An epiphytic planting method for improving the content of polysaccharide in dendrobium candidum by tea-dendrobium candidum symbiosis

Abstract

The application discloses a kind of epiphytic planting methods for improving dendrobium candidum polysaccharide content by tea tree-dendrobium candidum symbiosis, and the present application takes tea tree as host, and dendrobium candidum seedling is epiphytic on the sunny side of tea tree trunk, and red and blue light LED light supplement lamp is erected above the canopy of tea tree, and the red and blue light ratio and light intensity are dynamically adjusted according to the growth stage of dendrobium candidum: red and blue 5:5 in planting recovery period, red and blue 6:4 in vegetative growth period, red and blue 7:3 in early polysaccharide accumulation period, and red and blue 8:2 in polysaccharide accumulation peak period; and drought pulse, temperature difference pulse and light intensity pulse are implemented simultaneously in polysaccharide accumulation period, and recovery period is set between each pulse. Through the synergistic induction of dynamic regulation of light quality and multiple stress pulses, the present application significantly improves the polysaccharide content of dendrobium candidum, and is simple to operate, and is suitable for large-scale planting of dendrobium candidum epiphytic on tea trees represented by Shiqian moss tea.

Description

Technical Field

[0001] This invention belongs to the field of Chinese medicinal herb cultivation technology, specifically relating to an epiphytic cultivation method that increases the polysaccharide content of Dendrobium officinale through symbiosis between tea trees and Dendrobium officinale. Background Technology

[0002] Dendrobium officinale is a traditional and precious Chinese medicinal herb, and polysaccharides are its main active ingredients. The symbiotic epiphytic cultivation model of tea tree and Dendrobium officinale, with tea tree as the host, can significantly increase the polysaccharide content of Dendrobium officinale compared to greenhouse cultivation.

[0003] The existing tea tree-Dendrobium officinale symbiotic cultivation technology mainly has the following problems:

[0004] Firstly, the increase in polysaccharide content relies on the natural improvement brought about by the symbiosis between Dendrobium and tea trees, and lacks proactive and precise induction and regulation methods.

[0005] Secondly, light management is mostly based on a fixed pattern and is not dynamically adjusted according to the physiological needs of Dendrobium at different growth stages.

[0006] Third, light quality regulation, drought stress, and temperature pulse are all independent measures, mostly implemented in facility cultivation or post-harvest treatment, and no multi-factor synergistic induction schemes have been found that are organically combined with the tea tree epiphytic system. Summary of the Invention

[0007] To address the aforementioned problems, this invention provides an epiphytic cultivation method for increasing the polysaccharide content of Dendrobium officinale through tea tree-Dendrobium officinale symbiosis. This method combines dynamic regulation of light quality in the tea tree canopy with synergistic induction by drought pulses, temperature difference pulses, and light intensity pulses. Through a four-stage temporal synergistic design, the method achieves a targeted and efficient increase in polysaccharide content.

[0008] The technical solution of this invention is as follows:

[0009] An epiphytic cultivation method for increasing the polysaccharide content of Dendrobium officinale through tea tree-Dendrobium officinale symbiosis includes the following steps:

[0010] (1) Tea garden selection and epiphyte preparation: Select tea trees with an age of 5 years or more and a trunk diameter of ≥15 cm as epiphytes. Set up epiphyte sites on the sunny side of the tea tree trunk within a height range of 20-50 cm from the ground. After the Dendrobium officinale seedlings that have been hardened and domesticated are wrapped around the roots with a water-retaining and breathable substrate, they are fixed to the epiphyte sites.

[0011] (2) Dynamic control of light quality in the tea tree canopy: Red and blue LED supplemental lights are installed above the tea tree canopy. The ratio of red to blue light and the light intensity are dynamically adjusted according to the growth stage of Dendrobium officinale.

