Meet the lab team. Here you'll find information about our team members.
Current Team
Dr. Bruce Downie
Principle Investigator
(August 1998 to present)
Izabel Costa Silva Neta 
Ph.D. Candidate
(January 2015 to present)
Dr. Lynnette M.A. Dirk 
Research Analyst
(May 2013 to present)
Fabiola Krüger 
Ph.D. Candidate (August (2015 to present)
Prof. Arthur G. Hunt

Prof. Tianyong Zhao

Associate Prof. Sharyn Perry
Prof. Roberval D. Vieria
Prof. Steven Clarke
Prof. Maria Laene M. de Carvalhoo
Associate Prof. Sunny Zhou
The Experienced Experimenting in Natural Sciences (TEENS)



Barbara Willard 
Learning to genotype
(October 2014 to present)
Gene Smarte
Building specific-wavelength
chambers using LEDs
(July 2014 to present)

Visiting Scientists 
Prof. Rup Kumar Kar, Visva-Bharati, Santiniketan, India 

Associate Prof. Pratap Kumar Pati
(August 2011—August 2012) Fulbright Scholar, Guru Nanak Dev University, Amritsar, Punjab, India  
Dr. David Still, Cal Poly Pomona, Pomona, California, USA
Post-doctoral Scholars 
Dr. Tingsu Chen (January 2006—2007) 
Dr. Rekha Kushwaha (June 2010—July 2011) 
Dr. Santosh Kumar (January 2010—December 2011) 
Dr. Susmita Maitra-Majee (July 2006 in training 200x—2006) 
Dr. Manoj Majee (September 2004—2006) Currently, Staff Scientist IV, National Institute of Plant Genome Research, New Delhi, India 
Dr. Nihar R. Nayak (April 2008—December 2010) currently Senior Scientist at the Regional Plant Resource Centre in Bhubaneswar,                           Odisha, India. 
Dr. Bruno Guilherme Torres Licursi Vieira (January 2014) 
Dr. Tianyong Zhao (April 2000—October 2001)
Ph. D. Scholars 
Ms. Gulvadee Chaiyaprasithi (September 1998, now deceased) 
Jianchang Gao (July 2007—April 2008) 
Ms. Juliana Faria Dos Santos (May 2014—July 2014, November, 2014, expected Ph.D. 2015) 
Dr. Gunching Siriwitayawan (2002) 
Dr. Qilong Xu (December 2000—2004) 
Agricultural Biotechnology Undergraduate Researchers 
Marisa Belcastro (2003), now a physician 
Tracy Bonilla (2005), now a genetic consultant 
Cristiane Carvalho Pereira (September—December 2014) 
Brent Goodwin (January 2006)  
Taylor D. Lloyd, (January 2010—2011) (Chellgren Student Fellowship 2011, University of Kentucky Summer Research and Creativity Grant 2011, National Science Foundation (NSF) Research Experiences for Undergraduates Fellowship Summer 2010, American Society of Plant Biologists (ASPB) 2011 Summer Undergraduate Research Fellowship (SURF) Award, Astronaut Scholarship Foundation (ASF) NASA Astronaut Scholarship 2011, and Barry M. Goldwater Scholarship 2011), now a teacher 
Louai Salaita (2004], now a dentist
Zachary Sumpter (2007) 
Krista N. Whalen (November 2005—April 2006), now a dentist 

High School Student Reseachers 
Alyssa Eliopoulos [December 2007 - April 2009] Kentucky Young Researchers Program (KYRP) 
Research Analysts 
J. Willis Corum III, (Will Corum, 2000 to 2003), University of Kentucky employee 
David Martin (2003 to 2008) Kim R. Schäfermeyer (2008 to 2013) 
Deqing Zhang (1998 to 2000)

Intern Undergraduate Reseachers 
Leandro Reis, Federal University of Lavras, UFLA (May 2015 to July 2015).

Seed germination terms explained

Quiescent versus Dormant seeds
A quiescent seed
A dormant seed 

Orthodox versus Recalcitrant seeds
An orthodox seed
A recalcitrant seed 

Seed germination definition
Water uptake stages of orthodox seed germination

Imbibition phase
Lag phase
Embryo elongation phase

Seed germination (percentage versus rate) 

Quiescent versus Dormant seed

Quiescent seed

For some few seeds

Completes Germination

Now you know that it WAS quiescent

Dormant seed

For some few seeds

No protrusion of the embryo

Now you know that it IS (probably) dormant (or dead).

Possible deficiencies in treatment preventing dormancy alleviation. 
- Did not expose seed to cold while imbibed. 
- Did not warm THEN chill the seed while imbibed. 
Did not “afterripen” the seed i.e. leave it at warm temperatures but dehydrated for a couple of months. 
Light is inhibitory to the completion of germination, did not keep imbibed seeds in darkness. 

Both seeds started germinating (from imbibition). The quiescent seed has completed germination while the dormant seed has not and is still germinating. 

The attribute of the dormant seed influenced by the various treatments designed to alleviate dormancy are many and varied (e.g. embryo maturity, breakdown of physical barriers, destruction or silencing of negatively acting transcription factors, etc.). Baskin, C.C. and Baskin, J.M. Seeds: Ecology, Biogeography, and, Evolution of Dormancy and Germination. 2nd edition. 2014. Academic Press, ISBN: 978-0-12-416677-6.

Orthodox versus Recalcitrant seeds
Initially defined by Prof. Erik Roberts (Reading University, England), orthodox seeds undergoes maturation desiccation, i.e. dry to low moisture content at the end of their development. In this dehydrated state, the population of such seeds has a prolonged, predictable longevity under defined storage conditions.

