JP2001299090A - Method for diagnosing growth of plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new method for the diagnosis of the growth of a plant based on indices and analysis capable of more clearly and widely showing diagnostic result of the growth of plant while solving the problems of the conventional growth diagnosis using second order differentiation method such as a large number of evaluation factors necessary for the diagnosis. SOLUTION: The growth of a plant is diagnosed by irradiating the leaf of the plant with a laser beam, measuring the intensity of the generated fluorescence, making a graph of the variation of the fluorescent intensity with time, integrating the fluorescent intensity on the graph and comparing the result with preparatorily determined standard values comprising the normal activation value (NV) and the limit growth value (LB).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser-induced fluorescence (LIF) method that irradiates a plant, for example, a tree, with a laser beam when the leaf is irradiated with laser light.
The present invention relates to a method for diagnosing the growth state of a plant based on the data obtained by the measurement.

[0002]

2. Description of the Related Art Hitherto, diagnosis of a tree growth state is largely based on long-term empirical knowledge of a specialized management company, and it has been difficult to evaluate the growth state by a simple and objective method.
Further, until a change in the appearance of the tree, that is, a change such as discoloration of the leaves or fallen leaves, appears, deterioration of the growth state cannot be detected.

[0003] Therefore, in the growth and transplantation of trees, the quality of tree growth is selected based on the experience of a specialized management company. However, such experience accumulates over the years and cannot be obtained overnight. Moreover, the aging of the people involved in the growth and management of trees will make it more difficult to acquire and pass on such experience and knowledge in the future.

On the other hand, artificial natural spaces such as recent urban spaces are reproduced not only in outdoor parks and the like but also in indoor spaces such as atriums, so that tree planting is widely performed. It is becoming.
In such an environment, it is necessary to always maintain good condition by always taking care of the trees and replanting immediately if there is a tree with poor growth.

[0005] Therefore, there is a need for the development of a technique that can easily and objectively determine the growth state of a tree by some means. For example, in Japanese Patent No. 2,943,796, the present applicant has disclosed a method of measuring the intensity of fluorescence generated by irradiation with a laser beam, and diagnosing the growth state of a plant based on the obtained fluorescence intensity curve.

[0006] By the way, as can be seen from the above-mentioned publication, the fact that the intensity of the fluorescence generated from the leaves of a plant due to light irradiation changes with time is known as the Kautsky effect or the chlorophyll induction phase phenomenon. The correlation between these phenomena and photosynthetic activity, that is, the growth state of plants, is known. Since the photosynthetic activity can be measured without troublesome operations such as isolation of chloroplasts and extraction of adenylate, the method of measuring photosynthetic activity using the Kautsky effect is considered as a simple method for determining the growth state of plants. .

FIG. 1 is a graph showing a model of the Kautsky effect. In the illustrated example, the leaves in the dark place were irradiated with laser instead of light for 20 minutes, and fluorescence was generated after the laser irradiation. First, the fluorescence intensity increases from the position O in the steady state via the points I and D, starts decreasing after reaching the first maximum value P, passes through the points S and M, and returns to the steady state T again. Leads to.

In the above-mentioned patent, the inflection point of the fluorescence intensity curve thus obtained is determined, and the growth time of the plant is diagnosed based on the appearance time.

[0009]

However, empirically, when diagnosing actual plant activity using such an analysis method, considering practical simplicity,
It has been found that further improvements are needed.

That is, in the invention disclosed in Japanese Patent No. 2,943,796, an inflection point of a line of decrease in fluorescence intensity obtained from a plant is obtained by the LIF method, and a growth diagnosis is performed from the appearance time of the inflection point. I have. The secondary differentiation method is used for the analysis procedure, and two evaluation factors, a and Ip, are used at the time of diagnosis.

As a result of trial of the diagnosis by such a second-order differentiation method, it was found that there were the following points to be solved. (i) There are many evaluation factors (a, Ip). (ii) Appropriate for evaluating clear changes, but may not be able to respond to small changes. (iii) In some cases, it is not possible to evaluate a flat change in fluorescence intensity when subjected to extreme stress.

