Method for regulating growth morphological indexes of cupressus funebris seedlings

Abstract

The application discloses a method for regulating growth morphological indexes of Cunninghamia lanceolata seedlings and belongs to the technical field of plant growth promotion. ‑2 ·s ‑1 With 40 μmol m ‑2 ·s ‑1 mol m Blue light, red light, 1:1 L red / far red light, 1:2 L red / far red light and far red light with 40 μmol m The results show that the root system of the Cunninghamia lanceolata seedlings cultivated under 68% light intensity grows more vigorously, the increment of lateral branch length of the Cunninghamia lanceolata seedlings increases under low light intensity, the root-shoot ratio decreases, and the leaf area is large and thin.Compared with white light, blue light can promote the elongation of the Cunninghamia lanceolata seedling height, but the seedling stem thickening is inhibited, and the seedling root system grows weakly with low root-shoot ratio.Red light promotes the growth of the Cunninghamia lanceolata seedling leaves and root system, and the root-shoot ratio is high, but the elongation of the Cunninghamia lanceolata seedling height is inhibited.The far red light and the increase of the far red light proportion are beneficial to the elongation of the Cunninghamia lanceolata seedling height.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of plant growth promotion, and more particularly relates to a method for regulating growth morphological indexes of Cunninghamia lanceolata seedlings. BACKGROUND

[0002] Cunninghamia lanceolata (Lamb.) Hook is an important fast-growing afforestation tree species in southern China, and plays an important role in meeting wood demand and maintaining ecological safety. Due to the over pursuit of short-term economic benefits for a long time, a series of ecological problems such as soil fertility decline, low ecological service function and poor vegetation regeneration have occurred in Cunninghamia lanceolata plantations, which directly affects the sustainable management of Cunninghamia lanceolata plantations. With the rapid development of modern multi-functional forestry, afforestation has changed from mainly producing wood to mainly playing the role of forest ecological function service, and the research on some ecological processes and ecological functions of plantations, such as natural regeneration, has attracted more and more attention in the academic circle. Whether Cunninghamia lanceolata plantations can naturally regenerate is the key to sustainable management. Cunninghamia lanceolata plantation has poor natural seed dispersal regeneration ability, and existing studies have shown that seed source is not the main limiting factor affecting Cunninghamia lanceolata regeneration. The rainfall in the south is sufficient, and the temperature is suitable, so water and temperature are not the main factors affecting Cunninghamia lanceolata regeneration. The lack of light caused by high canopy density and many ferns in Cunninghamia lanceolata plantations may be the main reason for the survival and establishment of Cunninghamia lanceolata seedlings.

[0003] The problem of ozone layer reduction in global climate change is becoming more and more serious, so light has become the most important environmental factor with dynamic change, and its stress on plant growth is also more and more prominent. The growth and physiological response of plants are regulated by light, and different plants have different adaptive characteristics to light, whether in terms of light intensity or light quality. During the natural canopy process of Cunninghamia lanceolata plantations, the light intensity, red light and blue light received by Cunninghamia lanceolata seedlings under the forest are reduced, and the far red light is increased. Due to natural disasters, the emergence of gaps and canopy gaps, or artificial pruning and thinning in the process of stand management, Cunninghamia lanceolata seedlings originally growing in the shade will be suddenly exposed to strong light, and the light quality will also change. Field investigation also found that there are few Cunninghamia lanceolata seedlings naturally regenerated under the forest, but there are many Cunninghamia lanceolata seedlings naturally regenerated at the edge of the forest and along the road, which confirms that the main factor affecting the natural regeneration of Cunninghamia lanceolata may be the light environment, so it is of great significance to reveal the undergrowth regeneration obstacle of Cunninghamia lanceolata to study the morphological plasticity of Cunninghamia lanceolata seedlings under different light environments. SUMMARY

[0004] In view of the above problems existing in the prior art, the technical problem to be solved by the present application is to provide a method for regulating the growth morphological indexes of Cunninghamia lanceolata seedlings, which facilitates the early management of Cunninghamia lanceolata plantations.

