Nutrient solution for cultivating "black corn" of zea mays and application and cultivation method thereof

Abstract

The application relates to the technical field of rice planting methods, in particular to a nutrient solution for cultivating Xiang He Nu 'black He', and application and cultivation method thereof. The application can use the common rice nutrient solution added with exogenous amino acids, added with exogenous organic acids, and added with the common rice nutrient solution with a compound treatment of a final concentration of 0.4 mM phenylalanine and 5 mu M salicylic acid for 'black He'. The nutrient solution for cultivating Xiang He Nu 'black He' can be applied to improve the quality of rice, especially Xiang He Nu 'black He'. The nutrient solution for cultivating Xiang He Nu 'black He' can effectively improve the plant height, biomass (fresh weight), nitrogen content, chlorophyll content and single plant dry weight of 'black He'. The problem of poor growth and development of 'black He' in the common nutrient solution can be solved, the adaptability of 'black He' is enhanced to a certain extent, and the yield is slightly improved, which will be beneficial to the process of building green agriculture.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rice planting methods, in particular to a nutrient solution for cultivating Xianghe Nu "Heihe" and its application and cultivation method. BACKGROUND

[0002] Rice is one of the most important food crops in the world, providing food for nearly 50% of the world's population. China is a major producer and consumer of rice, with two-thirds of the population relying on rice as their main food. For a long time, China has been committed to rice breeding, focusing on improving the yield and quality of rice.

[0003] Xianghe Nu is a special ecological group of Oryza sativa L. formed by genetic evolution and co-evolution in a specific ecological region, and is one of the most representative traditional rice resources with mountain characteristics in Guizhou. Xianghe Nu has various types, some of which still retain the characteristics of wild rice, with excellent traits such as cold resistance, drought tolerance, waterlogging tolerance, shade tolerance, etc., and the rice has excellent nutritional quality with a strong aroma (Jiao, F. A. Investigation on the Utilization and Protection Status of Xianghe Nu Resources in the Dong Villages of Liping County, Guizhou Province [J]. Journal of Plant Genetic Resources, 2015, 16(1): 173-177). The colored rice in Xianghe Nu contains extremely rich nutrients, including protein, starch, vitamins, dietary fiber, etc., which can effectively prevent and reduce the occurrence of diseases such as atherosclerosis, cancer, and allergies. As a special germplasm resource, colored rice is of great significance to healthy diet and the development of human society (Dong, J. H., et al. Research Progress on Nutritional Characteristics and Functional Components of Colored Rice [J]. Journal of Yunnan University of Nationalities (Natural Science Edition), 2023, 32(04): 449-458). These characteristics exactly meet the requirements of modern agricultural development, so the planting area should be increased.

[0004] However, due to the strong regionalism of black rice "Heihe" in Xianghe Nu and the generally low yield, it is difficult to expand the planting of this "Xianghe Nu" variety. Moreover, it grows poorly and has poor resistance under conventional planting conditions, which greatly hinders the development of large-scale, intensive, and industrialized planting of "Heihe".

[0005] Therefore, it is extremely important to explore a planting and cultivation method suitable for cultivating Guizhou local high-quality characteristic rice "Heihe" to promote the breeding process of Xianghe Nu colored rice. SUMMARY

[0006] In order to solve the above technical problems in the prior art, the present application provides a nutrient solution for cultivating Xianghe Nu "Heihe" and its application and cultivation method, as follows:

[0007] A nutrient solution for cultivating Xianggenuo "Hehe", containing phenylalanine, salicylic acid or both.

[0008] Further, the final concentration of phenylalanine is 0.1 mM, 0.2 mM, 0.4 mM, 0.6 mM, 1 mM.

[0009] Further, the final concentration of salicylic acid is 5 μM, 10 μM, 15 μM, 20 μM, 25 μM.

[0010] Further, the nutrient solution contains both phenylalanine and salicylic acid. Specifically, it contains 0.4 mM phenylalanine and 5 μM salicylic acid.

