Rapid evaluation method for suitable plants in underground space based on photosynthetic physiological response

Abstract

This invention discloses a rapid evaluation method for plants adapted to underground spaces based on photosynthetic physiological responses, relating to the field of plant cultivation technology. The method includes: based on the plant's morphology, chlorophyll fluorescence parameters (maximum photochemical efficiency, electron transport rate, active / passive heat dissipation quantum yield), and photosynthetic respiration parameters (net photosynthetic rate, stomatal conductance, intercellular CO2 concentration) within a preset cultivation period, classifying the plant's photosynthetic response to complex environmental stresses in underground spaces into four modes: stable adaptation, stress adaptation, chronic inhibition, and irreversible damage. The plants to be evaluated are placed in a simulated complex environment and cultured for 30 days. The above parameters are collected on the first, middle, and last days, and their photosynthetic response mode is determined based on temporal changes, thereby indicating the plant's survival ability in underground spaces. This invention solves the problems of long evaluation cycles and single evaluation indicators in existing plant adaptability evaluation methods.

Description

Technical Field

[0001] This invention relates to the field of plant cultivation technology, specifically to a rapid evaluation method for plants suitable for underground spaces based on photosynthetic physiological responses. Background Technology

[0002] Underground spaces commonly present a complex stress environment characterized by high humidity, low light, and poor ventilation. When implementing greening projects in underground spaces, it is necessary to select plant varieties that can adapt to this unique environment. However, existing methods for evaluating plant adaptability have the following technical problems: I. Long evaluation cycle and low efficiency. Traditional methods rely on changes in morphological appearance (yellowing, wilting, and death of leaves) as the basis for judgment. Changes in morphological appearance of plants under stress conditions are usually lagging, and it often takes 2 to 3 months or even longer to make an accurate judgment, which seriously restricts the screening efficiency.

[0003] Second, there is a lack of early diagnostic capabilities. By the time leaves show obvious yellowing or wilting, irreversible damage to the plant's photosynthetic apparatus may have already occurred, missing the optimal time for evaluation. Current methods cannot predict a plant's adaptive potential before significant changes occur in its morphology.

[0004] Third, the evaluation indicators are too simplistic and fail to reveal the adaptation mechanisms. Existing methods mostly use macroscopic indicators such as survival rate and growth, which cannot distinguish whether the plant is in a state of "active adaptation" or "passive damage," nor can they determine the dominant factors of photosynthetic inhibition (stomatal restriction or non-stomatal restriction), resulting in a lack of theoretical support for the screening results.

[0005] Fourth, there is a lack of standardized quantitative grading systems. Different studies use inconsistent evaluation criteria, making it difficult to compare results across studies and preventing the formation of a systematic list of recommended plants. Summary of the Invention

[0006] To overcome the shortcomings of existing technologies, a rapid evaluation method for underground space-adaptive plants based on photosynthetic physiological response is provided to address the problems of long evaluation cycles and single evaluation indicators in existing plant adaptability evaluation methods.

[0007] To achieve the above objectives, a rapid evaluation method for suitable plants in underground spaces based on photosynthetic physiological responses is provided, comprising the following steps: Based on the morphology, chlorophyll fluorescence parameters, and photosynthetic respiration parameters of plant varieties within a preset cultivation period, the photosynthetic response of plant varieties to the complex environmental stress of underground space is divided into four modes. The chlorophyll fluorescence parameters include maximum photochemical efficiency, photosynthetic electron transport rate, active heat dissipation quantum yield, and passive heat dissipation quantum yield. The photosynthetic respiration parameters include net photosynthetic rate, stomatal conductance, and intercellular carbon dioxide concentration. The four modes include stable adaptation, stress adaptation, chronic inhibition, and irreversible damage. The plant varieties to be evaluated are placed in a composite environment simulating underground space and cultivated within the preset cultivation period; During the preset culture period, on the first, middle and last days of the preset culture period, the appearance morphology, chlorophyll fluorescence parameters and photosynthetic respiration parameters of the plant varieties to be evaluated were collected respectively. Based on the morphology, chlorophyll fluorescence parameters, and photosynthetic respiration parameters of the plant varieties to be evaluated, the photosynthetic response patterns of the plant varieties to be evaluated are determined to indicate their survival ability in underground spaces.

[0008] Furthermore, the preset culture period is 30 days.