[0012] Here, the object of the present invention is to solve the above two problems.
To provide a new growth diagnosis method based on indices and analytical methods that can solve problems such as a large number of evaluation factors in plant growth diagnosis using the second derivative method and that clearly and broadly show plant growth diagnosis. It is.

[0013]

Means for Solving the Problems The present inventors have conducted various studies to solve the above-mentioned problems, and as a result, measured the growth state of the leaves of the plant by a laser-induced fluorescence method (LIF method). Thus, the present inventors have found that it is effective to determine a diagnostic reference value by analysis using the integration method and to diagnose the growth state of a plant based on the reference value, and have completed the present invention.

Here, the present invention is as follows. (1) By irradiating the leaves of the plant with a laser beam, measuring the intensity of the generated fluorescence, for example, by graphing the change in the fluorescence intensity with respect to time, and obtaining an integrated value of the fluorescence intensity of the obtained graph, etc. A method of diagnosing the growth of the plant by calculating an integrated value of the fluorescence intensity with respect to time and comparing the integrated value with a predetermined reference value. (2) The reference value is a normal activity value (NV) and a growth limit value (L
B), wherein if the integrated value is smaller than the normal activity value, the growth state is determined to be normal, and if the integrated value is larger than the growth limit value, the growth state is determined to be poor. The method for diagnosing the growth of a plant according to the above.

[0015]

DETAILED DESCRIPTION OF THE INVENTION As described above, according to the present invention, the integral value (Iv) of the fluorescence intensity curve obtained from the measurement result by the LIF method is determined and referred to as a normal activity value (NV) and a growth limit value (LB). The growth status is diagnosed by comparison with two reference values.

As described above, regarding the relationship between the growth state of a tree and the chlorophyll fluorescence induction period phenomenon, in a previous study, the fluorescence intensity curve of the induction period phenomenon when the growth state of the tree deteriorated was as follows. Are known to change.

First, when growth is good, as shown in FIG. 2 (a), the fluorescence intensity shows a peak,
Draw and decay. When the growth condition deteriorates, the peak line gradually becomes gentler, and as shown in FIG. 2 (b), the attenuation curve after the peak does not show an S-shape, swells upward, and the rate of attenuation decreases.

Finally, the decay curve of the fluorescence intensity does not attenuate, and a flat line is drawn as shown in FIG. 2 (c). Here, according to the present invention, FIG.
All the characteristics of the change in the fluorescence intensity accompanying the change in the growth state in (a) to (c) can be analyzed.

First, according to the analysis procedure according to the present invention,
The fluorescence intensity decay curve observed as an induction period phenomenon is normalized with the minimum value being 0 and the peak P appearance time (about 1.0 second) being 1.

At this time, as shown in FIG. 3, an area S (shown as a hatched area in the figure) in a range surrounded by the decay curve and the time axis X axis is obtained, and the relative fluorescence intensity is represented by f (t). After all,
The following equation (3) is obtained.

[0021] In the present invention, this value is called an integral value (Iv: Integral value). The time of the integration region at this time is as shown in FIG.
The change in fluorescence intensity of (a) to (c) is determined as the shortest time that can be displayed in a distinguished manner. In the illustrated example, it is set to 24 seconds.

The region where the fluorescence intensity curve is created is performed in the following procedure as in the above-mentioned patent. (1) Collect the leaves, set them in the sample holder, and perform dark treatment in the holder. (2) After darkening, irradiate with laser light to obtain fluorescence from leaves.

The induction phase phenomenon of chlorophyll fluorescence lasts for about 3 to 5 minutes, but in the present invention, it can be diagnosed by the induction phase phenomenon of 24 seconds. Here, according to the present invention, the diagnostic index (Diagnos
is Index) is set in advance, and the growth state of the plant is determined by comparing with the integral value Iv.

Here, the definition and determination method of the diagnostic index are as follows. In order to diagnose the growth condition of a tree in the preferred embodiment of the present invention, it is preferable to determine a diagnostic index based on the following two values.

(I) Normal activity value: Normal Vitality value (N
V) A reference value indicating that the growth state is normal. (ii) Growth limit value: Life Boundary value (LB): A reference value indicating the growth limit.