[0011] Further, the Xianggenuo "Hehe" is a rice black rice germplasm resource collected in Congjiang County, Qiandongnan Prefecture. The growth period of "Hehe" is 162 days, the seeds are short and round, the seed coat is slightly brown, the awn rate is low, and the awn is short. The seeds of "Hehe" were collected in Qiandongnan Prefecture, Guizhou Province, and are now preserved in the Plant Hormone and Nutrient Molecular Regulation Laboratory of the Rice Industry Technology Research Institute of Guizhou University. They can also be purchased from local enterprises.

[0012] Further, the nutrient solution also contains the following ingredients: NaH2PO4·2H2O 63.000 mg / L, K2SO4 111.625 mg / L, CaCl2 39.55 mg / L, MgSO4·7H2O 506.250 mg / L, MnCl2·4H2O 1.761 mg / L, Na2MoO4·2H2O 0.127 mg / L, H3BO4 1.168 mg / L, ZnSO4·7H2O 0.044 mg / L, CuSO4·5H2O 0.039 mg / L, EDTA-Na2 15.000 mg / L, FeSO4·7H2O 11.140 mg / L.

[0013] Further, in the complex nutrient solution added with phenylalanine and salicylic acid, the final concentration is 0.1 mM Phe and 5 μM Salicylic acid, 0.1 mM Phe and 10 μM Salicylic acid, 0.1 mM Phe and 15 μM Salicylic acid, 0.1 mM Phe and 20 μM Salicylic acid, 0.1 mM Phe and 25 μM Salicylic acid, 0.2 mM Phe and 5 μM Salicylic acid, 0.2 mM Phe and 10 μM Salicylic acid, 0.2 mM Phe and 15 μM Salicylic acid, 0.2 mM Phe and 20 μM Salicylic acid, 0.2 mM Phe and 25 μM Salicylic acid, 0.4 mM Phe and 5 μM Salicylic acid, 0.4 mM Phe and 10 μM Salicylic acid, 0.4 mM Phe and 15 μM Salicylic acid, 0.4 mM Phe and 20 μM Salicylic acid, 0.4 mM Phe and 25 μM Salicylic acid, 0.5 mM Phe and 5 μM Salicylic acid, 0.5 mM Phe and 10 μM Salicylic acid, 0.5 mM Phe and 15 μM Salicylic acid, 0.5 mM Phe and 20 μM Salicylic acid, 0.5 mM Phe and 25 μM Salicylic acid, 1 mM Phe and 5 μM Salicylic acid, 1 mM Phe and 10 μM Salicylic acid, 1 mM Phe and 15 μM Salicylic acid, 1 mM Phe and 20 μM Salicylic acid, 1 mM Phe and 25 μM Salicylic acid.

[0014] The nutrient solution for cultivating Xianghenuo "Hehe" of the present application can be used to improve the quality of rice, especially Xianghenuo "Hehe". The nutrient solution for cultivating Xianghenuo "Hehe" of the present application can effectively improve the plant height, biomass (fresh weight), nitrogen content, chlorophyll content and dry weight per plant of "Hehe". It can solve the problem of poor growth and development of "Hehe" in ordinary nutrient solution, to a certain extent, enhance the adaptability of "Hehe" and achieve a small increase in yield, which will be conducive to the process of building green agriculture.

[0015] The application discloses a method for culturing black rice "Heihe" of Xiangheinu, and adopts a nutrient solution for culturing Xiangheinu "Heihe" to culture rice seedlings in the three-leaf stage to the five-leaf stage, and the variety of the rice seedlings is "Heihe".

[0016] Further, the three-leaf stage rice seedlings are obtained by the following method: water culture of rice seeds until the first incomplete leaf appears; the water is replaced with common rice nutrient solution, and the three-leaf stage rice seedlings are obtained by culturing to the three-leaf stage.

[0017] Compared with the prior art, the technical effects created by the application are embodied in:

