Christine Chang, PhD

christine

Plants prepare for winter by responding to shortening daylength and decreasing temperature in a process known as autumn cold acclimation. Future climate models predict elevated temperature and CO­2, leading to a decoupling of crucial daylength and temperature signals during spring and autumn. While there have been extensive studies on the individual effects of elevated temperature and elevated CO2 on growth and dormancy, there is still much to be learned about how their combined effects may impact plant responses to seasonal change. Christine uses physiological measurements and molecular techniques to assess photosynthesis, carbohydrate metabolism and cold hardening during autumn cold acclimation in Eastern white pine (Pinus strobus), a native North American conifer species.

Christine pursued her bachelor’s degree at Barnard College from 2005-2009. During these years as an undergraduate she worked as a research assistant with Dr. Matthew Wallenfang, where she studied the effects of aging on somatic stem cell populations in Drosophila and learned techniques of fly crossing, immunofluorescence, electron and confocal microscopy, and how to castrate dozens of flies in an hour. In 2007, Christine additionally began volunteering in the lab of Dr. Hilary Callahan and acquired a taste for ecological fieldwork while digging up and learning to identify fine roots of native North American tree species at field sites in upstate New York and Pennsylvania. After graduating in February 2009, Christine worked for a summer with Dr. Tuija Aronen at the Finnish Forest Research Institute in Punkaharju, Finland, to develop an assay for Scots pine telomerase activity. Christine joined the Ensminger lab as a Ph.D. student in August 2010, where she explored the response of conifer cold hardening to combinations of photoperiod, temperature and elevated CO2. Christine defended her Ph.D. in September 2016.

Email: yaoyun.chang@gmail.com

Christine's Researchgate profile can be found here.

1. Publications:

Chang C. Y., Unda F., Mansfield S. D., Ensminger I. Rapid response of photosynthesis and carbohydrate metabolism to low temperature, elevated temperature and elevated CO2 autumn scenarios in Pinus strobus seedlings. In preparation.

Chang C. Y., Ensminger I. Conifer cold acclimation: Physiology and molecular regulation. Submitted to Plant Physiology.

Chang C. Y., Fréchette E., Unda F., Mansfield S. D., Ensminger I. (2016) Elevated temperature and CO2 stimulate late-season photosynthesis but impair cold hardening in pine. Plant Physioldoi: 10.​1104/​pp.​16.​00753

Fréchette E., Chang C. Y., Ensminger I. (2016) Photoperiod and temperature constraints on the relationship between the photochemical reflectance index and the light use efficiency of photosynthesis in Pinus strobusTree Physiol. 36: 311-324. doi: 10.1093/treephys/tpv143

Fréchette E., Wong C. Y. S., Junker L. V., Chang C. Y., 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. J. Exp. Bot. 66: 7309-7323. doi: 10.1093/jxb/erv427

Ensminger I., Chang C. Y., Bräutigam K. (2015) Tree responses to environmental cues. In: A.-F. Adam-Blondon, C. Plomion (volume eds.), J.-P. Jacquot, & P. Gadal (serial eds.), Advances in Botanical Research Vol. 74 (p. 229-264), London: Elsevier Ltd. doi: 10.1016/bs.abr.2015.05.003

Chang C. Y., Unda F., Zubilewich A., Mansfield S. D., Ensminger I. (2015) Sensitivity of cold acclimation to elevated autumn temperature in field-grown Pinus strobus seedlings. Front. Plant Sci., 6: 165. doi: 10.3389/fpls.2015.00165

2. Conference presentations:

Fréchette E., Chang C., Ensminger I. (2014) Facultative and constitutive changes in pigment composition affect the relationship of the photosynthetic light-use efficiency and the photochemical reflectance index of Eastern white pine (Pinus strobus L.). Canadian Society of Plant Biology Eastern Regional Meeting, November 29, Guelph, Ontario, Canada.

