LU504717B1

LU504717B1 - Novel approach for preventing and controlling Dendrobium officinale Kimura et Migo southern blight disease in northern greenhouse in winter haze days

Info

Publication number: LU504717B1
Application number: LU504717A
Authority: LU
Inventors: Juan Zhang
Original assignee: Beijing Yukunsheng Tech Development Co Ltd
Priority date: 2023-07-11
Filing date: 2023-07-11
Publication date: 2024-01-11

Abstract

The present invention discloses a method for preventing and controlling a Dendrobium officinale southern blight in northern greenhouse in winter haze days. The method includes regulating light intensity, air humidity and culture substrate humidity for cultivating Dendrobium officinale, so as to focus on the source of the disease, that is, starting from environmental conditions of disease occurrence and physiological state of its host, so that breeding conditions of pathogens are fundamentally eliminated, environmental factors of healthy growth for Dendrobium officinale are strengthened, and the harm of southern blight is effectively prevented and curbed. According to the method of the present invention, it is conducive to the accumulation of carbon assimilation substances in photosynthesis of the leaves, reduction of nutrients consumption of individual plant cultivated in northern greenhouse in winter, and promote normal growth and development of Dendrobium officinale plants.

Description

Novel approach for preventing and controlling Dendrobium officinalé>°""7

Kimura et Migo southern blight disease in northern greenhouse in winter haze days

Technical field

The present invention relates to the technical field of plant-protection, specifically, to the technical field of diseases and pests prevention and treatment of plants, and more specifically, to a method for preventing and controlling diseases when cultivating a rare

Chinese herbal medicine Dendrobium officinale Kimura et Migo indoors.

Background technology

Dendrobium officinale is a perennial herb plant of Dendrobium Sw. in Orchidaceae, and is a valuable traditional Chinese medicine. Due to its seeds have no endosperm and are difficult to germ, a natural seedling rate is very low, so that a main way of artificial cultivation of the Dendrobium officinale is to breed a large number of seedlings through plant tissues.

However, a southern blight often appears during the cultivation of Dendrobium officinale seedlings, especially when a substrate is acidic. Southern blight is one of the main diseases of Dendrobium nobile and Dendrobium officinale cultivated artificially on a large scale. The source of the disease is Sclerotium rolfssi Sacc. More than 500 hosts worldwide can be infected by this pathogen. After infestation, glucose and starch in diseased leaves are taken as carbon sources, glyoxylic acid is oxidized by glyoxalate oxidase to produce large amounts of oxalic acid, which acts as a cytotoxic agent to disrupt plant cell membrane systems, increase membrane permeability, and lead to leakage of intracellular electrolytes, and these osmoregulatory substances can be used as nutrients for mycelial reproduction. At the same time, the pathogenic bacteria also secrete cell wall to degrade enzymes to disrupt cellular connections and cell swelling, resulting in the loss of a large number of organic molecules, and often causing root and rhizome rot and a large number of dead seedlings, leading to huge losses.

When the disease occurs, white silky mycelium can be seen on the surface of the substrate, and brown rapeseed-like nucleus is formed at the central part, so that the roots and stem segments near the ground are affected initially. Yellow or light brown watery spots appear on the stems of the plant near the substrate. Leaf is damaged from the leaf tip or leaf edge, which is initially brown watery spots, irregular and slightly sunken. The silky substances can spread on the surface of the substrate and the stem and leaf, and the spots turn brown or black-brown, the affected area rots and becomes soft, the plant collapses, and white silky substances are produced. The disease can cause rot at the base of the plant and expatd/504717 to the upper part of the stem and leaves. The infected area rots and becomes soft, and the plant rots and dies quickly, resulting in a large number of dead seedlings, with a general mortality rate of about 30 % and a serious mortality rate of over 70 %. For plants of

Dendrobium Sw. in Orchidaceae, the conditions for the development of the southern blight include darkness, high humidity, acidic environment, sufficient nutrients for the disease, and mycorrhizal stimulants.

There are three main ways to prevent and treat the southern blight of the Dendrobium officinale.: first, strict sterilization; when planting the Dendrobium officinale, 2 % of formalin solution is used for strictly sterilizing the substrate, sites, utensils and seedlings to eliminate the infestation. Second, adjusting the pH of the substrate; 3 % of lime water is used for watering the substrate. Third, drug control.