[0018] (1) Although adjusting the proportion of ammonia nitrogen and nitrate nitrogen in the nitrogen source of the rice nutrient solution, adding exogenous amino acids, adding exogenous organic acids and the like may have certain effects on the growth state of the rice. However, there is no clear method for increasing the yield of the colored rice "Heihe" in the prior art, and the inventors can only explore the cultivation method of the rice from scratch. In the experiment, the inventors added 5 different concentrations of phenylalanine and 5 different concentrations of salicylic acid to the common rice nutrient solution to form 10 treatments, and mixed 5 different concentrations of phenylalanine with 5 different concentrations of salicylic acid to add to the common rice nutrient solution to form 25 composite treatments, a total of 35 treatments, in order to screen out the best treatment condition. Finally, it was found that the composition of the nutrient solution can be adjusted to achieve different purposes. The common rice nutrient solution added with the composite treatment of a final concentration of 0.4 mM phenylalanine and 5 mu M salicylic acid can effectively improve the plant height, biomass (fresh weight), nitrogen content, chlorophyll content and dry weight per plant of "Heihe", and is the optimal treatment method. The scheme of the application can solve the problem of poor growth and development of "Heihe" in the common nutrient solution, to a certain extent, enhance the adaptability of "Heihe" and achieve a small increase in yield, which will be conducive to promoting the process of building green agriculture. "Xiangheinu" described in the scheme is a high-quality characteristic rice in Guizhou, which has been reported in many prior art documents. In addition to the documents mentioned in the background art, there are also: "Chen Huizha, Li Xiaobing, You Junmei, et al. Research on the protection and utilization of Guizhou special rice Xiangheinu germplasm resources [J]. Seed, 2023, 42(11): 61-67+2. Tang Wenhua, Jiang Tianzhi, Yang Xiaoyan, et al. Study on Zn·Cr content and physiological function of original ecological Danzha selenium rice [J]. Anhui Agricultural Sciences, 2009, 37(32): 15686-15687."

[0019] (2) The nutrient solution for cultivating Xianggeinu "Heige" of the present application can be used for improving the quality of rice, especially Xianggeinu "Heige". The nutrient solution for cultivating Xianggeinu "Heige" of the present application can effectively improve the plant height, biomass (fresh weight), nitrogen content, chlorophyll content and dry weight per plant of "Heige". It can solve the problem of poor growth and development of "Heige" in ordinary nutrient solution, to some extent, enhance the adaptability of "Heige" and achieve a small increase in yield, which will be conducive to the progress of building green agriculture.

[0020] (3) The present application determines the nutrient solution formula with certain promoting effect for Xianggeinu colored rice "Heige". When planting "Heige", using ordinary rice nutrient solution added with phenylalanine with a final concentration of 0.4 mM and salicylic acid with a final concentration of 5 μM complex treatment can effectively promote the planting effect of "Heige", especially in improving the biomass, plant height, nitrogen content and chlorophyll content of "Heige" plants.

[0021] (4) The present application provides a nutrient solution formula and cultivation method suitable for the growth and development of "Heige", which can be expected to solve the problem that "Heige" is difficult to be planted in different regions and cannot be adapted to ordinary rice nutrient solution water planting. It will be conducive to speeding up the process of "Heige" factory seedling, realizing the large-scale, intensive and factory planting management of "Heige" and large-area popularization and application. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The plant height, fresh weight, root length and dry weight statistical results and phenotype pictures of "Heige" under different concentration treatment conditions in the phenylalanine treatment group of Example 1 of the present application (the statistical results are represented as mean ± SD, n = 6; Duncan test is used for difference significance analysis, the data is marked with lowercase letters above, in the same statistical graph, different lowercase letters between them have significant difference, p < 0.05; the same lowercase letters between them represent the same significance level).

[0023] Figure 2 The plant height, fresh weight, root length and dry weight statistical results and phenotype pictures of "Heige" under different concentration treatment conditions in the salicylic acid treatment group of Example 1 of the present application (the statistical results are represented as mean ± SD, n = 6; Duncan test is used for difference significance analysis, the data is marked with lowercase letters above, in the same statistical graph, different lowercase letters between them have significant difference, p < 0.05; the same lowercase letters between them represent the same significance level).

[0024] Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 、 Figure 7Statistical results of plant height, fresh weight, root length and dry weight of‘Heihe’ under different concentrations of phenylalanine and salicylic acid complex treatment in Example 1 of the present application, and phenotype pictures (statistical results are expressed as mean ± SD, n = 6; Duncan's test was used for significant difference analysis, and the data are marked with lowercase letters above, and different lowercase letters in the same statistical graph indicate significant differences between them, p < 0.05; the same lowercase letter indicates that the significance level is consistent).

[0025] Figure 8 Statistical results of nitrogen percentage content of‘Heihe’ in Example 2 of the present application (statistical results are expressed as mean ± SD, n = 10; **, p < 0.01; *, p < 0.05).