[0009] Furthermore, the composite environment is a high humidity, low light and low ventilation environment, with a relative humidity of 65-75%, a light intensity of 400-800 lux and a wind speed of less than 0.3 m / s.

[0010] Furthermore, in stable and adaptable plant varieties, the maximum photochemical efficiency and photosynthetic electron transport rate remained stable or decreased briefly and then rebounded within the preset culture period, while the passive heat dissipation quantum yield did not increase significantly, and the apparent morphology was normal.

[0011] Furthermore, in the early stage of the preset culture cycle, the maximum photochemical efficiency and photosynthetic electron transport rate of stress-adapted plant varieties decreased, while the active heat dissipation quantum yield increased. In the later stage, some indicators rebounded, and the apparent morphology changed slightly.

[0012] Furthermore, in chronically inhibited plant varieties, the maximum photochemical efficiency and photosynthetic electron transfer rate continued to decline within the preset culture period, while the passive heat dissipation quantum yield gradually increased, and the apparent morphology showed yellowing but the plants were still able to survive.

[0013] Furthermore, irreversible damage can lead to severe wilting, root rot, and death within a short period of time.

[0014] The beneficial effects of this invention are that the rapid evaluation method for underground space-adapted plants based on photosynthetic physiological response shortens the preset culture period to 30 days. By monitoring the photosynthetic physiological response (chlorophyll fluorescence parameters and photosynthetic respiration parameters) of plants in a simulated underground space composite environment, the adaptability of plants can be judged in a short time. Compared with the traditional method that relies on morphological changes and requires 2 to 3 months, the screening efficiency is significantly improved.

[0015] The rapid evaluation method for underground space-adapted plants based on photosynthetic physiological response of the present invention can identify plant stress response patterns in advance by detecting sensitive photosynthetic indicators such as maximum photochemical efficiency, electron transport rate, and heat dissipation quantum yield before significant changes occur in the plant's morphology, thus predicting the plant's adaptation potential or irreversible damage trend in advance and avoiding missing the evaluation opportunity.

[0016] The present invention provides a rapid evaluation method for underground space-adapted plants based on photosynthetic physiological response. This method simultaneously collects morphological data, chlorophyll fluorescence parameters, and photosynthetic respiration parameters, which can distinguish between photosynthetic inhibition caused by stomatal limitation and non-stomatal limitation, and clarify whether the plant is in an active adaptation state or a passive damage state, providing theoretical support at the physiological mechanism level for the screening results. Attached Figure Description

[0017] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a flowchart illustrating the rapid evaluation method for suitable plants in underground spaces based on photosynthetic physiological response, as described in an embodiment of the present invention.

[0018] Figure 2 This is a graph showing the chlorophyll fluorescence and light and respiration related indicators of Asparagus setaceus in Example 1 of the present invention.

[0019] Figure 3 The images show the appearance morphology and chlorophyll fluorescence of Asparagus setaceus from Embodiment 1 of the present invention.

[0020] Figure 4 This is a graph showing the chlorophyll fluorescence and light and respiration related indicators of Peperomia obtusifolia in Example 2 of the present invention.

[0021] Figure 5 The images show the appearance morphology and chlorophyll fluorescence of Peperomia in Example 2 of this invention.

[0022] Figure 6 This is a graph showing the chlorophyll fluorescence and light and respiration related indicators of *Aglaonema* var. *mairei* in Example 3 of the present invention.

[0023] Figure 7 The images show the appearance morphology and chlorophyll fluorescence of *Aglaonema* var. *mairei* in Example 3 of this invention.

[0024] Figure 8 This is a morphological diagram of the maidenhair fern in Embodiment 4 of the present invention. Detailed Implementation

[0025] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] See Figure 1 This invention provides a rapid evaluation method for plants suitable for underground spaces based on photosynthetic physiological responses, comprising the following steps: S1. Based on the morphology, chlorophyll fluorescence parameters, and photosynthetic respiration parameters of plant varieties within a preset cultivation period, the photosynthetic response of plant varieties to the complex environmental stress of underground space is divided into four modes. The chlorophyll fluorescence parameters include maximum photochemical efficiency, photosynthetic electron transport rate, active heat dissipation quantum yield, and passive heat dissipation quantum yield. The photosynthetic respiration parameters include net photosynthetic rate, stomatal conductance, and intercellular carbon dioxide concentration. The four modes include stable adaptation, stress adaptation, chronic inhibition, and irreversible damage.

