Analytical methods for determining seed nutrient metabolism efficiency

Abstract

The present application relates to the seed breeding technical field, and particularly discloses a kind of analysis method for determining seed nutrient metabolism efficiency.The method for determining the vitality of a seed of the present application is to plant the seed under the condition without external nutrients, only using the nutrient stored in the seed, and the seedling will produce biomass collapse phenomenon in the growth process.Using the size of biomass collapse to represent the vitality of the seed, the smaller the degree of biomass collapse, the stronger the seed vitality.In addition, the photosynthesis of the seedling grown under this condition is determined during the seedling period, and the smaller the degree of photosynthesis inhibition under strong light, the stronger the seed vitality.The above two analysis methods are not used before, and the seed vitality can be accurately determined, which is more time-saving than the traditional method.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of seed selection, in particular to an analysis method for determining seed nutrient metabolism efficiency. BACKGROUND

[0002] When a seed gets proper humidity and temperature, various enzymes in the seed will be active, preparing to transform the nutrients stored in the seed, especially macromolecular nutrients such as starch, protein and fat, into small molecular nutrients required for the growth of the next generation. This nutrient metabolism is related to the survival and growth of the next generation of plants. The comparison of the advantages and disadvantages between two varieties can also start from the comparison of the seed germination stage nutrient metabolism efficiency.

[0003] The variety with the first excellent characteristic can transform the seed nutrient substances of the same quality more effectively to the seedlings, so that the seedlings grow and develop better. Because the nutrient quality stored in the small seed is limited, the higher the transformation efficiency of these nutrients is, the more beneficial to the production and development of the next generation of seedlings.

[0004] Then, how to identify the nutrient metabolism and transformation efficiency of a seed? Accordingly, there are many determination methods, direct or indirect. For example, directly observing the seedling emergence rate, seedling growth uniformity and whether the seedlings are healthy or not in the field; indirectly determining the enzyme activity related to seed vigor characteristics, respiration intensity, conductivity of the leaching liquid and the like in the laboratory. However, these methods have one-sidedness of taking partiality for the whole. SUMMARY

[0005] The present application provides an analysis method for determining seed nutrient metabolism efficiency with clear comparison and accurate conclusion to make up for the deficiencies of the prior art.

[0006] The present application is realized by the following technical solutions:

[0007] An analysis method for determining seed nutrient metabolism efficiency, characterized in that:

[0008] (1) At the seed stage, the activity is evaluated by biomass subsidence, the seed is cultivated in a non-nutrient water or sand culture medium, germination and growth are carried out under weak light conditions, fresh weight or dry weight is collected regularly, standard growth curves and subsidence curves of the biomass subsidence stage are drawn, and the seed vigor is expressed by the integral ratio of the growth curve and the subsidence curve;

[0009] (2) At the seedling stage after the seed germination, the seedling is cultivated in a non-nutrient water or sand culture medium, and the photosynthetic activity is analyzed, the seedling is placed in a light intensity of 30 mol·m -2 ·s -1Next, the light reaction curve is determined, and the photosynthesis inhibition curve of the seedling is analyzed, and finally the photosynthesis inhibition amount is calculated by using the light reaction curve function and the relative photosynthesis inhibition amount function to express the seed vigor.

[0010] The seed vigor determination method of the present application is to plant the seed under the condition without external nutrient, only using the nutrient stored in the seed, and the biomass of the seedling will fall during the growth. The size of the biomass fall is used to express the seed vigor, and the smaller the biomass fall, the stronger the seed vigor. In addition, the photosynthesis of the seedling grown under the above condition is determined during the seedling stage, and the photosynthesis inhibition under strong light is used to express the seed vigor, and the smaller the photosynthesis inhibition, the stronger the seed vigor. The above two analysis methods are not used before, and the seed vigor can be accurately determined, which is more time-saving than the traditional method.