[0026] Figure 9 Statistical results of chlorophyll content of‘Heihe’ in Example 3 of the present application (statistical results are expressed as mean ± SD, n = 10; **, p < 0.01; *, p < 0.05). DETAILED DESCRIPTION

[0027] The technical solutions of the present application will be further limited in combination with specific implementation manners, but the scope of protection is not only limited to the description.

[0028] Example 1: Effect of different phenylalanine concentrations on the growth and development of‘Heihe’.

[0029] Rice variety:‘Heihe’ involved in the present scheme is a black rice variety in‘Xiangge’nu’. The biological material rice seeds used in subsequent experiments are seeds of‘Heihe’ black rice variety in‘Xiangge’nu’, a high-quality characteristic rice in Guizhou. The growth period of‘Heihe’ is 162 days, the seeds are short and round, the seed coat is slightly brown, the awn rate is low, and the awn is short. The seeds of‘Heihe’ were collected in Qianzhuan, Guizhou Province, and are now preserved in the Plant Hormone and Nutrient Molecular Regulation Laboratory of the Rice Industry Technology Research Institute of Guizhou University.

[0030] Rice seed soaking: the rice seeds were soaked with 0.006% dilute nitric acid for 6-8 hours.

[0031] Rice seed culture: after soaking, the seeds were washed with deionized water for 3-5 times, divided into culture dishes, added with appropriate purified water, placed in an incubator at 37℃, and the water was changed 1-2 times a day.

[0032] Water culture: after the seed germination, the bud is grown to 1-2 cm, and is sowed in 96-hole plate and placed in 4L capacity culture box for clear water culture, and is cultured until the first incomplete leaf appears, and then is replaced with ordinary rice nutrient solution for culture until 3-leaf stage, and then is transplanted into 15L capacity culture pot, 12L ordinary rice nutrient solution is added into the culture pot respectively, 36 culture pots are set, 5 culture pots are set as phenylalanine treatment group, 5 culture pots are set as salicylic acid treatment group, 25 culture pots are set as phenylalanine and salicylic acid composite treatment group, 1 culture pot is set as normal control group without treatment.

[0033] The formula of the ordinary rice nutrient solution is the conventional culture solution in the prior art, as shown in Table 1 (without nitrogen source, i.e. nitrogen-free ordinary rice nutrient solution) (reference document: Yoshida S, Fomo DA, Cock JH, et al. Routine procedure for growing rice plants in culture solution. In: Laboratory manual for physiological studies of rice [J]. International Rice Research Institute, 61-66.). The inventors have found through a large number of studies that the conventional nitrogen-free ordinary rice nutrient solution can meet the growth needs of rice, and the ratio in Table 1 can meet the growth needs of rice, which is a specific presentation form of a nitrogen-free ordinary rice nutrient solution.

[0034] Table 1: Formula of ordinary rice nutrient solution

[0035]

[0036]

[0037] Phenylalanine and salicylic acid mother liquor is prepared, and the concentration of the mother liquor is 1 mol / L, which is used for preparation of the nutrient solution. The specific preparation conditions of the four groups in water culture (normal nutrient solution control group, phenylalanine treatment group, salicylic acid treatment group, and phenylalanine and salicylic acid composite treatment group) are as follows:

[0038] Normal nitrogen treatment group: only 12L ordinary nutrient solution is added.

[0039] Phenylalanine treatment group: in the 12L ordinary culture solution in the phenylalanine treatment group, the corresponding amount of mother liquor is added to prepare the concentration in Table 2. For example, 1.2ml, 2.4ml, 4.8ml, 7.2ml and 12ml of phenylalanine mother liquor are added into T1, T2, T3, T4 and T5 culture pots respectively, so that the concentration of phenylalanine in the five culture pots is 0.1mM, 0.2mM, 0.4mM, 0.6mM and 1mM respectively.

[0040] Salicylic acid treatment group: In the salicylic acid treatment group, 5 culture pots of 12L normal culture solution were added with corresponding amount of mother liquor to make the concentration in Table 2. For example, 60 μL, 120 μL, 180 μL, 240 μL, 300 μL of phenylalanine mother liquor was added to T1, T2, T3, T4, T5 five culture pots respectively, so that the concentration of phenylalanine in the five culture pots was 5 μM, 10 μM, 15 μM, 20 μM, 25 μM respectively.

