The effects of moisture and temperature on the ageing kinetics of pollen: interpretation based on cytoplasmic mobility

• Published in: Plant, cell and environment Vol. 23; no. 9; pp. 967 - 974
• Main Authors: Buitink, J, Leprince, O, Hemminga, M.A, Hoekstra, F.A
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01-09-2000; Blackwell; Wiley Subscription Services, Inc
• Subjects: ageing; AGING; ALMACENAMIENTO; Animal, plant and microbial ecology; Applied ecology; Biofysica; Biological and medical sciences; Biology and morphogenesis of the reproductive apparatus. Photoperiodism, vernalisation; Biophysics; CITOPLASMA; Conservation, protection and management of environment and wildlife; CONTENIDO DE HUMEDAD; CYTOPLASM; CYTOPLASME; ENVEJECIMIENTO; ENVIRONMENTAL FACTORS; EPR spectroscopy; EPS; FACTEUR DU MILIEU; FACTORES AMBIENTALES; Fundamental and applied biological sciences. Psychology; glass; Laboratorium voor Biofysica; Laboratorium voor Plantenfysiologie; Laboratory of Plant Physiology; longevity; MOISTURE CONTENT; molecular mobility; Parks, reserves, wildlife conservation. Endangered species: population survey and restocking; Plant physiology and development; POLEN; POLLEN; rotational motion; SACCHAROSE; STOCKAGE; STORAGE; SUCROSA; SUCROSE; TEMPERATURA; TEMPERATURE; TENEUR EN EAU; TYPHA LATIFOLIA; Vegetative and sexual reproduction, floral biology, fructification; VIEILLISSEMENT; Monocotyledones; Cytoplasmic movement; Ageing; Vitrification; EPR spectrometry; Temperature effect; Plant conservation; Typhaceae; Storage; Molecular mobility; Angiospermae; Humidity; Spermatophyta; Pollen; Aquatic plant; Kinetics; Typha latifolia; Viability; Glassy state
• ISSN: 0140-7791; 1365-3040
• DOI: 10.1046/j.1365-3040.2000.00601.x

ABSTRACT
This study shows that characterization of the molecular mobility in the cytoplasm of pollen provides a new understanding of the effects of moisture and temperature on ageing rates. Using EPR spectroscopy, we determined the rotational motion of the polar spin probe, 3‐carboxy‐proxyl, in the cytoplasm of Typha latifolia pollen, under different temperature and moisture content conditions. Increasing the temperature resulted in faster rotational motion, analogous to faster ageing rates. With decreasing moisture content, rotational motion first decreased until a minimum was reached, after which rotational motion slightly increased again. The moisture content at which this minimal rotational motion was observed increased with decreasing temperature, comparable to the pattern of ageing rate. A significant linear relationship was found between ageing rates and rotational motion in the cytoplasm, suggesting that these parameters are causally linked. Upon melting of the intracellular glass, a twofold increase in activation energy of rotational motion and ageing rate was observed. In contrast, melting of the sucrose glass resulted in an increase in rotational motion of five orders of magnitude. The difference in rotational motion upon melting glasses of pollen or sucrose suggests that other molecules beside sugars play a role in intracellular glass formation in pollen.