[0005] To solve the above technical problems, the technical scheme adopted by the present application is as follows:

[0006] A method for regulating the growth morphological indexes of Cunninghamia lanceolata seedlings, which regulates the morphological indexes of Cunninghamia lanceolata seedlings by adjusting the light intensity and / or controlling the light quality irradiation of Cunninghamia lanceolata seedlings; the regulation range of the light intensity is not more than 90000 Lux, the light quality includes white light, blue light, red light, 1:1 L red / far red light, 1:2 L red / far red light, and far red light; and the morphological indexes include the relative growth rate of plant height, the increment of lateral branch length, the height-diameter ratio, the specific leaf area, the relative growth rate of ground diameter, the root-shoot ratio, the seedling quality index, the leaf length, the leaf width, the leaf area, the total root length, the root surface area, the root volume, and the root tissue density.

[0007] The method for regulating the growth morphological indexes of Cunninghamia lanceolata seedlings increases the relative growth rate of plant height, the increment of lateral branch length, and the height-diameter ratio of Cunninghamia lanceolata seedlings, reduces the leaf width and the leaf area, increases the specific leaf area, reduces the total root length, the root surface area, and the root volume, and reduces the root tissue density of Cunninghamia lanceolata seedlings by reducing the light intensity within the range of not more than 90000 Lux.

[0008] The method for regulating the growth morphological indexes of Cunninghamia lanceolata seedlings increases the ground diameter of Cunninghamia lanceolata seedlings by using far red light irradiation within the range of light intensity from 400 μmol·m -2 ·s -1 to 40 μmol·m -2 ·s -1 .

[0009] The method for regulating the growth morphological indexes of Cunninghamia lanceolata seedlings promotes the elongation of the plant height of Cunninghamia lanceolata seedlings and increases the height-diameter ratio of Cunninghamia lanceolata seedlings by using blue light or far red light irradiation within the range of light intensity from 400 μmol·m -2 ·s -1 to 40 μmol·m -2 ·s -1 .

[0010] The method for regulating the growth morphological indexes of Cunninghamia lanceolata seedlings promotes the elongation of the lateral branches of Cunninghamia lanceolata seedlings by controlling the light quality from white light to blue light, red light, 1:1 L red / far red light, 1:2 L red / far red light, and far red light within the light intensity of 400 μmol·m -2 ·s -1 .

[0011] The method for regulating the growth morphological indexes of Cunninghamia lanceolata seedlings inhibits the elongation of the lateral branches of Cunninghamia lanceolata seedlings by controlling the light quality from white light to blue light and red light within the light intensity of 40 μmol·m -2 ·s -1 .

[0012] The method for regulating the growth morphological indexes of the Cunninghamia lanceolata seedlings, under the light intensity of 400 μmol·m -2 ·s -1 The method for regulating the growth morphological indexes of the Cunninghamia lanceolata seedlings, under the light intensity of 400 μmol·m -2 ·s -1 The method for regulating the growth morphological indexes of the Cunninghamia lanceolata seedlings, under the light intensity of 400 μmol·m

[0013] The method for regulating the growth morphological indexes of the Cunninghamia lanceolata seedlings, under the light intensity of 400 μmol·m -2 ·s -1 The method for regulating the growth morphological indexes of the Cunninghamia lanceolata seedlings, under the light intensity of 400 μmol·m

[0014] The method for regulating the growth morphological indexes of the Cunninghamia lanceolata seedlings, under the light intensity of 400 μmol·m -2 ·s -1 The method for regulating the growth morphological indexes of the Cunninghamia lanceolata seedlings, under the light intensity of 400 μmol·m -2 ·s -1 The method for regulating the growth morphological indexes of the Cunninghamia lanceolata seedlings, under the light intensity of 400 μmol·m

