Name: the use of high-resolution infrared thermography (hrit) for the study of ice nucleation and ice propagation in plants
Uploaded: 2015-05-08T14:00:00
Description: Watch this Scientific Journal Video about The Use of High-resolution Infrared Thermography HRIT for the Study of Ice Nucleation and Ice Propagation in Plants at JoVE.com

This research was funded by the Austrian Science Fund (FWF): P23681-B16.

1. Preparation of Plant Materials
<ol>
	<li>Use either leaves or whole plants of subject plant material (Hosta spp. or Phaseolus vulgaris).</li>
</ol>
2. Preparation of Water Solutions Containing Ice Nucleation Active (INA) Bacteria
<ol>
	<li>Culture the INA bacterium, Pseudomonas syringae (Strain Cit-7) in petri dishes at 25 &#176;C on Pseudomonas Agar F prepared with 10 g/L of 100% glycerol per the manufacturer&#8217;s direction.</li>
	<li>After cultures have grown...

<ol>
	<li>Taschler, D., Beikircher, B., Neuner, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Frost+resistance+and+ice+nucleation+in+leaves+of+five+woody+timberline+species+measured+in+situ+during+shoot+expansion.">Frost resistance and ice nucleation in leaves of five woody timberline species measured in situ during shoot expansion.</a> Tree Physiol. 24, 331-337 (2004).</li><li>Neuner, G., Hacker, J., L&#252;tz, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ice+formation+and+propagation+in+alpine+plants.">Ice formation and propagation in alpine plants.</a> Plants in alpine regions: Cell Physiology of adaptation and survival strategies. , 163-174 (2012).</li><li>Ladinig, U., Hacker, J., Neuner, G., Wagner, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=How+endangered+is+sexual+reproduction+of+high-mountain+plants+by+summer+frosts?+-+Frost+resistance,+frequency+of+frost+events+and+risk+assessment.">How endangered is sexual reproduction of high-mountain plants by summer frosts? - Frost resistance, frequency of frost events and risk assessment.</a> Oecologia. 171, 743-760 (2013).</li><li>Wisniewski, M. E., Gusta, L. V., Fuller, M. P., Karlson, D., Gusta, L. V., Wisniewski, M. E., Tanino, K. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ice+nucleation,+propagation+and+deep+supercooling:+the+lost+tribes+of+freezing+studies.">Ice nucleation, propagation and deep supercooling: the lost tribes of freezing studies.</a> Plant Cold Hardiness: from the laboratory to the field. , 1-11 (2009).</li><li>Bokhurst, S., Bjerke, J. W., Davey, M. P., Taulavuori, K., Taulavuori, E., Laine, K., Callaghan, T. V., Phoenix, G. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impacts+of+extreme+winter+warming+events+on+plant+physiology+in+a+sub-Arctic+heath+community.">Impacts of extreme winter warming events on plant physiology in a sub-Arctic heath community.</a> Physiol. Plant. 140, 128-140 (2010).</li><li>Taulavuori, K., Laine, K., Taulavuori, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+studies+on+Vaccinium+myrtillus.and+Vaccinium+vits-idea.in+relation+to+air+pollution+and+global+change+at+northern+high+latitudes:+A+review.">Experimental studies on Vaccinium myrtillus.and Vaccinium vits-idea.in relation to air pollution and global change at northern high latitudes: A review.</a> Env. Exp. Bot. 87, 191-196 (2013).</li><li>Wisniewski, M., Glenn, D. M., Gusta, L., Fuller, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Using+infrared+thermography+to+study+freezing+in+plants.">Using infrared thermography to study freezing in plants.</a> HortScience. 43, 1648-1651 (2008).</li><li>Gu, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+2007+eastern+US+spring+freeze:+increased+cold+damage+in+a+warming+world.">The 2007 eastern US spring freeze: increased cold damage in a warming world.</a> BioScience. 58, 253-262 (2008).</li><li>Augspurger, C. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spring+warmth+and+frost:+phenology,+damage,+and+refoliation+in+a+temperate+deciduous+forest.">Spring warmth and frost: phenology, damage, and refoliation in a temperate deciduous forest.</a> Func. Ecol. 23, 1031-1039 (2007).</li><li>Neuner, G., Erler, A., Hacker, J., Ladinig, U., Wagner, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Frost+resistance+of+reproductive+tissues+in+various+reproductive+stages+of+high+alpine+plant+species.">Frost resistance of reproductive tissues in various reproductive stages of high alpine plant species.</a> Physiol. Plant. 147, 88-100 (2013).