[0012] During the post-planting recovery period: the ratio of red to blue light is 5:5, the light intensity is 800-1200 lx, and supplemental lighting is provided for 4 hours per day;

[0013] During the vegetative growth period: the ratio of red to blue light is 6:4, the light intensity is 1500-2000 lx, and supplemental light is provided for 6 hours daily;

[0014] Early stage of polysaccharide accumulation: Red light to blue light ratio of 7:3, light intensity of 2000-2500 lx, supplemental light for 8 hours per day;

[0015] Peak period of polysaccharide accumulation: red to blue light ratio of 8:2, light intensity of 1800-2200 lx, and 10 hours of supplemental light per day;

[0016] (3) Pulsed stress induction: During the polysaccharide accumulation period of Dendrobium officinale, drought pulse, temperature difference pulse and light intensity pulse were applied in sequence, with a recovery period set between each pulse;

[0017] (4) Harvesting: Harvest mature stems of Dendrobium officinale in mid-to-late November, 18 months after planting.

[0018] Furthermore, the water-retaining and breathable substrate mentioned in step (1) is a mixture of sphagnum moss and tea tree leaf humus, wherein the volume percentage of tea tree leaf humus is 8% to 12%.

[0019] Furthermore, according to the method described in claim 1, the red light wavelength of the red and blue LED supplementary light in step (2) is 655-665 nm and the blue light wavelength is 445-455 nm; the supplementary light period is in the early morning and evening, avoiding the strong light period at noon.

[0020] Furthermore, step (2) also includes the step of dynamically adjusting the light transmittance of natural light by pruning the branches of the tea tree canopy:

[0021] During the post-planting recovery period: the canopy light transmittance should be controlled at 25%–30%;

[0022] During the vegetative growth period: the canopy transmittance should be controlled at 30%–35%;

[0023] Polysaccharide accumulation period: Canopy transmittance is controlled at 40%–45%.

[0024] Furthermore, the specific plan for the drought pulse in step (3) is as follows: a pre-adaptation drought pulse is implemented in mid-August, irrigation is stopped for 3 to 4 days, the substrate moisture content is reduced to 45% to 50%, and recovery is carried out for 5 days; a drought pulse is implemented in early September, late September and mid-October, irrigation is stopped for 5 to 7 days in each round, the substrate moisture content is reduced to 30% to 40%, and recovery is carried out for 7 days after each round.

[0025] Furthermore, the specific scheme of the temperature difference pulse in step (3) is as follows: one round of temperature difference pulse is implemented in early October and one round in late October, each round lasting for 7 days, controlling the day-night temperature difference to be 10-13℃, and restoring for 7 days after each round ends; at night, the heat insulation curtain above the tea tree canopy is opened to promote radiative cooling.

[0026] Furthermore, the specific scheme of the light intensity pulse in step (3) is as follows: a light intensity pulse is implemented once each in early October, late October and early November, and the light intensity is increased to 3000-3500 lx each time. After 2 hours, it is gradually restored to the normal light intensity. The pulse interval is 15 days.

[0027] Furthermore, the pulsed stress induction described in step (3) is implemented in a coordinated manner according to the following timing sequence:

[0028] Phase 1: Planting and recovery period: No stress is applied; light quality regulation is used to promote seedling survival.

[0029] The second stage is the vegetative growth period: mainly based on light quality regulation, and a pre-adaptation drought pulse is introduced in mid-August.

[0030] The third stage, the early stage of polysaccharide accumulation: upgrade the light quality regulation to red-blue 7:3, and implement two rounds of drought pulses in September;

[0031] The fourth stage is the peak period of polysaccharide accumulation: upgrade the light quality regulation to red-blue 8:2, and simultaneously implement the third round of drought pulse, two rounds of temperature difference pulse and three rounds of light intensity pulse.

[0032] The advantages of this invention are:

[0033] This invention, based on the physiological needs of Dendrobium officinale at different growth stages, increases the red-blue light ratio from 5:5 during the transplanting recovery period to 8:2 during the peak polysaccharide accumulation period, thus upgrading light quality from a fixed pattern to dynamic adjustment on demand. Simultaneously, before formal stress induction, this invention implements a mild drought pre-adaptation pulse in mid-August, allowing the plants to establish a pre-adapted state before gradually increasing the stress intensity, effectively avoiding irreversible damage caused by a single excessive stress.

[0034] This invention organically combines four inducing factors—dynamic regulation of light quality, drought pulse, temperature difference pulse, and light intensity pulse—according to a precise timeline. In September, drought pulse is the main factor activating defense metabolism; in October, temperature difference pulse and light intensity pulse are introduced to synergistically enhance the effect; and in November, light intensity pulse is used to finish the stress. This achieves synergistic enhancement of multiple stresses rather than simple superposition.