[0041] Phenylalanine and salicylic acid complex treatment group: in the complex treatment group 12L ordinary culture solution in 25 culture pots were added with corresponding amount of mother liquor to make the concentration in table 2. For example, 1.2ml of phenylalanine mother liquor and 60μL of salicylic acid mother liquor, 1.2ml of phenylalanine mother liquor and 120μL of salicylic acid mother liquor, 1.2ml of phenylalanine mother liquor and 180μL of salicylic acid mother liquor, 1.2ml of phenylalanine mother liquor and 240μL of salicylic acid mother liquor, 1.2ml of phenylalanine mother liquor and 300μL of salicylic acid mother liquor, 2.4ml of phenylalanine mother liquor and 60μL of salicylic acid mother liquor, 2.4ml of phenylalanine mother liquor and 120μL of salicylic acid mother liquor, 2.4ml of phenylalanine mother liquor and 180μL of salicylic acid mother liquor, 2.4ml of phenylalanine mother liquor and 240μL of salicylic acid mother liquor, 2.4μM of phenylalanine mother liquor and 300μL of salicylic acid mother liquor, 4.8ml of phenylalanine mother liquor and 60μL of salicylic acid mother liquor, 4.8ml of phenylalanine mother liquor and 120μL of salicylic acid mother liquor, 4.8ml of phenylalanine mother liquor and 180μL of salicylic acid mother liquor, 4.8ml of phenylalanine mother liquor and 240μL of salicylic acid mother liquor, 4.8ml of phenylalanine mother liquor and 300μL of salicylic acid mother liquor, 7.2ml of phenylalanine mother liquor and 60μL of salicylic acid mother liquor, 7.2ml of phenylalanine mother liquor and 120μL of salicylic acid mother liquor, 7.2ml of phenylalanine mother liquor and 180μL of salicylic acid mother liquor, 7.2ml of phenylalanine mother liquor and 240μL of salicylic acid mother liquor, 7.2ml of phenylalanine mother liquor and 300μL of salicylic acid mother liquor, 12ml of phenylalanine mother liquor and 60μL of salicylic acid mother liquor, 12ml of phenylalanine mother liquor and 120μL of salicylic acid mother liquor, 12ml of phenylalanine mother liquor and 180μL of salicylic acid mother liquor, 12ml of phenylalanine mother liquor and 240μL of salicylic acid mother liquor, 12ml of phenylalanine mother liquor and 300μL of salicylic acid mother liquor were added in 25 culture pots respectively, so that the final concentration in 25 culture pots were 0.1mM Phe and 5μM Salicylic acid, 0.1mM Phe and 10μM Salicylic acid, 0.1mM Phe and 15μM Salicylic acid, 0.1mM Phe and 20μM Salicylic acid, 0.1mM Phe and 25μM Salicylic acid, 0.2mM Phe and 5μM Salicylic acid, 0.2mM Phe and 10μM Salicylic acid, 0.2mM Phe and 15μM Salicylic acid, 0.2mM Phe and 20μM Salicylic acid, 0.2mM Phe and 25μM Salicylic acid, respectively.4 mM Phe and 5 μM Salicylic acid, 0.4 mM Phe and 10 μM Salicylic acid, 0.4 mM Phe and 15 μM Salicylic acid, 0.4 mM Phe and 20 μM Salicylic acid, 0.4 mM Phe and 25 μM Salicylic acid, 0.5 mM Phe and 5 μM Salicylic acid, 0.5 mM Phe and 10 μM Salicylic acid, 0.5 mM Phe and 15 μM Salicylic acid, 0.5 mM Phe and 20 μM Salicylic acid, 0.5 mM Phe and 25 μM Salicylic acid, 1 mM Phe and 5 μM Salicylic acid, 1 mM Phe and 10 μM Salicylic acid, 1 mM Phe and 15 μM Salicylic acid, 1 mM Phe and 20 μM Salicylic acid, 1 mM Phe and 25 μM Salicylic acid.

