Name: A Rapid Laser Probing Method Facilitates the Non-invasive and Contact-free Determination of Leaf Thermal Properties (Video) | JoVE Journal
Uploaded: 2017-01-07T17:00:00.000+00:00
Duration: 8 min 41 s
Description: Learn a rapid near-infrared laser probing method for non-invasive determination of leaf thermal properties in plant physiology. This contact-free technique enables precise plant health monitoring without sample damage.

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The authors are grateful to Dr. Thomas Rademacher and Ibrahim Al Amedi for cultivating the plants used in this study. We would like to thank Dr. Richard M. Twyman for his assistance with editing the manuscript. This work was in part funded by the European Research Council Advanced Grant "Future-Pharma", proposal number 269110, the Fraunhofer Zukunftsstiftung (Future Foundation), the Fraunhofer-Gesellschaft Internal Programs under Grant No. Attract 125-600164.

<ol><li>Wilhelm, E. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=author%3aWilhelm%2C+E+%22Heat+Capacities%3A+Liquids%2C+Solutions+and+Vapours%22">Heat Capacities: Liquids, Solutions and Vapours</a>. , Royal Society of Chemistry. 516(2010).</li>
<li>Costa, J. M., Grant, O. M., Chaves, M. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Thermography+to+explore+plant-environment+interactions%5BTitle%5D)+AND+%22J.+Exp.+Bot%22%5BJournal%5D)">Thermography to explore plant-environment interactions.</a> J. Exp. Bot. 64, 3937-3949 (2013).</li>
<li>Jayalakshmy, M. S., Philip, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Thermophysical+Properties+of+Plant+Leaves+and+Their+Influence+on+the+Environment+Temperature%5BTitle%5D)+AND+%22International+Journal+of+Thermophysics%22%5BJournal%5D)">Thermophysical Properties of Plant Leaves and Their Influence on the Environment Temperature.</a> International Journal of Thermophysics. 31, 2295-2304 (2010).</li>
<li>Buyel, J. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Process+development+strategies+in+plant+molecular+farming%5BTitle%5D)+AND+%22Curr.+Pharm.+Biotechnol%22%5BJournal%5D)">Process development strategies in plant molecular farming.</a> Curr. Pharm. Biotechnol. 16, 966-982 (2015).</li>
<li>Schuster, A. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Effectiveness+of+cuticular+transpiration+barriers+in+a+desert+plant+at+controlling+water+loss+at+high+temperatures%5BTitle%5D)+AND+%22AoB+PLANTS%22%5BJournal%5D)">Effectiveness of cuticular transpiration barriers in a desert plant at controlling water loss at high temperatures.</a> AoB PLANTS. 8, (2016).</li>
<li>Parker, W. J., Jenkins, R. J., Abbott, G. L., Butler, C. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Flash+Method+of+Determining+Thermal+Diffusivity%2C+Heat+Capacity%2C+and+Thermal+Conductivity%5BTitle%5D)+AND+%22J+Appl+Phys%22%5BJournal%5D)">Flash Method of Determining Thermal Diffusivity, Heat Capacity, and Thermal Conductivity.</a> J Appl Phys. 32, 1679-1684 (1961).</li>
<li>Hays, R. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+thermal+conductivity+of+leaves%5BTitle%5D)+AND+%22Planta%22%5BJournal%5D)">The thermal conductivity of leaves.</a> Planta. 125, 281-287 (1975).</li>