[0035] This invention integrates light quality control with tea tree canopy pruning management, achieving complementarity through dynamic adjustment of light transmittance and artificial lighting, without increasing additional operating costs and facilitating large-scale promotion. Furthermore, this invention integrates a soil moisture sensor, temperature and humidity recorder, and timer controller, enabling precise and quantifiable management of stress-induced stress, ensuring the repeatability and stability of the technical solution. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the overall technical roadmap of the present invention;

[0037] Figure 2 This is a flowchart of the dynamic control of light quality in this invention.

[0038] Figure 3 This is a timing diagram of the pulsed stress-induced synergistic induction of the present invention. Detailed Implementation

[0039] The specific embodiments of the present invention will be further described below. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0040] like Figure 1-3 As shown:

[0041] Example 1

[0042] This embodiment implements the method of the present invention with Shiqian moss tea as the main ingredient.

[0043] 1. Test site and materials

[0044] Experimental site: A tea garden of Shiqian moss tea group in Wude Town, Shiqian County, Tongren City, Guizhou Province. The tea garden is located at an altitude of about 500m, with a high terrain, good ventilation, and convenient water source.

[0045] Accompanying tea trees: Twenty Shiqian moss tea trees, aged 18 years and with a trunk diameter of 18–25 cm, were selected. Shiqian moss tea is a shrub type, medium-leaf variety, and mesophytic, with a semi-open growth habit, dense branching, and strong stress resistance. Due to its high branching density and stable canopy structure, this variety is suitable for installing LED supplementary lighting above its canopy and maintaining uniform light distribution. Furthermore, its strong stress resistance allows it to maintain normal physiological metabolic levels during drought pulses and temperature difference pulses, avoiding excessive stress that could damage the tree. Therefore, it is particularly suitable as an accompanying tea tree for implementing the dynamic light quality regulation and pulsed stress synergistic induction scheme of this invention.

[0046] Seedlings: Select Dendrobium officinale tissue culture seedlings that have been hardened and domesticated, with a height of 5-7 cm, robust growth, dark green leaves, and well-developed root system.

[0047] 2. Epiphytic planting

[0048] Planting was carried out in mid-April. For each Shiqian moss tea tree, the southeast and southwest-facing sunny sides were selected as epiphytic sites within a height of 20-50 cm from the ground. Moss and dead bark were removed from the trunk surface. Three layers of epiphytic rings were created for each tea tree, with a spacing of 35 cm between the layers.

[0049] Mix sphagnum moss and composted humus from fallen leaves of Shiqian tea (treated by composting) at a volume ratio of 9:1 to create a water-retaining and breathable substrate. Wrap the roots of the Dendrobium officinale seedlings tightly against the trunk with the substrate and secure them to the trunk with biodegradable hemp rope. Plant 18 clumps per epiphytic ring, with 3-5 plants per clump and a spacing of 9cm between clumps.

[0050] 3. Dynamic regulation of light quality in tea tree canopy

[0051] Two red and blue LED plant grow lights (red light wavelength 660nm, blue light wavelength 450nm) are installed 1.0 m above the canopy of each Shiqian moss tea tree, with two lights installed per tea tree.

[0052] Supplemental lighting should be provided in the early morning and late afternoon, avoiding the midday sun. Specifically: during the transplant recovery period, 6:00-8:00 AM; during the vegetative growth period, 5:30-8:30 AM and 5:00-8:00 PM; during the early polysaccharide accumulation period, 5:00-9:00 AM and 4:30-8:30 PM; and during the peak polysaccharide accumulation period, 5:00-10:00 AM and 4:00-9:00 PM.

[0053] Dynamic light quality control was implemented according to the following plan: During the post-planting recovery period (April to July), the red-blue light ratio was 5:5, the light intensity was 1000 lx, and supplemental lighting was provided for 4 hours daily; during the vegetative growth period (August), the red-blue light ratio was 6:4, the light intensity was 1800 lx, and supplemental lighting was provided for 6 hours daily; during the early polysaccharide accumulation period (September), the red-blue light ratio was 7:3, the light intensity was 2200 lx, and supplemental lighting was provided for 8 hours daily; during the peak polysaccharide accumulation period (October to November), the red-blue light ratio was 8:2, the light intensity was 2000 lx, and supplemental lighting was provided for 10 hours daily.

