Thermodynamic law for adaptation of plants to environmental temperatures*
R. S. Criddle1, L. D. Hansen1, B. N. Smith2, C. Macfarlane3, J. N. Church4, T. Thygerson2, T. Jovanovic5, and T. Booth5
1Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, USA; 2Department of Plant and Animal Sciences, Brigham Young University, Provo, UT 84602, USA; 3School of Plant Biology, The University of West Australia, 35 Stirling Highway, Crawley, WA 6009, Australia; 4Department of Pomology, University of California, Davis, CA 95616 USA; 5CSIRO Forestry and Forest Products, Kingston, ACT 2604, Australia
Abstract: A thermodynamic law of adaptation of plants to temperature is developed. Plant growth rate is proportional to the product of the metabolic rate and the metabolic efficiency for production of anabolic products. Over much of the growth temperature range, metabolic rate is proportional to mean temperature and efficiency is proportional to the reciprocal of temperature variability. The mean temperature and short-term (hours to weeks) variability of temperature during the growth season at a particular location thus determine the optimum energy and growth strategy for plants. Because they can grow and reproduce most vigorously, plants with a growth rate vs. temperature curve that matches the time-at-temperature vs. temperature curve during the growth season are favored by natural selection. The law of temperature adaptation explains many recent and long-standing observations of plant growth and survival, including latitudinal gradients of plant diversity and species range.
Keywords: Species distribution; respiration; temperature; thermodynamics; adaptation; species richness; latitude.
*Paper based on a presentation at the 18th IUPAC International Conference on Chemical Thermodynamics (ICCT-2004), 17-21 August 2004, Beijing, China. Other presentations are published in this issue, pp. 1297-1444.