Method for calculating nitrogen transport in plant body through 15N isotope field in-situ labeling

Abstract

The invention relates to the technical field of agricultural information, in particular to a method for calculating nitrogen transport in a plant through 15N isotope field in-situ labeling. The method specifically comprises the following steps: applying a 15N isotope labeled nitrogen fertilizer; all nitrogen accumulation amounts and < 15 > N accumulation amounts of nutritive organs and reproductive organs of the plant in two growth periods from the flowering period to the mature period are obtained, and the nitrogen transport amounts of the nutritive organs of the plant to the reproductive organs in the two growth periods are calculated; and calculating the accumulation amount of the nitrogen absorbed by the plant in the two growth periods in a nutritive organ and a reproductive organ so as to evaluate the source of the nitrogen in the reproductive organ of the plant. The method provided by the invention solves the problems that the accuracy of quantifying the nitrogen transfer in the plant body is low, the source of nitrogen in the reproductive organ of the plant cannot be accurately judged, and great errors exist in guiding variety breeding and nitrogenous fertilizer operation in the existing method.

Description

Technical Field

[0001] The present invention relates to the field of agricultural information technology, and in particular to a 15 A method for calculating nitrogen transport in plants using in situ N isotope labeling in the field. Background Art

[0002] Nitrogen is an important nutrient for crop growth and food production. Modern intensive agriculture is highly dependent on exogenous nitrogen fertilizers, such as urea. However, the efficiency of agricultural nitrogen fertilizer utilization is only 30% to 40%, resulting in resource waste and ecological health threats. Therefore, quantitative nitrogen transport in plants is crucial to the synergistic improvement of crop yield and nitrogen fertilizer utilization efficiency.

[0003] At present, the study of nitrogen transport in plants mostly adopts the subtraction method or black box analysis method. This method regards each organ of the plant as a black box, takes the difference of nitrogen content in each organ at different growth periods as the net transport amount, and indirectly estimates nitrogen transport in the plant. For example, the plant vegetative organs and reproductive organs are regarded as two interconnected black boxes. By measuring the nitrogen content of the organs at the end of plant vegetative growth and maturity, and calculating the difference between the two, the net transport amount of nitrogen from the vegetative organs to the reproductive organs, the source and proportion of nitrogen in the grains are indirectly estimated. Among them, for gramineous crops such as corn, wheat, and rice, the end of plant vegetative growth is the flowering period. However, this method is not only limited by local soil and climatic conditions, but also the comparability of results in different locations is poor; and it can usually only analyze nitrogen transport between the end of vegetative growth and maturity. At the same time, since the sources of nitrogen in reproductive organs can be divided into: nitrogen transported from vegetative organs to reproductive organs and nitrogen absorbed from the soil. The black box analysis method underestimates the amount of nitrogen transport from vegetative organs to reproductive organs; and the degree of underestimation varies for different vegetative organs. For example, the degree of underestimation for leaves is greater than that for stems. Therefore, the black box analysis method cannot accurately quantify the source of nitrogen in the reproductive organs of plants, which has a large error in guiding variety selection and nitrogen fertilizer management. Therefore, a method that is not limited by environmental conditions and can accurately quantify nitrogen transport in plants is urgently needed. Summary of the invention

[0004] In order to solve the problems that the existing methods have low accuracy in quantifying nitrogen transport in plants, cannot accurately determine the source of nitrogen in the reproductive organs of plants, and have large errors in guiding variety breeding and nitrogen fertilizer management, the purpose of the present invention is to provide a 15 A method for calculating nitrogen transport in plants using in situ N isotope labeling in the field.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows.

[0006] A first aspect of the present invention provides a 15The method for calculating nitrogen transport in plants by in situ labeling of N isotopes in the field includes the following steps:

[0007] When applying nitrogen fertilizer as a base or topdressing, apply 15 N isotope labeled nitrogen fertilizer; obtain the total nitrogen accumulation and 15 N accumulation, and compare the total nitrogen accumulation of the plant's vegetative organs during the two growth periods and 15 The difference rate of N accumulation is used to calculate the nitrogen transport amount from each vegetative organ to the reproductive organ of the plant in the two growth periods; by comparing the change values ​​of all nitrogen accumulation amounts of the vegetative organs of the plants in the two growth periods, and summing them up with the nitrogen transport amounts from the vegetative organs of the plants to the reproductive organs in the two growth periods, the accumulation amount of nitrogen absorbed by the plants in each vegetative organ in the two growth periods is obtained; at the same time, by comparing the difference of all nitrogen accumulation amounts of the reproductive organs of the plants in the two growth periods, and calculating the difference with the sum of nitrogen transport amounts from all vegetative organs to the reproductive organs in the two growth periods, the accumulation amount of nitrogen absorbed by the plants in the reproductive organs in the two growth periods is obtained, which is used to evaluate the source of nitrogen in the reproductive organs of the plants.

[0008] The object of the present invention is to quantify or differentiate the sources of nitrogen in each reproductive organ from nitrogen taken up by the plant from the soil during two growth periods; as well as the sources of nitrogen from multiple vegetative organs.

