Affiliations: Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA | Graduate School Experimental Plant Sciences, Laboratory of Plant Physiology, Wageningen University, Arboretumlaan 4, 6703 BD Wageningen, The Netherlands
Abstract: This essay shows how Fourier transform infrared (FTIR) microspectroscopy can be applied to study thermodynamic parameters and conformation of endogenous biomolecules in desiccation‐tolerant biological tissues. Desiccation tolerance is the remarkable ability of some organisms to survive complete dehydration. Seed and pollen of higher plants are well known examples of desiccation‐tolerant tissues. FTIR studies on the overall protein secondary structure indicate that during the acquisition of desiccation tolerance, plant embryos exhibit proportional increases in α‐helical structures and that β‐sheet structures dominate upon drying of desiccation sensitive‐embryos. During ageing of pollen and seeds, the overall protein secondary structure remains stable, whereas drastic changes in the thermotropic response of membranes occur, which coincide with a complete loss of viability. Properties of the cytoplasmic glassy matrix in desiccation‐tolerant plant organs can be studied by monitoring the position of the OH‐stretching vibration band of endogenous carbohydrates and proteins as a function of temperature. By applying these FTIR techniques to maturation‐defective mutant seeds of Arabidopsis thaliana we were able to establish a correlation between macromolecular stability and desiccation tolerance. Taken together, in situ FTIR studies can give unique information on conformation and stability of endogenous biomolecules in desiccation‐tolerant tissues.
Keywords: Desiccation‐tolerance, macromolecular stability, glasses, protein stability, FTIR
Journal: Spectroscopy, vol. 17, no. 2-3, pp. 297-313, 2003