[0028] In this embodiment, the preset cultivation period for the plant variety is 30 days.

[0029] The composite environment is characterized by high humidity, low light, and low ventilation. The relative humidity of the composite environment is 65-75%, the light intensity is 400-800 lux, and the wind speed is less than 0.3 m / s.

[0030] Stable and adaptable plant varieties maintained stable maximum photochemical efficiency and photosynthetic electron transport rate or decreased briefly and then rebounded within the preset culture period, with no significant increase in passive heat dissipation quantum yield and normal apparent morphology.

[0031] In the early stages of the preset culture cycle, stress-adaptive plant varieties showed a decrease in maximum photochemical efficiency and photosynthetic electron transport rate, an increase in active heat dissipation quantum yield, and a rebound in some indicators in the later stages, with slight changes in apparent morphology.

[0032] Chronic-inhibitory plant varieties showed a continuous decline in maximum photochemical efficiency and photosynthetic electron transfer rate within a preset culture period, while the passive heat dissipation quantum yield gradually increased. The plant exhibited a withered and yellowish appearance but was still able to survive.

[0033] Irreversible damage can lead to severe wilting, root rot, and death within a short period of time.

[0034] S2. The plant species to be evaluated are placed in a composite environment simulating underground space and cultured within a preset culture period.

[0035] The tested plant varieties were placed in a simulated environment for cultivation. This simulated environment accurately replicated the combined stress characteristics of underground space, characterized by high humidity (70±5%), low light (100~400 lux), and low ventilation. The cultivation period in the simulated environment was 30 days, during which watering and maintenance were carried out according to a uniform water management plan (the evaluated plant varieties and the control group used the same water management plan) to ensure that the plants grew under standardized environmental conditions.

[0036] S3. During the preset culture period, collect the appearance morphology, chlorophyll fluorescence parameters and photosynthetic respiration parameters of the plant varieties to be evaluated on the first, middle and last days of the preset culture period.

[0037] On day 1 (initial state), day 15, and day 30 of cultivation, the appearance and health status of the test plants were assessed. The changes in leaf color (yellowing, whitening, browning, necrotic spots, etc.), the proportion of withered and yellow leaves (number of withered and yellow leaves / total number of leaves × 100%), the overall growth vigor of the plant, the germination of new leaves, the compactness of the plant shape, and the lodging situation were observed and recorded to provide intuitive morphological evidence for subsequent comprehensive evaluation.

[0038] On day 1 (initial state), day 15, and day 30 of cultivation, mature functional leaves from the upper part of the plant were selected for dark adaptation treatment (30 minutes), and the plant leaves were picked to measure chlorophyll fluorescence parameters.

[0039] The following key parameters were measured using a portable modulated chlorophyll fluorometer (such as PAM-2500, MINI-PAM-II or similar equipment): F v / F m (Maximum photochemical efficiency), i.e., the maximum photochemical quantum yield of the PSII reaction center after dark adaptation, reflects the potential activity of the PSII reaction center, and is the maximum photochemical quantum yield of the PSII reaction center in normal plants. v / F m The value is generally between 0.75 and 0.85; a decrease indicates damage to the PSII reaction centers. ETR (Electron Transfer Rate), or photosynthetic electron transfer rate, reflects the photoreactivity. Y(NPQ) (Active Heat Dissipation) refers to the active heat dissipation quantum yield related to photoprotection mechanisms, reflecting the plant's ability to dissipate excess excitation energy through heat dissipation pathways. Y(NO) (passive dissipation), or non-regulated passive heat dissipation quantum yield, reflects the degree of passive damage to the PSII reaction center. An increase in Y(NO) indicates damage to the photosynthetic apparatus. Three to five leaves were selected from each plant for measurement, and the average value was taken as the representative value for that plant.

[0040] On days 1 (initial state), 15, and 30 of cultivation, gas exchange parameters of plant leaves were measured in situ using a portable photosynthetic respiration analyzer (such as LI-6800, GFS-3000, or similar equipment). Measurement conditions were: open gas path, leaf chamber temperature set at 25±1℃, and CO2 concentration set at 400±5 μmol·mol⁻¹. -1 The light intensity should be consistent with the culture environment (100~400 lux).