[0009] The present invention utilizes 15 N isotope in situ labeling in the field can quantify the accumulation of nitrogen in the vegetative organs during the reproductive growth stage, and then accurately calculate the amount of nitrogen transported from the vegetative organs of the plant to the reproductive organs and the accumulation of nitrogen absorbed by the plant in the reproductive organs, avoiding random errors caused by experimental environmental conditions and the inherent systematic errors of black box analysis methods. It solves the problems of low accuracy in quantifying nitrogen transport in plants and the inability to accurately determine the source of nitrogen in the reproductive organs of plants, which has large errors in guiding variety selection and nitrogen fertilizer management. It solves the problems of low accuracy in quantifying nitrogen transport in plants and the inability to accurately determine the source of nitrogen in the reproductive organs of plants, which has large errors in guiding variety selection and nitrogen fertilizer management.

[0010] Preferably, the calculation formula for the nitrogen transport amount from each vegetative organ to the reproductive organ of the plant during the two growth periods is:

[0011] N R =( 15 NC1- 15 NC2) / 15 NC1×NC1;

[0012] Among them, N R It represents the amount of nitrogen transported from the vegetative organs to the reproductive organs of the plant during the two growth periods; 15 NC1 indicates the vegetative organs of the plant in the previous growth period. 15 N accumulation; 15 NC2 indicates the growth of the plant's vegetative organs in the latter growth period. 15 N accumulation: NC1 refers to the total nitrogen accumulation of the plant's nutritional organs in the previous growth period.

[0013] The present invention uses the data of each vegetative organ to calculate the nitrogen transport amount from the vegetative organ to the reproductive organ. There is only one reproductive organ, and the vegetative organs can be divided into one or more according to the experimental purpose.

[0014] Preferably, the calculation formula for the accumulation of nitrogen absorbed by plants in one nutritional organ during two growth periods is:

[0015] N 1V =NC 2V -NC 1V +N R ;

[0016] Among them, N 1V Indicates the amount of nitrogen absorbed by plants in a nutritional organ during two growth periods; NC 2V Indicates the total nitrogen accumulation of a plant's vegetative organ in the next growth period; NC 1V It indicates the total nitrogen accumulation of a plant's nutritional organ in the previous growth period.

[0017] Preferably, the calculation formula for the accumulation of nitrogen absorbed by plants in one reproductive organ during two growth periods is:

[0018] N 1R =NC 2R -NC 1R -∑N R ;

[0019] Among them, N 1R Indicates the amount of nitrogen absorbed by plants in their reproductive organs during the two growth periods; NC 2R Indicates the total nitrogen accumulation of reproductive organs in the latter growth period; NC 1R Indicates the total nitrogen accumulation of reproductive organs in the previous growth period; ∑N R It represents the sum of nitrogen transport from all vegetative organs to reproductive organs during two growth periods.

[0020] Preferably, 15 N isotope-labeled nitrogen fertilizer is made with an atomic abundance of 10.21%. 15 N isotope labeled nitrogen fertilizer was obtained;15 The application rate of N isotope-labeled nitrogen fertilizer is 60-180 kg N / ha.

[0021] Preferably, the nitrogen fertilizer is urea; and the plant is any one of corn, wheat, rice, sorghum and oats.

[0022] Preferably, the two growth periods are two growth periods from 14 days before flowering to the mature stage; the growth period from 14 days before flowering to the mature stage includes 14 days before flowering, flowering stage, 14 days after flowering and the mature stage.

[0023] Preferably, the calculation formula for all nitrogen accumulation of corresponding organs of a plant during a growth period is:

[0024] NC = nitrogen concentration of the corresponding organ of the plant × dry weight of the corresponding organ of the plant; wherein NC represents the total nitrogen accumulation of the corresponding organ of the plant in a growth period, and the corresponding organ of the plant is a nutritional organ or a reproductive organ of the plant.

[0025] Preferably, the method further comprises: applying common nitrogen fertilizer when applying nitrogen fertilizer as base fertilizer or topdressing;

[0026] To apply 15 Plants labeled with N isotope urea were used as the treatment group; plants treated with ordinary urea were used as the control group; 15 The N isotope abundance of the control samples 15 The difference of N isotope abundance is calculated, and the calculated difference is multiplied by the nitrogen accumulation of the corresponding organs of the plant to calculate the nitrogen accumulation of the corresponding organs of the plant in a growth period from flowering to maturity. 15 N accumulation; the sample includes stems, upper leaves, middle leaves, lower leaves and female ears; the upper leaves are the second leaf and the upper leaves above the corn cob; the middle leaves are the leaves at the corn cob and one leaf above and below; the lower leaves are the second leaf and the lower leaves below the corn cob; the female ear is the reproductive organ.

[0027] Preferably, the corresponding organs of a plant during a growth period 15 The calculation formula for N accumulation is:

[0028] 15 NC=NC×(δ 15 N T -δ 15 N CK );

[0029] in, 15 NC represents the number of corresponding organs of a plant during a growth period. 15 N accumulation; NC refers to the total nitrogen accumulation of the corresponding organs of the plant during a growth period; δ15 N T Indicates application 15 N isotope labeled urea in plants 15 N isotope abundance; δ 15 N CK Indicates the application of ordinary urea to plants 15 N isotope abundance.

