Method for improving aroma accumulation of aromatic rice

Abstract

The application belongs to the technical field of aromatic rice cultivation, and specifically discloses a method for improving the accumulation of aroma in aromatic rice, which comprises the following steps: adding low-concentration zinc sulfate modified biochar to the substrate for seedling raising to improve the photosynthetic rate and biomass of seedlings, and spraying a high-molecular foliar fertilizer composed of gamma-polyglutamic acid and chitosan at the booting stage to improve the glutamic acid absorption efficiency of the aromatic rice, increase the foliar absorption, increase the accumulation of nitrogen sources and polyamines, and thus improve the content of 2-acetyl-1-pyrroline in the grains, so as to improve the accumulation of aroma during the formation of the grains. The method is low in cost, and the yield and aroma quality of the treated aromatic rice both reach a double-effect level.

Description

Technical Field

[0001] The invention relates to the technical field of fragrant rice cultivation, and in particular to a method for improving the aroma accumulation of fragrant rice. Background Art

[0002] Fragrant rice is 1-2 times more expensive than regular rice due to its unique flavor, aroma, and rich nutritional value, making it highly sought after by the market and consumers. The main characteristic of fragrant rice grains is their rich aroma, which comes from the accumulation of a characteristic substance, 2-acetyl-1-pyrroline, which accumulates throughout the rice's growth period. Therefore, it has high economic value and market prospects. However, the cultivation of fragrant rice is easily affected by factors such as the cultivation environment and cultivation methods. Therefore, research on cultivation methods that enhance the accumulation of fragrant rice aroma has become a key component of producing rich fragrant rice. However, current technologies struggle to achieve both high yield and high quality, and improving quality can easily lead to a decrease in yield.

[0003] Biochar, a biomass raw material, is environmentally friendly and pollution-free, contributing to increased crop yields. Zinc, a trace element in plants, is also essential for rice growth. While zinc fertilizers are currently used to enhance rice aroma and yield, they often overlook issues such as rice's absorption and transport of zinc. Long-term zinc fertilizer application can easily lead to soil zinc contamination and plant zinc poisoning. While zinc has been reported to enhance the aroma of fragrant rice, it's typically applied as a foliar fertilizer or solid fertilizer. While specialized substrates containing up to 45% organic matter are currently common, soil seedling cultivation is more suitable for low-cost, small-scale cultivation. This requires supplemental organic matter to address low organic matter content. Organic fertilizers, such as organic fertilizers, typically have drawbacks such as low efficiency, high usage, and the need for processing. Therefore, a simple, low-cost organic matter supplementation material that can rationally apply zinc fertilizer, thereby preventing soil contamination and achieving strong seedlings and high yields, holds great promise for development. However, zinc-modified biochar has not yet been developed as an organic matter supplement for seedling cultivation substrates.

[0004] Glutamic acid is one of the synthetic substrates of 2-acetyl-1-pyrroline, although it has been reported that exogenous foliar spraying of glutamic acid can achieve the effect of improving aroma, but the effect of single spraying is not significant, not only the absorption efficiency is low, but also the role of single substrate in synthesizing 2-acetyl-1-pyrroline is slow, therefore, how to improve the absorption efficiency of glutamic acid and the synthesis efficiency of 2-acetyl-1-pyrroline by aromatic rice is also a technical problem to be solved. Gamma-polyglutamic acid is a kind of homopolyamino acid polymerized by glutamic acid monomers through amide bond, which is a kind of water-soluble, non-toxic biological macromolecule with good water retention and film forming property, can be effectively absorbed by plants after spraying, and can be used as a biological fertilizer additive. There are records that polyglutamic acid foliar fertilizer has obvious yield-increasing effect on wheat, but its aroma-increasing effect has not been developed. Polyglutamic acid compounded with chitosan is generally used as polyglutamic chitosan oligosaccharide compound with root promoting effect, and is only used as soil improvement fertilizer synergist, therefore, a new type of foliar compound fertilizer with more significant aroma-increasing effect and aroma-increasing and yield-increasing effect has good market prospect. SUMMARY

[0005] In view of the above problems, the purpose of the present application is to provide a method for improving aroma accumulation of aromatic rice.

[0006] The technical content of the present application is as follows:

[0007] The present application provides a method for improving aroma accumulation of aromatic rice, specifically: preparing zinc modified biochar, mixing the zinc modified biochar with soil in a mass ratio of 1:38-42 during seedling raising period, then spraying a mixed agent on the leaf surface during the booting stage.