</li><li>Skre, O., Taulavuori, K., Taulavuori, E., Nilsne, J., Igeland, B., Laine, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+importance+of+hardening+and+winter+temperature+for+growth+in+mountain+birch+populations.">The importance of hardening and winter temperature for growth in mountain birch populations.</a> Env. Exp. Bot. 62, 254-266 (2008).</li><li>H&#228;nninen, H., Tanino, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tree+seasonality+in+a+warming+climate.">Tree seasonality in a warming climate.</a> Trends in Plant Science. 16, 412-416 (2011).</li><li>Katz, R. W., Brown, B. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extreme+events+in+a+changing+climate:+variability+is+more+important+than+averages.">Extreme events in a changing climate: variability is more important than averages.</a> Climate Change. 21, 289-302 (1992).</li><li>Wisniewski, M., Gusta, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Understanding+plant+cold+hardiness:+an+opinion.">Understanding plant cold hardiness: an opinion.</a> Physiol. Plant. 147, 4-14 (2013).</li><li>Wisniewski, M., Gusta, L., Neuner, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adaptive+mechanisms+of+freeze+avoidance+in+plants.+A+brief+update.">Adaptive mechanisms of freeze avoidance in plants. A brief update.</a> Env. Exp. Bot. 99, 133-140 (2014).</li><li>Burke, M. J., Gusta, L. V., Quamme, H. A., Weiser, C. J., Li, P. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Freezing+and+injury+in+plants.">Freezing and injury in plants.</a> Annu. Rev. Plant Physiol. 27, 507-528 (1976).</li><li>Ishikawa, M., Price, W. S., Ide, H., Arata, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visualization+of+freezing+behaviors+in+leaf+and+flower+buds+of+full-moon+maple+by+nuclear+magnetic+resonance+microscopy.">Visualization of freezing behaviors in leaf and flower buds of full-moon maple by nuclear magnetic resonance microscopy.</a> Plant Physiol. 115 (4), 1515-1524 (1997).</li><li>Ishikawa, M., Sakai, A., Li, P. H., Sakai, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characteristics+of+freezing+avoidance+in+comparison+with+freezing+tolerance:+a+demonstration+of+extra-organ+freezing.">Characteristics of freezing avoidance in comparison with freezing tolerance: a demonstration of extra-organ freezing.</a> Plant cold hardiness and freezing stress. , 325-340 (1982).</li><li>Buchner, O., Neuner, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Freezing+cytorrhysis+and+critical+temperature+thresholds+for+photosystem+II+in+the+peat+moss+Sphagnum+capillifolium.">Freezing cytorrhysis and critical temperature thresholds for photosystem II in the peat moss Sphagnum capillifolium.</a> Protoplasma. 243 (1), 63-71 (2010).</li><li>Pearce, R. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extracellular+ice+and+cell+shape+in+frost-stressed+cereal+leaves:+A+low+temperature+scanning+electron+microscopy+study.">Extracellular ice and cell shape in frost-stressed cereal leaves: A low temperature scanning electron microscopy study.</a> Planta. 175, 313-324 (1988).</li><li>Ashworth, E. N., Anderson, J. A., Davis, G. A., Lightner, G. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ice+formation+in+Prunus+persica.+under+field+conditions.">Ice formation in Prunus persica. under field conditions.</a> J. Am. Soc. Hort. Sci. 110 (3), 322-324 (1985).</li><li>Ashworth, E. N., Davis, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ice+formation+in+woody+plants+under+field+conditions.">Ice formation in woody plants under field conditions.</a> HortSci. 21, 1233-1234 (1986).</li><li>Pramsohler, M., Hacker, J., Neuner, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Freezing+pattern+and+frost+killing+temperature+of+apple+(Malus+domestica.)+wood+under+controlled+conditions+and+in+nature.">Freezing pattern and frost killing temperature of apple (Malus domestica.) wood under controlled conditions and in nature.</a> Tree Physiol. 32 (7), 819-828 (2012).</li><li>Wisniewski, M., Lindow, S. E., Ashworth, E. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Observations+of+ice+nucleation+and+propagation+in+plants+using+infrared+video+thermography.">Observations of ice nucleation and propagation in plants using infrared video thermography.</a> Plant Physiol. 113 (2), 327-334 (1997).</li><li>Lutze, J. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Elevated+atmospheric+[CO2]+promotes+frost+damage+in+evergreen+tree+seedlings.">Elevated atmospheric [CO2] promotes frost damage in evergreen tree seedlings.</a> Plant Cell Environ. (6), 631-635 (1998).</li><li>Ball, M. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Space+and+time+dependence+of+temperature+and+freezing+in+evergreen+leaves).">Space and time dependence of temperature and freezing in evergreen leaves).</a> Func. Plant Biol. 29 (11), 1259-1272 (2002).</li><li>Sekozawa, Y., Sugaya, S., Gemma, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Observations+of+ice+nucleation+and+propagation+in+flowers+of+Japanese+Pear+(Pyrus+Pyrifolia).">Observations of ice nucleation and propagation in flowers of Japanese Pear (Pyrus Pyrifolia).</a> Nakai) using infrared video. 73 (1), 1-6 (2004).</li><li>Hacker, J., Neuner, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ice+propagation+in+plants+visualized+at+the+tissue+level+by+IDTA+(infrared+differential+thermal+analysis).">Ice propagation in plants visualized at the tissue level by IDTA (infrared differential thermal analysis).</a> Tree Physiol. 27, 1661-1670 (2007).</li><li>Hacker, J., Neuner, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ice+propagation+in+dehardened+alpine+plant+species+studied+by+infrared+differential+thermal+analysis+(IDTA).">Ice propagation in dehardened alpine plant species studied by infrared differential thermal analysis (IDTA).</a> Arc. Antarc. Alp. Res. 40 (4), 660-670 (2008).</li><li>Hacker, J., Spindelb&#246;ck, J., Neuner, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mesophyll+freezing+and+effects+of+freeze+dehydration+visualized+by+simultaneous+measurement+of+IDTA+and+differential+imaging+chlorophyll+fluorescence.">Mesophyll freezing and effects of freeze dehydration visualized by simultaneous measurement of IDTA and differential imaging chlorophyll fluorescence.</a> Plant Cell Environ. 31, 1725-1733 (2008).</li><li>Neuner, G., XU, B., Hacker, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Velocity+and+pattern+of+ice+propagation+and+deep+supercooling+in+woody+stems+of+Castanea+sativa.,+Morus+nigra.+and+Quercus+robur.+measured+by+IDTA.">Velocity and pattern of ice propagation and deep supercooling in woody stems of Castanea sativa., Morus nigra. and Quercus robur. measured by IDTA.</a> Tree Physiol. 30, 1037-1045 (2010).</li><li>Hacker, J., Ladinig, U., Wagner, J., Neuner, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inflorescences+of+alpine+cushion+plants+freeze+autonomously+and+may+survive+subzero+temperatures+by+supercooling.">Inflorescences of alpine cushion plants freeze autonomously and may survive subzero temperatures by supercooling.</a> Plant Sci. 180, 149-156 (2011).</li><li>Kuprian, E., Briceno, V., Wagner, J., Neuner, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ice+barriers+promote+supercooling+and+prevent+frost+injury+in+reproductive+buds,+flowers+and+fruits+of+alpine+dwarf+shrubs+throughout+the+summer.">Ice barriers promote supercooling and prevent frost injury in reproductive buds, flowers and fruits of alpine dwarf shrubs throughout the summer.</a> Env. Exp. Bot. 106, 4-12 (2014).</li><li>Wisniewski, M., Glenn, D. M., Fuller, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+a+hydrophobic+particle+film+as+a+barrier+to+extrinsic+ice+nucleation+in+tomato+plants.">Use of a hydrophobic particle film as a barrier to extrinsic ice nucleation in tomato plants.</a> HortScience. 127, 358-364 (2002).</li><li>Aryal, B., &amp;Neuner, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Leaf+wettability+decreases+along+an+extreme+altitudinal+gradient.">Leaf wettability decreases along an extreme altitudinal gradient.</a> Oecologia. 162, 1-9 (2010).</li><li>Wisniewski, M., Fuller, M. P., Margesin, R., Schinner, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Ice nucleation and deep supercooling in plants: new insights using infrared thermography. In: Cold adapted organisms. Ecology, physiology, enzymologyandmolecularbiology. , 105-118 (1999).</li><li>Franks, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Biophysics and biochemistry at low temperatures. , (1985).</li><li>Neuner, G., Kuprian, E., Hincha, D., Zuther, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Infrared+thermal+analysis+of+plant+freezing+processes.">Infrared thermal analysis of plant freezing processes.</a> Methods in Molecular Biology: Plant Cold Acclimation. , 91-98 (2014).</li></ol>