[0030] Beneficial effects of the present invention:

[0031] 1. The present invention utilizes 15 N isotope in situ labeling in the field quantifies the accumulation of nitrogen in the vegetative organs during the reproductive growth stage, and then accurately calculates the amount of nitrogen transported from the vegetative organs of the plant to the reproductive organs and the accumulation of nitrogen absorbed by the plant in the reproductive organs, avoiding random errors caused by experimental environmental conditions and systematic errors inherent in the black box analysis method. It solves the problems of low accuracy in quantifying nitrogen transport in plants and being unable to accurately determine the source of nitrogen in the reproductive organs of plants, which leads to large errors in guiding variety selection and nitrogen fertilizer management.

[0032] 2. The method of the present invention can calculate the amount of nitrogen transport in the body of corn and other grass plants at any time interval from the elongation of the female ear primordium to the maturity period, and then accurately quantify the source of nitrogen in the reproductive organs, realize nitrogen traceability, and provide theoretical reference and practical guidance for the breeding of nitrogen-efficient crop varieties and the optimization of nitrogen fertilizer management. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The following are schematic diagrams of two methods for calculating nitrogen transport in plants. (a) is a schematic diagram of a method for calculating nitrogen transport in plants using an existing black box analysis method; (b) is a schematic diagram of a method for calculating nitrogen transport in plants provided by an embodiment of the present invention. N0 represents the nitrogen content of the vegetative organs at the flowering stage; N1 represents the nitrogen content of the vegetative organs at the mature stage; N g Indicates the nitrogen content of grains at maturity; N R It refers to the amount of nitrogen transported from the vegetative organs to the reproductive organs of plants during the two growth periods; N A It indicates the amount of nitrogen absorbed by plants in their reproductive organs during the two growth periods; N v It indicates the accumulation of nitrogen absorbed by plants in their nutritional organs during two growth periods. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution 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 used to limit the present invention.

[0035] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present invention.

[0036] At present, the research method for calculating nitrogen transport in plants is the subtraction method or black box analysis method. This method regards the plant's vegetative organs and reproductive organs as two interconnected black boxes. By measuring the nitrogen content of the organs at the end of the plant's vegetative growth and the mature stage, and calculating the difference between the two, the net nitrogen transport from the vegetative organs to the reproductive organs, the source of nitrogen in the grains and the proportion are indirectly estimated. Among them, for gramineous crops such as corn, wheat, and rice, the end of the plant's vegetative growth is the flowering stage. The calculation formula of the existing method is as follows:

[0037] N R =N0-N1; N A =N g -N R ; Net nitrogen transport ratio = N R / N g ×100%; Nitrogen absorption ratio after flowering = N A / N g ×100%; where N R It indicates the amount of nitrogen transported from the vegetative organs to the reproductive organs of the plant during the two growth periods; N0 indicates the nitrogen content of the vegetative organs during the flowering period; N1 indicates the nitrogen content of the vegetative organs during the mature period; N A Indicates the amount of nitrogen absorbed by the plant and accumulated in its reproductive organs after flowering; N g Indicates the nitrogen content of grains at maturity.

[0038] Figure 1 The following are schematic diagrams of two methods for calculating nitrogen transport in plants. (a) is a schematic diagram of a method for calculating nitrogen transport in plants using an existing black box analysis method; (b) is a schematic diagram of a method for calculating nitrogen transport in plants provided by an embodiment of the present invention. N0 represents the nitrogen content of the vegetative organs at the flowering stage; N1 represents the nitrogen content of the vegetative organs at the mature stage; N g Indicates the nitrogen content of grains at maturity; N R It refers to the amount of nitrogen transported from the vegetative organs to the reproductive organs of plants during the two growth periods; N A It indicates the amount of nitrogen absorbed by plants in their reproductive organs during the two growth periods; N v It indicates the accumulation of nitrogen absorbed by plants in their nutritional organs during two growth periods.

[0039] For the calculation method shown in Figure (a):

[0040] The calculation formula for the amount of nitrogen transported from the vegetative organs to the reproductive organs of plants during the two growth periods is: N R=N0-N1.

[0041] The calculation formula for the amount of nitrogen absorbed by the plant in its reproductive organs after flowering is: N A =N g -N R .

[0042] Analysis shows that the calculation method shown in Figure (a) uses the difference in nitrogen content in the vegetative organs during the flowering period and the mature period to represent the net nitrogen transport, ignoring the accumulation of nitrogen absorbed by the plant in the vegetative organs after the flowering period, resulting in an underestimation of the net nitrogen transport from the plant vegetative organs to the reproductive organs. Moreover, the accumulation of nitrogen in the vegetative organs after the flowering period is affected by many factors such as crop variety, soil fertility and climatic conditions, and it is difficult to correct it through empirical coefficients.

[0043] The calculation method for Figure (b) is:

[0044] The calculation formula for the amount of nitrogen transported from the vegetative organs to the reproductive organs of plants during the two growth periods is: N R =N0-(N1-N v ).

[0045] The calculation formula for the amount of nitrogen absorbed by the plant in its reproductive organs after flowering is: N A =N g -N R .