<li>Menzel, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Optimized+blanching+reduces+the+host+cell+protein+content+and+substantially+enhances+the+recovery+and+stability+of+two+plant+derived+malaria+vaccine+candidates%5BTitle%5D)+AND+%22Front.+Plant+Sci%22%5BJournal%5D)">Optimized blanching reduces the host cell protein content and substantially enhances the recovery and stability of two plant derived malaria vaccine candidates.</a> Front. Plant Sci. , (2015).</li>
<li>Buyel, J. F., Hubbuch, J., Fischer, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Blanching+intact+leaves+or+heat+precipitation+in+an+agitated+vessel+or+heat+exchanger+removes+host+cell+proteins+from+tobacco+extracts%5BTitle%5D)+AND+%22J.+Vis.+Exp%22%5BJournal%5D)">Blanching intact leaves or heat precipitation in an agitated vessel or heat exchanger removes host cell proteins from tobacco extracts.</a> J. Vis. Exp. , Under review (2015).</li>
<li>Beiss, V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Heat-precipitation+allows+the+efficient+purification+of+a+functional+plant-derived+malaria+transmission-blocking+vaccine+candidate+fusion+protein%5BTitle%5D)+AND+%22Biotechnol.+Bioeng%22%5BJournal%5D)">Heat-precipitation allows the efficient purification of a functional plant-derived malaria transmission-blocking vaccine candidate fusion protein.</a> Biotechnol. Bioeng. 112, 1297-1305 (2015).</li>
<li>Buyel, J. F., Gruchow, H. M., Tödter, N., Wehner, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Determination+of+the+thermal+properties+of+leaves+by+non-invasive+contact+free+laser+probing%5BTitle%5D)+AND+%22J.+Biotechnol%22%5BJournal%5D)">Determination of the thermal properties of leaves by non-invasive contact free laser probing.</a> J. Biotechnol. 217, 100-108 (2016).</li>
<li>Buyel, J. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Numeric+simulation+can+be+used+to+predict+heat+transfer+during+the+blanching+of+leaves+and+intact%5BTitle%5D)+AND+%22Biochem.+Eng.+J%22%5BJournal%5D)">Numeric simulation can be used to predict heat transfer during the blanching of leaves and intact.</a> Biochem. Eng. J. , (2015).</li>
<li>Hedlund, H., Johansson, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Heat+capacity+of+birch+determined+by+calorimetry%3A+implications+for+the+state+of+water+in+plants%5BTitle%5D)+AND+%22Thermochim+Acta%22%5BJournal%5D)">Heat capacity of birch determined by calorimetry: implications for the state of water in plants.</a> Thermochim Acta. 349, 79-88 (2000).</li>
<li>Chandrakanthi, M., Mehrotra, A. K., Hettiaratchi, J. P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Thermal+conductivity+of+leaf+compost+used+in+biofilters%3A+An+experimental+and+theoretical+investigation%5BTitle%5D)+AND+%22Environ.+Pollut%22%5BJournal%5D)">Thermal conductivity of leaf compost used in biofilters: An experimental and theoretical investigation.</a> Environ. Pollut. 136, 167-174 (2005).</li>
<li>Larcher, W. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=author%3aLarcher%2C+W+%22Physiological+Plant+Ecology%3A+Ecophysiology+and+Stress+Physiology+of+Functional+Groups%22">Physiological Plant Ecology: Ecophysiology and Stress Physiology of Functional Groups</a>. , Springer Science & Business Media. (2003).</li>
<li>Cowen, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((A+gamma-ray+burst%27s+enduring+fireball%5BTitle%5D)+AND+%22Science+News%22%5BJournal%5D)">A gamma-ray burst's enduring fireball.</a> Science News. 152, 197(1997).</li>