Water has the ability to supercool to temperatures well below 0 &#176;C and the temperature at which water will freeze can be quite variable.36 The temperature limit for supercooling of pure water is about -40 &#176;C and is defined as the homogeneous nucleation point. When water freezes at temperatures warmer than -40 &#176;C it is brought about by the presence of heterogenous nucleators that enable small ice embryos to form which then serve as a catalyst for ice formation and growth.37 There are a...

Freezing temperatures that occur when plants are actively growing can be lethal, particularly if the plant has little or no freezing tolerance. Such frost events often have devastating effects on agricultural production and can also play an important role in shaping community structure in natural populations of plants, especially in alpine, sub-arctic and arctic ecosystems 1-6. Episodes of severe spring frosts have had major impacts on fruit production in the USA and South America in recent years 7-9 and have been exacerbated by the early onset of warm weather followed by more typical mean low temperatures. The early warm weather induces buds to break, activating the growth of new shoots, leaves, and flowers all of which have very little to no frost tolerance 1,3,10-12. Such erratic weather patterns have been reported to be a direct reflection of ongoing climate change and are expected to be a common weather pattern for the foreseeable future 13. Efforts to provide economical, effective, and environmentally-friendly management techniques or agrochemicals that can provide increased frost tolerance have had limited success for a host of reasons but this can be partly attributed to the complex nature of freezing tolerance and freezing avoidance mechanisms in plants. 14
The adaptive mechanisms associated with frost survival in plants have traditionally been divided into two categories, freezing tolerance and freezing avoidance. The former category is associated with biochemical mechanisms regulated by a specific set of genes that allow plants to tolerate the stresses associated with the presence and the dehydrative effect of ice in its tissues. While the latter category is typically, but not solely, associated with structural aspects of a plant that determine if, when, and where ice forms in a plant 14. Despite the prevalence of freeze avoidance as an adaptive mechanism, little research has been devoted in recent times to understanding the underlying mechanisms and regulation of freeze avoidance. The reader is referred to a recent review 15 for greater details on this subject.
While the formation of ice at low temperatures may seem like a simple process, many factors contribute to determining the temperature at which ice nucleates in plant tissues and how it spreads within the plant. Parameters such as the presence of extrinsic and intrinsic ice nucleators, heterogeneous vs. homogeneous nucleation events, thermal-hysteresis (antifreeze) proteins, the presence of specific sugars and other osmolytes, and a host of structural aspects of the plant can all play a significant role in the freezing process in plants. Collectively, these parameters influence the temperature at which a plant freezes, where ice is initiated and how it grows. They can also affect the morphology of the resulting ice crystals. Various methods have been used to study the freezing process in plants under laboratory conditions, including nuclear magnetic resonance spectroscopy (NMR) 16, magnetic resonance imaging (MRI) 17, cryo-microscopy 18-19, and low-temperature scanning electron microscopy (LTSEM). 20 Freezing of whole plants in laboratory and field settings, however, has mainly been monitored with thermocouples. The use of thermocouples to study freezing is based on the liberation of heat (enthalpy of fusion) when water undergoes a phase transition from a liquid to a solid. Freezing is then recorded as an exothermic event. 21-23 Even though thermocouples are the typical method of choice in studying freezing in plants, their use has many limitations that limit the amount of information obtained during a freezing event. For instance, with thermocouples it is difficult to nearly impossible to determine where ice is initiated in plants, how it propagates, if it propagates at an even rate, and if some tissues remain free of ice.
Advances in high-resolution infrared thermography (HRIT) 24-27, however, have significantly increased the ability to obtain information about the freezing process in whole plants, especially when used in a differential imaging mode. 28-33 In the present report, we describe the use of this technology to study various aspects of the freezing process and various parameters that affect where and and at what temperature ice is initiated in plants. A protocol will be presented that will demonstrate the ability of the ice-nucleation-active (INA) bacterium, Pseudomonas syringae (Cit-7) to act as an extrinsic nucleator initiating freezing in a herbaceous plant at a high, subzero temperature.
High-resolution Infrared Camera
The protocol and examples documented in this report utilize a high resolution infrared video radiometer. The radiometer (Figure 1) supplies a combination of infrared and visible spectrum images and temperature data. The spectral response of the camera is in the range of 7.5 to 13.5 &#181;m and provides 640 x 480 pixel resolution. Visible spectrum images generated by the built-in camera can be fused with IR-images in real time, which facilitates the interpretation of complex, thermal images. A range of lenses for the camera can be used to make close-up and microscopic observations. The camera can be used in a stand-alone mode, or interfaced and controlled with a laptop using propietary software. The software can be used to obtain a variety of thermal data embedded in the recorded videos. It is important to note that a wide variety of infrared radiometers are commercially available. Therefore, it is essential that the researcher discuss their intended application with a knowledgeable product engineer and that the researcher test the ability of any specific radiometer to provide the information needed. The imaging radiometer used in the described protocol is placed in an acrylic box (Figure 2) insulated with Styrofoam in order to deter exposure to condensation during the warming and cooling protocols. This protection is not needed for all cameras or applications.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Infrared Camera</td>
			<td>FLIR</td>
			<td>SC-660</td>
			<td>Many models available depending on application</td>
		</tr>
		<tr>
			<td>Infrared Analytical Software</td>
			<td>FLIR</td>
			<td>ResearchIR 4.10.2.5</td>
			<td align="right">$3,500</td>
		</tr>
		<tr>
			<td rowspan="2">Pseudomonas syringae (strain Cit-7)</td>
			<td rowspan="2"></td>
			<td rowspan="2"></td>
			<td rowspan="2"><a href="mailto:icelab@berkeley.edu">Kindly provided by Dr. Steven Lindow, University of California&#160; Berkeley icelab@berkeley.edu</a></td>
		</tr>
		<tr>
		</tr>
		<tr>
			<td>Pseudomonas Agar F</td>
			<td>Fisher Scientific</td>
			<td>DF0448-17-1</td>
			<td></td>
		</tr>
	</tbody>
</table>

the use of high-resolution infrared thermography (hrit) for the study of ice nucleation and ice propagation in plants

Freezing events that occur when plants are actively growing can be a lethal event, particularly if the plant has no freezing tolerance. Such frost events often have devastating effects on agricultural production and can also play an important role in shaping community structure in natural populations of plants, especially in alpine, sub-arctic, and arctic ecosystems. Therefore, a better understanding of the freezing process in plants can play an important role in the development of methods of frost protection and understanding mechanisms of freeze avoidance. Here, we describe a protocol to visualize the freezing process in plants using high-resolution infrared thermography (HRIT). The use of this technology allows one to determine the primary sites of ice formation in plants, how ice propagates, and the presence of ice barriers. Furthermore, it allows one to examine the role of extrinsic and intrinsic nucleators in determining the temperature at which plants freeze and evaluate the ability of various compounds to either affect the freezing process or increase freezing tolerance. The use of HRIT allows one to visualize the many adaptations that have evolved in plants, which directly or indirectly impact the freezing process and ultimately enables plants to survive frost events.