[0042] The treatment methods of the normal hydroponic treatment group, the phenylalanine treatment group, the salicylic acid treatment group, and the phenylalanine and salicylic acid combined treatment group are shown in Table 2.

[0043] Table 2: Primary screening treatment (Note: Phe in the table is phenylalanine, and Salicylic acid is salicylic acid, unit: mM)

[0044]

[0045]

[0046] After the various treatments of the "black rice" were grown to the 5-leaf stage, the plant height, fresh weight, root length, and dry weight of the rice seedlings of the various treatments were measured. One seedling with a plant height near the average plant height was selected from each treatment of the normal nitrogen control group and the organic nitrogen treatment group and the inorganic nitrogen treatment group, and was placed on black cloth to spread out and connect to form a row. The plant phenotype, fresh weight, dry weight, plant height, and root length of the "black rice" under the treatment conditions of the phenylalanine treatment group are shown in Figure 1 A, 1B, 1C, 1D, 1E; the plant phenotype, fresh weight, dry weight, plant height, and root length of the "black rice" under the treatment conditions of the salicylic acid treatment group are shown in Figure 2 A, 2B, 2C, 2D, 2E; the plant phenotype, fresh weight, dry weight, plant height, and root length of the "black rice" under the treatment conditions of the phenylalanine and salicylic acid combined treatment group are shown in Figures 3-7 A, B, C, D, E.

[0047] According to the experimental results of Figure 1 , in the phenylalanine treatment group, the addition of phenylalanine alone showed different degrees of inhibition effect on the plant height, fresh weight, dry weight and root length of "Hege", and showed a downward trend compared with the control, especially when the concentration of phenylalanine reached 1 mM, the growth and development of "Hege" showed very obvious inhibition effect, such as Figure 1 B, 1D, 1E.

[0048] According to the experimental results of Figure 2 , in the salicylic acid treatment group, the most significant promotion effect on the growth and development of "Hege" was the addition of 10 μM salicylic acid, 15 μM salicylic acid and 25 μM salicylic acid in the ordinary nutrient solution, and the most significant was the addition of 25 μM salicylic acid; The corresponding weight showed that in the treatment group of adding 10 μM salicylic acid, 15 μM salicylic acid and 25 μM salicylic acid, the fresh weight and dry weight of "Hege" were higher than those of the control group, and the dry weight difference reached a significant difference, such as Figure 2 C; and the plant height of "Hege" in the treatment group of 25 μM salicylic acid was higher than that of the control, reaching a significant difference, such as Figure 2 D; in addition, the root length of "Hege" in the treatment group of 15 μM salicylic acid was higher than that of the control, such as Figure 2 E, and reached a significant difference.

[0049] According to the experimental results of Figures 3-7 , in the phenylalanine and salicylic acid compound treatment group, the treatment of adding 0.2 mM phenylalanine and 20 μM salicylic acid in the ordinary nutrient solution, the treatment of adding 0.2 mM phenylalanine and 25 μM salicylic acid in the ordinary nutrient solution, the treatment of adding 0.4 mM phenylalanine and 5 μM salicylic acid in the ordinary nutrient solution, the treatment of adding 0.4 mM phenylalanine and 10 μM salicylic acid in the ordinary nutrient solution, the treatment of adding 0.4 mM phenylalanine and 15 μM salicylic acid in the ordinary nutrient solution, and the treatment of adding 0.4 mM phenylalanine and 25 μM salicylic acid in the ordinary nutrient solution could significantly promote the plant height and fresh weight of "Hege", and the dry weight of the five treatments was also significantly higher than that of the control, as shown in Figure 4 B, 4D, 5B, 5D; and when the concentration of phenylalanine exceeded 1 mM, the compound treatment with salicylic acid showed significant inhibition effect on the growth of "Hege", and through the test of physiological indicators, it was found that the addition of 1 mM phenylalanine and more than 15 μM salicylic acid in the ordinary rice culture solution had the most serious inhibition effect on "Hege", as shown in Figure 7 .

[0050] The above results show that in the phenylalanine treatment group, the addition of phenylalanine alone in the basic rice general nutrient solution inhibits the growth and development of "Gou Neng Gu", resulting in poor growth and development; in the salicylic acid treatment group, the addition of 10 μΜ salicylic acid in the general nutrient solution is more conducive to the growth and development of "Hei He"; in the composite treatment, the addition of 0.4 mM phenylalanine and 5 μΜ salicylic acid in the general rice nutrient solution can effectively improve the plant height, biomass (fresh weight), nitrogen content, chlorophyll content, and dry weight per plant of "Hei He", and is the optimal treatment method.