<li>Jones, H. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Thermal+infrared+imaging+of+crop+canopies+for+the+remote+diagnosis+and+quantification+of+plant+responses+to+water+stress+in+the+field%5BTitle%5D)+AND+%22Funct.+Plant+Biol%22%5BJournal%5D)">Thermal infrared imaging of crop canopies for the remote diagnosis and quantification of plant responses to water stress in the field.</a> Funct. Plant Biol. 36, 978-989 (2009).</li>
<li>Defraeye, T., Verboven, P., Ho, Q. T., Nicolai, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Convective+heat+and+mass+exchange+predictions+at+leaf+surfaces%3A+Applications%2C+methods+and+perspectives%5BTitle%5D)+AND+%22Comput.+Electron.+Agric%22%5BJournal%5D)">Convective heat and mass exchange predictions at leaf surfaces: Applications, methods and perspectives.</a> Comput. Electron. Agric. 96, 180-201 (2013).</li>
<li>Arndt, S. K., Irawan, A., Sanders, G. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Apoplastic+water+fraction+and+rehydration+techniques+introduce+significant+errors+in+measurements+of+relative+water+content+and+osmotic+potential+in+plant+leaves%5BTitle%5D)+AND+%22Physiol.+Plant%22%5BJournal%5D)">Apoplastic water fraction and rehydration techniques introduce significant errors in measurements of relative water content and osmotic potential in plant leaves.</a> Physiol. Plant. 155, 355-368 (2015).</li>
<li>Jones, H. G., Schofield, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Thermal+and+other+remote+sensing+of+plant+stress%5BTitle%5D)+AND+%22General+and+Applied+Plant+Physiology%22%5BJournal%5D)">Thermal and other remote sensing of plant stress.</a> General and Applied Plant Physiology. 34, 19-32 (2008).</li>
<li>Jones, H. G., Archer, N., Rotenberg, E., Casa, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Radiation+measurement+for+plant+ecophysiology%5BTitle%5D)+AND+%22J.+Exp.+Bot%22%5BJournal%5D)">Radiation measurement for plant ecophysiology.</a> J. Exp. Bot. 54, 879-889 (2003).</li>
<li>Dupont, C., Chiriac, R., Gauthier, G., Toche, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Heat+capacity+measurements+of+various+biomass+types+and+pyrolysis+residues%5BTitle%5D)+AND+%22Fuel%22%5BJournal%5D)">Heat capacity measurements of various biomass types and pyrolysis residues.</a> Fuel. 115, 644-651 (2014).</li>
<li>Chaerle, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Multi-sensor+plant+imaging%3A+Towards+the+development+of+a+stress-catalogue%5BTitle%5D)+AND+%22Biotechnol.+J%22%5BJournal%5D)">Multi-sensor plant imaging: Towards the development of a stress-catalogue.</a> Biotechnol. J. 4, 1152-1167 (2009).</li>
<li>Hackl, H., Baresel, J. P., Mistele, B., Hu, Y., Schmidhalter, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((A+Comparison+of+Plant+Temperatures+as+Measured+by+Thermal+Imaging+and+Infrared+Thermometry%5BTitle%5D)+AND+%22J.+Agron.+Crop.+Sci%22%5BJournal%5D)">A Comparison of Plant Temperatures as Measured by Thermal Imaging and Infrared Thermometry.</a> J. Agron. Crop. Sci. , 415-429 (2012).</li>
<li>Yuan, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Spectral+analysis+of+winter+wheat+leaves+for+detection+and+differentiation+of+diseases+and+insects%5BTitle%5D)+AND+%22Field+Crops+Res%22%5BJournal%5D)">Spectral analysis of winter wheat leaves for detection and differentiation of diseases and insects.</a> Field Crops Res. 156, 199-207 (2014).</li>
</ol>