[0015] The method for regulating the growth morphological indexes of the Cunninghamia lanceolata seedlings, under the light intensity of 400 μmol·m -2 ·s -1 The method for regulating the growth morphological indexes of the Cunninghamia lanceolata seedlings, under the light intensity of 400 μmol·m -2 ·s -1 The method for regulating the growth morphological indexes of the Cunninghamia lanceolata seedlings, under the light intensity of 400 μmol·m

[0016] Compared with the prior art, the method has the beneficial effects that:

[0017] The method for regulating the growth morphological indexes of the Cunninghamia lanceolata seedlings, under the light intensity of 400 μmol·m -2 ·s -1 The method for regulating the growth morphological indexes of the Cunninghamia lanceolata seedlings, under the light intensity of 400 μmol·m -2 ·s -1Cunninghamia lanceolata seedlings were irradiated by blue light, red light, 1:1L red / far-red light, 1:2L red / far-red light and far-red light under 68%, 50%, 33%, 17% and 8% light intensity. The results showed that the root system of Cunninghamia lanceolata seedlings grew more vigorously under 68% light intensity, the increment of lateral branch length of Cunninghamia lanceolata seedlings increased, the root-shoot ratio decreased, and the leaf area was large and thin under low light intensity. Compared with white light, blue light could promote the elongation of Cunninghamia lanceolata seedling height, but the stem thickening of seedlings was inhibited, and the root system growth was weak, the dry biomass accumulation was less, and the root-shoot ratio was low. Red light promoted the growth of Cunninghamia lanceolata seedling leaves and roots, and the root-shoot ratio was high, but inhibited the elongation of Cunninghamia lanceolata seedling height. Far-red light and the increase of far-red light proportion were beneficial to the elongation of Cunninghamia lanceolata seedling height. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 Figure is the growth characteristics diagram of Cunninghamia lanceolata seedlings under different light intensities;

[0019] Figure 2 Figure is the leaf morphology and specific leaf area diagram of Cunninghamia lanceolata seedlings under different light intensities;

[0020] Figure 3 Figure is the root system morphology diagram of Cunninghamia lanceolata seedlings under different light intensities;

[0021] Figure 4 Figure is the growth characteristics diagram of Cunninghamia lanceolata seedlings under different light environments;

[0022] Figure 5 Figure is the leaf morphology and specific leaf area diagram of Cunninghamia lanceolata seedlings under different light environments;

[0023] Figure 6 Figure is the root system morphology diagram of Cunninghamia lanceolata seedlings under different light environments. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described below in combination with specific examples. In the following examples, the technical means used are all conventional means well known to those skilled in the art, unless otherwise specified.

[0025] Example 1

[0026] 1、The present application is carried out in a flat and open nursery in a state-owned forest farm in Shunchang County, Fujian Province, with full light as a control (without shading treatment), and the other four light intensity gradients are set up by building square iron frames (each side is 1.8 meters long) and covering them with black nylon mesh of different needle sizes. On sunny days, the light conditions under each treatment were measured at 12:00 every day for 7 consecutive days using a light meter (HiPoint HP350, Taiwan, China). According to the measurement results, the light transmittance of each shading net chamber was 68%, 27%, 12% and 5% of the full light, which is expressed as 68% light intensity, 27% light intensity, 12% light intensity and 5% light intensity in the following. At the same time, a handheld spectral measurement instrument (HP350) was used to measure the red / far-red light under each treatment (see Table 2-1). The shading net chambers were distributed parallel to the sun's movement track in the day to minimize the temporal and spatial variation of solar radiation, and were closed on all sides but the bottom line was 15 cm from the ground to maintain air circulation on the ground. Four replicates were set up for each light intensity gradient (i.e. four shading net chambers were set up for each light intensity gradient). During the experiment, air temperature and humidity recorders (RHD-07C, Hebei, China) were installed under each treatment to continuously monitor the air temperature and humidity. The instrument automatically counted every 20 minutes, and all the measured data during the experiment were analyzed to obtain the average air humidity and air temperature under each light intensity, as shown in Table 1.