[0041] The key parameters measured include: A (Net Photosynthetic Rate): The amount of CO2 absorbed net per unit leaf area per unit time, expressed in μmol·m⁻². -2 ·s -1 ; gs (stomatal conductance): The ability of stomata to conduct water vapor or CO2, measured in mol·m. -2 ·s -1 ; Ci (intercellular CO2 concentration): The CO2 concentration in the intercellular spaces of mesophyll cells, in μmol·mol⁻¹ -1 .

[0042] The discrimination method is as follows: When A decreases accompanied by a simultaneous decrease in gs and Ci, it indicates that photosynthetic inhibition is mainly caused by stomatal limitation; when A decreases accompanied by a decrease in gs but Ci remains stable or increases, it indicates that photosynthetic inhibition is mainly caused by non-stomatal limitation. The above distinction between stomatal limitation and non-stomatal limitation is not used as a single criterion, but rather in conjunction with the temporal changes in chlorophyll fluorescence parameters and morphology to determine the photosynthetic response pattern. Specifically, when stomatal limitation is dominant and F... v / F m If ETR remains stable or rises later, and Y(NO) does not continue to increase, it indicates that the photosynthetic apparatus has not suffered significant irreversible damage. This can be determined by combining the appearance and morphology to be either a stable adaptive or stress-adapted type; this is mainly due to non-stomatal limitation and F... v / F m A continuous decrease in ETR and a gradual increase in Y(NO) indicate that the photosynthetic apparatus is suppressed or damaged. This can be combined with the degree of mild apparent damage such as yellowing and wilting to determine whether it is a chronic inhibition type or an irreversible damage type.

[0043] S4. Based on the appearance, chlorophyll fluorescence parameters, and photosynthetic respiration parameters of the plant varieties to be evaluated, determine the photosynthetic response pattern of the plant varieties to be evaluated to indicate their survival ability in underground space.

[0044] The temporal variation patterns of each indicator on day 1 (initial state), day 15, and day 30 of the preset culture cycle in the simulated culture were analyzed to determine the photosynthetic response pattern (stable adaptation, stress adaptation, chronic inhibition, or irreversible damage) of the plant varieties to be evaluated, and finally the plant's adaptability was comprehensively evaluated and graded.

[0045] To facilitate standardized assessment of the photosynthetic response patterns of plants under evaluation, classification can be based on a comprehensive evaluation of morphology, chlorophyll fluorescence parameters, and photosynthetic respiration parameters, according to the following criteria. The following criteria use day 1 as the initial state, day 15 as the mid-culture period, and day 30 as the final culture period for time-series comparison; when the directions of change of various indicators are not entirely consistent, priority should be given to combining F... v / F m The results of comprehensive judgment based on ETR, Y(NO) and apparent morphology are used, while A, Ci and gs play a dominant role in helping to distinguish between stomatal-limited and non-stomatal-limited conditions.

[0046] I. Criteria for judging stable adaptive types: 1. F v / F m It is within the normal range, specifically 0.75 to 0.85, and there is no significant decrease during the middle and late stages of culture, or only a short-term slight decrease followed by a return to the normal range; 2. If the ETR remains stable, or decreases slightly in the early stage and then recovers to near the initial level, it indicates that the photosynthetic electron transport function has not been continuously inhibited. 3. Y(NPQ) did not show any significant abnormal increase, or it increased slightly in the early stage and then remained stable, indicating that the plant does not need to rely on excessive active heat dissipation to resist stress for a long time. 4. If Y(NO) does not increase significantly, or remains stable / decreases after a short period of fluctuation, it indicates that there is no significant passive damage to the PSII reaction center. 5. If A remains stable, or decreases slightly in the early stage and rebounds in the later stage, it indicates that the net photosynthetic carbon assimilation capacity is basically maintained. 6. Ci remains stable, or shows a decline followed by a rebound in the same way as A and gs, indicating that CO2 supply and utilization are relatively coordinated. 7. If gs remains stable, or decreases slightly in the early stage and then rebounds, it indicates that the stomatal regulation capacity has not been continuously impaired. 8. The appearance is normal, with no obvious yellowing, wilting, lodging, root rot or death. There may be a small amount of natural old leaf decline or new tissue formation.