[0011] The more preferred technical solution of the present application is:

[0012] In step (1), the growth trend of the seed conforms to the standard growth curve function equation:

[0013] ,

[0014] Among them, g1 is the biomass at a certain time point, which is the difference between the maximum value and the minimum value of the curve, g M is the maximum growth of the plant, e is the natural exponential base, α 1 is a constant, t is the time, τ 1 is the time middle point of the curve, g B1 is the initial biomass, including the cotyledon left by the seed, g 01 is the starting value of the curve, β 1 is a constant;

[0015] The function equation of the fall curve is:

[0016] ,

[0017] Among them, g 2 is the biomass at a certain time point, g D is the biomass when the biomass begins to fall, g B is the biomass at the tail of the curve;

[0018] Seed vigor .

[0019] The further preferred technical solution is that the absolute amount of biomass fall isg 1( t ) dt and g 2( t ) dt The median of the definite integral difference of the two curves is expressed as ; however, the absolute amount of biomass collapse only has meaning compared with the original biomass, so:

[0020] .

[0021] In step (2), the light reaction curve function equation is:

[0022] ,

[0023] where the dependent variable P N is the photosynthetic rate under a certain light intensity, and the independent variable I is the light intensity; P C is the maximum photosynthetic rate under high light intensity in theory; R D is the photosynthetic rate without light, that is, the respiration rate, and K is a constant;

[0024] Because the peanut seedling leaves grow under weak light, the photosynthetic rate is low, and thus, when the photosynthetic rate is measured under strong light, photosynthesis inhibition occurs. The relative photosynthesis inhibition amount function is:

[0025] ,

[0026] where P0 is the minimum photosynthetic rate after photosynthesis inhibition occurs, P D is the reduced photosynthetic amount, α' is a constant, and I i is the light intensity at which photosynthesis inhibition begins;

[0027] The photosynthesis inhibition amount is expressed by the following formula:

[0028] ,

[0029] where P N is the light reaction curve equation of photosynthesis, but the total photosynthesis without the respiration term is removed; P I is the photosynthesis inhibition curve equation, and the definite integral is integrated from a’ (PPI at which photosynthesis begins to decrease due to inhibition) to b’ (1600 μmol·m -2 ·s -1 ), is the area between the two curves of P N (i) and P I (i).

[0030] Further preferred technical solutions are that the light intensity I is the reciprocal of K,

[0031] ,

[0032] wherein θ = 1 - e -1 ≈ 0.632 is defined as the middle constant of photosynthesis, that is, the light intensity of 63.2% of the maximum photosynthetic capacity of the photosynthetic rate is suitable for the plant.

[0033] The seeds cultivated in the non-nutrient water or sand culture medium are granular seeds, block rhizomes or bulbs, which are common seed cultivation plants, so as to facilitate the selection and universal application of varieties.

[0034] The present application plants the seeds of the same plant from two varieties with equal quality under non-heterotrophic conditions, compares the growth conditions of the seedlings after germination, and the non-heterotrophic condition is that the seedlings after germination only use the nutrients stored in the seeds for growth without the supply of net photosynthetic products, and there is no inorganic or organic nutrient in the rhizosphere nutrient medium, and the present application is a novel and unique seed selection method. BRIEF DESCRIPTION OF DRAWINGS

[0035] The present application will be further described below in conjunction with the drawings.

[0036] Figure 1 It is a comparison diagram of the fresh weight change trend and the biomass collapse phenomenon of peanut seedlings of the present application;

[0037] Figure 2 It is a net photosynthetic reaction curve diagram of the present application. DETAILED DESCRIPTION

[0038] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the related drawings. The specific implementation cases of the present application are given in the drawings. However, the present application can be realized in many different forms, and is not limited to the implementation cases described herein. Therefore, the purpose of providing this case is to make the disclosure of the present application easier to understand.

[0039] Example: Analysis method for determining the nutrient metabolism efficiency of peanut seeds

[0040] 1. Plant material

[0041] The plant material used in this example is peanut (Arachis hypogaea L.), and the variety is 'Handachi'. The two seed materials used for comparison are from the same variety, but are cultivated with organic fertilizer and chemical fertilizer, respectively.