[0051] Example 2: Effect of different treatments on the total nitrogen content percentage of "Hei He"

[0052] The rice materials of this example all come from the above-mentioned culture materials, and nitrogen is the most required mineral element by plants, also known as "life element". When nitrogen is sufficient, plants can synthesize more proteins, promote cell division and enlargement, and the leaf area grows faster, and the photosynthesis is stronger. When nitrogen is severely deficient, organic matter synthesis is hindered, the plant is short, the leaves are yellow, and the old leaves are more yellow, so the nitrogen content in the plant can be used as a physiological index to judge the growth and development of the plant. The measurement method of nitrogen content in rice plants is referred to the literature (Nanjing Agricultural College. Soil and agricultural chemical analysis. Beijing: Agricultural Press, 1980. 193-197).

[0053] Rice plant sampling: From the above-mentioned organic nitrogen treatment group and inorganic nitrogen treatment group, select the treatments that promote and inhibit the growth and development of "Hei He" more obviously, plus the control, a total of 7 treatments, take three rice plants for each treatment, place them in an 80°C oven to dry overnight, then take out the dried plants and divide them into leaves and stems, use a pulverizer to pulverize the samples into powder for use.

[0054] Determination of plant nitrogen content:

[0055] I. Digestion:

[0056] 1. Weigh 0.5 g of sample (dry sample) with a one-hundredth balance and place it in a digestion tube.

[0057] 2. Weigh 0.5 g of copper sulfate pentahydrate and 4.5 g of potassium sulfate with a one-hundredth balance and place them in a digestion tube.

[0058] 3. Accurately aspirate 8 ml of concentrated sulfuric acid with a pipette and place it in a digestion tube.

[0059] 4. Turn on the instrument switch and start digestion. First, digest at 280°C for about 20 min, then at 350°C for about 20 min, and finally at 450°C until the digestion tube liquid turns emerald green, digest for 30-40 min, and complete digestion.

[0060] 5. Cool down to room temperature and ready for use.

[0061] II. Distillation and titration: The above digested sample solution needs to be diluted to 100 ml with distilled water, 5 ml of the test solution is taken into the long glass tube of the nitrogen determination instrument, 5 ml of boric acid indicator solution is taken into the large mouth flask, and after distillation for 3 min, it is taken out. Titration with a semimicro burette, the titration is from green to white to peach red. The data obtained are calculated according to the following formula to calculate the nitrogen content in the plant.

[0062] Plant total nitrogen (%) = equivalent concentration of H2SO4 standard solution x (volume of H2SO4 standard solution consumed in titration of sample - volume of H2SO4 standard solution in blank test) x dilution factor x 0.014 x 100 / sample weight

[0063] In the formula: the dilution factor is 20 according to the above method, because 100 mL contains 5 ml, and the sample weight is 0.5 g. Finally, the nitrogen content of the plant measured by the three groups of repeated experiments of each treatment is averaged.

[0064] The plant nitrogen content data measured for each treatment sample are statistically plotted, and the results are shown in Figure 8 As can be seen from the figure, the above results again show that in the organic nitrogen treatment group, the exogenous application of 0.4 mM Phe and 5 μM salicylic acid on the basis of ordinary nutrient solution can promote the growth and development of "black rice", and improve the problem of poor growth and development in ordinary nutrient solution.

[0065] Example 3 Effect of exogenous application of phenylalanine and salicylic acid on chlorophyll content in leaves of "black rice".

[0066] The materials of rice in this example are all from the above culture materials, and the chlorophyll content in rice leaves has certain correlation with photosynthetic rate and crop growth rate. In scientific research, chlorophyll content is often measured to represent the growth state of rice, and in production, leaf color change is often used as an important index for looking at seedlings and taking water and fertilizer measures. The measurement method of chlorophyll content in rice leaves is referred to the literature (Nurkamal Murat, Yang Yajie, Parhat Abudukizhim, et al. Comparison of wheat chlorophyll content determination methods [J]. Jiangsu Agricultural Science, 2021, 49(09): 156-159).