[0046] Compared with the calculation method shown in Figure (a), the calculation method shown in Figure (b) takes into account the accumulation of nitrogen in the vegetative organs after flowering, thereby accurately evaluating the net nitrogen transport from the plant's vegetative organs to the reproductive organs.

[0047] Based on this, the present invention calculates the amount of nitrogen transport in the body of grass plants such as corn at any time interval from the elongation of the female ear primordium to the maturity period, including: the amount of nitrogen transport from the vegetative organs to the reproductive organs, the accumulation of nitrogen absorbed by the plants in the vegetative organs and the accumulation of nitrogen absorbed by the plants in the reproductive organs, thereby accurately quantifying the source of nitrogen in the reproductive organs and realizing nitrogen traceability, providing theoretical reference and practical guidance for the breeding of nitrogen-efficient crop varieties and the optimization of nitrogen fertilizer management.

[0048] The present invention mainly utilizes 15 N isotope in situ field labeling quantifies the accumulation of nitrogen absorbed by plants in the nutritional organs during two growth periods, and then accurately calculates the amount of nitrogen transported from the nutritional organs of the plants to the reproductive organs and the accumulation of nitrogen absorbed by plants in the reproductive organs, avoiding random errors caused by experimental environmental conditions and systematic errors inherent in the black box analysis method, and solving the problems of poor soil climate adaptability, poor comparability of results, limited analysis period, and low nitrogen transport assessment in existing calculation methods.

[0049] In the following examples, the methods described are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0050] In the following embodiments, 14 days before flowering are recorded as R1-14d; the flowering period is recorded as R1; and 14 days after flowering is recorded as R1+14d.

[0051] In the following embodiments, the upper leaves of the corn sample are the second leaf and the upper leaf above the corn ear. The middle leaves of the corn sample are the leaves at the corn ear and one leaf above and below. The lower leaves of the corn sample are the second leaf and the lower leaf below the corn ear. The female ear of the corn sample is the reproductive organ.

[0052] The plants described in the method of the present invention are not limited to corn, but can also be gramineous plants such as wheat, rice, sorghum, and oats; the calculation of the nitrogen transport amount described in the method of the present invention is not limited to the flowering period to the maturity period, but is applicable to any period from the elongation of the female ear primordium to the maturity period.

[0053] The method of the present invention is further described below using corn as an example. The method of the present invention has no negative impact on agricultural production and food security.

[0054] One embodiment of the present invention provides a 15 The method for calculating nitrogen transport in plants by in situ labeling of N isotopes in the field includes the following steps:

[0055] Step 1, taking corn as an example, when applying nitrogen fertilizer as base or topdressing, use 10.21% atomic abundance 15 N isotope labeled urea is used to replace ordinary urea. For example, when the nitrogen application rate is 180 kg N / ha and the planting density is 67,500 plants / ha, 5.7971 g of urea is applied per corn plant. 15 N isotope labeled urea.

[0056] To apply 15 Corn plants with N isotope labeled urea were used as the treatment group, and corn plants with ordinary urea were used as the control group. The fertilization position was 3-4 cm beside the plants, the fertilization depth was 5 cm, and the soil was covered after fertilization.

[0057] Step 2: During the flowering and maturity stages, 15 N isotope labeled urea application 15Corn plants labeled with N isotope urea and corn plants treated with normal urea were decomposed into n vegetative organs and 1 reproductive organ; the n vegetative organs were labeled as vegetative organ 1, vegetative organ 2, vegetative organ 3, and vegetative organ n; the reproductive organs were female ears or kernels. The samples were dried at 105°C for 30 minutes and at 80°C for 72 hours, and the dry weight was measured. The nitrogen concentration and 15 N isotope abundance.

[0058] Step 3, calculation method of nitrogen transport is as follows:

[0059] The calculation formula for all nitrogen accumulation in the corresponding organs of a plant during a growth period is:

[0060] NC = nitrogen concentration of the corresponding organ of the plant × dry weight of the corresponding organ of the plant;

[0061] The corresponding organ of the plant is a vegetative organ or a reproductive organ of the plant; NC represents the total nitrogen accumulation of the corresponding organ of the plant.

[0062] The corresponding organs of a plant during a growth period 15 The calculation formula for N accumulation is:

[0063] 15 NC=NC×(δ 15 N T -δ 15 N CK );

[0064] Among them, the corresponding organ of a plant is a vegetative organ or a reproductive organ of the plant; 15 NC represents the number of corresponding organs of a plant during a growth period. 15 N accumulation; NC refers to the total nitrogen accumulation of the corresponding organs of the plant during a growth period; δ 15 N T Indicates application 15 N isotope labeled urea in plants 15 N isotope abundance; δ 15 N CK Indicates the application of ordinary urea to plants 15 N isotope abundance; Application 15 Plants treated with N isotope labeled urea were designated as the treatment group, and were labeled as T. Plants treated with normal urea were designated as the control group, and were labeled as CK.