[0042] Organic fertilizer: is by animal excrement or plant and animal residues and other rich in organic matter by-product resources as the main raw material, after fermentation and become fertilizer.

[0043] Chemical fertilizer: use chemical method to make contains one or several crops grow need nutrient element's fertilizer, has phosphorus fertilizer, nitrogen fertilizer, potassium fertilizer.

[0044] 2. Medium

[0045] The seedling medium used in this example is washed river sand, which contains almost no inorganic and organic nutrients. The plastic box (44 cm long, 32 cm wide, and 7.5 cm high) is filled with wet river sand. The plastic box has drainage holes at the bottom edge to remove excess water, and the height of the river sand in the plastic box is 5 cm.

[0046] 3. Growth conditions

[0047] The soaked peanut seeds are placed on the wet towel in the plastic box and incubated in an incubator at 25℃. When the radicle emerges 5 mm and the seed appears pigeon beak-shaped, the seeds are sown in the plastic box containing the river sand described above, with a row spacing and main spacing of 5 cm. The middle point of the long side is used as a boundary, and 24 organic seeds are planted on the left side and 24 chemical fertilizer seeds are planted on the right side. This process is repeated 5 times. The plastic box is placed in an artificial growth chamber with a temperature of 20±2 / 17±1℃ (day / night) and a humidity of 65±5%. The light period is from 8:00 to 20:00, and the average light intensity of the seedling canopy is 30 μmol·m -2 ·s -1 , which is close to the light compensation point of peanut (net photosynthetic rate equal to respiration rate).

[0048] 4. Investigation of fresh weight and dry weight of peanut seedling plants

[0049] 4.1 Fresh weight change curve of seedling plants

[0050] A seed, a bulb, a tuber, or a tuber, germinates and grows in water or sand medium without nutrients, relying on the nutrients stored in the seed and the activity of the seed, especially when the light intensity is close to the light compensation point.

[0051] Figure Figure 1 is the change in fresh weight of peanut seedlings grown in river sand and pure water. The light intensity is 30 μmol·m -2 ·s -1 , which is close to the light compensation point. Under such conditions, the nutrients stored in the seed and the activity of the seed are quite important. However, due to the depletion of seed nutrients during growth, the fresh weight suddenly decreases, and the plants turn yellow and die, which is called biomass collapse phenomenon.

[0052] The original growth trend is in line with the standard growth curve, whose function equation is where g1 is the biomass at a certain time point, g M is the difference between the maximum and minimum values of the curve, g B1 is the maximum growth of the plant, e is the natural exponential base (Euler number), a1 is a constant, t is time, τ1 is the time midpoint of the curve, g 01 is the initial biomass, including the cotyledons left by the seed, and β1 is a constant.

[0053] The original plant should grow in this curve mode, but because of the lack of net photosynthetic products and nutrient supply, the biomass falls in the middle of the way, showing an exponential decrease. This phenomenon is also known as the biomass collapse of the seedling. The curve equation of the collapse stage is where g2 is the biomass at a certain time point, g D is the biomass at the beginning of the biomass collapse, and g B is the biomass at the tail of the curve.

[0054] Here, the seed nutrient and related activity are combined and referred to as seed vigor (A), which can be expressed by the integral ratio of the above two functions, i.e.

[0055]

[0056] Therefore, in this test, the above method is used to culture the seeds in a nutrient-free medium and let them germinate and grow in weak light. The fresh or dry weight is collected to make a curve as Figure 1 for mathematical analysis.

[0057] 4.2 Dry weight change curve of seedling plants

[0058] Because the light of the seedling growth environment is close to the light compensation point, the dry weight of the seedling has not been able to exceed that of the seed, but gradually decreases, and sharply decreases in the biomass collapse stage. The first half of the curve is the right half of the modified Gaussian curve, and the second half is a negative exponential curve. The modified Gaussian equation of the first half of the curve is , and the negative exponential curve of the second half of the curve is similar to the fresh matter described above.