[0054] Regarding the dynamic adjustment of the canopy light transmittance of tea trees, the natural light transmittance was dynamically adjusted by pruning the canopy branches of the *Tea japonica* 'Shiqianmo' and combining it with artificial lighting. During the post-planting recovery period (April to July), only dead and diseased branches were pruned, and the canopy light transmittance was controlled at 28%. During the vegetative growth period (August), excessively dense branches in the inner canopy were moderately pruned, and the light transmittance was controlled at 33%. During the polysaccharide accumulation period (September to November), pruning was intensified, and some outer branches were thinned out, and the light transmittance was controlled at 42%. The above pruning measures, combined with red and blue light supplementation, provided the epiphytic *Dendrobium* with the optimal light environment.

[0055] 4. Pulsed stress synergistic induction

[0056] The dynamic regulation of light quality and pulsed stress induction will be implemented in a coordinated manner in the following four stages.

[0057] The first stage is the transplanting and recovery period (April to July), which focuses on light quality regulation (red to blue 5:5, 1000 lx, 4 hours / day), without applying any stress, to promote seedling rooting and survival.

[0058] The second stage is the vegetative growth period (August), which is mainly based on light quality regulation (red to blue 6:4, 1800 lx, 6 hours / day), and a pre-adaptation drought pulse is introduced in mid-August.

[0059] The third stage is the early stage of polysaccharide accumulation (September). The light quality regulation is upgraded to red-blue 7:3, light intensity 2200 lx, and supplemental light for 8 hours per day. At the same time, a drought pulse is implemented in early September and late September.

[0060] The fourth stage is the peak period of polysaccharide accumulation (October to November). The light quality regulation is upgraded to red-blue 8:2, light intensity 2000 lx, and 10 hours of supplemental lighting per day. At the same time, the third round of drought pulse, two rounds of temperature difference pulse and three rounds of light intensity pulse are implemented.

[0061] The specific parameters of the stress pulse at each stage are as follows.

[0062] (1) Drought pulse

[0063] From August 15th to 18th, a pre-adaptation pulse was implemented, irrigation was stopped for 4 days, the substrate moisture content dropped to 48%, and it took 5 days to recover.

[0064] The first round of pulse irrigation was implemented from September 5th to 10th, with irrigation suspended for 6 days. The substrate moisture content dropped to 38%, and it took 7 days to recover.

[0065] The second round of pulse irrigation was implemented from September 22 to 27, with irrigation suspended for 6 days. The substrate moisture content dropped to 37%, and it took 7 days to recover.

[0066] The third round of pulse irrigation was implemented from October 12 to 18, with irrigation stopped for 7 days. The substrate moisture content dropped to 32%, and harvesting resumed.

[0067] The substrate moisture content was monitored in real time using a TDR soil moisture sensor. Watering was resumed via spraying; the amount of water sprayed on the first day was 50% of normal, and the amount returned to normal on the second day.

[0068] (2) Temperature difference pulse

[0069] The first round of temperature difference pulse will be implemented from October 1st to 7th, with daytime temperatures of 26-28℃ and nighttime temperatures of 13-15℃, a temperature difference of 12-13℃, lasting for 7 days, followed by 7 days of recovery.

[0070] The second round of temperature difference pulse will be implemented from October 22 to 28, with daytime temperatures of 26-28℃ and nighttime temperatures of 13-15℃, a temperature difference of 12-13℃, lasting for 7 days.

[0071] At night (7:00 PM to 6:00 AM the next day), the heat-insulating curtain above the canopy of the Shiqian moss tea tree is uncovered to promote radiative cooling. Temperature and humidity recorders are set up in the epiphytic area to record the temperature every hour.

[0072] (3) Light intensity pulse

[0073] The first light intensity pulse was implemented on October 9th, increasing the light intensity to 3200 lx and lasting for 2 hours (6:00-8:00).

[0074] The second light intensity pulse was implemented on October 24, increasing the light intensity to 3200 lx and lasting for 2 hours (6:00-8:00).