[0065] The calculation formula for the amount of nitrogen transported from each vegetative organ to the reproductive organ of the plant during the two growth periods is: N R =( 15 NC A - 15 NCM ) / 15 NC A ×NC A ;

[0066] Among them, N R It represents the amount of nitrogen transported from the vegetative organs to the reproductive organs of the plant during the two growth periods; 15 NC A Indicates the vegetative organs of flowering plants 15 N accumulation; 15 NC M Denotes the vegetative organs of mature plants 15 N accumulation; NC A It indicates the total nitrogen accumulation of the vegetative organs of the plant during the flowering period; M indicates the maturity period; A indicates the flowering period; and R indicates the reproductive organs.

[0067] The calculation formula for the amount of nitrogen absorbed by plants in a nutritional organ from flowering to maturity is: N AV =NC M -NC A +N R ;

[0068] Among them, N AV Indicates the amount of nitrogen absorbed by plants in a nutritional organ from flowering to maturity; NC M Indicates the total nitrogen accumulation of a vegetative organ at maturity; NC A It refers to the total nitrogen accumulation of a vegetative organ during the flowering period; N R It indicates the amount of nitrogen transported from the vegetative organs to the reproductive organs of the plant during two growth periods.

[0069] The calculation formula for the accumulation of nitrogen absorbed by plants in reproductive organs from flowering to maturity is:

[0070] N AR =NC MR -NC AR -∑N R ;

[0071] Among them, N AR Indicates the amount of nitrogen absorbed by plants in their reproductive organs from flowering to maturity; NC MR Indicates the total nitrogen accumulation of reproductive organs at maturity; NC AR Represents the total nitrogen accumulation of reproductive organs during the flowering period; ∑N R It represents the sum of nitrogen transport from all vegetative organs to reproductive organs; M represents maturity; A represents flowering; R represents reproductive organs; and V represents vegetative organs.

[0072] The technical solution of the present invention is further described below through specific embodiments.

[0073] Example 1

[0074] The maize variety Zhengdan 958 was selected as the research plant. When nitrogen fertilizer was applied as basal fertilizer or topdressing, the atomic abundance of 10.21% was used. 15 N isotope labeled urea is used to replace ordinary urea. When the nitrogen application rate is 60 kg N / ha and the planting density is 67,500 plants / ha, 1.9324 g is applied per corn plant. 15 Urea is labeled with N isotope. Fertilizer is applied 3 to 4 cm away from the plant, at a depth of 5 cm, and covered with soil after fertilization.

[0075] Samples were collected 14 days before flowering, during flowering, and 14 days after flowering. The 14 days before flowering were recorded as R1-14d; the flowering period was recorded as R1; and the 14 days after flowering was recorded as R1+14d. The samples included stems, upper leaves, middle leaves, lower leaves, and female ears, a total of five parts; among them, the upper leaves were the second leaf and upper leaves above the corn ear; the middle leaves were the leaves at the corn ear and one leaf above and below; the lower leaves were the second leaf and lower leaves below the corn ear; and the female ear was the reproductive organ.

[0076] The obtained samples were quickly dried at 105°C for 30 minutes and at 80°C for 72 hours, and the dry weight was weighed. The nitrogen concentration and 15 N isotope abundance.

[0077] Example 2

[0078] The maize variety Zhengdan 958 was selected as the research plant. When nitrogen fertilizer was applied as basal fertilizer or topdressing, the atomic abundance of 10.21% was used. 15 N isotope labeled urea is used to replace ordinary urea. When the nitrogen application rate is 180 kg N / ha and the planting density is 67,500 plants / ha, 5.7971 g of urea is applied per corn plant. 15 Urea labeled with N isotope. Fertilizer application position is 3cm to 4cm beside the plant, the fertilizer application depth is 5cm, and the soil is covered after fertilization.

[0079] Samples were collected 14 days before flowering, during flowering, and 14 days after flowering. The 14 days before flowering were recorded as R1-14d; the flowering period was recorded as R1; and the 14 days after flowering was recorded as R1+14d. The samples included stems, upper leaves, middle leaves, lower leaves, and female ears, a total of five parts; among them, the upper leaves were the second leaf and upper leaves above the corn ear; the middle leaves were the leaves at the corn ear and one leaf above and below; the lower leaves were the second leaf and lower leaves below the corn ear; and the female ear was the reproductive organ.

[0080] The obtained samples were quickly dried at 105°C for 30 minutes and at 80°C for 72 hours, and the dry weight was weighed. The nitrogen concentration and 15 N isotope abundance.

[0081] Example 3

[0082] The maize variety Liangyu 99 was selected as the research plant. When nitrogen fertilizer was applied as basal fertilizer or topdressing, the nitrogen with atomic abundance of 10.21% was used. 15 N isotope labeled urea is used to replace ordinary urea. When the nitrogen application rate is 60 kg N / ha and the planting density is 67,500 plants / ha, 1.9324 g is applied per corn plant. 15 Urea is labeled with N isotope. Fertilizer is applied 3 to 4 cm away from the plant, at a depth of 5 cm, and covered with soil after fertilization.

[0083] Samples were collected 14 days before flowering, during flowering, and 14 days after flowering. The 14 days before flowering were recorded as R1-14d; the flowering period was recorded as R1; and the 14 days after flowering was recorded as R1+14d. The samples included stems, upper leaves, middle leaves, lower leaves, and female ears, a total of five parts; among them, the upper leaves were the second leaf and upper leaves above the corn ear; the middle leaves were the leaves at the corn ear and one leaf above and below; the lower leaves were the second leaf and lower leaves below the corn ear; and the female ear was the reproductive organ.