[0047] II. Criteria for judging stress-adaptive types: 1. F v / F m The PSII response center showed an initial decline but a subsequent rebound, eventually recovering to the normal range of 0.75–0.85 or close to the initial level, indicating that it still has the ability to recover after being subjected to short-term stress. 2. The ETR decreased in the early stage and rebounded in the later stage, indicating that the photosynthetic electron transport process gradually adapted to the simulated underground space environment after being suppressed for a short period of time. 3. Y(NPQ) increases in the early stage and decreases or falls back to a relatively stable level in the later stage, indicating that the plant consumes excess excitation energy through active heat dissipation in the early stage, and the stress is relieved or the adaptability is enhanced in the later stage. 4. If Y(NO) does not increase significantly in the early stage or only increases slightly in a short period of time, and then stabilizes or decreases in the later stage, it indicates that passive damage has not accumulated continuously. 5. A decrease in the early stage followed by a rebound or a significant reduction in the rate of decrease in the later stage indicates that although the net photosynthetic rate is affected by stress, it still has a recovery trend. 6. Ci decreases in the early stage and then rises in the later stage, or recovers synchronously when A rises, indicating that stomatal limitation is relieved after adaptation and adjustment; 7. The initial decrease in gs followed by a rebound indicates that the stomatal opening and gas exchange capacity partially recover after a short period of adaptation. 8. The appearance may show only slight changes, such as a few leaves becoming lighter in color, slight yellowing of older leaves, or a decrease in growth rate, but the plant as a whole still maintains its survival and ornamental value.

[0048] III. Diagnostic criteria for chronic suppressive type: 1. F v / F m A continuous decrease during the culture period, or a value below the lower limit of the normal range of 0.75 at the end of the period, indicates that the potential activity of PSII is continuously inhibited. 2. A continuous decline in ETR, or a decline followed by a failure to recover significantly in the later stages, indicates that the photosynthetic electron transport capacity is limited in the long term. 3. Y(NPQ) may increase in the early stage and decrease or be insufficient in the later stage, indicating that although the active light protection mechanism is activated, it is difficult to maintain it effectively in the long term. 4. A gradual increase or maintenance of a high level of Y(NO) indicates enhanced non-regulated energy dissipation and a tendency for photosynthetic mechanisms to be continuously suppressed or passively damaged. 5. A continuous decline in A or no significant recovery in the later stage indicates a long-term weakening of net photosynthetic carbon assimilation capacity; 6. A stable or elevated Ci, especially when A and gs decrease, suggests that photosynthetic inhibition may gradually shift from stomatal restriction to non-stomatal restriction. 7. A continuous decrease in gs or a long-term low level indicates that stomatal conductance and gas exchange capacity are continuously suppressed. 8. Obvious but non-fatal damage to the appearance, such as yellowing of lower leaves, shedding of old leaves, local wilting or weakened growth, but the plant can still survive, and some upper leaves or new tissues remain normal.

[0049] IV. Criteria for determining irreversible damage: 1. F v / F m A significant decrease in a short period of time, or a sustained drop below the lower limit of the normal range of 0.75 without any recovery trend, indicates that the PSII reaction center may be severely damaged. 2. A rapid decline in ETR that remains at a low level or nears stagnation indicates that the electron transport function of the photoreaction is severely impaired. 3. If Y(NPQ) cannot be effectively increased, or if it increases briefly and then drops rapidly, it indicates that the active photoprotection mechanism is insufficient to resist stress. 4. The significant increase in Y(NO) and its sustained high level indicate enhanced passive heat dissipation and continuous accumulation of damage to the photosynthetic apparatus. 5. A significant drop in A, approaching zero, or a lack of recovery indicates that the leaf's net photosynthetic carbon assimilation capacity is essentially lost. 6. Abnormally elevated or fluctuating Ci, or failure to recover synchronously with gs when A drops significantly, suggests that non-stomatal limitation or damage to the photosynthetic apparatus has become the dominant factor. 7. A significant decrease in gs, near-closing, or loss of stable regulation indicates that stomatal regulation and gas exchange capacity are severely impaired; 8. If the plant exhibits severe wilting, lodging, root rot, decay, large-scale yellowing and browning, or death in the early or middle stages of cultivation, and loses its ornamental value or survival ability, it can be directly identified as an irreversible damage type.

[0050] When making a comprehensive judgment, stable and stress-adaptable plants can be given priority as suitable plants for underground spaces; although chronically inhibited plants can survive, they should be used with caution in combination with ornamental value, maintenance costs and subsequent recovery ability; irreversible damage plants should not be recommended as plants for underground space greening.

