Method for regulating ornamental period and quality of leaf color of populus simonii × populus nigra var. italica

Abstract

The application provides a method for prolonging the ornamental period and quality of the leaf color of a medium red poplar tree, relates to the technical field of garden plant cultivation environment control, and comprises the following steps: providing a medium red poplar seedling; planting the medium red poplar seedling; building an environment monitoring control system; light intensity, light quality, temperature difference and soil regulation. The application creates a growth environment that can significantly prolong the leaf coloring period of'medium red poplar' and stabilize the color of the leaves, achieves very significant effects, and provides strong technical support for prolonging the ornamental period of the leaf color and improving the ornamental quality of other spring leaf tree species in a three-dimensional space habitat.

Description

Technical Field

[0001] This application relates to the field of environmental control technology for the cultivation of garden plants, and in particular to methods for regulating the period of leaf color viewing and quality of red poplar, a species of tree with spring-colored foliage. Background Technology

[0002] 'Zhonghongyang', a red-leaved bud mutation of the American black poplar '2025', fills a gap in my country's breeding of colorful-leaved poplars for timber, and is a rare colorful-leaved tree species with extremely high ornamental and economic value. As the first generation of red-leaved poplar varieties, 'Zhonghongyang' is an important foundation for the subsequent breeding and research of a series of colorful-leaved poplar varieties, and has a significant advantage in rapid growth compared to other colorful-leaved poplar varieties. 'Zhonghongyang' is a typical spring-colored foliage tree species, and its leaf color is easily affected by environmental factors and internal physiological metabolism.

[0003] The environmental requirements of 'Zhonghong Poplar' vary at different stages of its growth. Related technologies often employ simple or singular management methods, requiring system administrators to frequently adjust controller settings. The timing and measures for controlling light, temperature, or nutrient application are arbitrary and often rely on manual experience. This prevents the timely formation of a precise, close, and systematic environmental control system based on the dynamic changes in plant growth, resulting in a lack of dynamic synergy between environmental parameters and plant physiology. Consequently, the spring leaf change process of 'Zhonghong Poplar' is rapid. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a method for extending the viewing period and quality of the spring-flowering foliage of *Populus cerasifera*, thereby solving the problem of rapid leaf color change in submerged *Populus cerasifera* in existing technologies. The technical solution adopted by this application to solve the above-mentioned technical problem is as follows:

[0005] The embodiments of the present invention provide a method for extending the ornamental period and quality of the leaves of the red poplar tree species with spring-colored foliage, including the following steps:

[0006] S01. Provide seedlings of Chinese poplar;

[0007] S02. Planting Chinese poplar seedlings;

[0008] S03. Establish an environmental monitoring and control system;

[0009] SO4, light intensity, light quality, temperature difference and soil regulation.

[0010] In some embodiments, robust, pest-free two-year-old Populus tomentosa seedlings are provided; and / or

[0011] The seedlings of Populus tomentosa are 2.0 m to 2.5 m tall; and / or

[0012] The planting quantity of Chinese red poplar seedlings is 20 to 30 trees, with a spacing of 2.5m to 3m between trees.

[0013] In some embodiments, the method for establishing an environmental monitoring and control system includes:

[0014] S031. In the intelligent greenhouse, the controller component is installed on the wall by wall mounting;

[0015] S032. Install the data acquisition unit;

[0016] S033, Install execution unit.

[0017] In some embodiments, the data acquisition unit includes a multispectral sensor, an ambient temperature and humidity sensor, and a comprehensive soil sensor; and / or

[0018] The execution unit is connected to the controller component; and / or

[0019] The execution unit includes a spectral LED array, which comprises tunable spectral LEDs and fixed spectral LEDs, wherein the ratio of the number of tunable spectral LEDs to the number of fixed spectral LEDs is 2:1 to 3:1; and / or

[0020] The execution unit includes a gradient temperature control device, which includes a heating component, a cooling component, a humidifying component, and a temperature and humidity control component.

[0021] In some embodiments, the number of the multispectral sensor, the ambient temperature and humidity sensor, and the integrated soil sensor is the same as the number of microcontrollers in the controller assembly, and the multispectral sensor, the ambient temperature and humidity sensor, and the integrated soil sensor are each connected to a corresponding microcontroller; and / or

[0022] The heating element includes an electric heating film, which is laid 15cm to 20cm below the soil; and / or

[0023] The cooling components include an air-cooled system located at the top of the planting area of ​​Populus tomentosa, with 1-2 air-cooled systems configured per 100 m² of space; and / or

[0024] The humidification components include a high-pressure micro-mist system, positioned at a distance of 0.5m to 0.8m from the canopy of the Chinese poplar; and / or

[0025] Temperature and humidity control components include skylight wet curtains and ventilation fans, with 10-15 m² of skylight wet curtains and 1 ventilation fan configured per 100 m².

[0026] In some embodiments, the multispectral sensor is installed at a height of 0.8m to 1.2m above the seedlings; and / or

[0027] Install one ambient temperature and humidity sensor every 10m 2 ~15m 2 ; and / or

[0028] The number of integrated soil sensors is 3 to 4; and / or

[0029] The spectral LED array is installed at a height of 0.5m to 0.8m above the canopy of the poplar.