[0084] The obtained samples were quickly dried at 105°C for 30 minutes and at 80°C for 72 hours, and the dry weight was weighed. The nitrogen concentration and 15 N isotope abundance.

[0085] Example 4

[0086] The maize variety Liangyu 99 was selected as the research plant. When nitrogen fertilizer was applied as basal fertilizer or topdressing, the nitrogen with atomic abundance of 10.21% was used. 15 N isotope labeled urea is used to replace ordinary urea. When the nitrogen application rate is 180 kg N / ha and the planting density is 67,500 plants / ha, 5.7971 g of urea is applied per corn plant. 15 Urea is labeled with N isotope. Fertilizer is applied 3 to 4 cm away from the plant, at a depth of 5 cm, and covered with soil after fertilization.

[0087] Samples were collected 14 days before flowering, during flowering, and 14 days after flowering. The 14 days before flowering were recorded as R1-14d; the flowering period was recorded as R1; and the 14 days after flowering was recorded as R1+14d. The samples included stems, upper leaves, middle leaves, lower leaves, and female ears, a total of five parts; among them, the upper leaves were the second leaf and upper leaves above the corn ear; the middle leaves were the leaves at the corn ear and one leaf above and below; the lower leaves were the second leaf and lower leaves below the corn ear; and the female ear was the reproductive organ.

[0088] The obtained samples were quickly dried at 105°C for 30 minutes and at 80°C for 72 hours, and the dry weight was weighed. The nitrogen concentration and 15N isotope abundance of the samples were measured using an elemental analyzer tandem mass spectrometer.

[0089] The total nitrogen accumulation of each organ of the plant was calculated according to the calculation formula of the total nitrogen accumulation of the corresponding organs of the plant. The results are shown in Table 1. 15 Calculation formula for nitrogen accumulation in various plant organs 15 The results of N accumulation are shown in Table 2.

[0090] The nitrogen transport amount in corn from 14 days before flowering to the flowering period and the accumulation of absorbed nitrogen in various plant organs were calculated according to the following formula. The results are shown in Table 3.

[0091] The calculation formula for the amount of nitrogen transported from the vegetative organs of plants to the reproductive organs is:

[0092] N R =( 15 NC R1-14d - 15 NC R1 ) / 15 NC A ×NC A ;

[0093] Among them, N R It indicates the amount of nitrogen transported from the vegetative organs to the reproductive organs of the plant; 15 NC R1-14d Indicates the growth of various vegetative organs 14 days before flowering 15 N accumulation; 15 NC R1 Indicates the various vegetative organs during the flowering period 15 N accumulation; NC R1-14d It represents the total nitrogen accumulation of each vegetative organ 14 days before flowering; R1-14d represents 14 days before flowering; R1 represents flowering period; R represents reproductive organ.

[0094] The calculation formula for the accumulation of nitrogen absorbed by plants in a nutritional organ from 14 days before flowering to the flowering period is:

[0095] N AV =NC R1 -NC R1-14d +N R ;

[0096] Among them, N AV It indicates the amount of nitrogen absorbed by plants in a vegetative organ from 14 days before flowering to the flowering period; NC R1Indicates the total nitrogen accumulation of vegetative organs during flowering period; NC R1-14d It indicates the total nitrogen accumulation of vegetative organs 14 days before flowering; N R It indicates the amount of nitrogen transported from the vegetative organs to the reproductive organs of the plant.

[0097] The calculation formula for the accumulation of nitrogen absorbed by plants in reproductive organs from 14 days before flowering to the flowering period is: N AR =NC R1 -NC R1-14d -∑N R ;

[0098] Among them, N AR It indicates the amount of nitrogen absorbed by plants in their reproductive organs from 14 days before flowering to the flowering period; NC R1 Indicates the total nitrogen accumulation of reproductive organs during flowering period; NC R1-14d It represents the total nitrogen accumulation of reproductive organs 14 days before flowering; ∑N R It represents the sum of nitrogen transport from all vegetative organs to reproductive organs from 14 days before flowering to flowering period; R1-14d represents 14 days before flowering; R1 represents flowering period; R represents reproductive organ.

[0099] The amount of nitrogen transported in corn from the flowering stage to 14 days after flowering and the accumulation of absorbed nitrogen in various plant organs were calculated according to the following formula. The results are shown in Table 4.

[0100] The calculation formula for the amount of nitrogen transported from the vegetative organs to the reproductive organs of plants during the two growth periods is: N R =( 15 NC R1 - 15 NC R1+14d ) / 15 NC R1 ×NC R1 ;

[0101] Among them, N R It represents the amount of nitrogen transported from the vegetative organs to the reproductive organs of the plant during the two growth periods; 15 NC R1 Indicates the vegetative organs during flowering period 15 N accumulation; 15 NC R1+14d Indicates the growth of vegetative organs 14 days after flowering 15 N accumulation; NC R1 It represents the total nitrogen accumulation of vegetative organs during the flowering period; R1 represents the flowering period; R1+14d represents 14 days after flowering; R represents reproductive organs.