The authors have no conflicts of interest to disclose.

The contact-free, non-destructive measurement method described above can be used to determine cp,s and &#654; in a simultaneous and reproducible manner. The calculation of &#654; in particular depends on several parameters that are sensitive to errors. Nevertheless, the impact of these errors was either linear or sub-proportional, and the coefficient of variation for all parameters was found to be less than 10%. Even though the method can thus be regarded as robust, some technical improvements can be ...

The large-scale processing of biological materials often requires heat-treatment steps such as pasteurization. The equipment for such processes can be designed more precisely if the thermal properties of the biological materials are well characterized, including the specific heat capacity (cp,s) and thermal conductivity (λ). These parameters can be determined easily for liquids, suspensions and homogenates by calorimetry 1. However, measuring such parameters in solid samples can be labor intensive, and often requires direct contact with the sample or even its destruction 2. For example, photothermal techniques require direct contact between the sample and detector 3. Such limitations are acceptable during food processing, but are incompatible with highly regulated processes such as the production of biopharmaceutical proteins in plants in the context of good manufacturing practice 4. In such a context, repeated (e.g., weekly) monitoring of thermal properties may be required during a seven-week growth period for individual plants as a quality control tool. If such a monitoring would require and consume a leaf for each measurement, there would be no biomass left to process at the time of harvest.
Additionally, using only leaf parts instead would cause wounding to the plant and increase the risk of necrosis or pathogen infection, again diminishing the process yield. The likelihood of pathogen infection may also increase if a method with direct contact to the sample would be used, inducing the risk that an entire batch of plants can be infected through contact with a contaminated sensor device. Similar aspects have to be considered for the monitoring of plant stresses like drought, e.g., in an ecophysiological context. For example, water loss is often monitored by a change in the fresh biomass, which requires an invasive treatment of the plants under investigation 5, e.g., dissecting a leaf. Instead, determining the specific heat capacity, which depends on the water content of a sample, in a non-invasive manner as describe here, can be used as a surrogate parameter for the hydration status of plants. In both scenarios (pharmaceutical production and ecophysiology), artificial stresses induced by destructive or invasive measurement techniques would be deleterious as they can distort the experimental data. Therefore, previously reported flash methods 6 or the placement of samples between silver plates 7 are unsuitable for such processes and experiments because they either require direct contact to the sample or are destructive. The parameters cp,s and λ must be determined in order to design the process equipment for a blanching step that can simplify product purification and thus reduce manufacturing costs 8-10. Both cp,s and λ can now be rapidly determined by contact-free non-destructive near infrared (NIR) laser probing in a consistent and reproducible manner 11 and this new method will be explained in detail below. The results obtained with this method were successfully used to simulate heat transfer in tobacco leaves 12, allowing the design of appropriate processing equipment and the selection of corresponding parameters such as the blanching temperature.
The method is easy to set up (Figure 1) and has two phases, measurement and analysis, each of which comprises two major steps. In the measurement phase, a leaf sample is first locally heated by a short laser pulse and the maximum sample temperature is recorded. The temperature profile of the sample is then recorded for a duration of 50 s. In the analysis phase, leaf properties such as density (easily and accurately determined by pycnometric measurement) are combined with the maximum sample temperature to calculate cp,s. In the second step, the leaf temperature profile is used as the input for an energy balance equation, taking conduction, convection and radiation into account, to calculate λ.
Detailed step-by-step instructions are provided in the protocol section, expanding on the contents of the accompanying video. Typical measurements are then shown in the results section. Finally, the benefits and limitations of the method are highlighted in the discussion section along with potential improvements and further applications.
<img alt="Spectroscopy setup and diagram for optical excitation analysis; data control software interface." src="/files/ftp_upload/54835/54835fig1.jpg" data-altupdatedat="1788235205000" data-alt="Figure 1"> 
Figure 1: Apparatus used to determine leaf thermal properties. A. Photograph of the measurement apparatus used to determine the specific heat capacity and thermal conductivity of leaves. The peripheral devices (computers, oscilloscope) are not shown. B. Schematic representation of the measurement apparatus. The laser and connected equipment are highlighted in red, the NIR detector for temperature measurement is shown in purple, the leaf sample is green and the photodiode power sensor is blue. C. Drawing of the elements of the measurement setup with the same color code as in B. The size bar indicates 0.1 m. D. Screenshot illustrating the typical elements of the laser control software. <a href="http://cloudflare.jove.com/files/ftp_upload/54835/54835fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