[0059] As described above, the sum of the definite integrals of the first half and the second half of the curve is set as an index representing the seed vigor.

[0060] 4.3 Calculation and analysis of biomass collapse

[0061] The absolute amount of biomass collapse is represented by the median of the definite integral difference between the two curves g1(t)dt and g2(t)dt, i.e. .​

[0062] However, the absolute amount of biomass decline is meaningful only when compared with the original biomass. Therefore, .

[0063] 5. Analysis of photosynthetic activity

[0064] 5.1 Measurement and analysis of photosynthetic rate

[0065] The photosynthetic rate was measured in the tip leaflet of the expanded leaves of peanut seedlings two weeks after emergence using a Li-6400 portable photosynthesis system (LI-COR Inc. Lincoln, Nebraska, USA). The light intensity was varied in the range of 0-2000 mol m -2 ·s -1 (photons, PPF), and the data obtained were used to determine the light response curve as shown in Fig. 1. Figure 2

[0066] .

[0067] In this equation, the dependent variable P N is the photosynthetic rate at a certain light intensity, the independent variable I is the light intensity (PPF), P C is the maximum photosynthetic rate at a high light intensity in theory, R D is the photosynthetic rate in the absence of light, i.e., the respiration rate, and K is a constant.

[0068] When I (light intensity) is the reciprocal of K, the photosynthetic rate is 63.2% of the maximum photosynthetic capacity.

[0069] .

[0070] Here, θ = 1 - e -1 ≈ 0.632 is defined as the Silver constant. That is, the light intensity at which the photosynthetic rate reaches 63.2% of the maximum photosynthetic capacity is suitable for the plant.

[0071] 5.2 Analysis of photosynthetic inhibition effect

[0072] The photosynthetic rate of peanut seedling leaves is low due to growth under weak light. Therefore, when the photosynthetic rate is measured under strong light, photosynthetic inhibition occurs.

[0073] In addition to analyzing the light response curve of photosynthesis, the exponential equation was used to analyze the photosynthetic inhibition curve, and the relative photosynthetic inhibition amount was expressed as the median value of the definite integral (PI):

[0074] ,

[0075] ​P0 is the minimum photosynthetic rate after photosynthesis inhibition occurs, P D is the photosynthetic rate at the beginning of photosynthesis inhibition, and α' is a constant. The photosynthesis inhibition amount is expressed by the following equation:

[0076]

[0077] Here, P N is the light reaction curve equation of photosynthesis, but the total photosynthesis excluding the respiration term, P I is the photosynthesis inhibition curve equation. The definite integral is integrated from a' (PPI at the time when photosynthesis starts to decrease due to inhibition) to b' (1600 μmol m -2 ·s -1 ). In this equation, is the area between the two curves of PN (i) and PI (i).

[0078] 6. Experimental results

[0079] 6.1 Fresh weight change trend of peanut seedlings and biomass collapse phenomenon

[0080] (1) Fresh weight change trend

[0081] The growth of peanut seedlings should originally follow an S-shaped curve, but because the effective light quantum intensity is near the light compensation point, the increase in photosynthetic products (photosynthesis rate) is almost equal to the metabolic consumption (respiration rate), and the rhizosphere does not have inorganic and organic nutrients, when the existing cells expand to a certain extent, they cannot continue to expand, and the stored organic and inorganic nutrients in the seeds have been used up, and there is no raw material to synthesize enzymes and biological organisms to support the continued metabolism of plant cells, so the cells stop growing, stop metabolizing, and eventually die.