[0027] Table 1 Environmental conditions under different light intensity treatments

[0028]

[0029] Note: Data are expressed as mean ± standard error. Different lowercase letters indicate significant differences (p<0.05) between different light intensities.

[0030] The test seedlings were 1-year-old Cunninghamia lanceolata seedlings purchased from Yangkou State-owned Forest Farm in Shunchang County, Fujian Province in May 2020. The seedlings were transplanted into flowerpots (inner diameter 30 cm, height 32 cm) containing local mountain red soil, and the soil organic matter content was 4.03 ± 0.39 mg·g -1The seedlings were transplanted to the greenhouse for 1 month of acclimation, with one seedling per pot. After acclimation, 120 seedlings with similar growth and development were selected, with an average height of 33.14 ± 3.43 cm and an average ground diameter of 4.70 ± 0.57 mm. The seedlings were randomly divided into 5 groups, with each group having the same light intensity gradient. Each light intensity gradient had 4 replicates, and each replicate contained 6 seedlings. The selected seedlings were placed in different light intensity gradient treatments. To ensure that the seedlings received similar light conditions and that there was no mutual shading between adjacent plants, the plants were placed 40 cm apart. The pots were rotated weekly to maintain similar light conditions. No fertilization was performed during the experiment, but weeds were removed regularly, and the soil was watered 2-3 times per week to maintain soil moisture. The light intensity experiment lasted 4 months and ended in October 2020.

[0031] 2. The height (H), ground diameter (D), and branch length (BL) of all Chinese fir seedlings were measured before the light treatment began (June 2020) and at the final harvest (October 2020). The height-diameter ratio (H:D, cm·cm -1 ), relative growth rate of height [RGRh = (lnH2-lnH1) / t, cm·cm -1 month -1 ], relative growth rate of ground diameter [RGRd = (lnD2-lnD1) / t, mm·mm -1 month -1 ], and branch length increment (△BL = BL2-BL1, cm) were calculated. H1 and H2 represent the height measured before and after the light treatment, respectively. D1 and D2 represent the ground diameter measured before and after the light treatment, respectively. BL1 and BL2 represent the branch length measured before and after the light treatment, respectively. t represents the duration of the experiment, which was 4 months. After all the physiological and biochemical indicators were measured, the whole plant was harvested, and the roots, stems, and leaves were dried to constant weight. The dry biomass of each part (roots, stems, and leaves) was measured, and the root-shoot ratio (R:S) and seedling quality index [QI = whole plant dry weight / (height / ground diameter + stem dry weight / root dry weight)] were calculated.

[0032] The results, as shown in Figure 1 , showed that as the light intensity decreased, the Chinese fir seedlings exhibited greater relative growth rate of height, branch length increment, and height-diameter ratio, with a biomass allocation pattern consistent with the optimal partitioning theory, and a decreased root-shoot ratio. However, the relative growth rate of ground diameter and seedling quality index decreased, and the plant growth was weak.

[0033] 3. At harvest, 3 seedlings were randomly selected from each of the 4 replicates for leaf and root morphological measurements, i.e. 12 seedlings for each light intensity gradient. Leaves were collected from the same height and same position of the seedlings, and 10 intact, healthy, fully expanded green leaves were collected from each seedling. The collected leaves were numbered and stored in ice boxes. After all leaves were collected, the pots were watered and the roots were carefully excavated and washed with running water. The washed roots were collected and stored in ice boxes. The collected leaves and roots were brought back to the laboratory for root morphological scanning analysis. The leaves and roots were scanned one by one using a standard scanner (Epson Expression 10000XL, Tokyo, Japan), and WinRHIZO image analysis software (version 2003e, Regent Instruments, Quebec City, QC, Canada) was used to analyze leaf length (LL, cm), leaf width (LW, mm), leaf area (excluding petiole, LA, cm 2 ), total root length (TRL, m), root surface area (RSA, cm 2 ), root volume (RV, cm 3 ). If the roots were too many to be scanned at one time, they could be divided into several segments and scanned separately, and the results were finally summarized. The scanned leaves and roots were collected and placed in envelopes one by one, numbered, and placed in an oven at 105°C for 30 minutes, then at 80°C until the weight was constant, and then weighed and recorded the final dry biomass. According to the analysis results and the weighing results, the specific leaf area (SLA, cm 2 ·g -1 ) was calculated, which was the ratio of leaf area to leaf dry biomass, and the root tissue density (RTD, g·cm -3 ) was calculated, which was the ratio of root dry biomass to root volume.