<table><tbody><tr><td>1&quot; tube</td><td>Thorlabs</td><td>SM1L10E</td><td>Tube for fiber holder</td></tr><tr><td>Agarose</td><td>Sigma Aldrich</td><td>A0701</td><td>Agarose</td></tr><tr><td>Bi-Convex lense f=25.4</td><td>Thorlabs</td><td>LB1761</td><td>Lense</td></tr><tr><td>Digital Handheld Optical&amp;nbsp;Power and Energy Meter Console</td><td>Thorlabs</td><td>PM100D</td><td>Console for thermal surface absorber sensor</td></tr><tr><td>Digital Phosphor Oscilloscope&amp;nbsp;</td><td>Tektronix</td><td>DPO7104</td><td>Oscilloscope</td></tr><tr><td>DMR light microscope</td><td>Leica</td><td>n.a.</td><td>Light microscope</td></tr><tr><td>Falcon 50 mL Conical Centrifuge Tubes</td><td>Fisher Scientific</td><td>14-432-2</td><td>Pycnometer</td></tr><tr><td>Ferty 2 Mega</td><td>Kammlott</td><td>5.220072</td><td>Fertilizer</td></tr><tr><td>Fiber holder</td><td>Thorlabs</td><td></td><td>Fiber holder</td></tr><tr><td>Forma -86 &amp;#176;C ULT freezer</td><td>ThermoFisher</td><td>88400</td><td>Freezer</td></tr><tr><td>Greenhouse</td><td>n.a.</td><td>n.a.</td><td>For plant cultivation</td></tr><tr><td>Grodan Rockwool Cubes 10 x 10 cm</td><td>Grodan</td><td>102446</td><td>Rockwool block</td></tr><tr><td>Infrared Detector Optris CT</td><td>Optris</td><td>OPTCTLT15</td><td>Infrared detector</td></tr><tr><td>Infrared Detector Software Compact Connect</td><td>Optris</td><td>n.a.</td><td>Control software for infrared detector</td></tr><tr><td>Lambda 1050 UV/Vis spectrophotometer</td><td>PerkinElmer</td><td>L1050</td><td>UV/VIS Spectrophotometer</td></tr><tr><td>Laser 400 &amp;mu;m, 1,550&amp;nbsp;nm Conduction Cooled Single Bar Fiber Coupled Module</td><td>DILAS</td><td>M1F-SS2.1</td><td>Laser</td></tr><tr><td>Laser cover</td><td>Amtron</td><td>LM200</td><td>Laser Cover</td></tr><tr><td>Laser Driver&amp;nbsp;</td><td>Amtron</td><td>CS 408</td><td>Laser Driver</td></tr><tr><td>Osram cool white 36 W</td><td>Osram</td><td>4930440</td><td>Light source</td></tr><tr><td>Photodiode sensor&amp;nbsp;</td><td>Thorlabs</td><td>PDA20H-EC</td><td>Power sensor for transmission measurements</td></tr><tr><td>Precision weight Ohaus Analytical Plus</td><td>Ohaus</td><td>80251552</td><td>Precision weight</td></tr><tr><td>Sample frame</td><td>Fraunhofer ILT</td><td>n.a.</td><td>Fixation of the leaf sample</td></tr><tr><td>Software Pyro Control</td><td>Amtron</td><td>n.a.</td><td>Laser Power Control Software</td></tr><tr><td>Stainless-steel-holder</td><td>n.a.</td><td>n.a.</td><td>Holder for measurement set-up</td></tr><tr><td>Teflon plates 2 cm</td><td>Fraunhofer ILT</td><td>n.a.</td><td>Teflon attenuation</td></tr><tr><td>Thermal surface absorber Power sensor</td><td>Thorlabs</td><td>S314C</td><td>Sensor for laser power measurements</td></tr><tr><td>Vibratome</td><td>Leica</td><td>1491200S001</td><td>Vibratome</td></tr><tr><td>Zoc/Pro 6.51&amp;nbsp;</td><td>EmTec Innovative Software</td><td>n.a.</td><td>Laser Control Software&amp;nbsp;</td></tr></tbody></table>

a rapid laser probing method facilitates the non-invasive and contact-free determination of leaf thermal properties

A Rapid Laser Probing Method Facilitates the Non-invasive and Contact-free Determination of Leaf Thermal Properties

Plants can produce valuable substances such as secondary metabolites and recombinant proteins. The purification of the latter from plant biomass can be streamlined by heat treatment (blanching). A blanching apparatus can be designed more precisely if the thermal properties of the leaves are known in detail, i.e., the specific heat capacity and thermal conductivity. The measurement of these properties is time consuming and labor intensive, and usually requires invasive methods that contact the sample directly. This can reduce the product yield and may be incompatible with containment requirements, e.g., in the context of good manufacturing practice. To address these issues, a non-invasive, contact-free method was developed that determines the specific heat capacity and thermal conductivity of an intact plant leaf in about one minute. The method involves the application of a short laser pulse of defined length and intensity to a small area of the leaf sample, causing a temperature increase that is measured using a near infrared sensor. The temperature increase is combined with known leaf properties (thickness and density) to determine the specific heat capacity. The thermal conductivity is then calculated based on the profile of the subsequent temperature decline, taking thermal radiation and convective heat transfer into account. The associated calculations and critical aspects of sample handling are discussed.

Measurement of Leaf Properties
Using the above microscopic method, a leaf thickness of 0.22-0.29 × 10−3 m was determined for both N. tabacum (0.25±0.04 × 10−3 m, n=33) and N. benthamiana (0.26±0.02 × 10−3 m, n=24), which is well within the 0.20-0.33 × 10−3 m range previously reported for the leaves of variou...

A method was developed to determine the specific heat capacity and thermal conductivity of leaf tissue by non-invasive, contact-free near infrared laser probing, which requires less than 1 min per sample.

Plants can produce valuable substances such as secondary metabolites and recombinant proteins. The purification of the latter from plant biomass can be ...

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JoVE Journal

Biochemistry

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Learn a rapid near-infrared laser probing method for non-invasive determination of leaf thermal properties in plant physiology. This contact-free technique enables precise plant health monitoring without sample damage.

A Rapid Laser Probing Method Facilitates the Non-invasive and Contact-free Determination of Leaf Thermal Properties

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