Ice-nucleating activity of the Ice+ bacterium, Pseudomonas syringae (strain Cit-7)
A 10 &#181;l drop of water and 10 &#181;l of water containing P. syringae (Cit-7) were placed on the abaxial surface of a Hosta leaf (Hosta spp.) (Figure 4). As illustrated, the drop of water containing the INA bacteria froze first and was responsible for inducing the leaf to freeze while the drop of water on the leaf surface remained unfrozen.
<p class="jove_conte...

Watch this Scientific Journal Video about The Use of High-resolution Infrared Thermography HRIT for the Study of Ice Nucleation and Ice Propagation in Plants at JoVE.com

The Use of High-resolution Infrared Thermography HRIT for the Study of Ice Nucleation and Ice Propagation in Plants

Here we present a protocol that allows one to visualize sites of ice formation and avenues of ice propagation in plants utilizing high resolution infrared thermography (HRIT).

The Use of High-resolution Infrared Thermography (HRIT) for the Study of Ice Nucleation and Ice Propagation in Plants

Freezing events that occur when plants are actively growing can be a lethal event, particularly if the plant has no freezing tolerance. Such frost events ...

the-use-high-resolution-infrared-thermography-hrit-for-study-ice

Research

JoVE Journal

Environment

Expression of Recombinant Cellulase Cel5A from Trichoderma reesei in Tobacco Plants

Cellulose degrading enzymes, cellulases, are targets of both research and industrial interests. The preponderance of these enzymes in difficult-to-culture organisms, such as hyphae-building fungi and anaerobic bacteria, has hastened the use of recombinant technologies in this field. Plant expression methods are a desirable system for large-scale production of enzymes and other industrially useful proteins. Herein, methods for the transient expression of a fungal endoglucanase, Trichoderma reesei Cel5A, in Nicotiana tabacum are demonstrated. Successful protein expression is shown, monitored by fluorescence using an mCherry-enzyme fusion protein. Additionally, a set of basic tests are used to examine the activity of transiently expressed T. reesei Cel5A, including SDS-PAGE, Western blotting, zymography, as well as&#160;fluorescence and dye-based substrate degradation assays. The system described here can be used to produce an active cellulase in a short time period, so as to assess the potential for further production in plants through constitutive or inducible expression systems.

Expression of Recombinant Cellulase Cel5A from Trichoderma reesei in Tobacco Plants

Tobacco plants were used to produce a fungal cellulase, TrCel5A, via a transient expression system. The expression could be monitored using a fluorescent fusion protein, and the protein activity was characterized post-expression.

Cellulose degrading enzymes, cellulases, are targets of both research and industrial interests. The preponderance of these enzymes in difficult-to-culture ...

Enhancement of the Initial Growth Rate of Agricultural Plants by Using Static Magnetic Fields

Electronic devices and high-voltage wires induce magnetic fields. A magnetic field of 1,300-2,500 Gauss (0.2 Tesla) was applied to Petri dishes containing seeds of Garden Balsam (Impatiens balsamina), Mizuna (Brassica rapa var. japonica), Komatsuna (Brassica rapa var. perviridis), and Mescluns (Lepidium sativum). We applied magnets under the culture dish. During the 4 days of application, we observed that the stem and root length increased. The group subjected to magnetic field treatment (n = 10) showed a 1.4 times faster rate of growth compared with the control group (n = 11) in a total of 8 days (p &#60;0.0005). This rate is 20% higher than that reported in previous studies. The tubulin complex lines did not have connecting points, but connecting points occur upon the application of magnets. This shows complete difference from the control, which means abnormal arrangements. However, the exact cause remains unclear. These results of growth enhancement of applying magnets suggest that it is possible to enhance the growth rate, increase productivity, or control the speed of germination of plants by applying static magnetic fields. Also, magnetic fields can cause physiological changes in plant cells and can induce growth. Therefore, stimulation with a magnetic field can have possible effects that are similar to those of chemical fertilizers, which means that the use of fertilizers can be avoided.

The goal of this protocol is to demonstrate the acceleration of the initial growth rate of plants by applying static magnetic fields with no external energy.

Electronic devices and high-voltage wires induce magnetic fields. A magnetic field of 1,300-2,500 Gauss (0.2 Tesla) was applied to Petri dishes containing ...