[0030] In some embodiments, within the intelligent greenhouse, on cloudy days, when the light intensity is below 600 μmol / (m²·s) in the morning or evening, the light intensity is increased to 600 μmol / (m²·s)~800 μmol / (m²·s) using adjustable-spectrum LED supplemental lighting; and / or

[0031] The second supplementary light source, using an adjustable spectrum LED, achieves a blue light (450 nm) to red light (660 nm) ratio of 1.5:1, with daily illumination for 5 to 7 hours, for example, 5 hours, 5.5 hours, 6 hours, 6.5 hours, or 7 hours.

[0032] In some embodiments, the first supplemental lighting time is 7:00-9:00 AM and 5:00-6:30 PM, for 2.5-4.5 hours per day; and / or

[0033] The second supplemental lighting time is from 8:00 to 11:00 in the morning and from 15:00 to 18:00 in the afternoon, for 5 to 7 hours each day.

[0034] In some embodiments, by adjusting the power of the electric heating film and the airflow of the air-cooling system, the ambient temperature in the lower layer of the Populus tomentosa growing space, 0.5m to 1m above the soil surface, is maintained at 25℃ to 28℃; and / or

[0035] By adjusting the power of the electric heating film and the airflow of the air-cooling system, the ambient temperature during the day is maintained at 24℃~27℃; and / or

[0036] Maintain the ambient temperature at 15°C for 1 to 2 hours between 3 and 4 AM; and / or

[0037] Maintain humidity between 60% and 80% during the day and between 35% and 45% at night.

[0038] In some embodiments, the soil temperature in the Populus tomentosa planting area is 15°C to 30°C; and / or

[0039] The soil moisture content in the planting area of ​​Populus tomentosa is 12%~24%; and / or

[0040] The soil pH in the Populus tomentosa planting area is 6.5-7; and / or

[0041] The soil calcium content in the poplar planting area is 600 mg / kg ~ 900 mg / kg; and / or

[0042] The soil exchangeable magnesium content in the Populus tomentosa planting area is 90 mg / kg ~ 120 mg / kg; and / or

[0043] The soil phosphorus content in the Populus tomentosa planting area is 15 mg / kg ~ 30 mg / kg; and / or

[0044] The soil potassium content in the poplar planting area is 50 mg / kg to 70 mg / kg.

[0045] Compared with the prior art, the beneficial effects of the present invention are:

[0046] This application provides a dynamic coupling method for controlling the "light quality-light intensity-temperature difference-humidity" of the fast-growing, tall, colorful-leaved poplar 'Zhonghong''. By balancing the quantity and quality of vertical temperature difference and pulsed humidity in key growth environment factors affecting the leaf coloration of 'Zhonghong' (temperature difference, light intensity, light quality, soil nutrients, pH value, etc.), a natural diurnal rhythm is simulated in a three-dimensional space, creating a growth environment that significantly prolongs the leaf coloring period and stabilizes the leaf color, achieving remarkable results. This provides strong technical support for other spring-colored foliage tree species to extend their leaf color viewing period and improve their ornamental quality in a three-dimensional habitat.

[0047] This application establishes a user-friendly and intelligent environmental monitoring platform within the monitoring system, combining human design and planning with the system's intelligent data processing. Once monitored data exceeds preset thresholds, the system automatically triggers corresponding control measures, such as activating supplemental lighting, fan cooling, heating, or water spraying. Through real-time sensor feedback, it achieves full automation of "monitoring-analysis-execution," successfully controlling complex plants with specific regulatory needs, such as the spring-flowering foliage plant 'Chinese Red Poplar,' to regulate the leaf color viewing period and quality. Furthermore, in practice, it can further develop a mature monitoring program by combining manual operational experience memory with computer-automated learning and memory. Administrators can also optimize and modify the established monitoring strategies.

[0048] The leaf viewing period of the 'Zhonghong Yang' variety under the controlled treatment was extended by more than 30 days compared to the control (plants grown under normal conditions). While the leaves of the control plants had already turned green after May 13th, the anthocyanin content and chlorophyll content of the controlled plants were 195.80% higher than those of the control plants on May 28th. The anthocyanin / chlorophyll ratio was relatively stable, resulting in a better red leaf effect. By June 13th, the anthocyanin content and anthocyanin / chlorophyll ratio of the controlled plants were comparable to those of the control plants on May 13th, showing a clear greening phenomenon.

[0049] Under the controlled conditions described in this application, the red hue a* value of the leaves of 'Zhonghongyang' was consistently higher than that of the control, while the yellow hue b* value was relatively lower. After May 13th, the red hue a* value was significantly higher than that of the control group, and on June 13th, it was 188.74% higher than that of the control group. This invention significantly enhances the red color of 'Zhonghongyang' leaves. When the leaves of 'Zhonghongyang' turn green again under natural conditions in May and June, the red a* value of the leaves under the controlled conditions described in this application remains at a high level, and the red color of the leaves is more intense than that of the control. The viewing time and quality are significantly extended and improved compared to the control.