[0102] The calculation formula for the amount of nitrogen absorbed by plants in a nutritional organ from the flowering stage to 14 days after flowering is: N AV =NC R1+14d -NC R1 +N R ;

[0103] Among them, N AV It indicates the amount of nitrogen absorbed by plants and accumulated in a vegetative organ from the flowering stage to 14 days after flowering; NC R1+14d NC represents the total nitrogen accumulation in vegetative organs 14 days after anthesis; R1 It refers to the total nitrogen accumulation of vegetative organs during the flowering period; N R It indicates the amount of nitrogen transported from the vegetative organs to the reproductive organs of the plant.

[0104] The calculation formula for the accumulation of nitrogen absorbed by plants in reproductive organs from the flowering stage to 14 days after flowering is: N AR =NC R1+14d -NC R1 -∑N R ;

[0105] Among them, N AR Indicates the amount of nitrogen absorbed by plants in their reproductive organs from the flowering stage to 14 days after flowering; NC R1+14d NC represents the total nitrogen accumulation in reproductive organs 14 days after flowering; R1 Represents the total nitrogen accumulation of reproductive organs during the flowering period; ∑N R It represents the sum of nitrogen transport from all vegetative organs to reproductive organs from the flowering period to 14 days after flowering; R1 represents the flowering period; R1+14d represents 14 days after flowering; R represents the reproductive organ.

[0106] Table 1 Total nitrogen accumulation in each plant organ (unit: mg / plant)

[0107]

[0108] Note: R1-14d means 14 days before flowering; R1 means flowering period; R1+14d means 14 days after flowering.

[0109] Table 2 Plant organs 15 N accumulation (mg / plant)

[0110]

[0111] Table 3 Nitrogen transport and accumulation of absorbed nitrogen in various organs of corn from 14 days before flowering to flowering period (unit: mg / plant)

[0112]

[0113] Table 4 Nitrogen transport and nitrogen accumulation in various organs of corn from flowering to 14 days after flowering (unit: mg / plant)

[0114]

[0115] It can be seen from the results in Tables 1 to 4 that the method of the embodiment of the present invention can quantify the amount of nitrogen transport in the corn from R1-14d to R1 and from R1 to R1+14d and the amount of nitrogen absorbed in various organs. At a low nitrogen application rate of 60kg N / ha, from 14 days before flowering to flowering period, the amount of nitrogen absorbed in the reproductive organs of Zhengdan 958 was 225% higher than that of Liangyu 99; from flowering period to 14 days after flowering, the amount of nitrogen absorbed in the reproductive organs of Zhengdan 958 was 46% higher than that of Liangyu 99.

[0116] From the flowering stage to 14 days after flowering, the nitrogen transport from the vegetative organs to the reproductive organs of Zhengdan 958 was 117% higher than that of Liangyu 99. Among them, the nitrogen from the stems increased by 204%; the nitrogen from the lower leaves increased by 315%, and the nitrogen from the panicles and upper leaves decreased by 43% and 68% respectively.

[0117] Taking Zhengdan 958 with a nitrogen application rate of 60 kg / ha in Example 1 as an example, the total nitrogen accumulation of the female ear from 14 days before flowering to the flowering period increased by 77.8 mg N / plant, of which 30.32 mg N / plant came from the nitrogen accumulation absorbed from the soil, 47.48 mg N / plant came from the nitrogen transport of the nutritional organs, of which 13.19 mg N / plant came from the stems, 10.15 mg N / plant came from the upper leaves, 11.00 mg N / plant came from the middle leaves, and 13.14 mg N / plant came from the lower leaves. From the flowering stage to 14 days after flowering, the total nitrogen accumulation of the female ear increased by 351.84 mg N / plant, of which 179.91 mg N / plant came from the nitrogen accumulation absorbed from the soil, 171.93 mg N / plant came from the nitrogen translocation of the nutritional organs, of which 51.14 mg N / plant came from the stems, 5.33 mg N / plant came from the upper leaves, 11.72 mg N / plant came from the middle leaves, and 103.74 mg N / plant came from the lower leaves.

[0118] The above analysis shows that the embodiment of the present invention utilizes 15 In situ field labeling with N isotopes can quantify the accumulation of nitrogen in the vegetative organs after flowering, and then accurately calculate the amount of nitrogen transported from the vegetative organs of the plant to the reproductive organs and the accumulation of nitrogen absorbed by the plant in the reproductive organs, avoiding random errors caused by experimental environmental conditions and systematic errors inherent in the black box analysis method.

