RU2730680C1 - Device for determining fluctuating asymmetry of optical characteristics of plant leaves - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: device for determining fluctuating asymmetry of optical characteristics of plant leaves comprises a first clamp with first input and output optical connectors, a first light source, a first flexible light guide connecting the first light source to the first input optical connector, spectrometer, control device, wherein it additionally comprises a second clamp with second input and output optical connectors located thereon, a second light source, a second flexible light guide, a branched flexible light guide, guide, wherein the second flexible light guide connects the second light source to the second input optical connector, branched flexible light guide with its branched bundles is connected to the first and second output optical connectors, and unbranched bundle is connected to the spectrometer, first and second clamps are connected to guide with possibility of mutual movement and fixation on it, electrically control device is connected to first, second light sources and spectrometer.

EFFECT: invention enables to determine fluctuation asymmetry of optical characteristics of plant leaves to assess stability of their development.

1 cl, 1 dwg, 1 tbl, 1 ex

Description

The invention relates to the field of agriculture, bioindication, ecology, to the study of the optical properties of parts of plants and can be used for the rapid assessment of the stability of the development of plants grown both in natural and artificial conditions.

Environmental factors (temperature, light, humidity, etc.) have a great influence on the growth and development of plants. The correspondence of the factor levels to the required values is reflected in the phenomenon of plant development stability. Development stability as a phenomenon is a set of mechanisms that allow for sustainable development (phenotype support) of a living organism despite changes in environmental conditions or genetic deviations [Debat, V. and P. David. 2001. Mapping phenotypes: canalization, plasticity and developmental stability. T. Ecol. and Evol. 16 (10), 555-561].

The measure of developmental stability is the value of fluctuating asymmetry (FA) of bilateral (mirror) features. When the environmental conditions deviate from the optimal, small deviations of the values of biometric parameters are observed in symmetrical plant structures - leaf halves, opposite leaves, etc., which are random. As biometric parameters, linear and angular dimensions are used, for the determination of which a measuring compass, a ruler and a protractor are used [Mazurkin P.M., Semenova D.V. Method for measuring fluctuating asymmetry of birch leaves. Pat. RF No. 2556987. Application filing date 02.07.2013. Published on July 20, 2015 Byull. No. 20]. The FA value is determined by the formula

, (1)

, (1)

и

- значения принятого параметра для билатеральной структуры соответственно на левой и правой стороне листа, N – количество измерений.Where

and

- the values of the accepted parameter for the bilateral structure, respectively, on the left and right sides of the sheet, N - the number of measurements.

The disadvantage of the known technical solution is the great complexity of measuring linear and angular values. In addition, the FA value calculated through the geometric dimensions of bilateral structures does not adequately characterize the stability of plant development. Optical characteristics reflecting the physiological state of the plant are more informative. Thus, the reflectivity of leaves at different wavelengths directly depends on the content of pigments in them, which to a large extent determine the physiological processes in the plant.

The closest technical solution to the claimed one is a device for determining the spectral optical characteristics of plant leaves, containing the first clamp with the first input and output optical connectors located on it, the first light source, the first flexible light guide connecting the first light source with the first input optical connector, a spectrometer, control device. Information from the spectrometer through the control unit is sent to the computer, where it is stored for subsequent mathematical processing [https://www.cid-inc.com/plant-science-tools/leaf-spectroscopy/ci-710-miniature-leaf-spectrometer/] ...

The disadvantages of the known device, when used to determine the FA of the optical density of plant leaves, are as follows.

1. Insufficient functionality. When determining the PA value, paired measurements are required on the left and right sides of the bilateral structures. The use of a single-channel meter requires two measurements in succession. It is also necessary to process the received primary information in an external computer using statistical programs.

2. Lack of convenience in work. Rigid constructive combination of elements in one case, without the possibility of removing the clamp from the device into the cenosis, as well as the need for an external computer create inconvenience when taking measurements in the cenosis.

3. Low accuracy. The transfer of the measuring clamp from one point of the sheet surface to another during alternate measurements is carried out approximately, the exact positioning of the clamp sequentially to the required points is difficult.

4. Long measurement time. Taking two consecutive measurements takes a longer time than measuring two quantities at the same time.

The technical problem of the invention is to implement the purpose of the device, increase its functionality, ease of use, measurement accuracy and speed of their implementation.

EFFECT : determination of the value of fluctuating asymmetry of optical characteristics of plant leaves to assess the stability of their development as a complex indicator of the influence of environmental factors on plants when optimizing photoculture.

The technical result is achieved in that the device comprises a first clamp with the first input and output optical connectors located on it, a first light source, a first flexible light guide connecting the first light source with the first input optical connector, a spectrometer, a control device, a second clamp with second input and output optical connectors, a second light source, a second flexible light guide, a branched flexible light guide, a guide, while the second flexible light guide connects the second light source to the second input optical connector, the branched flexible light guide is connected with its branched bundles to the first and second output optical connectors , and is connected to the spectrometer by an unbranched bundle, the first and second clamps are connected to the guide with the possibility of mutual movement and fixation on it, the control device is electrically connected to the first, second light sources and the spectrometer.