[0050] This application achieves a method of intelligently and scientifically adjusting environmental factors to influence and mobilize the activities of key catalytic enzymes in the anthocyanin synthesis pathway of 'Zhonghong Yang' leaves: phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS), and anthocyanin synthase (ANS), providing sufficient energy and material basis for the synthesis of more anthocyanins. This significantly increases the anthocyanin content and anthocyanin / chlorophyll ratio in leaves, maintains a high a* value for red hue, extends the red leaf period by more than 30 days compared to the control, and significantly improves the ornamental quality of the leaves.

[0051] This application effectively overcomes the shortcomings of traditional greenhouses in real-time environmental data monitoring and control, providing a suitable environment for maintaining and prolonging leaf color without affecting the growth of spring-flowering plants. The method not only enhances the intelligence level of greenhouses but also solves the problem of seasonal plant growth by scientifically controlling the internal environment, significantly improving the efficiency and quality of forestry production. In addition to landscaping, the method supports modular expansion, making it suitable for different climatic regions, such as the high-humidity environment of the south and the dry environment of the north. It can be extended to high-end seedling export bases and urban vertical greening projects, enabling the transplantation of southern trees to the north and northern trees to the south in specific environments, creating exotic plant landscapes. Attached Figure Description

[0052] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of this application and are not intended to limit this application, wherein:

[0053] Figure 1 This is a flowchart of the method for extending the viewing period and quality of the leaves of the red poplar tree species in spring-flowering season, as described in this application. Detailed Implementation

[0054] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Furthermore, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application.

[0055] In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower states of the device in actual use or operation; in addition, in the description of this application, the term "comprising" means "including but not limited to".

[0056] In this application, "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural.

[0057] In this application, "at least one" means one or more, and "more than one" means two or more. "One or more", "at least one of the following", or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0058] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0059] Please see Figure 1 In a first aspect, embodiments of the present invention provide a method for extending the ornamental period and quality of the leaves of the red poplar tree species with spring-blooming foliage, comprising the following steps:

[0060] S01. Provide seedlings of Chinese poplar;

[0061] S02. Planting Chinese poplar seedlings;

[0062] S03. Establish an environmental monitoring and control system;

[0063] SO4, light intensity, light quality, temperature difference and soil regulation.

[0064] In S01:

[0065] In some embodiments, robust, disease- and pest-free two-year-old Chinese poplar seedlings are provided.

[0066] In some embodiments, the height of the Populus tomentosa seedlings is 2.0 m to 2.5 m, for example, 2.0 m, 2.1 m, 2.2 m, 2.3 m, 2.4 m, 2.5 m, etc.

[0067] In S02:

[0068] In some embodiments, the number of Populus tomentosa seedlings planted is 20 to 30, for example, 20, 22, 25, 26, 28, or 30 seedlings.

[0069] The spacing between plants and rows is 2.5m to 3m, for example, 2.5m, 2.6m, 2.7m, 2.8m, 2.9m, 3m, etc.

[0070] For example, the number of Chinese red poplar seedlings planted is 25, with a spacing of 3m between plants and rows.

[0071] In S03:

[0072] In some embodiments, the method for establishing an environmental monitoring and control system includes:

[0073] S031. In the intelligent greenhouse, the controller component is installed on the wall by wall mounting;

[0074] S032. Install the data acquisition unit;

[0075] S033, Install execution unit.

[0076] In S031:

[0077] It is understandable that the number of controller components is the same as the number of sensors.

[0078] In S032:

[0079] In some embodiments, the data acquisition unit includes a multispectral sensor, an ambient temperature and humidity sensor, and a comprehensive soil sensor.

[0080] Furthermore, the number of the multispectral sensor, the ambient temperature and humidity sensor, and the integrated soil sensor is the same as the number of microcontrollers in the controller assembly, and the multispectral sensor, the ambient temperature and humidity sensor, and the integrated soil sensor are respectively connected to their corresponding microcontrollers.

[0081] Furthermore, the installation height of the multispectral sensor is 0.8m to 1.2m above the seedlings, for example, it can be 0.8m, 0.85m, 0.9m, 0.95m, 1m, 1.5m, 1.8m, 2m, etc.

[0082] For example, the multispectral sensors are mounted on a height-adjustable bracket to ensure sufficient light reception, and their height is adjusted as the seedlings grow; the number of multispectral sensors installed is 180-200 m per plane in the three-dimensional space. 2 One multispectral sensor is installed inside, with an interval of 13 m to 14 m.

[0083] It is understandable that when installing a multispectral sensor, it is best to keep it as far away from the light source as possible and choose a location that can receive light evenly throughout the entire measurement area. This avoids the significant impact on the received data due to being too close to the light source or being directly exposed to it, thus ensuring the accuracy of the measurement results. The sensor should be installed horizontally to the ground plane, so that the photosensitive position is directly above the poplar seedlings, allowing for all-day spatial light measurement.

[0084] For example, the multispectral sensor is set with a wavelength range of 350-800nm ​​and a light intensity range of 10-2000µmol / m²•s. It is understood that IP65 dust and water resistance is provided to ensure the long-term accurate and stable operation of the sensor and to guarantee reliable feedback control.

[0085] Furthermore, one ambient temperature and humidity sensor is installed every 10m. 2 ~15m 2 For example, it can be 10m 2 11m 2 12m 2 13m 2 14m 2 15m 2 wait.