[0051] To further illustrate the determination and analysis of different plant varieties using the rapid evaluation method for suitable underground plants based on photosynthetic physiological response of the present invention, the following examples are provided. Example 1

[0052] In this embodiment, Asparagus setaceus was used as the plant variety to be evaluated. The Asparagus setaceus was cultured in a simulated composite environment for a preset culture period using the rapid evaluation method for underground space-adapted plants based on photosynthetic physiological response of this invention. Appearance morphology, chlorophyll fluorescence parameters, and photosynthetic respiration parameters were collected on days 1, 15, and 30 of the preset culture period.

[0053] See Figure 2 and 3 As shown, no Asparagus setaceus F was observed within the preset cultivation period. v / F m Significant changes were observed, and the ETR rate increased, indicating that the photosynthetic system of Asparagus setaceus has a self-regulating ability in the simulated composite environment. On day 30 of the preset cultivation period, there were no other negative changes in overall chlorophyll content and morphology, and new tissue was present. Therefore, the photosynthetic response pattern of Asparagus setaceus was determined to be stable and adaptive, demonstrating its potential as underground vegetation. Example 2

[0054] In this embodiment, *Peperomia obtusifolia* was used as the plant variety to be evaluated. *Peperomia obtusifolia* was cultured in a simulated composite environment for a preset culture period using the rapid evaluation method for underground space-adapted plants based on photosynthetic physiological response of this invention. Appearance morphology, chlorophyll fluorescence parameters, and photosynthetic respiration parameters were collected on days 1, 15, and 30 of the preset culture period.

[0055] like Figure 4 and 5 As shown, under conditions of high humidity, low light, and low ventilation, the photosynthetic system of *Peperomia* is subjected to continuous stress, manifested as insufficient light capture leading to a decrease in the photoelectron transfer rate (ETR), and the maximum photosynthetic efficiency (F) of photosystem II is reduced. v / F m The photosynthetic response of *Peperomia* was determined to be stress-adaptive, with high humidity and low ventilation inhibiting stomatal opening and gas exchange, and insufficient CO2 supply further suppressing the photoreaction. Active heat dissipation (Y(NPQ)) showed no significant change, while passive heat dissipation (Y(NO)) initially increased and then stabilized, indicating that the photosynthetic system's photoprotection mechanism shifted from a passive stress state to an active adaptation state. Although photosynthetic inhibition was observed in *Peperomia*, its morphology did not change significantly. The lack of significant changes in chlorophyll fluorescence images across three culture periods indicates that chlorophyll levels in *Peperomia* did not decrease significantly. Therefore, the photosynthetic response pattern of *Peperomia* was determined to be stress-adaptive, allowing for the selection of plants capable of surviving under simulated conditions. Example 3

[0056] In this embodiment, *Aglaonema* was used as the plant variety to be evaluated. *Aglaonema* was cultured in a simulated composite environment for a preset culture period using the rapid evaluation method for underground space-adapted plants based on photosynthetic physiological response of this invention. Appearance morphology, chlorophyll fluorescence parameters, and photosynthetic respiration parameters were collected on days 1, 15, and 30 of the preset culture period.

[0057] like Figure 6 and 7 As shown, in the early stage of the preset culture period (0-15 days), the light and carbon responses remained relatively stable, the photoprotection mechanism functioned normally, and the plant adapted to the low-light environment by adjusting electron transport efficiency. In the later stage of culture (15-30 days), the net photosynthetic rate and stomatal conductance decreased, and Y (NPQ) decreased, indicating that the activity of *Aglaonema* was inhibited to some extent. Phenomorphological analysis showed that the lower leaves of *Aglaonema* turned yellow, but the upper leaves grew normally and new leaf tissue was formed; the chlorophyll fluorescence image of the upper leaves did not show significant changes. These results indicate that *Aglaonema* needs to undergo an adaptation process when cultured in the simulated environment. Therefore, the photosynthetic response mode of *Aglaonema* was determined to be chronically inhibited, but it still has the potential to grow in the underground environment. Example 4

[0058] In this embodiment, *Adiantum capillus-veneris* was used as the plant species to be evaluated. *Adiantum capillus-veneris* was cultured in a simulated composite environment for a preset culture period using the rapid evaluation method for underground space-adapted plants based on photosynthetic physiological response of this invention. Appearance morphology, chlorophyll fluorescence parameters, and photosynthetic respiration parameters were collected on days 1, 15, and 30 of the preset culture period.