[0075] The third light intensity pulse was implemented on November 8th, increasing the light intensity to 3200 lx and lasting for 2 hours (6:00-8:00).

[0076] The light intensity gradually returns to normal within 30 minutes after each pulse ends.

[0077] 5. Field Management

[0078] In terms of water management, except during drought pulse periods, a micro-spraying system is used to spray water once in the morning and once in the evening for 8 minutes each time, maintaining a relative humidity of 80% to 90%.

[0079] In terms of nutrient management, apply 2.5 g of well-rotted sheep manure per clump at the time of planting; spray with Flower More Nutrient Solution diluted 3000 times every 15 days during the vegetative growth period; stop fertilizing during the polysaccharide accumulation period (September to November).

[0080] In terms of pest and disease control, insect traps containing sex hormones are set up (one trap per 30 m²); polyoxin, amino oligosaccharides, etc. are sprayed to prevent diseases, and chemically synthesized pesticides are not used.

[0081] 6. Harvesting and Testing

[0082] Harvesting should be carried out 18 months after transplanting (November 20th of the following year). Select mature stems that have grown for more than 2 years (stems that are plump, yellowish-green in color, and with full internodes), and cut them off from the 2nd to 3rd node at the base of the stem with scissors sterilized with 75% alcohol.

[0083] After harvesting, the fresh Dendrobium officinale stems were washed, dried (at 55℃), and pulverized. The polysaccharide content was determined using the phenol-sulfuric acid method. Specifically, the dried powdered sample was refluxed with ethanol to remove free sugars, and then polysaccharides were extracted with pure water. The absorbance was measured at 490 nm, and quantification was performed using the external standard method.

[0084] 7. Results

[0085] Testing revealed that the polysaccharide content of the Dendrobium officinale stems harvested in this embodiment was 42.3%. As a control, Dendrobium officinale grown in the same Shiqian tea garden using a conventional tea-Dendrobium officinale symbiotic method (without dynamic light quality control or pulsed stress induction) had a polysaccharide content of 28.6% at the same time of harvest. This embodiment showed a 47.9% increase in polysaccharide content compared to the control.

[0086] Example 2

[0087] The difference between this embodiment and Embodiment 1 is that the main tea tree variety is Fuding Da Bai Cha, while the other conditions are the same.

[0088] The experiment was conducted in a Fuding Da Bai tea garden in Wude Town, Shiqian County, Tongren City, Guizhou Province. Twenty Fuding Da Bai tea trees, each 18 years old and with a trunk diameter of 18–25 cm, were selected as the main tea trees.

[0089] The methods for planting, dynamic regulation of light quality, pulsed stress induction, field management, and harvest testing are the same as in Example 1.

[0090] Testing revealed that the polysaccharide content of the Dendrobium officinale stems harvested in this embodiment was 39.8%. The control group (using a conventional tea tree-Dendrobium officinale symbiotic relationship) had a polysaccharide content of 27.1%, representing a 46.9% increase in polysaccharide content compared to the control.

[0091] Example 3

[0092] The difference between this embodiment and Embodiment 1 is that the temperature difference pulse was not implemented, while the other conditions are the same.

[0093] The experimental site, the main tea tree (Shiqian moss tea), the planting method, the dynamic control scheme for light quality, the drought pulse scheme, and the light intensity pulse scheme were all the same as in Example 1, but the temperature difference pulse was not implemented.

[0094] Testing revealed that the polysaccharide content of the Dendrobium officinale stems harvested in this embodiment was 38.5%. The control group (conventional tea tree-Dendrobium officinale symbiosis) had a polysaccharide content of 28.6%, indicating a 34.6% increase in polysaccharide content compared to the control. This result is lower than that of Example 1 (42.3%), suggesting that temperature difference pulses, drought pulses, and light intensity pulses have a synergistic effect, and the combined implementation of all three has a better polysaccharide-enhancing effect than implementing only drought pulses and light intensity pulses.

[0095] Example 4

[0096] The difference between this embodiment and Embodiment 1 is that the drought pulse does not have a pre-adaptation phase, while the other conditions are the same.