[0086] For example, the temperature and humidity sensor is fixed by a lifting bracket. The temperature range of the ambient temperature and humidity sensor is 10℃~70℃ with an accuracy of ±0.5℃; the humidity range is 0-100%RH with an accuracy of ±3.0%RH; and it adopts IP65 dustproof and waterproof rating.

[0087] It is understandable that the ambient temperature and humidity sensors are evenly distributed in the center and around the planting area of ​​Populus tomentosa seedlings, and are fixed by lifting brackets to ensure that the equipment is stable and does not shake, and the height is kept at the middle of the Populus tomentosa canopy being observed, and the height is adjusted as the Populus tomentosa grows taller.

[0088] Furthermore, the number of integrated soil sensors is 3 to 4, located in the center and around the perimeter of the Populus tomentosa seedling planting area, with an installation spacing of 3m to 4m, for example, 3m, 3.2m, 3.3m, 3.5m, 3.6m, 3.8m, or 4m; and an installation depth of 20cm to 30cm, for example, 20cm, 22cm, 25cm, 26cm, 28cm, or 30cm.

[0089] For example, the temperature range is 0~80℃ with an accuracy of ±0.2℃; the humidity range is 0~24%; and the pH range is 5~8.5.

[0090] It is understandable that the installation location of each integrated soil temperature sensor can represent the soil condition at the center of the area to be measured or in different directions. This avoids placing the integrated soil temperature sensor at the edge of the three-dimensional environment or in a location that is greatly affected by external interference, so as to ensure that the measurement results can accurately reflect the overall soil condition in the observation area of ​​Populus tomentosa, and comprehensively and in real time monitor the temperature, moisture, pH value evolution and improvement dynamic changes of the soil for plant growth.

[0091] In S033:

[0092] In some embodiments, the execution unit is connected to the controller component.

[0093] In some embodiments, the execution unit includes a spectral LED array, which includes tunable spectral LEDs and fixed spectral LEDs, with the ratio of the number of tunable spectral LEDs to the number of fixed spectral LEDs being 2:1 to 3:1, for example, 2:1, 2.2:1, 2.5:1, 2.6:1, 2.8:1, or 3:1.

[0094] Furthermore, the installation height of the spectral LED array is 0.5m to 0.8m above the canopy of the mid-red poplar, for example, it can be 0.5m, 0.6m, 0.7m, 0.8m, etc.

[0095] It is understandable that every 100 square meters of the Populus tomentosa planting area requires 150 LED modules with a luminous efficacy of 2.5 μmol / J (IP65 or higher protection). Adjustable spectrum LEDs and fixed spectrum LEDs are controlled separately. The lights are installed on slide rails and arranged in a triangular pattern to improve coverage efficiency and reduce shadow areas. After installation, use light simulation software (such as DIALux, AGI32) to verify the uniformity of distribution. If necessary, add supplementary lights at the lower edge of the Populus tomentosa canopy.

[0096] In some embodiments, the execution unit includes a gradient temperature control device, which includes a heating component, a cooling component, a humidifying component, and a temperature and humidity control component.

[0097] Furthermore, the heating component includes an electric heating film, which is laid 15cm to 20cm below the soil, for example, 15cm, 16cm, 17cm, 18cm, 19cm, 20cm, etc.; with the root of the Chinese poplar trunk as the center, the electric heating film is laid within a range of 1m to 3m from the root.

[0098] Furthermore, an insulating material of the same size as the heating film is laid underneath it to reduce heat loss into the ground.

[0099] For example, the insulation material is XPS foam board.

[0100] Furthermore, the refrigeration components include an air-cooled system located at the top of the space in the Populus tomentosa planting area, with 1-2 air-cooled systems configured for every 100 m² of space.

[0101] For example, the air-cooled system is an axial flow fan with an air volume ≥ 10,000 m³ / h

[0102] Furthermore, the humidification component includes a high-pressure micro-mist system, which is positioned at a distance of 0.5m to 0.8m from the canopy of Populus tomentosa, for example, at 0.5m, 0.6m, 0.7m, 0.8m, etc.; it sprays downward and outward at an angle of 25° to 35°, for example, at an angle of 25°, 26°, 28°, 30°, 32°, 33°, 35°, etc.

[0103] For example, the high-pressure micro-mist system is a high-pressure pump with the following specifications: 10 MPa, flow rate 20 L / min, nozzle orifice diameter 0.15 mm, nozzle spacing 2 meters, and double-row staggered distribution (avoiding LEDs).

[0104] It's understandable that the high-pressure pump tries to avoid directly spraying the leaves of the Chinese poplar.

[0105] Furthermore, the temperature and humidity control components include skylight wet curtains and ventilation fans, with 10-15 m² of skylight wet curtains and 1 ventilation fan configured per 100 m².

[0106] It is understandable that skylights, wet curtains, and ventilators are installed on the gable walls to assist in temperature and humidity control, thereby regulating the ambient temperature and humidity by accelerating airflow and heat evaporation.