Currently, for the Dendrobium officinale, as mentioned above, most of them are not propagated by seeds, but by techniques such as tissue culture to perform cultivation through seedling-refining. In this process, the substrate and other materials can be disinfected, and the disinfection interval is usually controlled to be 3-5 days once. Because the Dendrobium officinale. 1s a valuable plant, and its own growth and cultivation are still to be further explored, too frequent disinfection also has a greater impact on the growth of the Dendrobium officinale. Byproducts after disinfection may be left in the final Chinese dendrobium products, which may lead to the deterioration of quality later. At the same time, although the adjustment of the pH of the substrate can control the process of the southern blight to a certain extent, it has a negative impact on the natural growth of the Dendrobium officinale.

Most of the Dendrobium officinale. are not propagated through seeds, so sterilization can only be controlled in the process of tissue culture. However, the existing control methods are mainly pharmaceutical (chemical control), and the drugs used include: benzopyrimethanil, chloramphenicol, methomyl emulsifiable oil, miepuling wettable powder, propamocarb hymexazol, polyversum, ethylicin, chlorothalonil, thiophanate methyl wettable powder, carbendazol wettable powder, etc. For example, for the diseased Dendrobium officinale plants, chloramphenicol injection can be applied in 500-1,000 times solution, once a day for 2-3 times, which is expected to control the disease. It is expected to control the disease by using “Myclobutanil”, “Dakinin”, 20 % of methomyl emulsifiable oil 800 times solution, 50 % of fudonin 300 times solution and 75 % of miepuling wettable powder 1,000 times soluyion.

However, there are many disadvantages of chemical control methods: firstly, it pollutes the environment and reduces the quality of herbs; secondly, although the effect of bacterial suppression is obtained, new stress is formed for the diseased plants at the same time, which is objectively not conducive to the rapid recovery of healthy growth; and thirdly, it 504717 difficult to eradicate the recurrence of the disease.

Summary of the invention

The present invention focuses on the origin of a southern blight during cultivation of

Dendrobium officinale, that is, starting from environmental conditions of disease occurrence and physiological state of its host, so that breeding conditions of pathogens are fundamentally eliminated, environmental factors of healthy growth of the Dendrobium officinale are strengthened. Thus, the present invention provides an optimized method for cultivating the Dendrobium officinale and preventing and treating diseases and pests.

The method for cultivating the Dendrobium officinale and preventing and treating diseases and pests includes: (1) in cultivating the Dendrobium officinale, illuminating the top of plants by using an

LED monochromatic spectral light during the whole day, so as to effectively control the number of photons received by the Dendrobium officinale, and meantime (2) controlling air humidity at the range of 50 %-60 %; and (3) controlling the culture substrate humidity of the Dendrobium officinale; maintaining the above conditions for a certain time, so as to effectively prevent and control the southern blight.

After a large number of studies and experiments by an inventor, it is found that during the development of the southern blight, its influencing or key control factors include temperature, pH value and so on. It is worth noting that light can promote the production of sclerotium in the southern blight, which can dormant under bad conditions and germinate under suitable conditions.

In addition, in previous studies, the inventor found that high temperature and high humidity are important conditions for the invasion of the southern blight of the Dendrobium officinale; high environmental humidity is very beneficial to the occurrence of diseases, promote the germination of sclerotium and increase the chance of infection to hosts.

In order to keep warm, the sealing performance of the greenhouse for cultivating the

Dendrobium officinale in winter in northern area must be guaranteed, which leads to the difficulty of ventilation. The air humidity in the greenhouse is high and the air is not circulating, which objectively creates favorable conditions for the breeding of germs. At the same time, due to the short sunshine time in winter and the severe smog in recent years, there were 27 times of smog in 2015, nearly half of which were concentrated in November,

December and January in winter. In the first 20 days of November 2015, the sunshine hours in Beijing were only 35 hours in total, which aggravated the dark state of the greenhouse.