Use of a Battery of Chemical and Ecotoxicological Methods for the Assessment of the Efficacy of Wastewater Treatment Processes to Remove Estrogenic Potency

Endocrine Disrupting Compounds pose a substantial risk to the aquatic environment. Ethinylestradiol (EE2) and estrone (E1) have recently been included in a watch list of environmental pollutants under the European Water Framework Directive. Municipal wastewater treatment plants are major contributors to the estrogenic potency of surface waters. Much of the estrogenic potency of wastewater treatment plant (WWTP) effluents can be attributed to the discharge of steroid estrogens including estradiol (E2), EE2 and E1 due to incomplete removal of these substances at the treatment plant. An evaluation of the efficacy of wastewater treatment processes requires the quantitative determination of individual substances most often undertaken using chemical analysis methods. Most frequently used methods include Gas Chromatography-Mass Spectrometry (GCMS/MS) or Liquid Chromatography-Mass Spectrometry (LCMS/MS) using multiple reaction monitoring (MRM). Although very useful for regulatory purposes, targeted chemical analysis can only provide data on the compounds (and specific metabolites) monitored. Ecotoxicology methods additionally ensure that any by-products produced or unknown estrogenic compounds present are also assessed via measurement of their biological activity. A number of in vitro bioassays including the Yeast Estrogen Screen (YES) are available to measure the estrogenic activity of wastewater samples. Chemical analysis in conjunction with in vivo and in vitro bioassays provides a useful toolbox for assessment of the efficacy and suitability of wastewater treatment processes with respect to estrogenic endocrine disrupting compounds. This paper utilizes a battery of chemical and ecotoxicology tests to assess conventional, advanced and emerging wastewater treatment processes in laboratory and field studies.

Endocrine Disrupting Compounds (EDC) pose a substantial risk to the aquatic environment. Municipal wastewater treatment plants are major contributors to the estrogenic potency of surface waters. The methodology provided in this paper allows for an assessment of the efficacy and suitability of wastewater treatment processes with respect to EDC removal.

Endocrine Disrupting Compounds pose a substantial risk to the aquatic environment. Ethinylestradiol (EE2) and estrone (E1) have recently been included in ...

Empirical, Metagenomic, and Computational Techniques Illuminate the Mechanisms by which Fungicides Compromise Bee Health

Growers often use fungicide sprays during bloom to protect crops against disease, which exposes bees to fungicide residues. Although considered &#34;bee-safe,&#34; there is mounting evidence that fungicide residues in pollen are associated with bee declines (for both honey and bumble bee species). While the mechanisms remain relatively unknown, researchers have speculated that bee-microbe symbioses are involved. Microbes play a pivotal role in the preservation and/or processing of pollen, which serves as nutrition for larval bees. By altering the microbial community, it is likely that fungicides disrupt these microbe-mediated services, and thereby compromise bee health. This manuscript describes the protocols used to investigate the indirect mechanism(s) by which fungicides may be causing colony decline. Cage experiments exposing bees to fungicide-treated flowers have already provided the first evidence that fungicides cause profound colony losses in a native bumble bee (Bombus impatiens). Using field-relevant doses of fungicides, a series of experiments have been developed to provide a finer description of microbial community dynamics of fungicide-exposed pollen. Shifts in the structural composition of fungal and bacterial assemblages within the pollen microbiome are investigated by next-generation sequencing and metagenomic analysis. Experiments developed herein have been designed to provide a mechanistic understanding of how fungicides affect the microbiome of pollen-provisions. Ultimately, these findings should shed light on the indirect pathway through which fungicides may be causing colony declines.

Microbial consortia within bumble bee hives enrich and preserve pollen for bee larvae. Using next generation sequencing, along with laboratory and field-based experiments, this manuscript describes protocols used to test the hypothesis that fungicide residues alter the pollen microbiome, and colony demographics, ultimately leading to colony loss.

Growers often use fungicide sprays during bloom to protect crops against disease, which exposes bees to fungicide residues. Although considered ...

Automated, High-resolution Mobile Collection System for the Nitrogen Isotopic Analysis of NOx

Nitrogen oxides (NOx = NO + NO2) are a family of atmospheric trace gases that have great impact on the environment. NOx concentrations directly influence the oxidizing capacity of the atmosphere through interactions with ozone and hydroxyl radicals. The main sink of NOx is the formation and deposition of nitric acid, a component of acid rain and a bioavailable nutrient. NOx is emitted from a mixture of natural and anthropogenic sources, which vary in space and time. The collocation of multiple sources and the short lifetime of NOx make it challenging to quantitatively constrain the influence of different emission sources and their impacts on the environment. Nitrogen isotopes of NOx have been suggested to vary amongst different sources, representing a potentially powerful tool to understand the sources and transport of NOx. However, previous methods of collecting atmospheric NOx integrate over long (week to month) time spans and are not validated for the efficient collection of NOx in relevant, diverse field conditions. We report on a new, highly efficient field-based system that collects atmospheric NOx for isotope analysis at a time resolution between 30 min and 2 hr. This method collects gaseous NOx in solution as nitrate with 100% efficiency under a variety of conditions. Protocols are presented for collecting air in urban settings under both stationary and mobile conditions. We detail the advantages and limitations of the method and demonstrate its application in the field. Data from several deployments are shown to 1) evaluate field-based collection efficiency by comparisons with in situ NOx concentration measurements, 2) test the stability of stored solutions before processing, 3) quantify in situ reproducibility in a variety of urban settings, and 4) demonstrate the range of N isotopes of NOx detected in ambient urban air and on heavily traveled roadways.