[0107] For example, the controller assembly is connected to the spectral sensor, the ambient temperature and humidity sensor, the integrated soil sensor, and the actuator unit via a standard interface, using bolts for fixing and conventional circuit wiring; the spectral sensor, the ambient temperature and humidity sensor, and the integrated soil sensor to be collected are correctly connected to the data input port of the controller assembly, ensuring a firm and reliable connection; the parameters for data acquisition are set using the controller assembly's operating interface, with the following acquisition frequencies: light intensity is collected every 30 minutes, the multispectral sensor is collected every 30 minutes, and the ambient temperature and humidity sensor is collected every 60 minutes.

[0108] In S04:

[0109] Furthermore, in the intelligent greenhouse, when the light intensity is below 600 μmol / (m²·s) on cloudy days, in the morning, and in the evening, the light intensity can be increased to 600 μmol / (m²·s)~800 μmol / (m²·s) through the first supplementary light of adjustable spectrum LEDs. For example, it can be 600 μmol / (m²·s), 650 μmol / (m²·s), 680 μmol / (m²·s), 700 μmol / (m²·s), 720 μmol / (m²·s), 750 μmol / (m²·s), 780 μmol / (m²·s), 800 μmol / (m²·s), etc.

[0110] Furthermore, the first supplemental lighting time is from 7:00 to 9:00 in the morning and from 17:00 to 18:30 in the afternoon, for 2.5 to 4.5 hours per day, for example, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, etc.

[0111] It is understandable that light intensity can affect the synthesis of pigments in Populus tomentosa and regulate the activity of related enzymes, thereby affecting the color and growth of Populus tomentosa. Light intensity directly affects the content and ratio of chlorophyll and anthocyanins, thus affecting the color of the leaves. Strong light conditions enable Populus tomentosa to show its best color.

[0112] Furthermore, by using tunable spectrum LEDs as a second supplementary light source, the ratio of blue light (450 nm) to red light (660 nm) is set to 1.5:1, with daily irradiation for 5 to 7 hours, for example, 5 hours, 5.5 hours, 6 hours, 6.5 hours, or 7 hours.

[0113] Furthermore, the second supplemental lighting time is from 8:00 to 11:00 in the morning and from 15:00 to 18:00 in the afternoon, for 5 to 7 hours a day, for example, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, etc.

[0114] It is understandable that light quality also has a significant impact on the leaf color of Populus tomentosa. Red and blue light can significantly increase the activity of PAL and ANS enzymes in the leaves, thereby increasing the anthocyanin content in the leaves and increasing the anthocyanin / chlorophyll ratio, making the leaves of Populus tomentosa appear red. Red light can also promote the synthesis of chlorophyll and increase the net photosynthetic rate of the leaves.

[0115] Furthermore, by adjusting the power of the electric heating film and the airflow of the air-cooling system, the ambient temperature in the lower layer of the Populus tomentosa growing space (0.5m-1m above the soil surface) is maintained at 25℃-28℃, for example, 25℃, 25.5℃, 26℃, 26.5℃, 27℃, 27.5℃, 28℃, etc.; and the ambient temperature in the Populus tomentosa canopy is maintained at 20℃-23℃, for example, 20℃, 20.5℃, 21℃, 21.5℃, 22℃, 22.5℃, 23℃, etc. It can be understood that achieving a vertical temperature difference of 5-8℃ between the canopy and root environments promotes the synthesis and stabilization of anthocyanins in the leaves.

[0116] It is understandable that the lower layer of the growing space of Populus tomentosa should be 0.5m to 1m away from the soil surface, for example, 0.5m, 0.6m, 0.7m, 0.8m, 0.9m, 1m, etc.

[0117] Furthermore, by adjusting the power of the electric heating film and the airflow of the air-cooling system, the ambient temperature during the day can be maintained between 24℃ and 27℃, for example, 24℃, 24.5℃, 25℃, 25.5℃, 26℃, 26.5℃, 27℃, etc.; and the ambient temperature at night can be maintained between 15℃ and 20℃, for example, 15℃, 15.5℃, 16℃, 16.5℃, 17℃, 18℃, 19℃, 20℃, etc.

[0118] Furthermore, the ambient temperature is maintained at 15°C for 1 to 2 hours between 3 and 4 a.m.

[0119] It is understandable that large temperature differences between day and night promote the synthesis of anthocyanins, increase the anthocyanin / chlorophyll ratio, and thus enhance and stabilize the red quality of the leaves.

[0120] Furthermore, the daytime humidity should be maintained at 60%~80%, for example, 60%, 65%, 70%, 75%, 80%; and the nighttime humidity should be maintained at 35%~45%, for example, 35%, 38%, 40%, 42%, 45%, etc.

[0121] It is understandable that the increased temperature difference between day and night is an important reason for the formation of red leaves in spring and autumn of the Chinese poplar, as the low temperature at night can promote the synthesis of anthocyanins.

[0122] Furthermore, the soil temperature in the planting area of ​​Populus tomentosa is 15℃~30℃, for example, it can be 15℃, 16℃, 18℃, 20℃, 22℃, 25℃, 26℃, 28℃, 30℃, etc.

[0123] Furthermore, the soil moisture content in the planting area of ​​Populus tomentosa is 12% to 24%, for example, it can be 12%, 14%, 16%, 18%, 20%, 22%, 24%, etc.

