Exogenous treatment method and system capable of promoting expansion of lily second-generation seedballs

Abstract

The invention belongs to the technical field of planting, and discloses an exogenous treatment method capable of promoting expansion of second-generation bulbs of lilies, which comprises the following steps: planting the second-generation bulbs of lilies in Pingsi peat soil, and when overground parts of the lilies grow to about 20cm, carrying out exogenous irrigation treatment by using a malic acid solution once every two weeks. The malic acid solution is adopted for exogenous irrigation of plants, and compared with a control group, the circumferential diameter of seedballs harvested in a treatment group is remarkably increased; the exogenous treatment method in the lily bulb cultivation process has the advantages of being low in cost, convenient to operate, high in production quality, green, free of pollution and the like, solves the problem of degradation of second-generation lily bulbs generally existing in the lily cultivation process, facilitates lily cultivation management and bulb expansion, and provides technical support for localization of the lily bulbs.

Description

Technical Field

[0001] The invention belongs to the field of planting technology, and in particular relates to an exogenous treatment method and system capable of promoting the expansion of second-generation lily bulbs. Background Art

[0002] Lilies (Lilium spp.), perennials belonging to the Liliaceae family, are widely beloved bulbs, earning them the title of "King of Bulbs." They possess exceptional ornamental, medicinal, and edible value. Lilies have been beloved by the Chinese since ancient times, not only for their beautiful appearance but also for their rich cultural connotations. China has always been a major consumer of lily cut flowers and bulbs. Currently, there are approximately 110 species in the genus Lilium, widely distributed from the subtropics to the coldest regions of the Northern Hemisphere. China, with approximately 55 species and 32 varieties, is considered the global center of lily diversity.

[0003] One of the key factors influencing the development of the lily industry both domestically and internationally is the quality of lily bulbs. Internationally, lily breeding research began early, and a monopoly on the lily bulb market has emerged, led by the Netherlands, the United States, and Japan. However, domestic lily bulb production is still in its developmental stages, subject to numerous limitations and widespread issues such as bulb degeneration. Furthermore, there are currently few companies in my country capable of large-scale independent production of lily bulbs, resulting in poor quality domestically produced bulbs and limited industrial application. However, the market demand for new varieties and commercialized bulbs is high, resulting in the annual importation of large quantities of high-quality bulbs from abroad.

[0004] my country's lily bulb industry has long faced issues with bulb enlargement. As commercial bulbs grow from a year of field cultivation to cut flower production, the lily plants continuously consume nutrients from the bulbs, resulting in a reduction in the size of the harvested second-generation bulbs, which may fail to bloom when planted the following year. These issues have led to a long-term reliance on imported lily bulbs in China, increasing production costs and severely hindering the growth of the lily industry and the expansion of consumer demand. Therefore, researching the issue of second-generation lily bulb enlargement and developing technologies to mitigate bulb degeneration and produce large quantities of high-quality lily bulbs will help promote the localization of lily bulbs and the development of my country's lily industry.

[0005] Through the above analysis, the problems and defects of the existing technology are as follows:

[0006] The lily bulb industry has always had the problem of bulb enlargement. After a year of field planting of commercial bulbs to produce cut flowers, the lily plants continue to consume nutrients in the bulbs, resulting in a reduction in the size of the harvested second-generation bulbs, which may cause them to fail to bloom when planted the following year. Summary of the Invention

[0007] In view of the problems existing in the prior art, the present invention provides an exogenous treatment method and system that can promote the expansion of second-generation lily bulbs.

[0008] The present invention is achieved by providing an exogenous treatment method capable of promoting the expansion of second-generation lily bulbs, comprising:

[0009] Step 1: Select healthy lily bulbs that are free of pests and diseases and of similar size;

[0010] Step 2, preparing the cultivation medium;

[0011] Step 3: Plant the second-generation lily bulbs in the cultivation medium and water them thoroughly;

[0012] Step 4, when the above-ground part of the lily grows to about 20 cm, the lily plants are irrigated with 10-500 mg / L malic acid (MA) solution, and the control group is irrigated with plain water, and the irrigated once every two weeks;

[0013] Step 5: When the lilies are in the bud-forming stage, remove the flower buds and measure the plant height, stem diameter, leaf length, and leaf width of the lily plants;

[0014] Step 6: After the above-ground parts of the lily plants wither, harvest the lily bulbs and measure the circumference of the bulbs.