These relationships are schematically shown in FIG. 4. If the integrated value Iv is equal to or less than the above-mentioned normal activity value (NV), the growth condition of the plant is determined to be normal, and if the integrated value Iv is equal to or greater than the growth limit value (LB). If so, the growth is poor and the tree is diagnosed as dead.

In the region between the normal activity value and the growth limit value, it is diagnosed that the growth of the tree is maintained but is not the best and some care is required. The normal activity value and growth limit value at this time are determined in advance as follows. These operations are performed for each tree type. Such a reference value can be set to various reference values by several criteria, but in the case of the present invention, the reference value is set based on the correlation between the change in the intracellular sugar concentration and the integrated value Iv. can do. Hereinafter, the setting operation will be described.

In the following, the present invention will be described by taking as an example a tree whose growth state is considered to be relatively difficult to determine, particularly mocktail. (1) The mocktail was carried into a plant growth chamber where temperature and humidity could be controlled and grown without light (darkening) (24 ° C, 40
% RH, 01x). (2) Fluorescence intensity measurement and leaf sugar concentration measurement by LIF method
It started immediately before the start of (1), and continued every 2 to 4 days after the start. In the measurement procedure, the leaves were collected, the Iv value was measured by the LIF method, and the leaves after the measurement were crushed, extracted,
After purification, the sugar concentration in leaves was measured by high performance liquid chromatography.

The sugar content in the leaves was determined by saccharose. FIG. 5 shows the changes in the sugar concentration in leaves and the integrated value Iv in the darkening measured in this manner.

From the decrease in the sugar concentration in the leaves, it was possible to grasp that the growth state was deteriorating. A decrease in the sugar concentration in the leaf indicates a decrease in the rate of photosynthesis, which means that growth after the decrease is difficult. Therefore, the diagnostic reference value can be considered as follows.

NV: Growth state outdoors in summer when the activity of the plant is the highest. LB: Growth state when the sugar concentration in leaves decreases after being placed in a dark place. FIG. 6 is a schematic diagram of FIG. Is a graph shown in FIG.
At the point, the intra-leaf sugar concentration starts to decrease, and at the LB point, the intra-leaf sugar concentration becomes the minimum value. NV and LB in the schematic diagram at this time
, The diagnostic reference value can be set as follows.

Diagnosis reference values: NV = 15, LB = 17 As described above, according to the present invention, two reference values (NV, LB) for diagnosis can be obtained. It has the following meaning:

NV: normal activity can be maintained if the value is equal to or less than the reference value. LB: tree growth can be maintained if the value is equal to or less than the reference value. When a similar experiment was performed, it was also found that the diagnostic reference value was different. That is, since the diagnostic reference value differs depending on the tree species, it is preferable to obtain a reference value for each tree species in advance and make a diagnosis based on the reference value.

[0034]

EXAMPLES (Example 1) In this example, a decay curve of the fluorescence intensity was prepared, and based on this, growth diagnosis was performed by the integration method according to the present invention. As a comparative example, the aforementioned Patent No. 2,943,
Growth diagnosis was performed by the second derivative method according to the method of No. 769.

The results are shown in graphs in FIGS. 7 (a), (b) and (c). In the figure, the Iv value indicated by a circle indicates the integrated value obtained by the present invention, and the a value indicated by a triangle indicates the value of 2 according to the comparative example.
Shows the second derivative. Black circles indicate the sugar concentration in leaves.

From these results, the following points were found. (i) In the summer (Fig. 7 (b)), the second derivative a and the integral
Both ivs showed a certain tendency after being placed in the dark. (ii) In the spring period (Fig. 7 (a)) and the autumn period (Fig. 7 (c)), after being placed in a dark place, the second derivative a does not show a constant tendency, whereas the integral value Iv is There was a tendency for the value to increase.

These tests were carried out on both species of the bayberry and mocktail. As shown in FIG. 8 (a), there was no difference between the tree species in the second derivative a. However, FIG.
As shown in (b), a difference between the bayberry and mockup was detected in the integrated value Iv.

These results are summarized in Table 1. As a result of comparing the two analysis methods as an analysis method for the induction period phenomenon, 2
It has been found that the integration method can evaluate more situations than the second differentiation method.

