John Choinski - Professor

Phone: 501-450-5918 (Office)
Address: Department of Biology I 201 Donaghey Avene LSC 180 I Conway AR 72035


University of Central Arkansas: Biology

Cluster Identification:
- Plant Productivity 'Set-Points' Cluster

Research Areas/Expertise:
- Abiotic Stress
- Photosynthesis
- Plant Environmental Physiology

Research Summary | Selected Publications | Lab Members | Key Collaborators | Research Projects | Links

Research Summary:

A great deal of research has investigated the effect of the environment on photosynthesis in mature leaves, but very little on how temperature, humidity, soil moisture or other climactic factors influence plant growth during the early stages of leaf expansion. To that end, we have been investigating the effect of environment on photosynthesis of both juvenile and mature leaf stages in both greenhouse and field-grown cotton (Gossypum hirsutum). Recent research in the laboratory has centered on the following questions:

1) What is the pattern of expression of photosynthetic activity during leaf expansion?

2) How does temperature and other environmental factors influence photosynthesis in expanding leaves?

3) What are the molecular mechanisms that explain why younger, newly expanded leaves are more photosynthetically thermotolerance than more mature leaves? Why does this difference decrease during the growing season?

The ultimate goal of our work is to understand how young cotton plants (that consist mostly of younger leaves) survive the crucial weeks after the seeds are planted. For example, we have found that young leaves mid-day experience surface temperatures far higher than the ambient air often exceeding 40°C, but also exhibit enhanced photosynthetic thermotolerance when compared to cooler more mature leaves. An understanding of the mechanism for this enhanced heat resistance may be a key to increasing cotton productivity  in the coming years as some climate models have predicted rising air temperatures and decreasing precipitation in the prime cotton growing regions of the USA.

Selected Publications:

Hall, T., Chastain, D.R., Horn, P.J., Chapman, K.D. and J.S. Choinski, Jr.  2014. Changes during leaf expansion of FPSII temperature optima in Gossypium hirsutum are associated with the degree of fatty acid lipid saturation. J. of Plant Physiology 171:411-420

Choinski, J.S., Jr. and K.S. Gould.  2010. Immature leaves of Weinmannia racemosa are more heat tolerant than mature leaves based on differences in chlorophyll a fluorescence, fatty acid composition and solute leakage. N. Z. J. Bot. 48: 163-177

Snider, J.L., J.S. Choinski, Jr. and W. Slaton. 2010. Differences in photosynthetic temperature optima of leaf developmental stages in Rhus glabra L. Botany 80:286-289.

Snider, J.L., Choinski, J.S., Jr. and R.R. Wise. 2009. Juvenile Rhus glabra leaves have higher temperatures and lower gas exchange rates than mature leaves when compared in the field during periods of high irradiance. J. of Plant Physiology 166: 686-696.

Choinski, J.S., Jr., Ralph, P. and D. Eamus. 2003. Changes in photosynthesis during leaf expansion in Corymbia gummifera.Australian J. of Botany 51:111-118.

Choinski, J.S., Jr. and R.R. Wise. 1999. Leaf growth and development related to gas exchange in Quercus marilandica Meunchh. J. of Plant Physiol. 154:302-309.

Lab Members:

John S. Choinski, Jr., Professor, UCA, Biology Department; (501) 450-5918 (Office)


Harold Owiti
MS student (Biology Department)


Key Collaborators

-Dr. Derrick Oosterhuis, University of Arkansas-Fayetteville: cotton physiology

-Dr. Kent Chapman, University of North Texas: lipid analyses

-Dr. Bob Wise, University of Wisconsin-Oshkosh: microscopy

-Dr. Will Slaton, Dept. of Physics and Astronomy, UCA: engineering of LeafTECH (leaf thermoelectric cooler/heater)

Research Projects

Analysis of FAD (fatty acid desaturase) gene expression during leaf expansion in pima and upland cotton.