[0034] The results, as shown in Figure 2 , showed that the light intensity change had a significant effect on the leaf length, leaf width, leaf area, and specific leaf area of Cunninghamia lanceolata seedlings (p < 0.05). With the decrease of light intensity, the leaf width and leaf area of Cunninghamia lanceolata seedlings decreased, while the specific leaf area increased, which was beneficial to improve the capture and interception ability of Cunninghamia lanceolata seedlings to limited light resources under shade conditions.

[0035] The results, as shown in Figure 3 , showed that the light intensity change had a significant effect on the total root length, root surface area, root volume, and root tissue density of Cunninghamia lanceolata seedlings (p < 0.05). With the decrease of light intensity, the total root length, root surface area, and root volume of Cunninghamia lanceolata seedlings decreased, and there was no significant difference among the full light, 68% and 27% light intensities. The root tissue density of Cunninghamia lanceolata seedlings was the largest under full light and the smallest under 5% light intensity.

[0036] Example 2

[0037] The experiment was conducted in an experimental greenhouse at Fujian Agriculture and Forestry University (26°4′30″~26°6′00″N, 119°13′30″~119°14′30″E). Based on the results of Example 1, two light intensity gradients (400 μmol·m⁻¹) were selected. -2 ·s -1 and 40 μmol·m -2 ·s -1 Six light quality treatments were set for each light intensity gradient: blue light (BL, 450–455 nm), red light (RL, 650–660 nm), 1:1 red / far-red light (1:1L), 1:2 red / far-red light (1:2L), far-red light (FrL, 715–735 nm), and white light (WL, 450–570 nm) as controls. Among them, 1:1 red / far-red light (1:1L) and 1:2 red / far-red light (1:2L) were achieved by evenly arranging red and far-red LED beads in a proportional manner.

[0038] All treatments were conducted in separate growth chambers (90cm × 100cm × 100cm cube-shaped steel frame structures). The different growth chambers were separated by a non-reflective, opaque black film to prevent light pollution. Each growth chamber was equipped with an upward airflow distribution system to control the temperature and ensure air circulation. Two LED light panels, each 40cm × 80cm in size, were horizontally mounted above each growth chamber. The vertical distance between the top of the seedling canopy and the LED light panels was maintained at 20cm. PPFD was measured at the top of the seedlings, and the brightness of the LED light panels was adjusted to maintain a value of 400 μmol·m⁻². -2 ·s -1 and 40 μmol·m -2 ·s -1 During the experiment, the distance between the LED light panels and the seedling canopy was adjusted in a timely manner according to the growth of the Chinese fir seedlings. All LED light panels were controlled by an automatic timer calibrator, providing 12 hours of light per day (from 6:00 to 18:00).

[0039] In April 2021, one-year-old Chinese fir seedlings were purchased from the nursery of Yangkou State-owned Forest Farm in Shunchang County, Fujian Province. The seedlings were transplanted into pots filled with a mixture of peat moss and vermiculite (volume ratio 2:1), with one seedling planted in each pot. The seedlings were then placed in an experimental greenhouse for one month. After the seedlings had recovered, 72 relatively uniformly grown (average height 31.55±5.32cm, average diameter at birth 3.69±0.31mm) and well-developed Chinese fir seedlings were selected and randomly divided into 12 groups. These groups were then placed in growing chambers with different light environments for another three months. Each treatment consisted of six seedlings, with each pot considered a replicate. The seedlings were randomly placed, ensuring they were exposed to the same light conditions, were independent of each other, and did not shade each other. To avoid light heterogeneity, the pots were adjusted weekly. No fertilizer was applied during the experiment; only regular weeding and watering 2-3 times per week were performed to maintain soil moisture.