[0097] The experimental site, the main tea tree (Shiqian moss tea), the planting method, the dynamic control scheme for light quality, the temperature difference pulse scheme, and the light intensity pulse scheme were all the same as in Example 1, but the drought pulse did not have a pre-adaptation stage (the pre-adaptation pulse was not implemented in mid-August, and the first round of drought pulse was implemented directly in early September).

[0098] Testing revealed that the polysaccharide content of the Dendrobium officinale stems harvested in this embodiment was 40.1%, while the polysaccharide content of the control (conventional tea tree-Dendrobium officinale symbiosis) was 28.6%, representing a 40.2% increase in this embodiment compared to the control. This result is lower than that of Example 1 (42.3%), but higher than that of Example 3 (38.5%), which did not undergo temperature pulse adjustment, indicating that pre-adaptation drought pulse adjustment helps to increase the final polysaccharide content.

[0099] Comparative Example 1

[0100] This comparative example uses a fixed light quality ratio (red:blue 8:2) without dynamic adjustment, and the other conditions are the same as in Example 1.

[0101] The experimental site, the main tea tree (Shiqian moss tea), the planting method, the pulsed stress induction scheme (drought pulse, temperature difference pulse, light intensity pulse), the field management and harvesting detection methods were all the same as in Example 1. However, the light quality control adopted a fixed red-blue ratio of 8:2 and did not dynamically adjust it with the growth stage. The light intensity was fixed at 2000 lx.

[0102] The test results showed that the polysaccharide content of the Dendrobium officinale stems harvested in this comparative example was 36.2%, which was lower than that in Example 1 (42.3%), indicating that dynamic regulation of light quality has a significant promoting effect on polysaccharide accumulation.

[0103] Comparative Example 2

[0104] This comparative example does not involve any stress induction, but only dynamic regulation of light quality, with the remaining conditions being the same as in Example 1.

[0105] The experimental site, the main tea tree (Shiqian moss tea), the planting method, the light quality dynamic control scheme, the field management and harvesting detection methods were all the same as in Example 1, but drought pulse, temperature difference pulse and light intensity pulse were not implemented.

[0106] The polysaccharide content of the Dendrobium officinale stems harvested in this comparative example was 34.8%, which was lower than that in Example 1 (42.3%). This indicates that pulsed stress induction has a significant promoting effect on polysaccharide accumulation, and the synergistic effect of light quality regulation and stress induction is better than that of light quality regulation alone.

[0107] This invention provides a simple, low-cost, and highly reproducible method suitable for the large-scale cultivation of Dendrobium officinale epiphytes on tea trees, exemplified by Shiqian moss tea. The polysaccharide content of Dendrobium officinale cultivated using this method is significantly higher than that of conventional tea-Dendrobium officinale symbiotic cultivation methods, demonstrating good economic value and application prospects. This invention can be promoted and applied in suitable tea-growing areas of Shiqian moss tea, such as Tongren City, Zunyi City, Guiyang City, Anshun City, Qiannan Prefecture, and Qiandongnan Prefecture in Guizhou Province, as well as other tea-growing regions.

[0108] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. An epiphytic cultivation method for increasing the polysaccharide content of Dendrobium officinale through tea tree-Dendrobium officinale symbiosis, characterized in that, Includes the following steps: (1) Tea garden selection and epiphyte preparation: Select tea trees with an age of 5 years or more and a trunk diameter of ≥15 cm as epiphytes. Set up epiphyte sites on the sunny side of the tea tree trunk within a height range of 20-50 cm from the ground. After the Dendrobium officinale seedlings that have been hardened and domesticated are wrapped around the roots with a water-retaining and breathable substrate, they are fixed to the epiphyte sites. (2) Dynamic control of light quality in the tea tree canopy: Red and blue LED supplemental lights are installed above the tea tree canopy. The ratio of red to blue light and the light intensity are dynamically adjusted according to the growth stage of Dendrobium officinale. During the transplanting and recovery period: the ratio of red to blue light is 5:5, the light intensity is 800-1200 lx, and supplemental lighting is provided for 4 hours per day; During the vegetative growth period: the ratio of red to blue light is 6:4, the light intensity is 1500-2000 lx, and supplemental light is provided for 6 hours per day; Early stage of polysaccharide accumulation: Red light to blue light ratio of 7:3, light intensity of 2000-2500 lx, supplemental light for 8 hours per day; Peak period of polysaccharide accumulation: red to blue light ratio of 8:2, light intensity of 1800-2200 lx, and 10 hours of supplemental light per day; (3) Pulsed stress induction: During the polysaccharide accumulation period of Dendrobium officinale, drought pulse, temperature difference pulse and light intensity pulse were applied in sequence, with a recovery period set between each pulse; (4) Harvesting: Harvest mature stems of Dendrobium officinale in mid-to-late November, 18 months after planting.