[0015] Furthermore, the cultivation medium in step 2 is imported Pin's peat soil. Before planting, large pieces of Pin's peat soil are crushed, and then the medium is moistened with clean water until the medium is watered thoroughly, so as to achieve the effect of moistening the medium before planting the bulbs.

[0016] Furthermore, in step 3, the specific method for planting the lily bulbs in the cultivation medium is as follows: a layer of white gauze is laid inside a 20 cm x 50 cm plastic frame, 5 to 7 cm of medium is evenly laid on the bottom of the plastic frame, and the lily bulbs are planted in the plastic frame, with 5 to 7 cm of medium covering the bulbs. Twelve lily bulbs are planted in each frame in a 3 x 4 pattern.

[0017] Furthermore, the malic acid solutions in step 4 are 10, 100 and 500 mg / L, and the volume of the solution used each time is 5 L.

[0018] Furthermore, in step 3, the lily plants were planted in a greenhouse and grown under natural light with the temperature controlled at 18° C.-25° C. In order to avoid any interference with the results, no fertilizer was used during the experiment.

[0019] Furthermore, in step 5, the stem thickness is measured as the stem thickness between the third and fourth leaves of the plant from the ground; the leaf thickness is measured as the length and width of the third leaf from the plant from the ground; and the plant height is measured as the maximum height of the above-ground part of the plant.

[0020] Another object of the present invention is to provide an exogenous treatment system capable of promoting the expansion of second-generation lily bulbs, comprising:

[0021] A selection module is used to select healthy lily bulbs that are free of pests and diseases and of similar size;

[0022] A configuration module, used for configuring the cultivation substrate;

[0023] The cultivation module is used to plant the second-generation lily bulbs in the cultivation medium and water them thoroughly.

[0024] The irrigation module is used to irrigate the lily plants with a 10-500 mg / L malic acid (MA) solution when the lily aboveground part grows to about 20 cm. The control group is irrigated with plain water, and the watering is carried out once every two weeks.

[0025] The bud removal module is used to remove the buds of lilies during their bud-forming stage and measure the plant height, stem diameter, leaf length and leaf width of the lily plants;

[0026] The harvesting and measuring module is used to harvest lily bulbs and measure the circumference of the bulbs after the above-ground parts of the lily plants wither.

[0027] In combination with the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solutions to be protected by the present invention are as follows:

[0028] First, the present invention relates to an exogenous treatment method capable of promoting the enlargement of second-generation lily bulbs. The second-generation lily bulbs are planted in Pinnacle peat soil and, when the above-ground parts of the lilies grow to approximately 20 cm, are exogenously irrigated with a malic acid solution, with irrigation occurring every two weeks. The present invention employs exogenous malic acid solution for exogenous irrigation of the plants. Compared with the control group, the circumference of the bulbs harvested from the treatment group increased significantly. The exogenous treatment method for the cultivation of lily bulbs of the present invention has the characteristics of low cost, convenient operation, high production quality, and being environmentally friendly and pollution-free. It solves the common problem of degeneration of second-generation lily bulbs during lily cultivation, is beneficial to the cultivation and management of lilies and the enlargement of bulbs, and provides technical support for the localization of lily bulbs.

[0029] Second, lily bulb production in my country is still in the exploratory and developmental stages. High-quality bulbs for production are mostly imported. Due to limitations in climatic conditions and breeding techniques, bulb degeneration, poor forcing cultivation, and low propagation coefficients are common problems. The present invention promotes the expansion of lily bulbs through exogenous malic acid treatment, thereby delaying their degeneration.

[0030] This study has developed a second-generation bulb enlargement technology system for lilies (Lilium spp.) based on exogenous malic acid (MA) regulation. Key parameters include: MA concentrations set at 10, 100, and 500 mg / L, with root irrigation using a 5-L volume per plant, every two weeks until the lilies naturally wither; the cultivation medium is imported Pinnacle peat soil, which is physically crushed and thoroughly moistened to maintain a stable moisture environment; and the lilies are planted in a 3x4 arrangement within a 20 cm x 50 cm plastic frame, with multiple layers of white gauze and matrix. The entire experiment was conducted in a constant temperature greenhouse at 18°C–25°C under natural light, eliminating fertilization interference throughout the process to ensure that malic acid was the sole variable in the regulation.