According to the inventor’s research, when illumination hours are less than 3 hours wit}504717 above 100 u molphoton m-2 s-1 and the air humidity in the greenhouse is higher than 86 % throughout the day, which lasts for more than 72 hours, white silky mycelium will appear at the base of the cultivated Dendrobium officinale, as shown in FIG. 1.

Therefore, the invention focuses on the causes of disease occurrence, that is, starting from the environmental conditions of disease occurrence and the physiological state of the host, fundamentally eliminating the breeding conditions of pathogens and strengthening the environmental factors for healthy growth of the Dendrobium officinale.

In conclusion, according to the present invention, the light intensity and the environmental humidity are controlled to perform comprehensive prevention and treatment, thereby starting from the causes of the southern blight. The environmental factors are regulated and controlled to make it deviate from the external conditions of the disease, the health status of the host is improved and the ability of resisting the infection of the sclerotium of the disease is enhanced, thereby fundamentally eliminating the breeding conditions of the germs and strengthening the environmental factors for the healthy growth of the Dendrobium officinale. Thus, an optimized method for cultivating the Dendrobium officinale and preventing and treating diseases and pests is provided to the northern area.

The method for cultivating the Dendrobium officinale and preventing and controlling diseases and pests includes the following steps: (1) in cultivating Dendrobium officinale, illuminating the top of plants by using an LED monochromatic spectral light during the whole day, so as to effectively control the number of photons received by Dendrobium officinale, and (2) controlling air humidity at the range of 50%-60 %; and (3) controlling the culture substrate humidity of Dendrobium officinale, maintaining the above conditions for a certain time, so as to effectively prevent and control the southern blight.

Wherein: in the condition (1), in cultivating the Dendrobium officinale, illuminating the top of plants by using an LED monochromatic spectral light during the whole day, so as to effectively control the number of photons received by the Dendrobium officinale.

Preferably, the light source employs an ultra bright LED monochromatic spectral light; each light bead is 2-5 W, a red light wavelength is 660+20 nm, and a blue light wavelength is 450+20 nm.

More preferably, the light source employs the ultra bright LED monochromatic spectral light; each light bead is 3 W, a red light wavelength is 660 nm, and a blue light wavelength is 450 nm.

Preferably, the light source is arranged at a distance of 50-70 cm from the top end ofl4/504717 plant curtain of the plant. More preferably, the light source is arranged at a distance of 60 cm from the top end of the plant curtain of the plant.

Preferably, the light intensity of the light source is 180-220 jumolm-2s-1, and a 5 photoperiod is 10-14 h/d. More preferably, the light intensity of the light source is 200 umolm-2s-1, and the photoperiod is 12 h/d. Preferably, illumination duration of the light source is from 7:00 am to 19:00 pm.

Preferably, the number of the red light to the blue light of the light source is 1.78-1.85:1.

Preferably, the number of the red light to the blue light of the light source is 1.82:1.

Preferably, the LED light is in rectangle, each light contains 130-150 light beads with 2- 5 W, and red and blue beads are alternatively arranged. More preferably, the LED light is in rectangle, each light contains 141 light beads with 3 W, and red and blue beads are alternatively arranged.

In the optimal cultivation condition control method, step (1) is as follows: in cultivating Dendrobium officinale, illuminating the top of plants by using an ultra bright LED monochromatic spectral light during 7:00 am to 19:00 pm, so as to effectively control the number of photons received by Dendrobium officinale The ultra bright LED monochromatic spectral light is that: each light bead is 3 W, the red light wavelength is 660+20 nm, blue light wavelength is 450420 nm, 60 cm from the top of the leaf curtain of the plants, the light intensity is 200 umolm”s"!, photoperiod is 12 h/d, 7:00 am-19:00 pm, and the ratio of the red light to the blue light is 1.82:1 =R/B. The LED light is in rectangle, each light contains 141 light beads with 3 W, and red and blue beads are alternatively arranged, a configuration mode of the LED monochromatic light is shown in FIG. 2.

Preferably, Li-250A photometers produced by LICOR Company of USA are used to monitor the photon flux density. Photon flux density is the number of optical photos with incident wavelength of 400-700 nm on a blade per unit area in unit time.