[0059] like Figure 8 As shown, Figure 8 This is a schematic diagram of the appearance of maidenhair fern during the first 15 days of cultivation. Because the maidenhair fern showed visible signs of decay before the first observation period, it failed the morphological screening step. Through morphological analysis, the maidenhair fern exhibited obvious lodging, wilting, and root rot before day 15 of the preset cultivation period, losing its ornamental value and directly proving that these two plants lack the ability to grow in underground spaces.

[0060] The rapid evaluation method for underground space-adapted plants based on photosynthetic physiological response of the present invention shortens the preset culture period to 30 days. By monitoring the photosynthetic physiological response (chlorophyll fluorescence parameters and photosynthetic respiration parameters) of plants in a simulated underground space composite environment, the adaptability of plants can be judged in a short time. Compared with the traditional method that relies on morphological changes and requires 2 to 3 months, the screening efficiency is significantly improved.

[0061] The rapid evaluation method for underground space-adapted plants based on photosynthetic physiological response of the present invention can identify plant stress response patterns in advance by detecting sensitive photosynthetic indicators such as maximum photochemical efficiency, electron transport rate, and heat dissipation quantum yield before significant changes occur in the plant's morphology, thus predicting the plant's adaptation potential or irreversible damage trend in advance and avoiding missing the evaluation opportunity.

[0062] The rapid evaluation method for underground space-adapted plants based on photosynthetic physiological response of the present invention simultaneously collects appearance morphology, chlorophyll fluorescence parameters and photosynthetic respiration parameters, which can distinguish photosynthetic inhibition caused by stomatal limitation and non-stomatal limitation, and clarify whether the plant is in an active adaptation state (such as increased active heat dissipation) or a passive damage state (such as increased passive heat dissipation), providing theoretical support at the physiological mechanism level for the screening results.

[0063] The rapid evaluation method for plants suitable for underground spaces based on photosynthetic physiological response of the present invention systematically classifies the photosynthetic response patterns of plants into four standard types: stable adaptation, stress adaptation, chronic inhibition, and irreversible damage. It also provides clear criteria for each type. The evaluation results of different plant varieties can be compared under a unified framework, which facilitates the formation of a systematic recommended list of plants suitable for underground spaces.

[0064] The rapid evaluation method for underground space-adapted plants based on photosynthetic physiological response of the present invention uses a portable chlorophyll fluorometer and a photosynthetic respiration meter for in situ or in vitro measurements. The sampling time points are clearly defined (first day, middle day, last day), and the measurement conditions are uniform (humidity 65~75%, light intensity 400~800 lux, wind speed <0.3 m / s). The method has a high degree of standardization and is easy to promote and apply in different laboratories or application scenarios.

[0065] The rapid evaluation method for suitable plants in underground spaces based on photosynthetic physiological response of the present invention can quickly screen out stable and stress-adaptive plant varieties (such as Asparagus fern and Peperomia obtusifolia), providing reliable plant materials for underground space greening; at the same time, it can identify the adaptation potential of chronically inhibited plants (such as Aglaonema) and the elimination criteria of irreversibly damaged plants (such as Adiantum capillus-veneris), thereby improving the scientific nature and success rate of underground space greening.