[0031] Existing second-generation bulb production faces bottlenecks such as low expansion rate, uneven volume, and poor commercial quality. This is primarily due to aboveground vegetative growth and flower bud differentiation occupying a large amount of assimilated products, resulting in insufficient energy supply from underground storage organs. This invention introduces malic acid treatment at the 20 cm plant height stage to effectively improve root activity and photosynthetic efficiency, enhancing the transfer of substances from the aboveground to the underground part. Simultaneously, artificial bud removal at the budding stage cuts off competition for nutrients from reproductive growth, significantly improving the deposition efficiency of assimilated products in the bulb, and addressing the key issue of limited expansion at the source.

[0032] Malic acid, a key intermediate metabolite in the tricarboxylic acid cycle, has multiple functions, including regulating cellular osmotic potential, activating respiratory metabolism, and promoting ion transport. The present invention activates rhizosphere metabolism and sink organ absorption capacity through exogenous MA treatment, increasing the net photosynthetic rate of leaves and the transport efficiency of carbon assimilation products. Combined with a bud removal strategy, lily plants exhibited simultaneous increases in nutritional growth indicators such as plant height, stem diameter, leaf length, and leaf width. Ultimately, the average bulb diameter at harvest was significantly increased, with the treated group increasing by 10–30% compared to the control group, indicating a significant optimization of the source-sink relationship.

[0033] Unlike existing methods that rely on high-cost hormone treatments or complex nutrient management systems, the malic acid treatment method provided by the present invention is simple to operate, highly repeatable, and environmentally friendly. No exogenous fertilizers are applied in the entire experimental system, and it relies entirely on malic acid to guide changes in carbon flow and sink effect, achieving a low-input, high-return yield improvement strategy. This method can effectively improve the commerciality and specification consistency of lily bulbs by only intervening with controllable exogenous substances without changing the conventional cultivation structure. It has strong practicality and promotion prospects and is particularly suitable for large-scale bulb breeding under facility horticulture conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a flow chart of an exogenous treatment method for promoting the enlargement of second-generation lily bulbs provided by an embodiment of the present invention.

[0035] Figure 2This is a system structure diagram of an exogenous treatment method for promoting the enlargement of second-generation lily bulbs provided by an embodiment of the present invention.

[0036] Figure 3 This is a circumference classification diagram of each group of lily bulbs before cultivation provided by an embodiment of the present invention.

[0037] Figure 4 This is a graph showing changes in the average circumference of lily bulbs provided by an embodiment of the present invention.

[0038] Figure 5 This is a physical diagram of the change in average circumference of lily bulbs provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0040] like Figure 1 As shown, an embodiment of the present invention provides an exogenous treatment method for promoting the expansion of second-generation lily bulbs, comprising the following steps:

[0041] S101, select healthy lily bulbs that are free of pests and diseases and of similar size;

[0042] S102, preparing a cultivation medium;

[0043] S103, plant the second-generation lily bulbs in the cultivation medium and water them thoroughly.

[0044] S104: When the lily plants grew to about 20 cm above ground, they were irrigated with 10-500 mg / L malic acid (MA) solution. The control group was irrigated with plain water, and the treatment was conducted every two weeks.

[0045] S105, when the lilies were in the bud-forming stage, the buds were removed and the plant height, stem diameter, leaf length and leaf width of the lilies were measured;

[0046] S106, after the above-ground parts of the lily plants wither, harvest the lily bulbs and measure the circumference of the bulbs.

[0047] In traditional cultivation systems, the development of second-generation lily (Lilium spp.) bulbs often suffers from insufficient expansion, uneven individual size, and low commercial value, severely limiting their application stability in commercial production. This is primarily due to a shift in nutrient distribution toward the aboveground parts, intensified competition between reproductive and vegetative growth, and inefficient source-sink coordination mechanisms in the late stages of cultivation, which hinders the efficient transport and accumulation of photosynthetic products in the bulbs.

[0048] Current research focuses primarily on macro-management measures such as lighting, watering, and fertilizer, lacking specific exogenous interventions specifically targeting carbon metabolism and the assimilation capacity of sink organs (such as bulbs). Existing exogenous substances, such as hormones, are costly, have significant side effects, or lack targeted effects, making it difficult to achieve controlled promotion of bulb enlargement. This is particularly true for enhancing the development of underground organs without disrupting nutrient balance, a technological gap still remaining.

[0049] This study introduces malic acid (MA) as a metabolic regulator for the first time. Based on its physiological function in the tricarboxylic acid cycle, low-dose root irrigation enhances rhizosphere activity and the efficient transfer of photosynthate to bulbs. Experiments have shown that MA treatment significantly increases the deposition efficiency of soluble sugars, starch, and dry matter in bulbs, with a clear dose-response effect at different concentrations. This provides a reliable technical means for increasing lily bulb yield and size.