Automated, High-resolution Mobile Collection System for the Nitrogen Isotopic Analysis of NOx

Previous work suggests that the nitrogen isotopic composition of atmospheric nitrogen oxides might distinguish the influence of different sources in the environment. We report on an automated, mobile, field-based method for the high collection efficiency of atmospheric NOx for N isotopic analysis at an hourly time resolution.

Nitrogen oxides (NOx = NO + NO2) are a family of atmospheric trace gases that have great impact on the environment. NOx concentrations directly influence ...

The Calibration and Use of Capacitance Sensors to Monitor Stem Water Content in Trees

Water transport and storage through the soil-plant-atmosphere continuum is critical to the terrestrial water cycle, and has become a major research focus area. Biomass capacitance plays an integral role in the avoidance of hydraulic impairment to transpiration. However, high temporal resolution measurements of dynamic changes in the hydraulic capacitance of large trees are rare. Here, we present procedures for the calibration and use of capacitance sensors, typically used to monitor soil water content, to measure the volumetric water content in trees in the field. Frequency domain reflectometry-style observations are sensitive to the density of the media being studied. Therefore, it is necessary to perform species-specific calibrations to convert from the sensor-reported values of dielectric permittivity to volumetric water content. Calibration is performed on a harvested branch or stem cut into segments that are dried or re-hydrated to produce a full range of water contents used to generate a best-fit regression with sensor observations. Sensors are inserted into calibration segments or installed in trees after pre-drilling holes to a tolerance fit using a fabricated template to ensure proper drill alignment. Special care is taken to ensure that sensor tines make good contact with the surrounding media, while allowing them to be inserted without excessive force. Volumetric water content dynamics observed via the presented methodology align with sap flow measurements recorded using thermal dissipation techniques and environmental forcing data. Biomass water content data can be used to observe the onset of water stress, drought response and recovery, and has the potential to be applied to the calibration and evaluation of new plant-level hydrodynamics models, as well as to the partitioning of remotely sensed moisture products into above- and belowground components.

The hydraulic capacitance of biomass is a key component of the vegetation water budget, which serves as a buffer against short and long-term drought stresses. Here, we present a protocol for the calibration and use of soil moisture capacitance sensors to monitor water content in the stems of large trees.

Water transport and storage through the soil-plant-atmosphere continuum is critical to the terrestrial water cycle, and has become a major research focus ...

Stress Distribution During Cold Compression of Rocks and Mineral Aggregates Using Synchrotron-based X-Ray Diffraction

We report detailed procedures for performing compression experiments on rocks and mineral aggregates within a multi-anvil deformation apparatus (D-DIA) coupled with synchrotron X-radiation. A cube-shaped sample assembly is prepared and compressed, at room temperature, by a set of four X-ray transparent sintered diamond anvils and two tungsten carbide anvils, in the lateral and the vertical planes, respectively. All six anvils are housed within a 250-ton hydraulic press and driven inward simultaneously by two wedged guide blocks. A horizontal energy dispersive X-ray beam is projected through and diffracted by the sample assembly. The beam is commonly in the mode of either white or monochromatic X-ray. In the case of white X-ray, the diffracted X-rays are detected by a solid-state detector array that collects the resulting energy dispersive diffraction pattern. In the case of monochromatic X-ray, the diffracted pattern is recorded using a two-dimensional (2-D) detector, such as an imaging plate or a charge-coupled device (CCD) detector. The 2-D diffraction patterns are analyzed to derive lattice spacings. The elastic strains of the sample are derived from the atomic lattice spacing within grains. The stress is then calculated using the predetermined elastic modulus and the elastic strain. Furthermore, the stress distribution in two-dimensions allow for understanding how stress is distributed in different orientations. In addition, a scintillator in the X-ray path yields a visible light image of the sample environment, which allows for the precise measurement of sample length changes during the experiment, yielding a direct measurement of volume strain on the sample. This type of experiment can quantify the stress distribution within geomaterials, which can ultimately shed light on the mechanism responsible for compaction. Such knowledge has the potential to significantly improve our understanding of key processes in rock mechanics, geotechnical engineering, mineral physics, and material science applications where compactive processes are important.

We report detailed procedures for compression experiments on rocks and mineral aggregates within a multi-anvil deformation apparatus coupled with synchrotron X-radiation. Such experiments allow quantification of the stress distribution within samples, that ultimately sheds light on compaction processes in geomaterials.

We report detailed procedures for performing compression experiments on rocks and mineral aggregates within a multi-anvil deformation apparatus (D-DIA) ...