[0082] By germinating and growing peanut seeds in weak light, the fresh weight or dry weight of peanut seedlings was collected as shown in Table 1, and the curves in the attached and were made and analyzed. Figure 1

[0083]

[0084] Table 1 Analysis data of fresh matter change curve and collapse curve of peanut seedlings

[0085] During the process of cell death, existing organic compounds are rapidly decomposed, and fresh tissues begin to dry out. This is the meaning and significance of the curves in the attached Figure 1 Figure 1 ​​The two solid lines show that although the biological mass of the seeds in both treatments was the same, the fresh weight of the plants was consistently higher in organic seeds than in seeds grown with chemical fertilizers. This indicates that organic seeds contain more nutrients, enzymes, or growth factors that promote cell expansion compared to seeds grown with chemical fertilizers.

[0086] (2) Fresh weight change curve and its analysis

[0087] Appendix Figure 1 The equations for the two S-shaped curves are as described above. The parameters for curve analysis are listed in the left half of Table 1.

[0088] Among them, the maximum fresh weight increment is g M There was a significant difference between the two treatments, with organic seeds showing a higher rate, consistent with the overall trend of the curve.

[0089] Initial fresh weight depends on the quality of the seeds selected artificially, so there should be no significant difference. τ1 represents the midpoint of the curve; in the curve for organic seeds, τ1 is one day later, indicating a relatively greater growth potential. The α1 of fertilizer-grown seeds is relatively higher (0.282 > 0.213), indicating that the fresh weight curve of fertilizer-grown seeds has a greater curvature and is inhibited by certain factors earlier. The constant term g... B1 In (1-β1t), g B1 This is the initial biomass, including the cotyledons left from the seeds. Seed residues such as cotyledons should decrease over time, and the rate of decrease can be expressed in grams (g). B1 The biomass reduction rate is represented by the magnitude of (1-β1t). This rate of biomass reduction is relatively small in organically grown seeds, which is also related to the active portion of the seed.

[0090] (3) Fresh weight collapse curve and its analysis

[0091] Plants should ideally continue growing in this curved pattern, but due to a lack of net photosynthetic products and nutrients, their biomass collapses along the way, decreasing exponentially. This phenomenon is known as biomass collapse in plant seedlings. The equation for the collapse phase is... Here, the combined nutrient provision and related activities of the seed are termed seed vigor (A). It can be expressed as the integral ratio of the two functions mentioned above, i.e. ,in, The lower limit of integration, a, is 0, and the upper limit, c, is the time when the fresh weight begins to decrease. The lower limit of integration is c, and the upper limit is b.

[0092] Therefore, this experiment used the above method to cultivate the seeds in a nutrient-free culture medium, allowing them to germinate and grow under low light, and then collecting fresh or dry weight data to produce the following: Figure 1 We will analyze the curve.

[0093] 6.2 Photosynthetic Inhibition

[0094] As PPF increases, the response function of photosynthetic rate is: I is the effective photon flux for photosynthesis, and the maximum photon utilization efficiency is defined as Y. Q =KP C (Togari 1973; Steven 1998; Xu 2000).

[0095] Because peanut seedlings grow under very weak light conditions, they cannot adapt to strong light. Therefore, the rate of photosynthesis should increase with the increase of light intensity. However, when the light intensity increases to a certain level, the photosynthetic mechanism is inhibited by strong light, and the rate of photosynthesis begins to decline, subsequently showing a gradual decreasing trend.

[0096] The curve after the point when the decline begins is as follows: , where P I It is the dependent variable of the curve function, P0 is the photosynthetic rate at the tail of the curve; P D α' is the rate of photosynthesis when photosynthesis is inhibited; α' is a constant (Xu et al. 2000).

[0097] Photosynthetic inhibition (P(i)) is quantified by the median difference between the definite integrals of the original photosynthetic response curve and the photosynthetic inhibition curve. The formula is as follows: Among them, P N It is the light response curve function that originally had no photosynthetic inhibition; P I It is the photosynthetic inhibition curve function. The definite integral extends from a' (the point where photosynthetic inhibition begins) to b' (1700). It is P N and P I The integral area between the two curves.