[0008] The soil is derived from the sun-dried and hammer-crushed southern paddy field soil, and the physicochemical properties are: organic matter 16.41g / kg, total nitrogen 1.01g / kg, total phosphorus 0.82g / kg, total potassium 23.56g / kg, available nitrogen 90.58mg / kg, available phosphorus 45.73mg / kg, available potassium 69.31mg / kg and pH 6.1;

[0009] The preparation of the zinc modified biochar is to dry and crush the coconut shell, soak it in 7-hydrated zinc sulfate, ultrasonic, dry, calcine and sieve to obtain the zinc modified biochar;

[0010] The mass ratio of the coconut shell to 7-hydrated zinc sulfate is 1:5-10;

[0011] The mass ratio of the coconut shell to 7-hydrated zinc sulfate is 1:10;

[0012] The mixed agent is a mixture of gamma-polyglutamic acid and chitosan in a mass ratio of 20-40:50;

[0013] The mixed agent is a mixture of gamma-polyglutamic acid and chitosan in a mass ratio of 40:50.

[0014] The invention provides a mixture for improving the aroma accumulation of fragrant rice. The mixture comprises gamma-polyglutamic acid and chitosan in a mass ratio of 20-40:50.

[0015] The present invention also provides an application of a mixture for improving aroma accumulation of fragrant rice, which is sprayed during the heading stage of the fragrant rice.

[0016] Beneficial effects: In the method for improving the aroma accumulation of fragrant rice provided by the present invention, under the premise that other cultivation measures are carried out according to the fragrant rice planting regulations, zinc sulfate-modified discarded coconut shells are used as biochar as an organic matter supplementary material for seedling cultivation substrates to be mixed with soil to retain moisture and nutrients, thereby improving the photosynthetic rate and biomass of the seedlings, and spraying a high-molecular foliar fertilizer containing γ-polyglutamic acid and chitosan can increase the leaf absorption capacity, improve the efficiency of fragrant rice in absorbing glutamate, and increase the accumulation of nitrogen, polyamines and other substances, which can be converted into amino acids such as spermidine and then synthesized into 2-acetyl-1-pyrroline, thereby improving the synthesis efficiency of 2-acetyl-1-pyrroline, thereby increasing the 2-acetyl-1-pyrroline content in the grains, and further improving the aroma accumulation during grain formation, so that the quality and yield of fragrant conventional indica rice are significantly improved;

[0017] In the method for improving the aroma accumulation of fragrant rice of the present invention, the raw materials used are easy to prepare and obtain, are green and environmentally friendly, and have low cost; the method of the present invention enriches the technology for enhancing the aroma of fragrant rice, and experiments have verified that the optimal experimental conditions are a mixture of low-concentration zinc-modified biochar with a mass ratio of 1:10 and a mixture of gamma-polyglutamic acid:chitosan with a mass ratio of 40:50, which can achieve the best aroma enhancement and yield stabilization effect; the zinc-modified biochar is added as an organic matter supplement to the soil during the seedling raising period, the absorption rate of zinc by the fragrant rice seedlings is high, and the use amount of zinc is lower than the general use amount to achieve the effect of strong seedlings and stable yield, which not only expands the types of organic matter supplements but also overcomes the zinc pollution problem in the prior art.

[0018] Figures in the specification

[0019] Figure 1 This is the scanning electron microscope energy spectrum of coconut shell biochar;

[0020] Figure 2 This is the scanning electron microscope energy spectrum of BC1 zinc-modified coconut shell biochar;

[0021] Figure 3 This is the scanning electron microscope energy spectrum of BC2 zinc modified coconut shell biochar;

[0022] Figure 4 is the net photosynthetic rate of fragrant rice seedlings under zinc-modified biochar treatment;

[0023] Figure 5 is the intercellular CO2 concentration of fragrant rice seedlings under zinc-modified biochar treatment;

[0024] Figure 6 This is the stomatal conductance diagram of fragrant rice seedlings treated with zinc-modified biochar;

[0025] Figure 7 is the transpiration rate of fragrant rice seedlings under zinc-modified biochar treatment;

[0026] Figure 8 Biomass of fragrant rice seedlings under zinc-modified biochar treatment;

[0027] Figure 9 The effect of the mixture on the aroma of fragrant rice grains;

[0028] Figure 10 The effect of the mixture on the total nitrogen content of fragrant rice grains;

[0029] Figure 11 The effect of the mixture on the total carbon content of fragrant rice grains;