[0050] Compared to traditional management measures, this method utilizes an exogenous liquid treatment method that is simple to operate and easily standardized, without changing the cultivation system. Through scientific bud removal combined with periodic MA irrigation, the average bulb diameter can be significantly increased (by 10–30%), with improved batch consistency and significantly enhanced reproductive efficiency. This technology offers the advantages of low cost, high operability, and no risk of pesticide residues, making it suitable for large-scale breeding and the production of high-quality commercial bulbs.

[0051] Before exogenous treatment, healthy lily bulbs (Lilium spp.), free of significant pest and disease symptoms, and of similar size were selected to ensure experimental consistency and reduce confounding variables caused by differences in physiological status. The cultivation medium was preferably well-aerated, well-drained Pinnacle peat soil, with a pH maintained between 5.8 and 6.5, to optimize root expansion and water retention, providing a stable growth environment for subsequent malic acid treatment.

[0052] Plant the bulbs in the growing medium, covering them with soil to a depth of 3–5 cm. Initial irrigation ensures sufficient moisture to approximately 80% of the field capacity to promote bulb germination and root establishment. Cultivating the bulbs in a greenhouse with stable environmental conditions (15–25°C, at least 12 hours of light per day) promotes robust growth of the lily's aerial parts, laying a good foundation for exogenous malic acid application.

[0053] When the lilies reach approximately 20 cm above ground (approximately 4–6 true leaves), malic acid (MA) treatment is initiated. As an intermediate product of the tricarboxylic acid cycle, malic acid can promote root vitality and the distribution of photosynthetic products to underground organs by regulating cellular metabolic activity and enhancing ion transport capacity. The experimental group received irrigation with a 10–500 mg / L MA solution, while the control group received water. Treatment was performed every two weeks until flowering. After flower bud differentiation is complete, manual bud removal during the budding phase effectively reduces competition between reproductive growth and vegetative growth, facilitating nutrient transfer to the bulb. Morphological indicators such as plant height, stem diameter, leaf length, and leaf width were simultaneously recorded during this phase to assess the effectiveness of MA in promoting vegetative growth.

[0054] As plants enter senescence, their aerial parts gradually wither and yellow, losing their photosynthetic function. At this point, most of the assimilated products from the aerial parts have been transported to the underground bulbs. Harvesting occurs after complete withering. The bulb circumference (the length of the diameter) was measured as an indicator of bulb volume expansion to assess the effect of exogenous MA treatment on bulb volume accumulation. MA may indirectly promote bulb volume expansion by enhancing carbon assimilation efficiency, improving source-sink coordination, and activating soluble sugar and starch synthases, thereby achieving high-quality accumulation of second-generation propagation material.

[0055] The cultivation medium in S102 provided in the embodiment of the present invention is imported Pinnacle peat soil. Before planting, large pieces of Pinnacle peat soil are crushed, and then the medium is moistened with clean water until the medium is watered thoroughly, so as to achieve the effect of moistening the medium before planting the bulbs.

[0056] In step S103 of the embodiment of the present invention, the specific method for planting lily bulbs in a cultivation medium is as follows: a layer of white gauze is laid inside a 20 cm x 50 cm plastic frame, 5 to 7 cm of medium is evenly laid on the bottom of the plastic frame, and the lily bulbs are planted in the plastic frame, with 5 to 7 cm of medium covering the bulbs. Twelve lily bulbs are planted in each frame in a 3 x 4 pattern.

[0057] The malic acid solutions in S104 provided in the embodiment of the present invention are 10, 100 and 500 mg / L, and the volume of the solution used each time is 5 L.

[0058] In S103 provided in the embodiment of the present invention, the lily plants are planted in a greenhouse and grown under natural light. The temperature is controlled at 18° C.-25° C. In order to avoid any interference with the results, no fertilizer is used during the experiment.

[0059] In S105 provided in the embodiment of the present invention, the stem thickness is measured as the stem thickness between the third and fourth leaves of the plant from the ground; the leaf length and width are measured as the third leaf from the ground; and the plant height is measured as the maximum height of the aboveground part of the plant.