[0124] Furthermore, the soil pH in the planting area of ​​Populus tomentosa is 6.5-7, for example, it can be 6.5, 6.6, 6.7, 6.8, 6.9, 7, etc.

[0125] Furthermore, the soil calcium content in the Chinese poplar planting area is 600 mg / kg to 900 mg / kg, for example, it can be 600 mg / kg, 650 mg / kg, 700 mg / kg, 750 mg / kg, 800 mg / kg, 850 mg / kg, 900 mg / kg, etc.

[0126] The exchangeable magnesium content in the soil of the Chinese poplar planting area is 90 mg / kg to 120 mg / kg, for example, it can be 90 mg / kg, 95 mg / kg, 100 mg / kg, 105 mg / kg, 110 mg / kg, 115 mg / kg, 120 mg / kg, etc.

[0127] The soil phosphorus content in the planting area of ​​Populus tomentosa ranges from 15 mg / kg to 30 mg / kg, for example, it can be 15 mg / kg, 18 mg / kg, 20 mg / kg, 22 mg / kg, 25 mg / kg, 28 mg / kg, 30 mg / kg, etc.

[0128] The soil potassium content in the planting area of ​​Populus tomentosa is 50 mg / kg to 70 mg / kg, for example, it can be 50 mg / kg, 55 mg / kg, 60 mg / kg, 65 mg / kg, 70 mg / kg, etc.

[0129] It is understandable that by comprehensively monitoring soil temperature, moisture and pH value through soil sensors, and by regulating soil temperature through electric heating film, air cooling system and high pressure micro-mist system, soil moisture content is maintained at 12% to 24%, and soil pH value is maintained between 6.5 and 7.0 through the application of organic matter and fertilizer.

[0130] It can also be understood that the effective absorption of calcium, magnesium, and copper ions from the soil by *Populus tomentosa* can form complexes with anthocyanins and chlorophyll, enhancing the synthesis and stability of anthocyanins and thus improving leaf color. Furthermore, calcium, magnesium, and copper ions are essential trace minerals for the life activities of *Populus tomentosa*, and are important components of some oxidases, promoting metabolism and protein synthesis, thereby increasing resistance. Soil pH is the most important factor affecting the color of *Populus tomentosa* leaves by influencing anthocyanin structure; slightly acidic or neutral soils promote colorful leaves, while alkaline soils inhibit color development.

[0131] Application examples

[0132] Select healthy, disease-free, two-year-old 'Zhonghong Poplar' seedlings with a height of 2.0-2.5m.

[0133] Under the greenhouse environment conditions of this invention, 25 'Zhonghongyang' seedlings were planted as the experimental group, with a plant spacing of 3m. The method of this invention for extending the leaf color viewing period and quality control of the spring-flowering tree species Zhonghongyang was adopted. Under the outdoor field environment, 25 'Zhonghongyang' seedlings were planted as the control group, with a plant spacing of 3m, and were managed according to normal field conditions.

[0134] Effects on the content and ratio of pigments in leaves

[0135] When the first leaf unfolded in late March and reached a width of 1.5-2 cm, the chlorophyll and anthocyanin content of the leaves were measured every 15 days, and the anthocyanin / chlorophyll ratio was calculated. The results are shown in Table 1. The growth rates in the table are all the growth rates of the experimental group compared with the control group.

[0136] Table 1. Changes and differences in pigment content and proportion in leaves at different time periods

[0137] As shown in Table 1, before April 28th, there was little difference in anthocyanin content between the experimental group and the control group of 'Zhonghongyang' leaves. On May 13th, the anthocyanin content in the control group of 'Zhonghongyang' leaves began to decrease to below 1.0 mg•g⁻¹, while the anthocyanin content in the experimental group of 'Zhonghongyang' leaves remained at a higher level, only starting to decrease to below 1.0 mg•g⁻¹ on June 13th. From May 13th to June 13th, the anthocyanin content in the experimental group of 'Zhonghongyang' leaves was significantly higher than that in the control group, reaching 195.80% higher on May 28th.

[0138] On March 28, the chlorophyll content of the leaves of the experimental group 'Zhonghongyang' was 9.45% lower than that of the control group. Subsequently, the chlorophyll content of the leaves of the experimental group was slightly higher than that of the control group. Overall, there was little difference in the chlorophyll content of the leaves of 'Zhonghongyang' between the experimental group and the control group.

[0139] Between March 28 and April 28, the anthocyanin / chlorophyll ratio of leaves in the experimental group and the control group was not significantly different. However, between May 13 and June 13, the anthocyanin / chlorophyll ratio of leaves in the experimental group was significantly higher than that in the control group.

[0140] Studies have shown that the ratio of anthocyanins to chlorophyll directly affects the color of leaves, with anthocyanin content being the most direct factor. A higher ratio results in a better red leaf appearance, while a lower ratio leads to leaves turning green again. Experimental results showed that on March 28th, the newly unfolded leaves of the experimental group 'Zhonghong Yang' had an anthocyanin / chlorophyll ratio greater than 3 compared to the control group, resulting in bright red leaves. From April 13th to April 28th, both groups showed a significant increasing trend in anthocyanin and chlorophyll content, while the anthocyanin / chlorophyll ratio remained relatively stable, maintaining a good red color. From May 13th to June 13th, the chlorophyll content in both the experimental and control groups continued to increase, while the anthocyanin content in the control group decreased significantly, leading to a noticeable decrease in the anthocyanin / chlorophyll ratio and a significant greening of the leaves. However, the anthocyanin content in the leaves of the experimental group 'Zhonghong Yang' remained at a relatively high level, only showing a significant greening phenomenon on June 13th.