Protocol for Producing Three-Dimensional Infrared Video of Freezing in Plants

Freezing in plants can be monitored using infrared (IR) thermography, because when water freezes, it gives off heat. However, problems with color contrast make 2-dimensions (2D) infrared images somewhat difficult to interpret. Viewing an IR image or the video of plants freezing in 3 dimensions (3D) would allow a more accurate identification of sites for ice nucleation as well as the progression of freezing. In this paper, we demonstrate a relatively simple means to produce a 3D infrared video of a strawberry plant freezing. Strawberry is an economically important crop that is subjected to unexpected spring freeze events in many areas of the world. An accurate understanding of the freezing in strawberry will provide both breeders and growers with more economical ways to prevent any damage to plants during freezing conditions.
The technique involves a positioning of two IR cameras at slightly different angles to film the strawberry freezing. The two video streams will be precisely synchronized using a screen capture software that records both cameras simultaneously. The recordings will then be imported into the imaging software and processed using an anaglyph technique. Using red-blue glasses, the 3D video will make it easier to determine the precise site of ice nucleation on leaf surfaces.

Here, we present a protocol to image a strawberry plant freezing in 3 dimensions. Two infrared cameras positioned at slightly different angles are used to produce a red-blue anaglyph video to observe the freezing of the plant in 3 dimensions.

Freezing in plants can be monitored using infrared (IR) thermography, because when water freezes, it gives off heat. However, problems with color contrast ...

Long-term Video Tracking of Cohoused Aquatic Animals: A Case Study of the Daily Locomotor Activity of the Norway Lobster (Nephrops norvegicus)

We present a protocol related to a video-tracking technique based on the background subtraction and image thresholding that makes it possible to individually track cohoused animals. We tested the tracking routine with four cohoused Norway lobsters (Nephrops norvegicus) under light-darkness conditions for 5 days. The lobsters had been individually tagged. The experimental setup and the tracking techniques used are entirely based on the open source software. The comparison of the tracking output with a manual detection indicates that the lobsters were correctly detected 69% of the times. Among the correctly detected lobsters, their individual tags were correctly identified 89.5% of the times. Considering the frame rate used in the protocol and the movement rate of lobsters, the performance of the video tracking has a good quality, and the representative results support the validity of the protocol in producing valuable data for research needs (individual space occupancy or locomotor activity patterns). The protocol presented here can be easily customized and is, hence, transferable to other species where the individual tracking of specimens in a group can be valuable for answering research questions.

Long-term Video Tracking of Cohoused Aquatic Animals: A Case Study of the Daily Locomotor Activity of the Norway Lobster Nephrops norvegicus

Here we present a protocol to individually track animals over a long period of time. It uses computer vision methods to identify a set of manually constructed tags by using a group of lobsters as case study, simultaneously providing information on how to house, manipulate, and mark the lobsters.

We present a protocol related to a video-tracking technique based on the background subtraction and image thresholding that makes it possible to ...

A Telemetric, Gravimetric Platform for Real-Time Physiological Phenotyping of Plant&ndash;Environment Interactions

Food security for the growing global population is a major concern. The data provided by genomic tools far exceeds the supply of phenotypic data, creating a knowledge gap. To meet the challenge of improving crops to feed the growing global population, this gap must be bridged.
Physiological traits are considered key functional traits in the context of responsiveness or sensitivity to environmental conditions. Many recently introduced high-throughput (HTP) phenotyping techniques are based on remote sensing or imaging and are capable of directly measuring morphological traits, but measure physiological parameters mainly indirectly.
This paper describes a method for direct physiological phenotyping that has several advantages for the functional phenotyping of plant&#8211;environment interactions. It helps users overcome the many challenges encountered in the use of load-cell gravimetric systems and pot experiments. The suggested techniques will enable users to distinguish between soil weight, plant weight and soil water content, providing a method for the continuous and simultaneous measurement of dynamic soil, plant and atmosphere conditions, alongside the measurement of key physiological traits. This method allows researchers to closely mimic field stress scenarios while taking into consideration the environment&#8217;s effects on the plants&#8217; physiology. This method also minimizes pot effects, which are one of the major problems in pre-field phenotyping. It includes a feed-back fertigation system that enables a truly randomized experimental design at a field-like plant density. This system detects the soil-water-content limiting threshold (&#952;) and allows for the translation of data into knowledge through the use of a real-time analytic tool and an online statistical resource. This method for the rapid and direct measurement of the physiological responses of multiple plants to a dynamic environment has great potential for use in screening for beneficial traits associated with responses to abiotic stress, in the context of pre-field breeding and crop improvement.

A Telemetric, Gravimetric Platform for Real-Time Physiological Phenotyping of Plant&amp;#8211;Environment Interactions

This high-throughput, telemetric, whole-plant water relations gravimetric phenotyping method enables direct and simultaneous real-time measurements, as well as the analysis of multiple yield-related physiological traits involved in dynamic plant&#8211;environment interactions.

Food security for the growing global population is a major concern. The data provided by genomic tools far exceeds the supply of phenotypic data, creating ...