[0098] As attached Figure 2 As shown, due to the very low light intensity, the photosynthetic capacity of the peanut seedling leaves is very low, and the P in the fertilizer area is low. C Only 6.42 μmol·m -2 ·s -1 The photosynthetic rate of peanut leaves in the wild is 20–30 μmol·m⁻¹. -2 ·s -1With the increase of light quantum flux, photosynthesis inhibition phenomenon appears, i.e. the decrease of photosynthesis ability due to the damage of photosynthesis mechanism of plants by strong light, which is usually caused by the exposure of leaves to strong light at the supersaturation point (Noam et al. 2003). In this extremely adverse light environment, the maximum photosynthetic potential of leaves of seedlings grown from organically cultivated peanut seeds is still higher than that of seedlings grown from chemical fertilizer cultivated seeds. Moreover, the light intensity point at which photosynthesis inhibition of the organically seeded area starts (i = 592 μmol·m -2 ·s -1 ) is also higher than that of the chemical fertilizer seeded area (i = 452 μmol·m -2 ·s -1 ), and the residual photosynthetic rate (P0) after a period of photosynthesis inhibition is also higher than that of the chemical fertilizer seeded area. The quantified value of photosynthesis inhibition can be represented by , and also by the integral median value (P (i) ).

[0099] Both of them are smaller in the organically seeded area than in the chemical fertilizer seeded area, which also indicates that the peanut seedlings in the organically seeded area have higher ability to resist adverse light environment, i.e. have higher vigor.

[0100]

[0101] Table 2 Analysis of photosynthesis characteristics of peanut seedling leaves

[0102] It is proved by the above experiments and analysis that the determination of the vigor of a seed can make the seed be planted in the condition without external nutrients, and only the nutrients stored in the seed are used, and the biomass collapse phenomenon will occur in the growth of the seedling. The vigor of the seed can be represented by the size of the biomass collapse, and the smaller the biomass collapse degree is, the stronger the seed vigor is. In addition, the photosynthesis of the seedling grown under this condition can also be determined, and the seed vigor can be represented by the degree of photosynthesis inhibition under strong light, and the smaller the photosynthesis inhibition degree is, the stronger the seed vigor is.

[0103] In the above embodiments, the best mode of the present application is described, and it is obvious that many changes can be made under the inventive concept of the present application. Here, it should be noted that any change made under the inventive concept of the present application will fall within the protection scope of the present application.

Claims

1. An analytical method for determining the nutrient metabolism efficiency of peanut seedlings, characterized in that: Peanut seedlings were cultivated in nutrient-free water or sand culture media after germination. Photosynthetic activity was analyzed by placing the seedlings in a light intensity of 30 mol·m⁻¹. -2 ·s -1 The light response curve was measured, and the photosynthetic inhibition curve of peanut seedlings was analyzed. Finally, the photosynthetic inhibition amount was calculated using the light response curve function and the relative photosynthetic inhibition amount function to describe the peanut seed vigor. The functional equation for the light response curve is: Among them, the dependent variable P N Let P be the photosynthetic rate at a certain light intensity, where I is the light intensity; C R represents the theoretical maximum photosynthetic rate under high light intensity. D Let K be the photosynthetic rate in the absence of light, which is also the respiratory rate, and K be a constant; the relative photosynthetic inhibition function is: Where P0 is the minimum photosynthetic rate after photosynthetic inhibition occurs, P D To reduce the amount of photosynthesis, α' is a constant, I i This is the light intensity at the onset of photosynthetic inhibition; the amount of photosynthetic inhibition is expressed by the following formula: , where P N It is the equation for the light-dependent reaction curve of photosynthesis, but the total photosynthesis term (respiration) has been removed; P I It is the equation for the photosynthetic inhibition curve, and the definite integral is derived from... a’ Points to b’ , For P N (i) and P I (i) The area between the two curves; When the light intensity I is the reciprocal of K, Where θ = 1 - e -1 ≈ 0.632 is defined as the constant of the mean.

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