[0030] Figure 12 The effect of the mixture on the relative content of spermine in fragrant rice grains;

[0031] Figure 13 The effect of the mixture on the relative content of spermidine in aromatic rice grains;

[0032] Figure 14 The effect of the mixture on the relative content of putrescine in fragrant rice grains;

[0033] Figure 15 The effect of the mixture on the relative content of arginine in fragrant rice grains;

[0034] Figure 16 Effects of the mixture on the relative expression of PAO (polyamine oxidase) in fragrant rice grains;

[0035] Figure 17 The effect of the mixture on the relative expression of SAMDC (spermidine synthase) in aromatic rice grains;

[0036] Figure 18 The effect of the mixture on the relative expression of SPDSYN (S-adenosylmethionine decarboxylase) in fragrant rice grains;

[0037] Figure 19 The effect of the mixture on the grain yield of fragrant rice;

[0038] Figure 20 This is a correlation analysis diagram between acetyl-1-pyrroline and polyamines;

[0039] Figure 21 Effect of the method on the content of 2-acetyl-1-pyrroline in fragrant rice grains;

[0040] Figure 22Statistical chart of the effect of the method on the yield of aromatic rice. DETAILED DESCRIPTION

[0041] The application will be further described in the following detailed description of specific embodiments, which should be regarded as merely illustrative and not limiting the scope of the application, which will be defined by the appended claims. Various modifications of the application in accordance with the description will occur to those skilled in the art upon reading the description.

[0042] Unless otherwise specified, all raw materials and reagents of the application are conventional market raw materials and reagents.

[0043] Example 1

[0044] A method for improving the accumulation of aroma in aromatic rice

[0045] Dry coconut shells were crushed into 2 cm 2 pieces at a mass ratio of 1:5, soaked in 7 water, dried after ultrasonic treatment, and dried in a muffle furnace at a temperature increase of 10℃ / min to 450℃, calcined for 2 hours, sieved through a 40 mesh sieve, and zinc-modified biochar was obtained. The zinc-modified biochar was mixed with dry paddy field soil (soil physical and chemical properties: organic matter 16.41 g / kg, total nitrogen 1.01 g / kg, total phosphorus 0.82 g / kg, total potassium 23.56 g / kg, available nitrogen 90.58 mg / kg, available phosphorus 45.73 mg / kg, available potassium 69.31 mg / kg, and pH 6.1) at a ratio of 1:40, and the conventional seeding and seedling raising method was used, including: before seeding, seeds were selected to remove unproductive seeds, and the seeds were disinfected (with 25% prochloraz at 2000-3000 times), soaked (conventional rice for 24-36 hours, with the standard of just breaking the chest and showing white), and germinated (dark germination for 3-5 days); before seeding, the seedbed was fertilized and leveled, and 2-3 days before germination, the seedbed was watered and the seedlings were hardened off.

[0046] During the booting stage, 10-15 liters of a mixture of γ-polyglutamic acid and chitosan in a mass ratio of 20:50 was sprayed per square meter. Other management methods followed conventional fragrant rice cultivation techniques, including: ploughing the fields and burying the stubble and other debris in the soil layer to make them fine and level. Then, a base fertilizer of 300 kg of bio-organic fertilizer, 150 kg of urea, 375 kg of superphosphate, 120 kg of potassium chloride, and 30 kg of zinc chloride was applied per hectare. After harrowing the fields, Transplant (throw) the seedlings only after the slurry has settled for 1 day; determine the planting density based on factors such as paddy field fertility and variety characteristics, and refer to NY / T1607-2008 "Technical Regulations for Rice Transplanting" for seedling throwing technology; apply 150kg of urea and 105kg of potassium chloride per hectare 6-7 days after transplanting (throwing) the seedlings; maintain shallow water for tillering in the early stage after transplanting (throwing) the seedlings, drain the field and expose it to the sun after the seedlings are grown, expose more and expose less to the sun, control ineffective tillering, do a good job in disease, insect, rodent and weed control in the later stage, and harvest in time after maturity.

[0047] Example 2

[0048] Effect of carbon-zinc ratio on the preparation of zinc-modified biochar

[0049] The ratio of biochar and zinc was changed and named as BC, BC1 and BC2, as shown in Table 1;

[0050] Table 1 Modified biochar with different carbon-zinc mass ratios

[0051]

[0052] The biochars BK, BC1 and BC2 were analyzed by scanning electron microscope energy spectrum. Figures 1-3 ,It can be seen from the figure that zinc is attached to the ,modified biochar, and the ratio of zinc to carbon is close to the ,immersion ratio, indicating that the biochar is zinc modified ,biochar.