Wherein, in the condition (2), in the cultivation process, the air humidity is controlled at the range of 50-60 %. Preferably, the air humidity is controlled at the range of 52-59 %.

More preferably, the air humidity is controlled at the range of 53-58 %. More preferably, the air humidity is controlled at the range of 54-56 %. Most preferably, the air humidity is controlled at 55 %.

Wherein, in the condition (3), in the cultivation process, culture substrate humidity of

Dendrobium officinale is controlled. Preferably, the substrate humidity is controlled under 26 %. If the substrate humidity is too high, it is not conducive to the development of

Dendrobium officinale Although Dendrobium officinale is a moisture-loving and shadeVS04717 loving plant, the humidity of the substrate should not be too high because the fleshy roots are prone to decay with much water. The so-called moisture-loving refers to the environment of the air humidity suitable to Dendrobium officinale is higher. As a typical epiphyte, the root system of Dendrobium officinale is not the only organ that absorbs water. Therefore, the key to humidity control is to ensure that the air humidity is relatively high while the substrate is relatively dry without causing various molds. Through extensive experiments, the inventor has found that 26 % is an effective threshold, below which, with the specific light conditions and air humidity described above, is very effective in controlling the occurrence of the southern blight. If the humidity is above this value, it would be favorable for the occurrence of the southern blight. If the humidity is too low, it is not conducive to the development of

Dendrobium officinale

Preferably, the substrate is a pine bark substrate.

Preferably, the light intensity, air humidity and substrate humidity conditions should be kept for at least one week.

On the basis of keeping the above conditions for a week, the disease can be prevented and treated, and the effect can reach to 92 %. Calculation method: (The number of comparative infected plants - the number of treated infected plants)/ the number of comparative infected plants.

The southern blight of Dendrobium officinale is a problem that has been troubling the industry, especially in the northern winter, Dendrobium officinale must overwinter in the greenhouse, which is highly susceptible to the southern blight, especially in hazy weather. It has been found that the incidence of the southern blight of Dendrobium officinale in greenhouse cultivation is very high when there is insufficient light, and at present, even with chemical methods, the incidence of the southern blight of Dendrobium officinale in greenhouse in winter is becoming more and more difficult to control. An apparent view of the southern blight in cultivating Dendrobium officinale in greenhouse caused by continuous haze days in winter is shown in FIG. 1.

The method of the present invention is suitable for cultivating Dendrobium officinale, especially the control of pests and diseases during the seedling-refining and cultivation, especially the prevention and treatment of diseases prone to high humidity, and more specifically, the method is suitable for the control of the southern blight of Dendrobium officinale, especially an effective method for the control of diseases in northern greenhouse in winter.

The beneficial technical effects of the present invention are: the present inventidiW504717 overcomes the shortcomings of the prior art, and focuses on the causes of disease occurrence, that 1s, starting from the environmental conditions of disease occurrence and the physiological state of the host, fundamentally eliminating the breeding conditions of pathogens and strengthening the environmental factors for healthy growth of Dendrobium officinale The method of the present invention is simple and easy to control, the cost in human and material resources is very low, the harm to the environment is also very small, and no harmful substances are introduced during the cultivation and pest control of

Dendrobium officinale Therefore, the quality of Dendrobium officinale is objectively improved. At the same time, the conditions of the method of the present invention are more favorable to the growth of Dendrobium officinale, which is conducive to the accumulation of carbon assimilation substances in photosynthesis. While effectively preventing and controlling diseases, especially the southern blight, it does not have negative impact on the development of Dendrobium officinale itself, and the growth of Dendrobium officinale is better, the tissue of pseudobulbs is fuller, and the content of active ingredients is higher, among which polysaccharide of Dendrobium officinale can be increased by 4.24 %.

According to the method of the present invention, the nutrient consumption of Dendrobium officinale in winter in northern greenhouse is reduced, the normal growth and development of the plant is improved, the quality of Dendrobium officinale is enhanced, and at the same time, the environment is not affected. Therefore, it has a better effect on the prevention and control of the southern blight of Dendrobium officinale in northern greenhouse in winter haze days.

Brief description of the drawings

FIG. 1 is an apparent view of a southern blight in cultivating Dendrobium officinale in greenhouse caused by continuous haze days in winter.