[0119] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A 15 The method for calculating nitrogen transport in plants by in-situ labeling of N isotopes in the field is characterized in that: The following steps are involved: When applying nitrogen fertilizer as a base or topdressing, apply 15 N isotope-labeled nitrogen fertilizer; Obtain the total nitrogen accumulation and nitrogen content of the vegetative organs and reproductive organs of the plants at any two growth stages from 14 days before flowering to maturity. 15 N accumulation, and compare the total nitrogen accumulation of the plant's vegetative organs during the two growth periods and 15 The difference rate of N accumulation was used to calculate the amount of N transported from each vegetative organ to the reproductive organ of the plant during the two growth periods; By comparing the changes in the total nitrogen accumulation of the plant's vegetative organs during the two growth periods and summing them with the nitrogen transport from the plant's vegetative organs to its reproductive organs during the two growth periods, the accumulation of nitrogen absorbed by the plant in each vegetative organ during the two growth periods was obtained. At the same time, by comparing the difference in the amount of all nitrogen accumulation in the reproductive organs of the plants during the two growth periods and calculating the difference with the sum of the nitrogen transported from all nutritional organs to the reproductive organs during the two growth periods, the accumulation of nitrogen absorbed by the plants in the reproductive organs during the two growth periods was obtained, which was used to evaluate the source of nitrogen in the reproductive organs of the plants.

2. according to claim 1 15 The method for calculating nitrogen transport in plants by in-situ labeling of N isotopes in the field is characterized in that: The calculation formula for the amount of nitrogen transported from each vegetative organ to the reproductive organ of the plant during the two growth periods is: <h2 style=";text-align:left;direction:ltr">N<h2 style=";text-align:left;direction:ltr"> R <h2 style=";text-align:left;direction:ltr"> =(<h2 style=";text-align:left;direction:ltr"> 15 <h2 style=";text-align:left;direction:ltr"> NC1-<h2 style=";text-align:left;direction:ltr"> 15 <h2 style=";text-align:left;direction:ltr"> NC2) / <h2 style=";text-align:left;direction:ltr"> 15 <h2 style=";text-align:left;direction:ltr"> NC1×NC1; Among them, N R It represents the amount of nitrogen transported from the vegetative organs to the reproductive organs of the plant during the two growth periods; 15 NC1 indicates the vegetative organs of the plant in the previous growth period. 15 N accumulation; 15 NC2 indicates the growth of the plant's vegetative organs in the latter growth period. 15 N accumulation: NC1 refers to the total nitrogen accumulation of the plant's nutritional organs in the previous growth period.

3. According to claim 2 15 The method for calculating nitrogen transport in plants by in-situ labeling of N isotopes in the field is characterized in that: The calculation formula for the accumulation of nitrogen absorbed by plants in a nutritional organ during two growth periods is: N 1V =NC 2V -NC 1V +N R 4 Among them, N 1V Indicates the amount of nitrogen absorbed by plants in a nutritional organ during two growth periods; NC 2V Indicates the total nitrogen accumulation of a plant's vegetative organ in the next growth period; NC 1V It indicates the total nitrogen accumulation of a plant's nutritional organ in the previous growth period.

4. according to claim 2 15 The method for calculating nitrogen transport in plants by in-situ labeling of N isotopes in the field is characterized in that: The calculation formula for the accumulation of nitrogen absorbed by plants in one reproductive organ during two growth periods is: N 1R =NC 2R -NC 1R −∑N R 4 Among them, N 1R Indicates the amount of nitrogen absorbed by plants in their reproductive organs during the two growth periods; NC 2R Indicates the total nitrogen accumulation of reproductive organs in the latter growth period; NC 1R Represents the total nitrogen accumulation of reproductive organs in the previous growth period; ∑N R It represents the sum of nitrogen transport from all vegetative organs to reproductive organs during two growth periods.

5. According to claim 1 15 The method for calculating nitrogen transport in plants by in-situ labeling of N isotopes in the field is characterized in that: 15 N isotope-labeled nitrogen fertilizer is made with an atomic abundance of 10.21%. 15 N isotope labeled nitrogen fertilizer was obtained; 15 The application rate of N isotope-labeled nitrogen fertilizer is 60-180 kg N / ha.

6. According to claim 1 15 The method for calculating nitrogen transport in plants by in-situ labeling of N isotopes in the field is characterized in that: The nitrogen fertilizer is urea; and the plant is any one of corn, wheat, rice, sorghum and oats.

7. According to claim 1 15 The method for calculating nitrogen transport in plants by in-situ labeling of N isotopes in the field is characterized in that: The growth period from 14 days before flowering to the mature stage includes 14 days before flowering, flowering period, 14 days after flowering and mature stage.

8. According to claim 1 15 The method for calculating nitrogen transport in plants by in-situ labeling of N isotopes in the field is characterized in that: The calculation formula for all nitrogen accumulation in the corresponding organs of a plant during a growth period is: NC = nitrogen concentration of the corresponding organ of the plant × dry weight of the corresponding organ of the plant; Wherein, NC represents the total nitrogen accumulation of the corresponding organ of the plant in the corresponding growth period, and the corresponding organ of the plant is a nutritional organ or a reproductive organ of the plant.

9. The method according to claim 8 15 The method for calculating nitrogen transport in plants by in-situ labeling of N isotopes in the field is characterized in that: The corresponding organs of a plant during a growth period 15 The calculation formula for N accumulation is: 15 NC=NC×(δ 15 N T -d 15 N CK ); in, 15 NC represents the number of corresponding organs of a plant during a growth period. 15 N accumulation; NC refers to the total nitrogen accumulation of the corresponding organs of the plant during a growth period; δ 15 N T Indicates application 15 N isotope labeled urea in plants 15 N isotope abundance; δ 15 N CK Indicates the application of ordinary urea to plants 15 N isotope abundance.

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