[0053] In the seedling test, the three modified biochars obtained above were mixed in the soil at a ratio of 1:40, and the control ratio without adding biochar was set as CK. The seedlings were raised according to the conventional seedling raising method, and the zinc content and biomass of the 30-day-old seedlings were measured. Figures 4-8 ; As can be seen from the figure, compared with the samples without biochar addition and the samples without biochar modification, modified biochars with different zinc concentrations significantly increased the net photosynthetic rate, photosynthesis, stomatal conductance and photosynthetic rate of the fragrant rice seedlings. Among them, the net photosynthetic rate of the biochar modified with low concentration zinc was higher, which significantly increased the biomass of the fragrant rice seedlings. In order to achieve the purpose of strengthening the seedlings, BC1 was selected for subsequent experiments.

[0054] Example 3

[0055] Effects of mixtures with different mass ratios on the quality and yield of aromatic rice

[0056] Mixtures CK, G1 and G2 with different proportions were prepared, and their specific composition contents are shown in Table 2.

[0057] Table 2 Mixtures with different ratios

[0058]

[0059]

[0060] In the field test, 10-15 liters of the mixture per square meter was sprayed during the booting stage. The rice was managed according to conventional aromatic rice cultivation techniques. The relative contents of 2-acetyl-1-pyrroline, total carbon, total nitrogen, and polyamines (broad-target metabolite group) and their related gene expression (qPCR) and yield were measured in the mature grains. Figures 9-20 ;

[0061] Depend on Figures 9-19 It can be seen that compared with no foliar fertilizer application, foliar fertilizers with different ratios all significantly increased the content of 2-acetyl-1-pyrroline. Among them, the foliar fertilizer composed of γ-polyglutamic acid and chitosan with a mass ratio of 40:50 significantly increased the total nitrogen content, spermidine, putrescine and arginine relative content of fragrant rice. There was no significant difference in yield among the three treatments, indicating that the exogenous spraying of this application improved the fragrance quality without reducing the yield.

[0062] Depend on Figure 20 Correlation analysis between 2-acetyl-1-pyrroline and polyamines showed that the content of 2-acetyl-1-pyrroline was significantly positively correlated with the expression levels of SPDSYN and SAMDC, and arginine was significantly positively correlated with spermidine and putrescine. This indicates that the foliar fertilizers polyglutamate and chitosan applied to rice during the booting period of the present invention provide glutamate and nitrogen sources as substrates, thereby increasing the content of arginine and putrescine through the glutamate-arginine pathway, and under the regulation of SPDSYN and SAMDC, increasing the content of spermidine, and finally increasing the accumulation of 2-acetyl-1-pyrroline.

[0063] Example 4

[0064] Combined effects of mixtures and zinc-modified biochar

[0065] In the field experiment, the prepared 1:10 zinc-modified biochar was mixed with soil to raise seedlings. A mixture of γ-polyglutamic acid and chitosan at a ratio of 40:50 was sprayed at the booting stage. Conventional seedling cultivation was designated as CK, only zinc-modified biochar was used for seedling cultivation as BC1, only the mixture was sprayed as G2, and a combination of the two methods was designated as BC1+G2. The 2-acetyl-1-pyrroline content and yield of grains at maturity were measured. Figures 21-22 As can be seen from the figure, the foliar fertilizer of low-concentration zinc-modified biochar combined with high-concentration y-polyglutamic acid increased the content of 2-acetyl-1-pyrroline most significantly, and the yield increased, but did not reach a significant difference, achieving the purpose of increasing fragrance and stabilizing yield.

Claims

1. A method for improving the aroma accumulation of fragrant rice, characterized in that: The process includes the following steps: preparing zinc-modified biochar, mixing the zinc-modified biochar with soil at a mass ratio of 1:38-42, and then raising seedlings; and then spraying 10-15 L / m 2 The mixture is on the leaves; The zinc-modified biochar is prepared by drying and crushing coconut shells, soaking them in hexahydrated zinc sulfate, ultrasonically drying them, calcining them, and sieving them to obtain the zinc-modified biochar. The mass ratio of the coconut shell to zinc sulfate heptahydrate is 1:10; The mixture is a mixture of gamma-polyglutamic acid and chitosan in a mass ratio of 40:50.

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