[0067] Sample collection of rice leaves: Three rice seedlings (T1 as control) were selected from the above treatment groups, and the leaf blades were cut and mixed uniformly. 0.2-0.3 g of leaf fragments were weighed into 15 ml centrifuge tubes, and 10 ml of anhydrous ethanol was added. The leaf weight was labeled, and three repeated experiments were performed, and the average value was taken. All centrifuge tubes containing rice leaf fragments and anhydrous ethanol were wrapped with tin foil and stored in the dark for 3 days, and were shaken several times during the period.

[0068] Chlorophyll content determination: After 3 days, the chlorophyll extract of all samples was obtained. Prepare 8 cuvettes, one of which adds 4 ml of anhydrous ethanol as a control, and the other 7 cuvettes add 3 sets of repeated chlorophyll extract of each treatment sample. Measure the absorbance at 663 nm and 645 nm, respectively. The data obtained are calculated according to the following formula to calculate the chlorophyll content.

[0069] Total chlorophyll content = (20.21D645 nm + 8.02D663 nm) x V / 1000 x m

[0070] Where D663 nm and D645 nm are the absorbances at 663 nm and 645 nm, respectively; V is the volume of the sample to be tested (ml); and m is the fresh weight of the leaf sample (g) or the leaf area (cm2). Finally, the total chlorophyll content of each treatment is calculated by averaging the three repeated experiments.

[0071] The measured chlorophyll content is statistically plotted, and the results are shown in Figure 9 On the basis of the ordinary nutrient solution for rice, the addition of phenylalanine and salicylic acid to a final concentration of 0.4 mM Phe and 5 μM salicylic acid significantly increased the total chlorophyll content of "black rice" compared to the control. The chlorophyll content in the leaves is an important indicator of the nutritional status of plants, and a high total chlorophyll content represents a stronger photosynthetic potential, which can synthesize more nutrients required for plant growth and development, which again confirms that changing the nutrient solution formula can greatly improve the growth and development of "black rice" in the Xianghe Nuo variety, and solve the problem of poor growth and development in the ordinary nutrient solution, which makes it difficult to industrialize seedling raising. In the context of the gradual loss of rural labor, it is necessary to accelerate the process of large-scale, intensive, and industrialized planting and management of high-quality colored rice varieties.

[0072] The above examples are only representative of the present application. Obviously, the technical solutions of the present application are not limited to the above examples, and there can be many variations. All variations that can be directly derived or inferred from the content disclosed in the present application by those skilled in the art should be considered as falling within the scope of protection of the present application.

Claims

1. The use of a nutrient solution for cultivating "Black Khor" of Oryza sativa L. cv. "Khor" in improving the quality of "Black Khor" of Oryza sativa L. cv. "Khor", characterized in that, The Xiangwenlu "Heihe" is a rice black rice germplasm resource collected in Congjiang County, Qiandongnan Prefecture, Guizhou Province, China, from Xiangwenlu, and the nutrient solution contains 0.4 mM phenylalanine and 5 μM salicylic acid; and further contains the following components: NaH2PO4·2H2O 63.000 mg / L, K2SO4 111.625 mg / L, CaCl2 39.55 mg / L, MgSO4·7H2O 506.250 mg / L, MnCl2·4H2O 1.761 mg / L, Na2MoO4·2H2O 0.127 mg / L, H3BO4 1.168 mg / L, ZnSO4·7H2O 0.044 mg / L, CuSO4·5H2O 0.039 mg / L, EDTA-Na2 15.000 mg / L, FeSO4·7H2O 11.140 mg / L.

2. A method of cultivating black rice "Black Gao" in Xianghe Nu, characterized in that, The rice seedlings in the three-leaf stage are cultured in the nutrient solution for culturing Xiangwenlu "Heihe" according to claim 1 until the five-leaf stage, and the variety of the rice seedlings is "Heihe".

3. The method of claim 2, wherein, The rice seedlings in the three-leaf stage are obtained by the following method: rice seeds are water-cultured until the first incomplete leaf appears; the water is replaced with a common rice nutrient solution, and the rice seedlings in the three-leaf stage are obtained by culturing until the three-leaf stage.

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