[0060] like Figure 2 As shown, an embodiment of the present invention provides an exogenous treatment system capable of promoting the expansion of second-generation lily bulbs, comprising:

[0061] A selection module is used to select healthy lily bulbs that are free of pests and diseases and of similar size;

[0062] A configuration module, used for configuring the cultivation substrate;

[0063] The cultivation module is used to plant the second-generation lily bulbs in the cultivation medium and water them thoroughly.

[0064] The irrigation module is used to irrigate the lily plants with a 10-500 mg / L malic acid (MA) solution when the lily aboveground part grows to about 20 cm. The control group is irrigated with plain water, and the watering is carried out once every two weeks.

[0065] The bud removal module is used to remove the buds of lilies during their bud-forming stage and measure the plant height, stem diameter, leaf length and leaf width of the lily plants;

[0066] The harvesting and measuring module is used to harvest lily bulbs and measure the circumference of the bulbs after the above-ground parts of the lily plants wither.

[0067] The present invention is specifically implemented as follows:

[0068] 1. Setting of MA solution concentration gradient

[0069] This experiment used second-generation 'Mumen' lily bulbs as experimental material. MA was selected as the reagent, with three concentration gradients established. A control experiment was also conducted. After the lily bulbs were planted, when the aerial parts of the lily plants reached approximately 20 cm, the plants were irrigated with an exogenous MA solution to investigate the effect of this exogenous MA solution on the expansion of the second-generation lily bulbs. The experimental treatment design is shown in Table 1.

[0070] Table 1 MA solution treatment concentration gradient

[0071]

[0072] During the bud-forming stage, the plant height, stem diameter, leaf length and leaf width of the lily plants were statistically analyzed; the circumference of the harvested lily bulbs was graded, and the average circumference of the bulbs and the number of bulbs of different grades were counted.

[0073] 2. Effects of different concentrations of MA solution on the growth morphology of cultivated lily plants

[0074] As can be seen from Table 2, the three different concentrations of MA solutions all significantly promoted the growth of cultivated lily plants.

[0075] Table 2 Effect of MA solution on the growth morphology of cultivated lily plants

[0076]

[0077] The four index data of each treatment were significantly higher than those of the 0 mg / L MA treatment, among which the 10 mg / L MA treatment had the best effect. The average plant height increased by 15.71 cm compared with the 0 mg / L MA treatment, the average stem diameter of the plant increased by 0.46 cm, and the average leaf length and leaf width of the plant increased by 3.90 cm and 0.63 cm respectively.

[0078] 3. Effects of different concentrations of MA solution on the expansion of the second-generation lily bulbs

[0079] from Figure 3 (A, B) It can be seen that the circumference of the lily bulbs in each group before cultivation was the same, which were 13-16 cm and 16-19 cm respectively. After harvesting, the rotten bulbs were removed and the harvested lily bulbs were graded for circumference. All the bulbs were divided into three grades: 13-16 cm, 16-19 cm and 19-22 cm. Figure 3 (C, D) It can be seen that after harvest, the number of lily bulbs in the largest grades (16-19 cm and 19-22 cm) in each treatment group increased significantly compared with the control group. Before expansion, the number of 16-19cm bulbs in each treatment was 16, accounting for 40%. After expansion, the number of 16-19cm bulbs in the control group remained unchanged, accounting for 57.14%. The number of 16-19cm bulbs in the 10mg / LMA treatment group was 20, accounting for 71.43%. The number of 16-19cm bulbs in the 100mg / L MA treatment group was 20, accounting for 55.56%. The number of 16-19cm bulbs in the 500mg / L MA treatment group was 32, accounting for 88.89%. Before expansion, there were no 19-22cm lily bulbs in each treatment. After expansion, the number of 19-22cm bulbs in the control group was 4, accounting for 14.29%. The number of 19-22cm bulbs in the 10mg / L MA treatment group was 8, accounting for 28.57%. The number of bulbs in the MA treatment group that were 19-22 cm was 16, accounting for 44.44%; the 10 and 100 mg / L MA treatment groups had a better effect on the enlargement of the second generation lily bulbs. Figure 4 and Figure 5 It can be seen that the most obvious increase in the average circumference of the bulbs after treatment was in the 10 and 100 mg / L MA treatment groups, which were significantly different from the control group, with the circumference increasing by 13.51% and 12.97%, respectively.

[0080] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with this technical field within the technical scope disclosed by the present invention and within the spirit and principles of the present invention should be covered by the scope of protection of the present invention.

