental examples 11-20 also satisfy that a ratio of photon numbers between the red light (600-780 nm) and the blue light (400-499 nm) is 4:1. When harvesting, the CBD level in the cannabis is determined, and the dry weight of the inflorescence is collected at the same time to calculate the CBD yield per plant. The experimental results are shown in Table 3.

(13) TABLE-US-00003 TABLE 3 Ratio of Ratio of Ratio of Peak 400-499 nm 600-780 nm 500-599 nm WL photons in photons in photons in of Inflores- 380-780 nm 380-780 nm 380-780 nm green CBD cence CBD Comb. light light light light/ level DW yield Irradiation source (%) source (%) source (%) nm (%) g/plant g/plant Cont. Ex. 3 20 80  0 — 7.52 74.70 5.62 Exptl. Ex. 11 16.4 65.6 18 505 8.19 75.21 6.12 Exptl. Ex 12 16.4 65.6 18 511 8.28 77.84 6.38 Exptl. Ex 13 16.4 65.6 18 515 8.35 78.02 6.46 Exptl. Ex 14 16.4 65.6 18 520 8.01 79.75 6.39 Exptl. Ex 15 16.4 65.6 18 523 7.98 77.65 6.20 Exptl. Ex 16 16.4 65.6 18 526 7.92 78.21 6.19 Exptl. Ex 17 16.4 65.6 18 545 7.78 77.45 6.03 Exptl. Ex 18 16.4 65.6 18 565 7.74 74.06 5.73 Exptl. Ex 19 16.4 65.6 18 571 7.72 75.18 5.80 Exptl. Ex 20 16.4 65.6 18 590 8.21 77.69 6.38

(14) The results suggest that, on the basis of adding 18% green-yellow light into the combined red and blue light, green-yellow lights at different wave band in the range of 505-590 nm will results different CBD level. The preferred treatment can promote the CBD level up to 11.04%. At the same time, the green-yellow light is beneficial to improve the accumulation of inflorescence weight of cannabis and increase the CBD yield per plant.

(15) 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.