[0040] At the end of the seedling establishment period (May 2021) and at the end of the light treatment period (August 2021), the plant height (H), ground diameter (D), and lateral branch length (BL) of all seedlings were measured. Based on the measurement results, the height-to-diameter ratio (H:D), plant height increment (△H=H2-H1), ground diameter increment (△D=D2-D1), and lateral branch length increment (△BL) of all Chinese fir seedlings were calculated. H1 and H2 represent the plant height measured before and after the light treatment, D1 and D2 represent the ground diameter measured before and after the light treatment, and BL1 and BL2 represent the lateral branch length measured before and after the light treatment.

[0041] The results are as follows Figure 4 As shown, the increase in diameter at ground level of Chinese fir seedlings decreased significantly with decreasing light intensity, but the response to changes in light quality differed under different light intensities; at 400 μmol·m -2 ·s -1 Under varying light intensity, changes in light quality had no significant effect on the diameter increase of Cunninghamia lanceolata seedlings (p = 0.239), while the diameter increase was relatively small under blue light; at 40 μmol·m -2 ·s -1 Under light intensity, except for a significant increase in the diameter increase of Chinese fir seedlings under far-red light, there were no significant differences in light quality among the other light intensities. Figure 4 A). As light intensity decreased, the increase in height of Chinese fir seedlings fluctuated less. Except for a significant decrease under red light, there were no significant changes under other light qualities, and the trend of change was basically consistent under different light qualities. Compared with white light, the height growth of Chinese fir seedlings under red light was slow and the increase was small, while blue light and far-red light significantly promoted the elongation of the seedlings, with the largest increase under far-red light, which was 1.44 times (400 μmol·m) higher than that under white light. -2 ·s -1 ) and 1.92 times (40 μmol·m -2 ·s -1) and the increment of plant height increased with the increase of the proportion of far-red light Figure 4 B) With the decrease of light intensity, the SLR of Cunninghamia lanceolata seedlings increased significantly, and the change trend was basically consistent among different light qualities. Compared with white light, the SLR of seedlings under red light decreased slightly, but there was no significant difference with white light, while the SLR under blue light and far-red light increased significantly. With the increase of the proportion of far-red light, the SLR of Cunninghamia lanceolata seedlings increased Figure 4 C) With the decrease of light intensity, the increment of lateral branch length of Cunninghamia lanceolata seedlings decreased, but the response to light quality was different under different light intensities; under 400 μmol·m -2 ·s -1 With the change of light quality, the elongation of lateral branches of Cunninghamia lanceolata seedlings was promoted compared with white light under 400 μmol·m -2 ·s -1 Under 40 μmol·m -2 ·s -1 light, the change of light quality was not conducive to the elongation of lateral branches of Cunninghamia lanceolata seedlings, and the inhibitory effect of blue light and red light was more significant Figure 4 D).

[0042] Leaf samples were collected from the same height and same position of seedlings under different light environments, and 10 complete, healthy, fully expanded green leaves per seedling were selected for leaf morphology scanning analysis. Standard scanner (Epson Expression 10000XL, Tokyo, Japan) was used for scanning, and WinRHIZO image analysis software (version 2003e, Regent Instruments, Québec City, QC, Canada) was used for analysis of leaf length (LL), leaf width (LW), and leaf area (LA). The scanned leaves were placed in envelopes one by one, numbered and placed in an oven at 105℃ for 30 minutes, and then placed in an oven at 80℃ until constant weight to obtain leaf dry biomass and calculate specific leaf area (SLA).

