Laura Verena Junker, PhD student

laura

I am a plant physiologist interested into plant responses to abiotic stress as well as the interplay between plant physiology, ecology and remote-sensing. During my PhD at the University of Toronto Mississauga, I studied the intraspecific variation of photosynthesis and photoprotective mechanisms in drought-stressed Douglas-fir, Pseudotsuga menziesii. My PhD thesis was conducted in the framework of the DougAdapt project, which was initiated by Ingo Ensminger at the Forest research institute of Baden-Wuerttemberg (FVA Freiburg) in Germany. In this interdisciplinary project, my findings about intraspecific variation in photosynthesis and photosynthetic pigments were linked with analyses of transcriptomes, volatile isoprenoid emission, isotope signatures, wood properties and tree growth conducted by our project partners. 
As part of my PhD, I developed an improved protocol for the HPLC-analysis of photosynthetic pigments. Furthermore, I got interested in the colorful appearance of senescing Sugar maple leaves, Acer saccharum, and investigated how changes in pigment content can serve as markers for physiological processes during senescence using remote-sensing techniques as spectral reflectance measurements and digital image analysis (“Phenocams”). After my PhD, I moved on to the Research Center Juelich in Germany, to focus my research on non-invasive assessment of plant stress responses.

Have a look at my website or my ResearchGate profile!


Publications from my PhD
Junker LV, Kleiber A, Jansen K, Gessler A, Kreuzwieser J, Ensminger I: Douglas-fir provenances vary in isoprenoid-mediated photoprotective mechanisms under controlled drought conditions. (In preparation)
Jansen K, Junker LV, Kleiber A, Bergk AB, Kayler Z, Wildhagen H, Kreuzwieser J, Ensminger I, Gessler A: Site specific climate sensitivity: Relations between leaf stable isotope composition, gas exchange and osmotic adjustments in Douglas-fir. (In preparation)
Du B, Kreuzwieser J, Dannenmann M, Kleiber A, Eiblmeier M, Junker LV, Jansen K, Ensminger I, Gessler A, Kohnle U, Rennenberg H, Wildhagen: Foliar nitrogen metabolism of adult Douglas fir trees is affected by soil water availability and varies little among provenances. (In preparation)
Kleiber A, Duan Q, Jansen K, Junker LV, Kammerer B, Rennenberg H, Ensminger I, Gessler A, Kreuzwieser J: Drought effects on root and needle terpene content of a coastal and an interior Douglas fir provenance. (Accepted with major revisions by Tree physiology)
Junker LV, Kleiber A, Jansen K, Wildhagen H, Hess M, Kayler Z, Kammerer B, Schnitzler JP, Kreuzwieser J, Gessler A, Ensminger I (2017): Variation in short-term and long-term responses of photosynthesis and isoprenoid-mediated photoprotection to soil water availability in four Douglas-fir provenances. Scientific reports 7 : 40145.
Junker LV and Ensminger I (2016): Fast detection of leaf pigments and isoprenoids for ecophysiological studies, plant phenotyping and validating remote-sensing of vegetation. Physiologia Plantarum 158 (4): 369–381.
Hess M, Wildhagen H, Junker LV, Ensminger I (2016): Transcriptome responses to temperature, water availability and photoperiod are conserved among mature trees of two divergent Douglas-fir provenances from a coastal and an interior habitat. BMC Genomics 17: 682.
Junker LV and Ensminger I (2016): Relationship between leaf optical properties, chlorophyll fluorescence and pigment changes in senescing Acer saccharum leaves. Tree Physiology 36 (6): 694-711. 
Fréchette E, Wong CYS, Junker LV, Chang CY and Ensminger I (2015): Zeaxanthin-independent energy quenching and alternative electron sinks cause a decoupling of the relation between the photochemical reflectance index (PRI) and photosynthesis in an evergreen conifer during spring. Journal of Experimental Botany 66 (22): 7309–7323.
Du B, Jansen K, Junker LV, Eiblmeier M, Kreuzwieser J, Gessler A, Ensminger I, Rennenberg H (2014): Elevated temperature differently affects foliar nitrogen partitioning in diverse Douglas fir provenances. Tree physiology 34 (10): 1090-1101. 
Junker L, Wildhagen H, Rott A, Ensminger I, Kreuzwieser J (2011): Photoprotective isoprenoids as physiological markers for the adaptation of Douglas-fir to drought stress in context of climate change. In: Opportunities and risks for Douglas fir in a changing climate. (Hrsg.) Forstwissenschaftliche Fakultät der Universität Freiburg und Forstliche Versuchs- und Forschungsanstalt Baden Württemberg, Freiburger Forstliche Forschung – Berichte, Freiburg, 2011, Heft 85, Seite: 41-43.
Conference presentations during my PhD
Junker LV, Ensminger I (2015): Assessing autumn physiology of Acer saccharum using spectral reflectance and digital image vegetation indices. Oral presentation, Biology 2015, Edmonton, Canada.
Junker LV, Ensminger I (2014): Influence of senescence-associated pigment changes on leaf spectral properties in Acer saccharum. Oral presentation, Eastern Regional Meeting of the Canadian Society of Plant Biologists, Guelph, Canada.
Junker LV, Wildhagen H, Ensminger I (2013): Field grown Douglas-fir provenances differ in photosynthetic performance under conditions of limited water availability. Oral presentation, Eastern Regional Meeting of the Canadian Society of Plant Biologists, Mississauga, Canada.
Junker L, Wildhagen H, Ensminger I (2013): Douglas-fir provenances vary in their physiological response to limited water availability. Poster presentation, Canadian Society of Plant Biologists, Quebec City, Canada.
Junker L V, Ensminger I (2012): Isoprenoid-related mechanisms of drought tolerance in field-grown Douglas-fir provenances. Oral presentation, Eastern Regional Meeting of the Canadian Society of Plant Biologists, Waterloo, Canada.
Junker L, Wildhagen H, Ensminger I (2012): Isoprenoid-related mechanisms of drought tolerance in Douglas-fir provenances. Poster presentation, Plant Biology, Freiburg, Germany.
Junker L, Wildhagen H, Ensminger I (2012): Drought stress tolerance of Douglas-fir provenances. Poster presentation, Plant abiotic stress tolerance II conference, Vienna, Austria.
Junker L V, Wildhagen H, Ensminger I (2011): Intraspecific variation of drought stress tolerance in Douglas fir. Oral presentation, Eastern Regional Meeting of the Canadian Society of Plant Physiologists, Ottawa, Canada.
Rott A, Junker L, Ensminger I, Kreuzwieser J (2011): Photoprotective Isoprenoids as Physiological Markers for Drought and Heat Stress in Douglas-fir. Opportunities and risks for Douglas fir in a changing climate-Symposium, Forest Research Institute, Freiburg, Germany.
Junker L, Ensminger I (2011): Photoprotection mediates adaptation to drought in Douglas fir provenances. Poster presentation, Swiss Plant Science Web Summer school “Terrestrial Ecosystem Dynamics in a Changing World”, Mürren, Switzerland.
Junker L, Rott A, Kreuzwieser J, Ensminger I (2010): Photoprotective isoprenoids increase drought stress tolerance of Douglas fir. Poster presentation, Eastern Regional Meeting of the Canadian Society of Plant Physiologists, St. Catharines, Ontario, Canada.
Junker L V, Ensminger I (2010): Photoprotective Isoprenoids as Indicators for Drought Stress Tolerance. Oral presentation, Landscape Genomics Workshop, Trento, Italy.