FIG. 2 is a field light source configuration diagram of using LED monochromatic red and blue lights to prevent and treat a southern blight in a continuous smog greenhouse in winter according to Example 1 of the present invention.

Detailed description

The following examples are used solely to illustrate rather than limiting the scope of the present invention.

Oryza sativa varieties Shengdao 808 (SD808), indica rice varieties Dualr, and Shiokari used in the following examples are standard varieties. Oryza sativa narrow-leaf mutant sd110 is from the Institute of Crop Science, Chinese Academy of Agricultural Sciences.

Example 1 An optimal cultivation condition control method

Time: winter in December, 2015, address: greenhouse of Beijing Forestry University LU504717

Ultra bright LED monochrome spectrum light with each light bead is 3 W.

The red light wavelength is 660 nm and the blue light wavelength is 450 nm.

The light source is arranged at a distance of 60 cm from the top end of the plant curtain of the plant.

The light intensity is 200 umolm-2s-1, photoperiod is 12 h/d, from 7:00 am to 19:00 pm, and the ratio of the red light to blue light is 1.82: 1=R/B.

The LED light is in rectangle, each light contains 141 light beads with 3 W, and red and blue beads are alternatively arranged.

Li-250A photometers produced by LICOR Company of USA are used to monitor the photon flux density.

The humidity is controlled: the air humidity is controlled at 55+2 %, the humidity of the pine bark substrate is controlled under 26 %. A week in a row.

Result: the prevention and treatment effects against the southern blight reach to 94%.

Calculation method: (The number of comparative infected plants - the number of treated infected plants)/ the number of comparative infected plants.

Example 2 An optimal cultivation condition control method

Time: winter in December, 2015, address: greenhouse of Beijing Forestry University

Ultra bright LED monochrome spectrum light with each light bead is 3 W.

The red light wavelength is 680nm and the blue light wavelength is 460nm.

The light source is arranged at a distance of 70cm from the top end of the plant curtain of the plants.

The light intensity is 180 umolm-2s-1, photoperiod is 13 h/d, from 7:00 am to 20:00 pm, and the ratio of the red light to blue light is 1.78: 1=R/B.

The LED light is in rectangle, each light contains 135 light beads with 3 W, and red and blue beads are alternatively arranged.

Li-250A photometers produced by LICOR Company of USA are used to monitor the photon flux density. The humidity is controlled: the air humidity is controlled at 54+2 %, the humidity of the pine bark substrate is controlled under 26 %. A week in a row.

Result: the prevention and treatment effects against the southern blight reach to 92 %.

Example 3 Effects of treating Dendrobium officinale in different cultivation conditions

T1, T2, T3, T4, T5 and T6 represent treatment methods under different environmenth}504717 conditions respectively, in which, T1 represents the method recorded in the Example 1 of the present invention;

T2 is the same as T1 except for replacing the LED light in T1 with a high-pressure sodium light of the same strength;

T3 represents that, in the cultivation process of the Dendrobium officinale, only LED lights (the parameter conditions are the same as the LED light illumination of Example 1) are used for illuminating, without other treatment;

T4 represents that, in the cultivation process of the Dendrobium officinale, only high pressure sodium lights (the light intensity and duration are the same as the LED light illumination of Example 1) are used for illuminating, without other treatment;

TS represents that, in the cultivation process of the Dendrobium officinale, only the substrate humidity is controlled under 26 % (the parameter conditions are the same as the substrate humidity controlling of Example 1), without other treatment; and

T6 represents that, in the cultivation process of the Dendrobium officinale, only the air humidity is controlled at 53 %-57 % (the parameter conditions are the same as the air humidity controlling of Example 1), without other treatment.

The effective components in stem segments of the Dendrobium officinale, including polysaccharide, mannose and crude fiber, are determined by the following methods:

The polysaccharide is determined by using a phenol-sulfuric acid method in Chinese

Pharmacopoeia (2015 Edition 1), polysaccharide contents of all kinds of stems are extracted and determined. The determination of each treatment is designed for 6 parallel tests.