New essential features : the device additionally contains a second clip with second input and output optical connectors located on it, a second light source, a second flexible light guide, a branched flexible light guide, a guide, while the second flexible light guide connects the second light source to the second input optical connector, branched the flexible light guide with its branched bundles is connected to the first and second output optical connectors, and the unbranched bundle is connected to the spectrometer, the first and second clamps are connected to the guide with the possibility of mutual movement and fixation on it, the control device is electrically connected to the first, second light sources and the spectrometer.

The technical result is provided by the fact that:

- a set of new structural elements in interaction with known ones ensures the implementation of the device's purpose;

- the use of two measurement channels increases the functionality of the device and reduces the measurement time;

- the spatial separation of the clamps located on the leaf of the plant and the control device, which is in the hands of the operator during measurements, increases the convenience in work;

- the ability to position the clamps on the plant leaf using a guide increases the measurement accuracy.

The possibility of using the proposed invention in biomonitoring and in agriculture when growing plants, the popularity of software and hardware methods and tools with which it is possible to implement the device as a whole and its individual blocks in the described form allows us to conclude that the proposed technical solution meets the criterion of "industrial applicability" ...

The analysis of the prior art did not reveal a device for the same purpose as the proposed technical solution, which is characterized by a set of essential features given in the independent claim, which indicates that the proposed technical solution meets the "novelty" criterion.

The essence of the invention does not follow explicitly for a specialist from the prior art, since the knowledge of the influence of features that coincide with the distinctive features of the claimed invention on the main technical result - the implementation of the purpose of the invention has not been revealed. The invention uses a previously unknown effect found by the authors in experimental studies, namely, the possibility of determining fluctuating asymmetry by the optical characteristics of a plant leaf, determined at paired points of the leaf surface. The proposed invention meets the condition of an inventive step, since based on the addition of a known technical solution (measurement of the reflection coefficients from a certain point on the surface of a plant leaf) with new features, which are substantiated by the new knowledge obtained by the authors, while an unexpected technical result is achieved due to the relationship of additional and known features.

FIG. 1 shows the design of the claimed device: 1 - the first clamp, 2 - the first input optical connector, 3 - the first output optical connector, 4 - the first light source, 5 - the first flexible light guide, 6 - spectrometer, 7 - control device, 8 - second clamp , 9 - second input optical connector, 10 - second output optical connector, 11 - branched flexible light guide, 12 - second light source, 13 - second flexible light guide, 14 - guide, L - plant leaf.

The invention is based on the following provisions .

Combinations of environmental factors, even in artificial, specially selected conditions, may not fully meet the requirements of plants. Stress influences cause disturbances in the process of plant growth and development. The ability of a living organism to maintain the trajectory of its development is manifested in the phenomenon of stability, which is a sensitive indicator of the state of the plant. Accordingly, developmental instability is observed when, under the influence of external factors, the body is not able to correct their manifestation. Developmental instability is evidenced by deviations in the symmetry of bilateral (mirror) morphological structures, which are assessed by the FA of various characters. Geometric parameters are most widely used as the latter: leaf width, distances between characteristic points of the leaf surface, angles between veins. Morphological signs are the most accessible for determining the value of PA and make it possible to obtain an integral assessment of the state of the organism with the entire complex of possible influences. However, such measurements are quite laborious, and ensuring their accuracy is a serious problem.

Pigments are an important biochemical component of the molecular apparatus that ensures the course of various processes in a plant. Therefore, the assessment of the stability of plant development is possible not only by geometric characteristics, but also by the content of pigments in symmetrical leaf structures, the value of which can be found by measuring its spectral characteristics.

The main pigments of green leaves are carotenoids and chlorophylls. Chlorophyll supports the process of photosynthesis in the plant. Carotenoids perform a number of unique physicochemical and photophysical functions: they play an important role in the organization of photosynthetic membranes, participate in the collection of light, energy transfer, quenching of excited states of chlorophyll, and dissipation of excess energy in chloroplasts. Preservation of carotenoids during chlorophyll degradation is a photoprotection mechanism during leaf aging. Changes in the content of carotenoids in leaves are used to diagnose the physiological state of plants during development, aging, acclimatization and adaptation to various environments and stresses. Promising for determining the content of pigments in plant leaves is the use of non-destructive optical methods [Dar A. Roberts, Keely L. Roth, Ryan L. Perroy. Hyperspectral Vegetation Indices. https://www.researchgate.net/publication/288952459].

For example, the number of carotenoids in a plant leaf can be determined by the value of the CRI (Carotenoid Reflection Index)

, (2)

, (2)

,

- значения коэффициентов отражения на длинах волн 510 и 550 нм соответственно.Where

,

- the values of the reflection coefficients at the wavelengths of 510 and 550 nm, respectively.

The values of the reflection coefficients R at the corresponding wavelengths for formula 2 are obtained empirically as the ratio of the magnitude of the reflected flux to the incident flux at a given wavelength. Making measurements on the left and right sides of the leaf, according to formula 1, the FA value of the CRI index is obtained, and hence the assessment of the uneven distribution of carotenoids between the leaf halves, which is used to judge the stability of plant development.