2. The epiphytic cultivation method for increasing the polysaccharide content of Dendrobium officinale through tea tree-Dendrobium officinale symbiosis according to claim 2, characterized in that: The water-retaining and breathable substrate mentioned in step (1) is a mixture of sphagnum moss and tea tree leaf humus, wherein the volume percentage of tea tree leaf humus is 8% to 12%.

3. The epiphytic cultivation method for increasing the polysaccharide content of Dendrobium officinale through tea tree-Dendrobium officinale symbiosis according to claim 1, characterized in that: According to the method described in claim 1, the red light wavelength of the red and blue LED supplementary light in step (2) is 655-665 nm and the blue light wavelength is 445-455 nm; the supplementary light period is in the early morning and evening, avoiding the strong light period at noon.

4. The epiphytic cultivation method for increasing the polysaccharide content of Dendrobium officinale through tea tree-Dendrobium officinale symbiosis according to claim 1, characterized in that: Step (2) also includes the step of dynamically adjusting the light transmittance of natural light by pruning the branches of the tea tree canopy: During the post-planting recovery period: the canopy light transmittance should be controlled at 25%–30%; During the vegetative growth period: the canopy transmittance should be controlled at 30%–35%; Polysaccharide accumulation period: Canopy transmittance is controlled at 40%–45%.

5. The epiphytic cultivation method for increasing the polysaccharide content of Dendrobium officinale through tea tree-Dendrobium officinale symbiosis according to claim 1, characterized in that: The specific plan for the drought pulse in step (3) is as follows: In mid-August, a pre-adaptation drought pulse is implemented, irrigation is stopped for 3 to 4 days to reduce the substrate moisture content to 45% to 50%, and then it is restored for 5 days; in early September, late September and mid-October, a drought pulse is implemented, irrigation is stopped for 5 to 7 days in each round to reduce the substrate moisture content to 30% to 40%, and then it is restored for 7 days after each round.

6. The epiphytic cultivation method for increasing the polysaccharide content of Dendrobium officinale through tea tree-Dendrobium officinale symbiosis according to claim 1, characterized in that, The specific scheme of the temperature difference pulse in step (3) is as follows: one round of temperature difference pulse is implemented in early October and one round in late October, each round lasts for 7 days, and the day-night temperature difference is controlled at 10-13℃. After each round, it is restored for 7 days. At night, the heat insulation curtain above the tea tree canopy is opened to promote radiative cooling.

7. The epiphytic cultivation method for increasing the polysaccharide content of Dendrobium officinale through tea tree-Dendrobium officinale symbiosis according to claim 1, characterized in that, The specific scheme of the light intensity pulse in step (3) is as follows: a light intensity pulse is implemented once in early October, late October and early November, and the light intensity is increased to 3000-3500 lx each time. After 2 hours, it is gradually restored to the normal light intensity. The pulse interval is 15 days.

8. The epiphytic cultivation method for increasing the polysaccharide content of Dendrobium officinale through tea tree-Dendrobium officinale symbiosis according to claim 1, characterized in that, The pulsed stress induction described in step (3) is implemented in a coordinated manner according to the following timing sequence: Phase 1: Planting and recovery period: No stress is applied; light quality regulation is used to promote seedling survival. The second stage is the vegetative growth period: mainly based on light quality regulation, and a pre-adaptation drought pulse is introduced in mid-August. The third stage, the early stage of polysaccharide accumulation: upgrade the light quality regulation to red-blue 7:3, and implement two rounds of drought pulses in September; The fourth stage is the peak period of polysaccharide accumulation: upgrade the light quality regulation to red-blue 8:2, and simultaneously implement the third round of drought pulse, two rounds of temperature difference pulse and three rounds of light intensity pulse.

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