[0141] Effects on leaf color parameters

[0142] When the first leaf unfolded in late March and reached a width of 1.5-2 cm, the leaf color parameters a* and b*, as well as the brightness L* value, were measured every 15 days using a portable Konica Minolta CR-400 colorimeter (imported from Japan). The results are shown in the table below. The growth rates in the table are all the growth rates of the experimental group compared to the control group.

[0143] Table 2. Changes and differences in leaf color parameters at different time periods

[0144] The parameter a* reflects the hue of the red and green attributes. A change from a negative value to a positive value indicates that green is weakened and red is strengthened. The parameter b* reflects the hue of the yellow and blue attributes. A change from a negative value to a positive value means that blue is gradually fading and yellow is strengthening. L* reflects the brightness of the color. When the L* value goes from 0 to 100, the brightness gradually increases, that is, from black to white.

[0145] As shown in Table 2, the a* value of the leaves in the experimental group 'Zhonghongyang' was consistently higher than that in the control group, with little difference before April 28. After May 13, the a* value of the leaves in the experimental group 'Zhonghongyang' was consistently significantly higher than that in the control group, reaching 188.74% higher on June 13. The red hue of the leaves in the experimental group was very stable, while the a* value of the leaves in the control group had dropped to 0.693, with very weak red color and enhanced green color.

[0146] The b* value of the leaves in the experimental group 'Zhonghongyang' was consistently lower than that in the control group. The leaves in the experimental group showed a weaker yellow hue and a stronger blue tendency compared to the control group, resulting in a more intense red color and better ornamental quality. The difference became more pronounced after May 13th, when the b* value of the leaves in the experimental group was 59.57% lower than that in the control group, and remained 22.14% lower as of June 13th.

[0147] Between March 28 and May 28, the leaf brightness L* value of the experimental group 'Zhonghongyang' was slightly lower than that of the control group, but the difference was not significant, indicating that the leaf brightness was slightly lower. This is related to the deeper color of the leaves of the experimental group 'Zhonghongyang'.

[0148] In summary, from May 13th to June 13th, when the red color of the leaves of 'Zhonghong Yang' plants grown in natural environments significantly decreased and the leaves gradually turned green, the red a* value of the leaves of 'Zhonghong Yang' plants under the controlled environment of this invention remained at a high level, and the yellow b* value was also relatively low. This extended the optimal leaf color retention period of 'Zhonghong Yang' in spring and summer by more than 30 days, and the red color of the leaves was more intense, significantly improving the ornamental quality and economic benefits of 'Zhonghong Yang'.

[0149] Effects on the activity of anthocyanin-related synthases in leaves

[0150] The activities of phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS), and anthocyanin synthase (ANS) in leaves were measured on April 13, May 13, and June 13, respectively. The results are shown in Table 3. The growth rates in the table are the growth rates of the experimental group compared with the control group.

[0151] Table 3. Changes and differences in the activity of anthocyanin-related synthases in leaves at different time periods

[0152] Environmental factors (low temperature, light quality, pH value, etc.) can significantly affect the activities of amino acid ammonia-lyase (PAL), chalcone synthase (CHS), and anthocyanin synthase (ANS) in the anthocyanin synthesis pathway. These three active enzymes play important roles in key reactions such as the synthesis of anthocyanin phenylpropionic acid, the synthesis and metabolism of flavonoids, and the modification of the anthocyanin skeleton after synthesis. A significant increase in their activity can affect the synthesis of anthocyanins, thereby increasing the anthocyanin / chlorophyll ratio, which makes the leaves appear red.

[0153] Test results show that:

[0154] The activities of key enzymes PAL, CHS, and ANS in the anthocyanin synthesis pathway of 'Zhonghong Yang' plants, regulated by this invention, were significantly increased compared to the control on May 13th and June 13th, with the differences gradually widening. On June 13th, the activities of PAL, CHS, and ANS increased by 34.56%, 160.11%, and 23.91% respectively compared to the control group, demonstrating a particularly significant effect of this invention on the synthesis and metabolism of flavonoids in leaves. This invention achieves a method of intelligently and scientifically regulating environmental factors, effectively mobilizing the activity of endogenous substances affecting anthocyanin synthesis in plants, providing sufficient motivation and material basis for the synthesis of more anthocyanins. It significantly increases the anthocyanin content and anthocyanin / chlorophyll ratio in the leaves of 'Zhonghong Yang', a spring-flowering tree, maintaining a high level of a* value for the red hue of the leaves, extending the red leaf period by more than 30 days, and improving the ornamental quality of the leaves.

[0155] The basic concepts have been described above. Obviously, for those skilled in the art, the detailed disclosure above is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application, and therefore remain within the spirit and scope of the exemplary embodiments of this application.