There are some seeds that do not undergo maturation desiccation which prohibits their storage at sub-zero temperatures, curtailing longevity in storage. These seeds were named recalcitrant, because of this behavior (Eric H.Roberts (1973) Predicting the storage life of seeds. Seed Sci. Technol. 1, 499-514.)  
Research on seeds that do not conform to the stereotypical norm represented by the orthodox seeds has since identified a continuum of seed drying and storage behaviors (Patricia Berjak and N.W. Pammenter, 2002. Plant Cell Biology Research Unit, School of Life Sciences, University of Natal, Durban, 4041 South Africa. Orthodox and Recalcitrant Seeds. In: Tropical Tree Seed Manual. J.A. Vozzo, Ed., Chapter 4, pgs. 137-147, Washington DC: USDA Forest Service, Agriculture Handbook 721. 
Seed germination definition
For an orthodox seed, germination includes all the events from the time the seed takes up water to the time that some part of the embryo protrudes from the seed covers. This definition has been embraced by seed physiologists as it precisely encompasses an enigmatic period when, despite intensive cellular activity upon the advent of hydration sufficient to support metabolism, from the outside, little visible alteration can be observed, apart from swelling in some species and deployment of mucilage in some others. 
Due to the paucity of exterior alterations to the seed during germination, seed biologists have used whatever they could to track its progress. One measure that has been used is that of water uptake, defining three separate stages of germination. Imbibition is the period of initial water uptake that ends when no further net gain of water occurs. From this point, water uptake appears to cease (giving rise to the term, “Lag Phase”). However, seeds at this stage, in well watered conditions, are in a state of dynamic flux acquiring water from the substrate while losing as much through evaporation. Finally, in those seeds that are about to complete germination, cell elongation of the embryo results in a further uptake of water, permitting the embryo to protrude from the seed covers and completing the process of germination. 

Redrawn and modified from Fig. 4.3 Bewley and Black. 1994. Seeds Physiology of Development and Germination. Plenum Press, New York, London. 
The capacity of seeds to take up water is considerable, capable of exerting surprising amounts of pressure (see these excellent videos). 
In most studies, the comparisons between/among different genotypes or treatments is not done seed-by-seed but rather by using a collective of individual seeds to track their responses in the collective. Typically, what is monitored are those seeds that complete the germination event. The protrusion of some part of the embryo from the seed covers is the event that scientists are capable of quantifying, but which indicates the end of the very germination event seed biologists wish to study. 
How one portrays germination for seed biologists is depicted below along with several definitions. 
Figure 1 portrays a time course of seed germination. The cumulative percentage of seeds completing germination at each time point is presented, with seed percentages on the Y-axis. The hours after seed imbibition (HAI) is on the X-axis.  

Figure 1: A germination time course for a typical seed sample. The zero on the x-axis is the time when the seeds were first placed on water. The sigmoidal curve describes the cumulative percentage of seeds that complete germination during the period after imbibition. Germination, of course starts just after time 0. The first seed to complete germination does so around 36 hours, while the last seed to complete germination prior to the end of the experiment does so at 180 hours. This is not apparent from the average ± S.E. presented here from four replications of 100 seeds each. 
Greater than 100% germination is not possible. Do not label tick marks so.
Figure 2: The same germination time course as shown in Figure 1 but with the Y-axis depicting potential values of the seed germination percentage that are possible. Points are the average ± S.E. from four replications of 100 seeds each of the percentage of seeds that completed germination at each of the hours following imbibition until the end of the test.  
Note in Figure 2, the nonsensical Y-axis 120 percent tick label has been removed. Although there may be reasons to extend the Y-axis beyond the 0 or 100 percent tick marks the Y-axis in graphs of seed germination percentage must not provide tick labels less than 0 or greater than 100. 
Figure 3 portrays a Y-axis on which I have purposely presented a label that is incorrect. The rate of seed germination is a separate calculation that is not provided in Figure 3.

Figure 3: The same germination time course as shown in Figure 2 but now with the Y-axis erroneously labeled as the Germination rate.

This label is incorrect for these data. These data are showing cumulative germination percentage. Beside this point, when is rate ever given in percent? 

If you wish to report the germination rate, below are some means of doing so

Figure 4 uses a measure capturing the average speed (in hours) with which those seeds capable of completing germination do so, the mean germination time [(n/(t • n))] MGT (red dot). It is a single parameter that is based on the final percentage germination and the number of seeds completing germination at each time point at which data is collected (green dots). The calculation of both the MGT and its reciprocal, the germination rate, [((t • n))/ n] GR (also a single parameter) can be found in any edition of Bewley and Black, Seeds Physiology of Development and Germination, Plenum Press, New York, London. An excellent overview of various parameters used to calculate aspects of a seed germination time course, including MGT and GR, is presented in Marli A. Ranal and Denise Garcia De Santana. 2006. How and why to measure the germination process? Revista Brasil. Bot., V.29: 1-11.

Figure 4: The same germination time course as shown in Figure 3 also depicting the Mean Germination time (MGT; red dot) i.e. the time it takes the average seed capable of completing germination to do so, measured in this case in hours. The graph also portrays the average percentage of seeds completing germination at every 12 h interval during the entire germination time course (green dots). 

Cumulative Mean Germination Percentage (black dots). 
Mean Germination time (red dot). 
Percentage of seeds completing germination each 12 h period (green dots).