Claims

1. An exogenous treatment method for promoting the expansion of second-generation lily bulbs, characterized in that: The following steps are involved: Step 1: Select healthy, pest-free, and similar-sized second-generation lily bulbs; Step 2, preparing the cultivation medium; Step 3: Plant the second-generation lily bulbs in the cultivation medium and water them thoroughly; Step 4, when the above-ground part of the lily grows to about 20 cm, the lily plants are irrigated with 10-500 mg / L malic acid (MA) solution, and the control group is irrigated with plain water, and the irrigated once every two weeks; Step 5: When the lilies are in the bud-forming stage, remove the flower buds and measure the plant height, stem diameter, leaf length, and leaf width of the lily plants; Step 6: After the above-ground parts of the lily plants wither, harvest the lily bulbs and measure the circumference of the bulbs.

2. The exogenous treatment method for promoting the expansion of the second-generation lily bulbs according to claim 1, characterized in that: The second-generation lily bulbs selected in the step 1 are specifically: the commercial lily bulbs are planted in a glass greenhouse and subjected to daily management; after the leaves of the lily plants wither, the second-generation lily bulbs are taken out, placed in a plastic frame, and covered with a 3-5 cm moist substrate, which is Pinnaceous peat soil; the second-generation lily bulbs are placed in a 4°C cold storage for 30 days to break the dormancy of the bulbs.

3. The exogenous treatment method for promoting the expansion of the second-generation lily bulbs according to claim 1, characterized in that: The cultivation medium in step 2 is imported Pin's peat soil. Before planting, large pieces of Pin's peat soil are crushed, and then the medium is moistened with clean water until the medium is watered thoroughly, so as to achieve the effect of moistening the medium before planting the bulbs.

4. The exogenous treatment method for promoting the expansion of the second-generation lily bulbs according to claim 1, characterized in that: In step 3, the lily bulbs are planted in the cultivation medium as follows: a 20 cm x 50 cm plastic frame is covered with a layer of white gauze, and a 5-7 cm layer of medium is evenly spread on the bottom of the plastic frame. The lily bulbs are then planted in the plastic frame, with a 5-7 cm layer of medium covering the bulbs. Twelve lily bulbs are planted in each frame in a 3 x 4 pattern.

5. The exogenous treatment method for promoting the expansion of the second-generation lily bulbs according to claim 1, characterized in that: The malic acid solutions in step 4 were 10, 100, and 500 mg / L, with a volume of 5 L used each time. The malic acid solutions were prepared by weighing the required amount of malic acid and dissolving it completely in distilled water to obtain malic acid solutions of varying concentrations. The control group used distilled water.

6. The exogenous treatment method for promoting the expansion of the second-generation lily bulbs according to claim 1, characterized in that: In step 3, the lily plants were planted in a greenhouse and grown under natural light. The temperature was controlled at 18° C.-25° C. In order to avoid any interference with the results, no fertilizer was used during the experiment.

7. The exogenous treatment method for promoting the expansion of the second-generation lily bulbs according to claim 1, characterized in that: In step 5, the stem thickness is measured as the stem thickness between the third and fourth leaves of the plant from the ground; the leaf thickness is measured as the length and width of the third leaf from the plant from the ground; and the plant height is measured as the maximum height of the above-ground part of the plant.

8. The exogenous treatment method for promoting the expansion of the second-generation lily bulbs according to claim 1, characterized in that: In step 6, after the lily plants enter the withering stage and most of the leaves of the plants wither, the lily bulbs in the matrix are taken out, the matrix on the surface of the bulbs is removed, and the maximum circumference perpendicular to the axis of the bulb is measured with a soft ruler.

9. An exogenous treatment system for promoting the expansion of second-generation lily bulbs, which implements the exogenous treatment method for promoting the expansion of second-generation lily bulbs as claimed in any one of claims 1 to 8, characterized in that: include: A selection module is used to select healthy lily bulbs that are free of pests and diseases and of similar size; A configuration module, used for configuring the cultivation substrate; The cultivation module is used to plant the second-generation lily bulbs in the cultivation medium and water them thoroughly. The irrigation module is used to irrigate the lily plants with a 10-500 mg / L malic acid (MA) solution when the lily aboveground part grows to about 20 cm. The control group is irrigated with plain water, and the watering is carried out once every two weeks. The bud removal module is used to remove the buds of lilies during their bud-forming stage and measure the plant height, stem diameter, leaf length and leaf width of the lily plants; The harvesting and measuring module is used to harvest lily bulbs and measure the circumference of the bulbs after the above-ground parts of the lily plants wither.

Images