[0043] The results are shown in Figure 5 With the decrease of light intensity, the leaf length of Cunninghamia lanceolata seedlings decreased significantly, and the change trend was basically consistent under different light qualities; under two light intensity gradients, the change range of leaf length of Cunninghamia lanceolata seedlings under blue light was small and the difference was not significant compared with white light, the leaf length under red light was significantly higher than that under other light qualities, and the leaf length of seedlings under 1:1 red / far-red light, 1:2 red / far-red light and far-red light decreased Figure 5 A) With the decrease of light intensity, the leaf width of Cunninghamia lanceolata seedlings decreased, and the decrease range under white light, 1:1 red / far-red light and far-red light was large and significant; under 400 μmol·m -2 ·s -1Under different light intensities, compared to white light, the leaf width of Chinese fir seedlings decreased under blue and red light, while it increased under 1:1 red / far-red, 1:2 red / far-red, and far-red light. The leaf width under far-red light was significantly greater than under other light qualities. At 40 μmol·m⁻², the leaf width of Chinese fir seedlings decreased. -2 ·s -1 Under varying light intensity, changes in light quality significantly increased leaf width compared to under white light. Figure 5 B). As light intensity decreased, the leaf area of ​​Chinese fir seedlings decreased significantly, with the largest decrease observed under red light treatment at all light intensities; at 400 μmol·m -2 ·s -1 Under different light intensities, there was no significant difference in leaf area among Chinese fir seedlings of different light qualities (p = 0.051); at 40 μmol·m -2 ·s -1 Under different light intensities, the leaf area of ​​Chinese fir seedlings was smallest under white light. The leaf area was larger under all other light qualities than under white light, with the largest leaf areas observed under red light, 1:2 red / far-red light, and far-red light. Figure 5 C). As light intensity decreased, the specific leaf area of ​​Chinese fir seedlings increased significantly; at 400 μmol·m -2 ·s -1 Under light intensity, compared with white light, the specific leaf area of ​​Chinese fir seedlings increased under blue light, red light, and far-red light; at 40 μmol·m -2 ·s -1 Under light intensity, except for a decrease in specific leaf area under far-red light, the specific leaf area increased under all other light qualities, with the largest increase observed under red light. Figure 5 D).

[0044] At the final harvest, carefully excavate the root system and rinse it clean. Using the same method as for leaf morphology analysis, first scan the roots with a standard scanner (Epson Expression 10000XL, Tokyo, Japan), and then analyze the total root length (TRL), root surface area (RSA), and root volume (RV) of each cedar seedling using WinRHIZO image analysis software (version 2003e, Regent Instruments, Québec City, QC, Canada). If the root system is too large to be scanned in one go, it can be divided into several segments, scanned separately, and the results can be summarized.

[0045] The results are as follows Figure 6 As shown, the total root length of *Cunninghamia lanceolata* seedlings decreased significantly with decreasing light intensity, but the response to changes in light quality differed under different light intensities; at 400 μmol·m⁻¹, the total root length decreased significantly. -2 ·s -1 Under different light intensities, compared with white light, except for red light where the total root length of Chinese fir seedlings was larger, the total root length was lower under all other light qualities than under white light, and was significantly lower under blue light; at 40 μmol·m -2 ·s-1 Under different light intensities, there was no significant difference in the total root length of Chinese fir seedlings with different light qualities (p = 0.134). Figure 6 A). As light intensity decreased, the root volume of *Cunninghamia lanceolata* seedlings decreased significantly, but the response to changes in light quality differed under different light intensities; at 400 μmol·m⁻¹... -2 ·s -1 Under different light intensities, compared with white light, except for a significant decrease in root volume of Chinese fir seedlings under blue light, the differences in other light qualities were not significant, but were relatively larger under red light; at 40 μmol·m -2 ·s -1 Under varying light intensities, the root volume of Chinese fir seedlings was largest under 1:1 red / far-red light, followed by far-red light, then blue light, white light, 1:2 red / far-red light, and finally red light. Figure 6 B). As light intensity decreased, the root surface area of ​​the Chinese fir seedlings decreased significantly, exhibiting a similar trend to that of the root volume; at 400 μmol·m -2 ·s -1 Under different light intensities, compared with white light, the root surface area of ​​Chinese fir seedlings was significantly reduced under blue light, while there were no significant differences between other light qualities and white light. The root surface area was largest under red light. At 40 μmol·m -2 ·s -1 Under different light intensities, there was no significant difference in root surface area among Chinese fir seedlings of different light qualities (p = 0.087). Figure 6 C).