The mannose is determined by using a high performance liquid chromatography method in Chinese Pharmacopoeia (2015 Edition 1), mannose contents of all kinds of stems are extracted and determined. The determination of each treatment is designed for 6 parallel tests.

Chromatographic conditions: C18 chromatographic column, octadecyl silane bonded silica gel is taken as a filler, acetonitrile (D)-0.02 mol/L of ammonium acetate solution (B) (20:80) as a mobile phase; gradient elution: 0-18min, 18.5- 20 % D; 18-35min, 20 % D; the detection wavelength is 250 nm, the column temperature is 30 DEG C, the flow rate is 1 mL/min, and the sample injection is 10 pL.

The crude fiber is determined by a national standard (GB/T 5009.10-2003) method for the determination of crude fiber in plant foods, and the crude fiber contents of various stems are extracted and determined. The determination of each treatment is designed for 6 parallel tests.

Six methods are adopted in the example to cultivate the Dendrobium officinale, and th&504717 2 treatment method is shown in Table 1. It can be seen from the Table 1, the treatment T1 has the best effect, the polysaccharide content of Dendrobium officinale stem is 30.41 %, which is 4.24 % higher than the average 26.17 %. It indicates that the treatment method of the

Example 1 of the present invention can effectively prevent and treat the southern blight of the Dendrobium officinale, and can improve the polysaccharide content of the Dendrobium officinale significantly.

Table 1 Contents of effective components in Dendrobium officinale stems under different environmental treatments

Number Polvsaccharide/95 Marnose/6 Crude fiber:% Treatment method x N LED light, control

Ti MARE asad SEHE substraie humidity and air humidity ™ IR Thad TRE ag $a gyda fight, control substrate

Fo MERS AEG AN itn ESS DAME NS x Ein à «Dé fav dity and air

TH 2109 rare lat aes IED bem

TE IRRRLI0 ALTE ARN High pressure sodium ight

TS 2630200 Eee AERAAES comsot a aides

SER SI ISATIE SELLES ses

Although the present invention has been described in detail by general description and specific embodiments above, on the basis of the present invention, some modifications or improvements of the present invention can be made, which is apparent to those skilled in the art. Therefore, those modifications or improvements made within the spirit of the present invention all belong to the scope of protection of the present invention.

Claims

CLAIMS LU504717

1. A method for cultivating Dendrobium officinale and preventing and controlling diseases of fungus, wherein adjusting and maintaining the following conditions: (1) in cultivating Dendrobium officinale, illuminating the top of plants by using an LED monochromatic spectral light during the whole day, so as to effectively control the number of photons received by Dendrobium officinale, and (2) regulating air humidity at the range of 50-60 %; and (3) regulating culture substrate humidity of Dendrobium officinale; and maintaining the above conditions for a certain time, so as to effectively prevent and treat the southern blight.

2. The method according to claim 1, wherein in the condition (1), the light source employs the LED monochromatic spectral light; each light bead is 2-5 W, a red light wavelength is 660+20 nm, and a blue light wavelength is 450+20 nm.

3. The method according to claim 1, wherein in the condition (1), the light source employs the LED monochromatic spectral light; each light bead is 3 W, a red light wavelength is 660 nm, and a blue light wavelength is 450 nm.

4. The method according to claim 1, wherein in the condition (1), the light source is arranged at a distance of 50-70 cm from a top end of a plant curtain of the plant.

5. The method according to claim 1, wherein in the condition (1), light intensity of the light source is 180-220 u molm-2s-1, and a photoperiod is 10-14 h/d.

6. The method according to claim 1, wherein in the condition (1), the number of the red and blue lights of the light source is 1.78-1.85:1.

7. The method according to claim 1, wherein in the condition (1), the LED light is in rectangle, each light contains 130-150 light beads with 2-5 W, and red and blue beads are alternatively arranged.

8. Any one of the methods according to claims 1-7, wherein in the condition (2), the air humidity is controlled at 52 %-59 %.

9. Any one of the methods according to claims 1-7, wherein in the condition (3), the substrate is a pine bark substrate, and the humidity is controlled under 26 %.

10. Application of any one of the methods in the prevention and control of Dendrobium officinale southern blight according to claims 1-9.