Chang C., Fréchette E., Ensminger I. (2013) Sensitivity of autumn cold acclimation to elevated temperature in Pinus strobus. Canadian Society of Plant Biology Eastern Regional Meeting, December 7, Mississauga, Ontario, Canada.

Fréchette E., Chang C., Ensminger I. (2013) The photochemical index (PRI) as an indicator of photochemical efficiency in Pinus strobus during the autumn. Canadian Society of Plant Biology Eastern Regional Meeting, December 7, Mississauga, Ontario, Canada.

Chang C., Fréchette E., Ensminger I. (2013) Temperature, Photoperiod and CO2: Effects of simulated climate change on autumn photosynthesis and freezing tolerance in Pinus strobus. Canadian Society of Plant Biology Annual Meeting, June 28, Québec City, Québec, Canada.

Fréchette E., Chang C., Ensminger I. (2013) The photochemical reflectance index as an indicator of photochemical efficiency of Eastern white pine (Pinus strobus) in a temperature manipulated field experiment​. Canadian Society of Plant Biology Annual Meeting, June 28, Québec City, Québec, Canada.

Fréchette E., Chang C., Ensminger I. (2012) Temperature affects the spectral properties of Eastern white pine during the autumn downregulation of photosynthesis. Canadian Society of Plant Physiology Annual Meeting, June 25, Edmonton, Alberta, Canada.

Chang C., Fréchette E., Bin Yameen T., Ensminger I. (2012) Effects of simulated future climate on autumn freezing tolerance of Pinus strobus. Canadian Society of Plant Biology Eastern Regional Meeting, December 1, Waterloo, Ontario, Canada.

Chang C., Fréchette E., Bin Yameen T., Ensminger I. (2012) Impact of simulated future climate on autumn photosynthesis and cold hardening in Pinus strobus. Canadian Society of Plant Physiology Annual Meeting, June 25, Edmonton, Alberta, Canada.

Chang C., Weisser A., Wildhagen H., Ensminger I. (2011) Physiological performance reveals different responses to drought in Douglas-fir provenances adapted to contrasting environments. American Society of Plant Biology Annual Meeting, August 6, Minneapolis, Minnesota, USA.

3. Other presentations:

Chang C., Fréchette E., Unda F., Mansfield S. D., Ensminger I. (2015) Autumn simulations reveal sensitivity of Eastern white pine seedlings to photoperiod, temperature, and elevated CO2. UTM Graduate Research Colloquium, May 4, Mississauga, Ontario, Canada.

Chang C., Fréchette E., Ensminger I. (2013) Effects of simulated climate change on autumn photosynthesis and freezing tolerance in Pinus strobus. Cell & Systems Biology Departmental Graduate Seminar, November 6, Toronto, Ontario, Canada.

Chang C., Ensminger I. (2012) Effects of future climate change on autumn cold acclimation in Pinus strobus. Plant Biology Seminar, March 20, University of Toronto Mississauga, Mississauga, Ontario, Canada.

Chang C., Ensminger I. (2012) Examining the effects of future climate change on autumn cold acclimation in Pinus strobus. University of Toronto Ph.D. Transfer Day, February 24, Toronto, Ontario, Canada.

4. Undergraduate work:

Chang C., Wallenfang M. (2008) The effects of aging on somatic stem cells in the Drosophila melanogaster testis. Senior Thesis Symposium, December 14, Barnard College, New York City, New York, USA.

Chang C., Wallenfang M. (2008) Effects of aging on somatic stem cells in the Drosophila melanogaster testis. Senior Thesis Poster Session, April 22, Barnard College, New York City, New York, USA.

Ahamed T., Bari K., Chang C., Wallenfang M. (2007) Effects of oxidative damage on male germline stem cell cycle activity. Drosophila Annual Conference, March 7-11, Philadelphia, Pennsylvania, USA.

Chang C., Wallenfang M. (2007) Investigating a mysterious overproliferation of aged germ cells in D. Melanogaster. SURF/Amgen Research Symposium, January 21, Columbia University, New York City, New York, USA.