The advantage of this integration method is that even if the analysis results using the second-order differentiation method indicate that stress has occurred,
The ability to detect tree responses to stress in spring and fall, where further detailed assessment was not possible.

In the integration method, differences in tree species can be detected, whereby evaluation criteria for each tree species can be obtained, and diagnosis according to the tree species can be made.

[0041]

[Table 1]

(Example 2) In the spring, a bayberry having a height of about 3 m was installed indoors, and the growth state was compared with a bayberry installed outdoors.

Indoor environmental conditions: temperature of 24 ° C., humidity of 40%, illuminance at the top of the tree canopy 1700 lx diagnostic reference value of bayberry: normal activity value (NV) = 21, growth limit value (LB) = 24 These results are graphed in FIG. Indicated by

As a result, the leaves of the bayberry installed indoors began to fall from 30 days after the start of the experiment, and the growth was poor. The integral (Iv) also exceeded LB. On the other hand, the outdoor bayberry showed good growth with sprouting of new leaves observed. The integrated value also showed a value near or below NV.

[0045]

According to the present invention, the growth state of a plant can be easily diagnosed by analyzing the decay curve of the fluorescence intensity from a leaf by the LIF method by an integration method. Further, by obtaining a diagnostic reference value specific to a plant species, more accurate diagnosis has been made possible. Therefore, the growth management of the plant can be extremely finely and accurately performed, and the activity of the plant can be sufficiently brought out.

Therefore, by implementing the present invention, the management of planted trees can be simplified, and the tree management cost can be reduced without depending on a specialized company. In addition, it can be applied as a tree growth diagnosis technology by remote sensing.

[Brief description of the drawings]

FIG. 1 is a graph showing a model of a kautsky effect.

2 (a) to 2 (c) are graphs showing the relationship between the growth state of trees and the induction period phenomenon.

FIG. 3 is a graph showing an integration region.

FIG. 4 is a diagram showing a diagnostic index and a diagnostic reference value (NV, LB).

FIG. 5 is a graph showing changes (mocks) in sugar concentration in leaves and Iv after dark treatment in summer: July to September.

FIG. 6 is a schematic graph of FIG. 5 showing the setting of a diagnostic reference value.

FIG. 7 (a) shows the second derivative a and the integrated value I after dark processing in spring, FIG. 7 (b) in summer, and FIG. 7 (c) in autumn, respectively.
v, a graph showing the change in sugar concentration in leaves.

FIG. 8 (a) is a graph showing a change in a secondary differential coefficient a after dark processing by a tree species, and FIG. 8 (b) is a graph showing a change in an integral value Iv.

FIG. 9 is a graph showing a change in an integrated value Iv of a bayberry after the start of an experiment.

Continuing from the front page (71) Applicant 500178164 Kenji Kurata 3-12-2-502 Morinosato, Atsugi City, Kanagawa Prefecture (72) Inventor Mika Sagawa 41 Wadai, Tsukuba City, Ibaraki Prefecture Shinryo Corporation (72) ) Inventor Kunio Takahashi 5-10-13, Kiyomidaiminami, Kisarazu-shi, Chiba (72) Inventor Kenichi Minei 3-15-8, Gion, Kisarazu-shi, Chiba (72) Inventor Kenji Kurata 3-12-, Morinosato, Atsugi-shi, Kanagawa 2-502 F term (reference) 2G043 AA03 BA16 CA07 EA01 FA03 FA07 GA08 GB21 JA01 KA09 LA01 NA01

Claims (2)

[Claims] 1. A method of irradiating a leaf of a plant with a laser beam, measuring the intensity of the generated fluorescence, obtaining an integrated value of the fluorescent intensity with respect to time, and comparing the integrated value with a predetermined reference value. A method for diagnosing the growth of a plant, comprising diagnosing the growth of the plant. 2. The reference value is a normal activity value (NV) and a growth limit value (LB). If the integrated value is smaller than the normal activity value, the growth state is determined to be normal, and the integrated value is determined as the normal value. 2. The method for diagnosing the growth of a plant according to claim 1, wherein the growth state is judged to be poor if the growth is larger than the growth limit value.