The device includes (Fig. 1) a first clip 1, a first input optical connector 2, a first output optical connector 3, a first light source 4, a first flexible light guide 5, a spectrometer 6, a control device 7, a second clip 8, a second input optical connector 9, a second output optical connector 10, a branched flexible light guide 11, a second light source 12, a second flexible light guide 13, a guide 14,

The first flexible light guide 5 connects the first light source 4 to the first input optical connector 2, the second flexible light guide 13 connects the second light source 12 to the second input optical connector 9, the branched flexible light guide 11 is connected to the first 3 and second 10 output optical connectors with its branched bundles, and an unbranched cord is connected to the spectrometer 6, the control device 7 is electrically connected to the first 4, the second 12 light sources and the spectrometer 6. The first 1 and second 8 clamps are connected to the guide 14 with the possibility of mutual movement and fixation on it. The lengths of the flexible light guides 5, 11 and 13 in the design of the device are selected from the possibility of removing the clamps 1 and 8 inside the cenosis.

The device works as follows . Before measurements, the device is calibrated using a white diffusely reflecting plate instead of a plant leaf to determine the emission spectra of the first 4 and second 12 light sources and take into account the possible asymmetry of the measurement channels.

On the surface of the leaf of the plant, two points are marked, located on the left and right symmetrically relative to the central vein of the leaf. The first 1 and the second 8 clamps move along the guide 14 until the points of measurement of the optical characteristics of the sheet coincide with these points and fix them on the guide. The sheet selected for measurement is placed in the clamps.

The signal coming from the control device 7 turns on the first light source 4. The light flux through the first flexible light guide 5 through the first input optical connector 2 falls on the surface of the sheet at the first point of its surface. The flux reflected from the surface through the first output optical connector 3 through the corresponding branched bundle enters the spectrometer 6 and further to the control device 7, where the spectral reflectances of the sheet are calculated at the first point.

After stabilization of the measured values, the control device 7 turns off the first 4 and turns on the second 12 light sources. The light flux through the second flexible light guide 13 through the second input optical connector 9 falls on the surface of the sheet at the second point of its surface. The flux reflected from the surface through the second output optical connector 10 through the corresponding branched bundle enters the spectrometer 6 and then to the control device 7, where the spectral reflectances of the sheet are calculated at the second point. After stabilization of the measured values, the control device 7 turns off the second light source 12 and determines the value of the FA index for the given plant leaf. The measurement results are stored in the memory included in the control device 7. To ensure statistically reliable values, the measurements are repeated on other leaves with the determination of the average value of the FA index.

An example . The assessment of the fluctuating asymmetry of the reflection coefficients of tomato leaves was carried out in the block of greenhouses "Mezhvidi". The measurements were carried out on tomato plants of two varieties, Encore and Bolzano, grown under the same conditions. We measured the optical characteristics (spectral reflectances) of the leaves of the lower layer, without signs of chlorosis, reaching a length of 25-30 cm. The measurements were carried out on 60 samples of plants of each variety.

The table shows the average values of the reflection coefficients R at two wavelengths, the CRI index and the PA value for different varieties of tomato.

As follows from the experimental results, the differences between both the reflection coefficients R and between the CRI indices (and, therefore, between the concentration of carotenoids in the leaf), calculated for leaf halves, are insignificant (the value of k differs by a few percent) for two tomato varieties and cannot be used to analyze the influence of the variety and environmental conditions on the stability of plant development. On the contrary, the PA concentration of carotenoids (i.e., uneven distribution between the left and right parts of the leaf) for tomato plants of the Bolzano variety is 1.26 times higher than that for plants of the Encore variety.

Variety R ₅₁₀ ,% R ₅₅₀ ,% CRI, rel. L R L R L R F Anchor 14.7 14.8 24.2 24.4 0.0267 0.0271 0.0407 Bolzano 14.0 14.3 23.1 23.6 0.0284 0.0281 0.0514 k 0.95 0.97 0.96 0.97 1.07 1.04 1.26

Thus, using the proposed device, it is possible to assess the stability of plant development by the FA of optical characteristics (in particular, the reflection coefficients) of plant leaves. This device can be used both for assessing the state of a plant in the process of biomonitoring in natural conditions, and under conditions of photoculture, for a comprehensive assessment of the effect of environmental factors on plants.

Claims (1)

A device for determining the fluctuating asymmetry of the optical characteristics of plant leaves, comprising a first clamp with first input and output optical connectors located on it, a first light source, a first flexible light guide connecting the first light source with a first input optical connector, a spectrometer, a control device characterized by that it additionally comprises a second clip with second input and output optical connectors located on it, a second light source, a second flexible light guide, a branched flexible light guide, a guide, while the second flexible light guide connects the second light source to the second input optical connector, a branched flexible light guide with its own branched bundles are connected to the first and second output optical connectors, and an unbranched bundle is connected to the spectrometer, the first and second clamps are connected to the guide with the possibility of mutual movement and fixation on it, electrically the control device is connected but with the first, second light sources and a spectrometer.

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