[0066] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A rapid evaluation method for underground space-adapted plants based on photosynthetic physiological response, characterized in that, Includes the following steps: Based on the morphology, chlorophyll fluorescence parameters, and photosynthetic respiration parameters of plant varieties within a preset cultivation period, the photosynthetic response of plant varieties to the complex environmental stress of underground space is divided into four modes. The chlorophyll fluorescence parameters include maximum photochemical efficiency, photosynthetic electron transport rate, active heat dissipation quantum yield, and passive heat dissipation quantum yield. The photosynthetic respiration parameters include net photosynthetic rate, stomatal conductance, and intercellular carbon dioxide concentration. The four modes include stable adaptation, stress adaptation, chronic inhibition, and irreversible damage. The plant varieties to be evaluated are placed in a composite environment simulating underground space and cultivated within the preset cultivation period; During the preset culture period, on the first, middle and last days of the preset culture period, the morphology, chlorophyll fluorescence parameters and photosynthetic respiration parameters of the plant varieties to be evaluated were collected respectively. Based on the morphology, chlorophyll fluorescence parameters, and photosynthetic respiration parameters of the plant varieties to be evaluated, the photosynthetic response pattern of the plant varieties to be evaluated is determined to indicate the survival ability of the plant varieties to be evaluated in underground space. The preset culture period is 30 days; The composite environment is a high humidity, low light and low ventilation environment, with a relative humidity of 65-75%, a light intensity of 400-800 lux and a wind speed of less than 0.3 m / s. Criteria for judging stable adaptation: The maximum photochemical efficiency was within the normal range, ranging from 0.75 to 0.85, and there was no significant decrease during the middle and late stages of cultivation, or only a short-term slight decrease followed by a return to the normal range. The photosynthetic electron transport rate remains stable, or decreases slightly in the early stage and then recovers to near the initial level in the later stage; Active heat dissipation quantum yield did not show a significant abnormal increase, or it increased slightly in the early stage and then remained stable; The passive heat dissipation quantum yield did not increase significantly, or remained stable / decreased after a short period of fluctuation; The net photosynthetic rate remains stable, or decreases slightly in the early stage and then rebounds in the later stage; Intercellular CO2 concentration remained stable, or showed an early decrease and a later increase in sync with net photosynthetic rate and stomatal conductance; Stomatal conductance remains stable, or decreases slightly in the early stage and then rebounds; The appearance is normal, with no obvious yellowing, wilting, lodging, root rot or death, and a small number of naturally decaying old leaves or new tissue formation; Criteria for judging stress-adaptive personality: The maximum photochemical efficiency decreases in the early stage but recovers in the later stage, and can return to the normal range of 0.75 to 0.85 or close to the initial level in the final stage; The photosynthetic electron transport rate decreases in the early stage and then recovers in the later stage; Active heat dissipation quantum yield increases in the early stage, then decreases or falls back to a relatively stable level in the later stage; The passive heat dissipation quantum yield does not increase significantly in the early stage or only increases slightly in a short period of time, and then stabilizes or decreases in the later stage. The net photosynthetic rate decreases in the early stage, and then recovers or the rate of decrease decreases significantly in the later stage. Intercellular CO2 concentration initially decreases and then recovers, or recovers synchronously when net photosynthetic rate recovers; Porous conductance decreases in the early stage and then recovers in the later stage; The appearance has only changed slightly, but the plant as a whole still retains its survival and ornamental value; Diagnostic criteria for chronic suppressive type: The maximum photochemical efficiency continued to decline during the culture period, or fell below the lower limit of the normal range of 0.75 at the end of the period; The photosynthetic electron transport rate continues to decline, or it declines in the early stage but fails to recover significantly in the later stage; Active heat dissipation quantum yield may increase in the early stage, but decrease or remain insufficient in the later stage; The yield of passive heat dissipation quantum gradually increases or remains at a high level; The net photosynthetic rate continues to decline or shows no significant recovery in the later stages; The intercellular CO2 concentration is stable or increases when the net photosynthetic rate decreases and the stomatal conductance decreases. Porous conductance continues to decline or remains at a low level for a long period of time; The plant shows obvious but non-fatal damage, but it is still able to survive, and some upper leaves or new tissues remain normal. Criteria for determining irreversible damage: The maximum photochemical efficiency decreased significantly in a short period of time, or remained below the lower limit of the normal range of 0.75 without any recovery trend; The rate of photosynthetic electron transport declines rapidly and remains at a low level, or nearly stagnates. Active heat dissipation quantum yield cannot be effectively increased, or it increases briefly and then drops rapidly. The passive heat dissipation quantum yield has increased significantly and remained at a high level. Net photosynthetic rate drops sharply, approaches zero, or shows no recovery; Abnormal increases or fluctuations in intercellular CO2 concentration, or failure to recover synchronously with stomatal conductance when net photosynthetic rate is severely reduced; Stomatal conductance decreased significantly, approached closure, or lost its stable regulatory tendency; When the plant exhibits severe wilting, lodging, root rot, decay, large-scale yellowing and browning, or death in the early or middle stages of cultivation, and loses its ornamental value or survival ability, it is directly identified as an irreversible damage type. When the changes in various indicators are not entirely consistent, a comprehensive judgment should be made by combining the maximum photochemical efficiency, photosynthetic electron transfer rate, active heat dissipation quantum yield, and apparent morphology. In the comprehensive judgment, stable and stress-adaptive plants can be given priority as suitable plants for underground spaces. Chronic inhibited plants should be selected based on their ornamental value, maintenance cost, and subsequent recovery ability. Irreversible damage plants are not recommended as plants for underground space greening.

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