[0046] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A method for regulating growth morphological indexes of Cunninghamia lanceolata seedlings, characterized in that, By adjusting light intensity and controlling light quality irradiation treatment of Chinese fir seedlings, the morphological index regulation of Chinese fir seedlings is realized; the light intensity is changed in the range from 400 μmol·m -2 ·s -1 to 40 μmol·m -2 ·s -1 , the light quality includes white light, blue light, red light, 1:1 L red / far red light, 1:2 L red / far red light, far red light, and the morphological index includes height-diameter ratio, specific leaf area, leaf length, leaf width, leaf area, total root length, root surface area, root volume, plant height, ground diameter, lateral branch length. At light intensity from 400 μmol·m -2 ·s -1 - 40 μmol·m -2 ·s -1 , far-red light irradiation achieved an increase in the ground diameter of Chinese fir seedlings. Under the light intensity from 400 μmol·m -2 ·s -1 -40 μmol·m -2 ·s -1 , the blue light or far-red light irradiation realized promoting the height elongation of Chinese fir seedlings and increasing the height-diameter ratio of Chinese fir seedlings. Under the light intensity from 400 μmol·m -2 ·s -1 -40 μmol·m -2 ·s -1 , the red light irradiation realized the growth of Cunninghamia lanceolata seedling leaf length, and the irradiation under 1:1 red / far-red light, 1:2 red / far-red light and far-red light realized the reduction of Cunninghamia lanceolata seedling leaf length; Light intensity varied from 400 μmol·m -2 ·s -1 to 40 μmol·m -2 ·s -1 and increasing specific leaf area of Chinese fir seedlings was achieved by using blue and red light irradiation.

2. The method for regulating the growth morphological indexes of Cunninghamia lanceolata seedlings according to claim 1, characterized in that, At 400 μmol·m -2 ·s -1 Under the light intensity, the light quality was controlled to change from white light to blue light, red light, 1:1 L red / far red light, 1:2 L red / far red light, and far red light to promote the elongation of lateral branches of Chinese fir seedlings.

3. The method for regulating the growth morphological indexes of Cunninghamia lanceolata seedlings according to claim 1, characterized in that, At 40 μmol·m -2 ·s -1 Under the light intensity, the light quality was controlled from white light to blue light and red light, which achieved the inhibition of the elongation of the lateral branches of Cunninghamia lanceolata seedlings.

4. The method for regulating the growth morphological indexes of Cunninghamia lanceolata seedlings according to claim 1, characterized in that, At 400 μmol·m -2 ·s -1 Under the irradiance intensity, the light quality was controlled from white light to blue light and red light to irradiate the Cunninghamia lanceolata seedlings, which realized the decrease of leaf width of Cunninghamia lanceolata seedlings. The light quality was controlled from white light to 1:1 red / far-red light, 1:2 red / far-red light and far-red light to irradiate the Cunninghamia lanceolata seedlings, which realized the increase of leaf width of Cunninghamia lanceolata seedlings.

5. The method for regulating the growth morphological indexes of Cunninghamia lanceolata seedlings according to claim 1, characterized in that, At 400 μmol m -2 ·s -1 Light intensity, using red light irradiation of Chinese fir seedlings growth of seedlings of Chinese fir total root length, using blue light irradiation of Chinese fir seedlings reduce the volume of Chinese fir seedlings; in 40 μmol m -2 ·s -1 Light intensity, using 1:1 red / far red light irradiation of Chinese fir seedlings increase the volume of Chinese fir seedlings.

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