[0156] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

Claims

1. A method for extending the ornamental period and improving the quality of the leaves of the red poplar, a tree species known for its spring-blooming colors, characterized by: Includes the following steps: We provide Chinese red poplar seedlings; Planting Chinese red poplar seedlings; Establish an environmental monitoring and control system; Light intensity, light quality, temperature difference, and soil regulation; The methods for establishing an environmental monitoring and control system include: Inside the smart greenhouse, the controller components are mounted on the wall. Install the data acquisition unit; Install execution unit; The execution unit includes a spectral LED array, which includes adjustable spectral LEDs and fixed spectral LEDs, with the ratio of the number of adjustable spectral LEDs to the number of fixed spectral LEDs being 2:1 to 3:

1. Inside the intelligent greenhouse, on cloudy days, when the light intensity is below 600 μmol / (m²·s) in the morning and evening, the light intensity is increased to 600 μmol / (m²·s)~800 μmol / (m²·s) by adjusting the first supplementary light of the LED. The ratio of blue light (450 nm) to red light (660 nm) is 1.5:1 through the tunable spectrum LED secondary supplementary light, and the illumination time is 5 to 7 hours per day. By adjusting the power of the electric heating film and the air volume of the air-cooling system, the ambient temperature in the lower layer of the Populus tomentosa growing space (0.5m~1m from the soil surface) is maintained at 25℃~28℃, and the ambient temperature in the Populus tomentosa canopy layer is maintained at 20℃~23℃.

2. The method for extending the ornamental period and quality of the leaves of the red poplar tree (Poplar rubrum) in spring according to claim 1, characterized in that, Provide robust, disease- and pest-free two-year-old Chinese poplar seedlings; and / or The seedlings of Populus tomentosa are 2.0 m to 2.5 m tall; and / or The planting quantity of Chinese red poplar seedlings is 20 to 30 trees, with a spacing of 2.5m to 3m between trees.

3. The method for extending the ornamental period and quality of the leaves of the spring-flowering poplar tree, as described in claim 1, is characterized in that... The data acquisition unit includes a multispectral sensor, an ambient temperature and humidity sensor, and a comprehensive soil sensor; and / or The execution unit is connected to the controller component; and / or The execution unit includes a gradient temperature control device, which includes a heating component, a cooling component, a humidifying component, and a temperature and humidity control component.

4. The method for extending the ornamental period and quality of the leaves of the spring-flowering poplar tree as described in claim 3, characterized in that, The number of the multispectral sensor, ambient temperature and humidity sensor, and integrated soil sensor is the same as the number of microcontrollers in the controller assembly, and the multispectral sensor, ambient temperature and humidity sensor, and integrated soil sensor are respectively connected to their corresponding microcontrollers; and / or The heating element includes an electric heating film, which is laid 15cm to 20cm below the soil; and / or The cooling components include an air-cooled system located at the top of the planting area of ​​Populus tomentosa, with 1-2 air-cooled systems configured per 100 m² of space; and / or The humidification components include a high-pressure micro-mist system, positioned at a distance of 0.5m to 0.8m from the canopy of the Chinese poplar; and / or Temperature and humidity control components include skylight wet curtains and ventilation fans, with 10-15 m² of skylight wet curtains and 1 ventilation fan configured per 100 m².

5. The method for extending the ornamental period and quality of the leaves of the spring-flowering poplar tree as described in claim 3, characterized in that, The multispectral sensor is installed at a height of 0.8m to 1.2m above the seedlings; and / or Install one ambient temperature and humidity sensor every 10m 2 ~15m 2 ; and / or The number of integrated soil sensors is 3 to 4; and / or The spectral LED array is installed at a height of 0.5m to 0.8m above the canopy of the poplar.

6. The method for extending the ornamental period and quality of the leaves of the red poplar tree (Poplar rubrum) according to claim 1, characterized in that, The first supplemental lighting time is 7:00-9:00 AM and 5:00-6:30 PM, for 2.5-4.5 hours daily; and / or The second supplemental lighting time is from 8:00 to 11:00 AM and from 3:00 to 6:00 PM.

7. The method for extending the ornamental period and quality of the leaves of the spring-flowering poplar tree according to claim 4, characterized in that, By adjusting the power of the electric heating film and the airflow of the air-cooling system, the ambient temperature during the day is maintained at 24℃~27℃; and / or Maintain the ambient temperature at 15°C for 1 to 2 hours between 3 and 4 AM; and / or Maintain humidity between 60% and 80% during the day and between 35% and 45% at night.

8. The method for extending the ornamental period and quality of the leaves of the red poplar tree (Poplar rubrum) according to claim 1, characterized in that, The soil moisture content in the planting area of ​​Populus tomentosa is 12%~24%; and / or The soil pH in the Populus tomentosa planting area is 6.5-7; and / or The soil calcium content in the poplar planting area is 600 mg / kg ~ 900 mg / kg; and / or The soil exchangeable magnesium content in the Populus tomentosa planting area is 90 mg / kg ~ 120 mg / kg; and / or The soil phosphorus content in the Populus tomentosa planting area is 15 mg / kg ~ 30 mg / kg; and / or The soil potassium content in the poplar planting area is 50 mg / kg to 70 mg / kg.

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